tag:blogger.com,1999:blog-12330732531158842082024-03-13T06:03:17.718-06:00Dan’s DiaryDan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.comBlogger74125tag:blogger.com,1999:blog-1233073253115884208.post-1341582525410058712022-02-06T20:38:00.013-07:002022-05-06T20:58:45.117-06:00Dorothy<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEivqoF3TS9Dl4Dwtceh2gIm4Gqkr1Sh_hJdFMHLw4oz0fMcXhIkJw71J5lOzlSAc7foEerQSdmXisQsGYLmC7wb7n1kRtrndjJGG8gn7i2fJINIkqp7L0uOb4VJqVZdWb8ip7JjfIcn7Gf7JjIvaSl-j4-kRlhH06BCVv9q1XcBFkaZGt8NDyM17qHXCw=s1313" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="1313" data-original-width="908" height="320" src="https://blogger.googleusercontent.com/img/a/AVvXsEivqoF3TS9Dl4Dwtceh2gIm4Gqkr1Sh_hJdFMHLw4oz0fMcXhIkJw71J5lOzlSAc7foEerQSdmXisQsGYLmC7wb7n1kRtrndjJGG8gn7i2fJINIkqp7L0uOb4VJqVZdWb8ip7JjfIcn7Gf7JjIvaSl-j4-kRlhH06BCVv9q1XcBFkaZGt8NDyM17qHXCw=s320" width="221" /></a></div>
<p>My mother, Dorothy Schroeder, would have turned 92 today. She was an amazing woman—more amazing than the words below can convey.<br /></p><p></p>
<p>She was born Dorothy Alice Schneider, to parents Otto and Marcella (née Beckemeier). Her grandparents on both sides were German immigrants who settled in north St. Louis in the late 1800s. Dorothy grew up in what was then a bustling urban neighborhood, within walking distance of <a href="https://en.wikipedia.org/wiki/Sportsman%27s_Park">Sportsman’s Park</a> and <a href="https://www.builtstlouis.net/churches/church01.html">Bethlehem Lutheran Church</a>. The church was the social hub for all the Lutherans in the neighborhood, and ran a parochial school that Dorothy attended through eighth grade. The neighborhood also had a strong contingent of Catholics, but I remember Mom saying that the Catholic and Lutheran kids were discouraged from playing together. She attended a public high school, though, and grew up to believe that people of all religions are fundamentally good.</p>
<p>Otto Schneider, my grandfather, worked his whole career as a bookkeeper for Rice-Stix dry goods company. Marcella, my grandmother, was a homemaker who never learned to drive. Neither of them graduated from high school, though I remember my grandfather talking about “business college,” where he had learned his bookkeeping skills. In any case, Otto seems to have managed to support his family through the Great Depression with little hardship.</p>
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<p>Mom had two brothers: Donald, two years older, who attended the state engineering college in Rolla, served in the Korean War, and became a chemical engineer; and Norman, two years younger, who became a Lutheran minister. But when Dorothy graduated from high school with high grades in 1948, it was apparently understood that she, unlike her brothers, would not be attending college. Perhaps that was just the norm among the families in her social class, or perhaps the colleges were so flooded with young men on the GI Bill that it was difficult for women to be admitted.</p>
<p>So she took a job as a secretary at Concordia Publishing House, the big Lutheran publishing company across town. There she met my father, <a href="http://dvschroeder.blogspot.com/2009/10/happy-birthday-dad.html">Vernon Schroeder</a>, an ordained minister who hadn’t lasted long as pastor to a congregation but had gotten a job answering mail for a <a href="https://en.wikipedia.org/wiki/Walter_A._Maier">popular radio preacher</a>. Dorothy and Vernon were married at Bethlehem Church in September 1949, when she was 19 and he was about to turn 32. She changed the middle three letters of her last name.</p>
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<p>The Schroeder newlyweds then moved to Chicago, where my father pursued his dream of running a “tract mission,” collecting and distributing religious pamphlets among multiple protestant denominations. He never made any real money at it, so it fell upon my mother to be the main breadwinner. She was smart, hard-working, and just plain <i>capable</i>. Her longest job during those years was running a Christian bookstore.</p>
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<p>After seven years in Chicago, the Schroeders gave up on the tract mission and moved back to St. Louis. Dad got a job as a proofreader at Concordia Publishing House, while Mom found secretarial work until, rather unexpectedly, I came along in 1962. My brother Paul followed in 1964, and Mom stayed home, now in the suburb of Webster Groves, raising the two of us until we were both in school.</p>
<p>I don’t remember those years well at all, but I think they were happy ones for Mom. My parents later told me they had always wanted children and were disappointed when none arrived sooner. Dorothy was a devoted mother who took tremendous interest in everything Paul and I did. She showered us with gifts for our birthdays and Christmas, and encouraged us to learn and grow in countless ways. She filled the house with books that she hoped would interest us, and read aloud to us until we were old enough to read on our own. She had the old upright piano moved from her parents’ house so I could practice on it. She enrolled Paul in sports leagues so he could develop his remarkable athletic talent.</p>
<p>Soon after Paul started first grade, Mom went back to working outside the home. We needed the money, with Dad in a dead-end job that didn’t pay well. But more importantly, Mom needed a new challenge—and a distraction from what had become an unhappy marriage.</p>
<p>Fortunately, we lived a mile and a half from <a href="https://en.wikipedia.org/wiki/Webster_University">Webster College</a>, a former Catholic women’s school that had gone co-ed and secular during the 1960s. They hired Mom as secretary to the Director of Publications, whose job was to manage the design and printing of everything from event advertisement posters to the college catalog.</p>
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<p>It wasn’t long before Mom was doing essentially all of her boss’s job. Within a few years he was gone and she was running the office—with neither the job title nor the salary that the responsibilities called for. But working at the college did offer one important perk: she could enroll in classes tuition-free and work toward her bachelor’s degree, building on some credits she had already earned at the local community college and through CLEP. She graduated in 1979 with a major in religion. Then, degree in hand, she demanded and got a job title and a raise.</p>
<p>As the college grew to become Webster University, Mom’s office expanded until she was supervising a team of about half a dozen. Her coworkers became some of her best friends, and she also interacted with numerous contractors for design, typesetting, and printing. She loved working with people and was extremely good at it, though she had little tolerance for laziness or incompetence.</p>
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<p>Then at age 63, as she was starting to look forward to a well-earned retirement, Mom was diagnosed with late-stage ovarian cancer. That abruptly ended her career at Webster University, where she used up a year of accrued sick leave before transitioning to disability benefits. Surgery and chemotherapy gave her three more years of life, most of which she spent getting the house ready to sell and otherwise making sure things would go as smoothly as possible for the rest of us after she was gone.</p>
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<p>As should be apparent by now, Mom’s faith was a huge part of her life. It sustained her through the hard times, and underlay her work ethic and endless goodwill toward the people around her. It also steered her toward the political left during the era of civil rights campaigns and the Vietnam War, as she stuck to her belief in a God of peace who loves all humans equally. Eventually she parted ways with the Missouri Synod Lutherans, whose doctrine had become more narrow and exclusive. Mom just couldn’t conceive of a God who would condemn most of humanity to an eternity of torture merely for their nonbelief. During her last two decades she attended more liberal Protestant churches.</p>
<p>Although Mom’s life was often stressful and much too short, she had a positive outlook and never spoke of any regrets. Her style was to throw herself into whatever work was before her, taking pride in that work and finding joy in the process. She was always conscious of how being a woman had put her at a disadvantage in her education and career, and she would stand up to that kind of injustice when she saw an opportunity to make a difference. But she was never bitter about the lot she had drawn, even if she had every right to be.</p>
<p>Naturally I wonder how her life might have played out if she’d had more opportunities. What if as a young woman she had gone to college and been able to plan her own career, rather than devoting herself to supporting her husband’s dreams? Or what if she’d had a decade or two of active retirement, to take on an ambitious volunteer project or develop her ability as a writer? She had the intelligence, skills, and work ethic to accomplish the sorts of things that our society finds memorable. Yet she wasn’t ambitious on her own personal behalf, and her interests tended to be more broad than deep, so perhaps she would have kept a low profile and simply found more ways to support the people around her.</p><p></p>Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com0tag:blogger.com,1999:blog-1233073253115884208.post-7579758360739521532021-08-09T08:55:00.003-06:002021-08-09T10:58:31.534-06:00A New Blog: Especially about the Future<p>Over the last few years I’ve gotten more interested in understanding some of the big global issues—population, prosperity, health, technology, energy, climate, and so on—and how these things might play out in the future. As I’ve read about these issues I’ve often been tempted to post some reactions here on my personal blog. But this blog has always been too unfocused, jumping among too many different topics that interest me.<br /></p><p>So instead, I’ve decided to launch a separate blog to focus on these global topics:</p><p style="margin-left: 40px; text-align: left;"><a href="https://especiallyfuture.blogspot.com/">Especially about the Future</a></p><p style="text-align: left;">Please check it out, see what you think, and leave a comment there or on <a href="https://twitter.com/dvs1444">Twitter</a>. If nothing else, please look at the <a href="https://especiallyfuture.blogspot.com/2021/07/recommended-reading.html">recommended reading list</a>.<br /></p><p style="text-align: left;">Meanwhile, any thoughts on other topics that I find time to write about will continue to go here on Dan’s Diary.</p><p style="text-align: left;">Thank you for reading!<br /></p>Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com0tag:blogger.com,1999:blog-1233073253115884208.post-28236018667296465232020-06-14T07:41:00.001-06:002020-07-11T17:00:38.732-06:00Coronavirus in Utah: The First Three MonthsThree months ago, when my university campus and so much more of Utah shut down due to the pandemic, I was hopeful.<br />
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For one thing, we were lucky. On March 12 the number of known COVID-19 cases in Utah stood at only four, out of 1500 nationally. The initial onslaught in the U.S. had mainly hit the coasts, giving Utah more time to prepare.<br />
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Also, Governor Herbert and other state officials were taking the virus seriously. They shut down the <a href="https://kutv.com/news/coronavirus/timeline-how-utahs-school-closure-dominoes-fell">public schools</a>, <a href="https://www.sltrib.com/news/2020/03/12/coronvirus-plans-utah/">university campuses</a>, and <a href="https://coronavirus.utah.gov/recommendations-issued-by-task-force-to-limit-spread-of-covid-19/">other large gatherings</a> more quickly than I had thought possible. The state was putting out good public information on how to stop the virus’s spread, and efforts to ramp up testing were well underway.<br />
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Meanwhile, the Church of Jesus Christ of Latter Day Saints <a href="https://www.deseret.com/faith/2020/3/12/21177623/mormon-church-lds-meetings-canceled-worldwide-coronavirus-covid-19">shut down its large gatherings</a> with equally stunning abruptness. In doing so it not only prevented untold numbers of superspreader events on Sundays, but also sent a clear message to its two million Utah members that they had a responsibility to protect themselves and their neighbors.<br />
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<b>Exponential growth</b><br />
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Then, while I scrambled to teach my classes online, I watched the numbers climb.<br />
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Of course they would climb. The experiences in China and elsewhere had taught us that the virus was highly contagious and could spread unnoticed, with an incubation time of about a week before symptoms appeared. Even then, many victims had mild enough symptoms that they mistook COVID-19 for a common cold or flu. And testing, in Utah in mid-March, was available only to those with the most severe symptoms.<br />
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But even knowing all this, and even being familiar with the mathematics of exponential growth, I found it morbidly breathtaking to watch the number of known cases in Utah grow to more than 1000 by the beginning of April—doubling eight times in only 20 days. (Some of this growth was due to actual spread of the virus over time, while some was due to the expansion of testing.)<br />
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And then, also predictably, the exponential growth stopped. It stopped because of the shutdowns enacted in mid-March, plus a testing capacity that by early April exceeded 2000 per day, plus the tireless contact tracing carried out by the heroes at Utah’s health departments. The rate of newly confirmed COVID-19 cases in Utah stabilized at about 150 per day. While the virus was raging out of control in many parts of the U.S., Utah had flattened the curve!<br />
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And there was even more cause for hope. On April 2 state officials and the Silicon Slopes folks <a href="https://www.sltrib.com/news/2020/04/02/silicon-slopes-develops/">announced a program</a> of even more testing, to not just flatten but “crush the curve.” By mid-April Utah was testing about 4000 people per day, and I eagerly watched for when the daily case numbers would begin to drop.<br />
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<b>The long plateau</b><br />
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But the drop never happened. April came to an end, along with my spring semester classes. As the weeks of May went by, <a href="http://physics.weber.edu/schroeder/utahcovid.html">the rate of new cases held steady</a>. Tragically, Utah’s coronavirus death toll rose steadily as well, reaching 100 by Memorial Day.<br />
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Why weren’t we crushing the curve? Health department officials know the answer to this question in detail, because they’ve interviewed nearly every known victim and traced the sources of most infections. Those details are confidential, so the rest of us can only piece together a partial answer from statistical data and news reports. But the broad picture seems pretty clear.<br />
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You see, the virus arrived in Utah by infecting cruise passengers, ski vacationers, and other travelers. These people were mostly white and well-off, like Utah’s elected officials and health department administrators. So understandably, these officials targeted their response to white, well-off people like the early victims and themselves.<br />
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If you thought you might be infected, they told you to contact your primary health-care provider. They set up test sites in suburban neighborhoods, for drive-through access. They put out information mostly in English, through media channels that white and well-off people use.<br />
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But by early April, it was no longer us white, well-off people who were most at risk. Most of us were able to do our office jobs from home, avoiding nearly all human contact. Our homes also tend to be spacious enough that we can isolate ourselves from family members if necessary.<br />
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Meanwhile, the virus continued to spread in places where isolation was difficult or impossible: <a href="https://www.sltrib.com/news/2020/05/14/utah-discloses-which-long/">nursing homes</a>, <a href="https://www.deseret.com/utah/2020/4/17/21225058/south-salt-lake-shelter-94-covid19-positive-homeless-coronavirus">homeless shelters</a>, meatpacking plants, and the more crowded home environments of lower-income Utahns. Many of the people at risk had no primary health-care provider to call. Many couldn’t get to a drive-through testing center. Many weren’t tuned in to the government’s information channels. Many were immigrants who understood little English.<br />
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Of course our public officials knew about these risks from the start, and they’ve made <a href="https://www.sltrib.com/news/2020/04/23/with-utah-latinos/">well-intended efforts</a> to better target at-risk populations. Many of these efforts have been successful. When I look at that long plateau through April and May on the chart of new case numbers, I see it as a succession of dozens of overlapping local outbreaks among a wide variety of at-risk communities, with health officials rushing in to put out each fire as soon as they learn about it.<br />
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What I don’t see, unfortunately, is enough effort by health officials to prevent these local outbreaks among at-risk populations from happening in the first place. I’ve read almost nothing about testing at-risk workers in locations where there isn’t yet a known outbreak, or about inspecting workplaces and punishing employers who don’t maintain safe working conditions, or even about <a href="https://www.fox13now.com/news/local-news/utah-county-health-dept-denies-public-records-request-to-name-businesses-involved-in-outbreaks">publicly disclosing the specific locations of known outbreaks</a>. Perhaps there’s some of this going on in Utah (and again I’m not in a position to know most of the details), but it’s obviously not enough.<br />
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<b>A new surge</b><br />
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We know it’s not enough because we haven’t crushed the curve. And now, since late May, <a href="http://physics.weber.edu/schroeder/utahcovid.html">the curve is again rising</a>. The number of new cases reported each day has again doubled, to more than 300. On a per-capita basis we’re now reporting more new cases than <a href="https://twitter.com/NateSilver538/status/1271566534364839940">all but five of the other states</a>.<br />
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And we’ve just witnessed Utah’s <a href="https://www.sltrib.com/news/2020/06/08/cache-valley-providing/">biggest outbreak so far</a>: 800 new cases reported in the Bear River district over the last 16 days, when the district had previously been averaging only three new reported cases per day. Nearly all of these 800 new cases seem to be tied to the JBS meatpacking plant in Hyrum, where most of the employees are immigrants from Latin America, Asia, and Africa.<br />
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An outbreak of that size does not develop in just 16 days: it must have been in progress for several weeks before the authorities became aware of it. And yet it seems they were completely unaware until approximately May 29, when they reported the first big jump in positive test results.<br />
<br />
I know only one way to describe this kind of blindness on the part of public officials: institutional racism.<br />
<br />
As if to underscore this description, right in the midst of this outbreak the all-white Cache County Council <a href="https://www.sltrib.com/news/2020/06/10/cache-county-wants-move/">voted</a> to petition the state to go to <a href="https://coronavirus.utah.gov/utahs-health-guidance-system/">“green” status</a>, removing most of the remaining measures to protect public health.<br />
<br />
The sad irony is that if public officials had done more to address the threats to Utah’s disadvantaged populations back in April and May, they would have crushed the curve by now and we probably <i>could</i> take most of the state to “green” status. More importantly, we could have saved many lives, and we could be confident that reopening schools and universities in the fall won’t put undue numbers of students, teachers, and their families at risk. But with new cases being discovered at a rate of 300 per day, I fear that the contact tracers won’t be able to keep up, and the only way to prevent another period of exponential growth may be a return to “orange” or even “red” status.<br />
<br />
Let me hasten to add that I’m not a big advocate of draconian population-wide restrictions as the main way to control the virus, so long as the case load remains low enough for testing and contact tracing to keep up. What we need (as far as I can determine as an amateur outsider who merely reads news reports) are more efforts focused on high-risk populations and high-risk workplaces. Utah’s white and well-off public officials need to work harder to understand these risks and develop more aggressive ways to prevent outbreaks. And Utah’s white and well-off voters need to understand that their personal situations during this pandemic are very different from those of the workers who are keeping food on their tables.<br />
<br />
<b>Update, 17 June 2020</b><br />
<br />
On the same day that I posted this armchair analysis, the Salt Lake Tribune published an <a href="https://www.sltrib.com/news/2020/06/14/utah-wasnt-prepared-help/">in-depth article</a> with plenty of real reporting on how “Utah wasn’t prepared to reach out to its Hispanic residents when the virus struck.” This article also mentions a challenge that I hesitated to speculate about: “Another fear Hispanics harbor, particularly those who are undocumented, is that information they give while at a testing site could be sent to immigration officials.”<br />
<br />
And today (three days later), the Trib has a <a href="https://www.sltrib.com/news/2020/06/16/more-than-new/">summary of some very troubling comments</a> from state epidemiologist Dr. Angela Dunn to a legislative committee: Utah is already at the point where contact tracing is falling behind, due to the high rate of new infections and the large number of contacts that must be traced for each infected person. “As long as that’s going on, it’s not realistic to focus restrictions only on specific ‘hotspots.’”<br />
<br />
The Tribune is providing free public access to its fantastic reporting on the pandemic, but someone has to pay for all this work. Please, if you can, <a href="https://www.sltrib.com/support/">sign up for a subscription</a> to the nonprofit Salt Lake Tribune.Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com2tag:blogger.com,1999:blog-1233073253115884208.post-62322779077832854472019-05-06T12:51:00.000-06:002019-05-06T12:53:44.049-06:00Five Years of DrivingIt’s been five years since <a href="http://dvschroeder.blogspot.com/2014/03/little-blue-and-big-blue.html">I bought my Subaru</a>. Time for an assessment.<br />
<br />
The odometer now reads 12,575, so I’ve driven the car about 2500 miles per year. To most Americans that won’t sound like much, but it would be a long way to walk, and it’s about twice the mileage I put on my bicycle.<br />
<br />
Today’s cars are made to be driven hundreds of thousands of miles, so I feel kinda ridiculous for investing $25k in a new one and then using it so much less than I could. It seemed like the best of several bad options at the time, and I still can’t really think of a better one.<br />
<br />
Unsurprisingly, the car has been virtually trouble-free. I get its oil changed once a year whether it needs it or not. The battery ran low a couple of times this last winter, while the car sat in the driveway unused for weeks at a time. The only other service it’s needed was also due to lack of use: a warranty-covered replacement of the fuel line vent valve, which had gotten clogged with spider webs.<br />
<br />
I do nearly all of my commuting, grocery shopping, and other short errands by bicycle, so generally I use the car around town only when I need to carry a passenger or some other large cargo. Most of the miles on the car are from recreational trips: up into the mountains to hike or to ski, plus a couple of trips each year to neighboring states. It’s never been farther from home than northwestern New Mexico.<br />
<br />
I chose a Subaru Crosstrek for its high clearance, and I’ve taken it a few places where high clearance was necessary, but only a few. I’m conflicted over whether those few trips were worth the added expense and/or added carbon emissions, compared to (say) a low-clearance economy hatchback.<br />
<br />
<b>Fuel economy</b><br />
<br />
So far I’ve filled the car’s gas tank 31 times, for a total of 412 gallons. At the last fill-up the mileage was 12,218, so the overall fuel economy comes to 29.6 miles per gallon. Here is a chart that shows the variability from one fill-up to the next:<br />
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<div class="separator" style="clear: both; text-align: center;">
<a href="https://3.bp.blogspot.com/-GzTsFMi21vk/XNB61mAV4NI/AAAAAAAACLg/wY9P3pRpcuwdZTFYIOeRVlRJi9vDHhThgCLcBGAs/s1600/FuelEconomyOverTime.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="284" data-original-width="439" src="https://3.bp.blogspot.com/-GzTsFMi21vk/XNB61mAV4NI/AAAAAAAACLg/wY9P3pRpcuwdZTFYIOeRVlRJi9vDHhThgCLcBGAs/s1600/FuelEconomyOverTime.png" /></a></div>
<br />
As expected, the best fuel economy has been on summer road trips, while the worst has been in winter city driving. But this tank-by-tank data doesn’t provide the precision one might like, because the tank size is pretty generous and I typically drive about 400 miles before each refill. Except on long trips, those 400 miles always include quite a mix of driving conditions.<br />
<br />
In principle I could get more detailed information from the dashboard fuel economy display. But care is required, because its calibration is off. As the next chart shows, the displayed fuel economy is higher than the calculated-at-the-pump fuel economy by an average of 2.6 mpg:<br />
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<a href="https://3.bp.blogspot.com/-thie59E8JOY/XNB6-npy1XI/AAAAAAAACLk/4JOwJYrQJI4enPgy8_k9RGgkxdqRvsX7gCLcBGAs/s1600/DisplayedVsActual.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="311" data-original-width="447" src="https://3.bp.blogspot.com/-thie59E8JOY/XNB6-npy1XI/AAAAAAAACLk/4JOwJYrQJI4enPgy8_k9RGgkxdqRvsX7gCLcBGAs/s1600/DisplayedVsActual.png" /> </a></div>
<div class="separator" style="clear: both; text-align: center;">
<br /></div>
With this calibration inaccuracy in mind, I’ll report that on one occasion—a round trip from Ogden to Salt Lake City in September 2014—the dashboard reported a fuel economy as high as 40.8 mpg. I’ve seen higher numbers only for one-way partial trips that were mostly downhill.<br />
<br />
My car’s official <a href="https://www.fueleconomy.gov/feg/Find.do?action=sbs&id=34234">EPA-estimated fuel economy</a> is 25 mpg in the city, 32 on the highway, and 28 overall. So I’ve been doing slightly better than the official estimate. That’s mostly because I do proportionally more highway driving than the EPA assumes, and very little of my highway driving is at the absurdly wasteful (and dangerous!) <a href="https://www.iihs.org/iihs/topics/laws/speedlimits/mapmaxspeedonruralinterstates">freeway speeds</a> that Utah allows.<br />
<br />
<b>Carbon footprint</b><br />
<br />
Burning a gallon of gasoline produces just under 20 pounds of carbon dioxide, so at 2500 miles per year and 30 miles per gallon, my Subaru has been emitting roughly 20×2500/30 = 1660 pounds of CO<sub>2</sub> per year, or 0.75 metric tons. The <a href="https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P10023GQ.TXT">EPA estimates</a> that upstream emissions from producing and transporting the gasoline add on another 24 to 31 percent, so my car’s annual carbon footprint is probably about 2100 pounds or 0.95 tons of CO<sub>2</sub>. (This doesn’t include the substantial emissions from manufacturing the car in the first place.)<br />
<br />
My personal driving-related carbon footprint isn’t the same as my car’s, because the car sometimes carries other passengers and I sometimes travel in other cars. I haven’t kept the records I’d need to determine which of these effects is larger, so let’s just assume they cancel each other out. Then it’s meaningful to compare my Subaru’s carbon footprint to my own carbon emissions via <a href="http://dvschroeder.blogspot.com/2015/06/air-travel.html">other</a> <a href="http://dvschroeder.blogspot.com/2015/05/home-energy-use.html">means</a>, and to <a href="https://www.fhwa.dot.gov/ohim/onh00/bar8.htm">national</a> and <a href="https://www.gapminder.org/tools/#$state$marker$axis_y$which=co2_emissions_tonnes_per_person&domainMin:null&domainMax:null&zoomedMin:null&zoomedMax:26&spaceRef:null;&size$which=yearly_co2_emissions_1000_tonnes&domainMin:null&domainMax:null&spaceRef:null;;;&chart-type=bubbles">international</a> per-capita averages.<br />
<br />
Even though my carbon footprint from driving is several times smaller than the U.S. average, I don’t feel like I’m sacrificing anything to keep it so small. I’ve always disliked driving, so I’ve always naturally chosen to live within biking distance of where I work, and to just say no to most of the driving opportunities that continually present themselves. It helps that I also dislike shopping. Rarely, on a cold, rainy night, I’ll give in to the temptation to jump in the car when I need some groceries. But as a modern American who sits on his ass indoors most of the time, I rarely want to sit on my ass, <a href="http://www.mrmoneymustache.com/2013/04/22/curing-your-clown-like-car-habit/">wrapped up in a tin can</a>, even when I’m outdoors.<br />
<br />
Of course the future of cars is electric, but it’s hard to guess when an electric car might be in my future. Electric cars are best for <a href="https://www.youtube.com/watch?v=fk2YRpLnmdU">daily commuting</a>—precisely the type of driving that I never do. Charging stations are still rare to nonexistent along Utah’s two-lane highways, not to mention remote trailheads. Subaru actually just came out with a plug-in hybrid version of the Crosstrek, but its range on battery power is only 17 miles (not even enough for a round trip to the upper Ogden Valley), and it costs an extra $10k. Finally, a full <a href="https://www.eia.gov/state/analysis.php?sid=UT">70% of Utah’s electricity</a> still comes from coal, so there’s little or no CO<sub>2</sub> reduction from driving an electric car around here. All these things are bound to change, but that change may take a while.Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com2tag:blogger.com,1999:blog-1233073253115884208.post-47852960016524366702019-04-13T12:04:00.000-06:002019-04-13T12:06:37.645-06:00TaxesThe other day I finished my taxes for 2018.<br />
<br />
As a result of the Tax Cuts and Jobs Act of 2017, my federal income tax went up by roughly $500. (Yes, I computed what it would have been this year under the old rules and tax tables.)<br />
<br />
I don’t mind the increase. Actually I think my taxes should be still higher. But I don’t like the way they did it, lowering the bracket rates and then reducing much of the incentive to make charitable contributions.<br />
<br />
Instead they should do away with the distinction between wages and investment income, lowering the tax rate on wages and raising the tax rate on investments. Don’t ever believe politicians who say they value work while they continue to support taxing wages at a higher rate than dividends and capital gains. And don’t even get me started on inherited wealth.<br />
<br />
Treating all income in the same way would also have simplified my tax calculations quite a bit, saving me a couple of hours of time. The new tax law simplified my filing process only slightly. The paid tax preparers and software vendors are still, I’m sure, very happy.<br />
<br />
Incidentally, although I do think they should restore the old incentive to make charitable contributions, I’d also be fine with greatly restricting the definition of “charitable” to include only true charities—not churches or elite schools or thinly disguised political organizations.Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com0tag:blogger.com,1999:blog-1233073253115884208.post-62502716508375646742017-11-29T20:03:00.000-07:002018-01-18T15:02:14.367-07:00Six Ways to Measure Your Electricity UseMaybe you want to save money. Maybe you want to save the planet. Maybe you just want to understand what’s going on inside your home. Or maybe, like me, you’re motivated in all three of these ways. Whatever the reason, let’s talk about how you can measure your household electricity use.<br />
<br />
In this article I’ll describe six practical electricity measurement methods, starting with the simplest and progressing toward those that require more effort. Beginners will want to get comfortable with each method before moving on to the next. More advanced readers should feel free to skip ahead to the methods they don’t already know.<br />
<br />
Ready? Here we go...<br />
<br />
<b>1. Look at your bills.</b><br />
<br />
You probably receive an electricity bill every month. Of course the bill shows how much money you owe, but it also shows how much electricity you’ve used. (If your bill gets sent to a landlord who doesn’t let you see it, then you’ll have to skip this method and go on to the next one.)<br />
<br />
Even if all you really care about is money, it’s not enough to look only at the dollar amount on your bill because that amount might not be a good measure of how much electricity you’ve used. It probably includes a base rate that you pay even if you use no electricity, and it might include other utilities besides electricity. Worse, your utility company might have you on an “equal billing” plan that averages your bill over the course of a year, hiding the interesting seasonal changes.<br />
<br />
So you want to look on your bill for a number that’s not in dollars but rather in kilowatt-hours, or kWh for short. That number is the actual amount of electrical energy you used during the month. For example, here’s my bill from February 2014, during which I used 146 kWh:<br />
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<a href="https://3.bp.blogspot.com/-v1lEV3BB4jA/Wh9v94HHqvI/AAAAAAAAB9k/98P4h9A7JFk_VVFXVjHqpqs9ZXqpwfqLwCLcBGAs/s1600/ElecBillFeb2014.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="272" data-original-width="580" src="https://3.bp.blogspot.com/-v1lEV3BB4jA/Wh9v94HHqvI/AAAAAAAAB9k/98P4h9A7JFk_VVFXVjHqpqs9ZXqpwfqLwCLcBGAs/s1600/ElecBillFeb2014.png" /></a></div>
<div class="separator" style="clear: both; text-align: center;">
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Don’t be shocked if your monthly usage is a lot more than mine! According to official <a href="https://www.eia.gov/tools/faqs/faq.php?id=97&t=3">government data</a>, the average American household uses nearly 900 kWh per month.<br />
<br />
Besides comparing your monthly electricity use to the average American household (or, if you prefer, to <a href="http://dvschroeder.blogspot.com/2015/05/home-energy-use.html">my own</a>), you can learn a lot by comparing to your own usage in other months. Look at a whole year’s worth of bills if you can, to see the seasonal patterns. Many Americans use the most electricity in the summer, when they use their air conditioners; others use the most in the winter, for heating and lighting.<br />
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<b>What’s a kilowatt-hour anyway?</b><br />
<br />
A kilowatt-hour is a unit for measuring energy, just as a mile is a unit for measuring distance and a dollar is a unit for measuring money. As with those other units, you’ll develop an intuitive feel for kilowatt-hours as you encounter more examples. Here are a few common household uses that typically consume <i>approximately</i> one kWh each:<br />
<ul>
<li>Running a central air conditioner for 20 minutes</li>
<li>Running an electric space heater for 40 minutes</li>
<li>Running a modern no-frills refrigerator for one day</li>
<li>Baking a batch of cookies in an electric oven</li>
<li>Drying 1/3 of a load of laundry in an electric dryer</li>
<li>Leaving an LED light bulb on for a few days</li>
<li>Fully charging a laptop computer battery 10 times</li>
</ul>
And what does each of these activities cost? Most Americans pay between 10 and 20 cents for a kWh of electrical energy.<br />
<br />
At some point you may want to compare electrical energy to <a href="http://www.feynmanlectures.caltech.edu/I_04.html">other forms of energy</a>, such as chemical energy (in food or fuels), or thermal energy (heat). Because we can convert one type of energy into another, we <a href="https://books.google.com/books?id=SJNPDgAAQBAJ&lpg=PA74&dq=feynman%20%22the%20amount%20of%20energy%20in%20food%22&pg=PA74#v=onepage&q=feynman%20%22the%20amount%20of%20energy%20in%20food%22&f=false">really should use the same unit</a> to measure all types—but we don’t! Our inconvenient tradition is to measure food energy in Calories (abbreviated Cal, which scientists call large calories or kilocalories) and, here in the U.S., to measure heat in British thermal units (Btu). You can convert between kWh, Cal, and Btu using Google or various other web sites. The approximate conversion factors are<br />
<blockquote class="tr_bq">
1 kWh = 860 Cal = 3400 Btu.</blockquote>
So the typical American consumes enough food to provide two to three kWh of energy each day (1700 to 2600 Cal), and a typical household furnace can provide about 22 kWh of heat each hour (75,000 Btu). A gallon of gasoline, if you’re curious, provides about 31,000 Cal, or 120,000 Btu, or 36 kWh of energy.<br />
<br />
<b>2. Read your meter.</b><br />
<br />
The main problem with electricity bills is that you get only one per month! But the power company determines your billed usage by reading your meter, and you can read it yourself just as easily, as often as you like. (The exception would be if you live in a multi-unit building in which the electricity isn’t metered separately for each unit. In that case you’ll have to go on to method 3.)<br />
<br />
Reading the old <a href="https://www.wikihow.com/Read-an-Electric-Meter">dial-style meters</a> used to be a bit tricky, but nowadays nearly everyone has a digital meter with a simple numerical readout:<br />
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<div class="separator" style="clear: both; text-align: center;">
<a href="https://3.bp.blogspot.com/-AlqBGzuZQLc/Wh5bcUQoPgI/AAAAAAAAB6c/gEaYxuWoCGsKx5oHgZ2A_gF0zBlD7_wTQCLcBGAs/s1600/MeterPhoto.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="370" data-original-width="400" height="295" src="https://3.bp.blogspot.com/-AlqBGzuZQLc/Wh5bcUQoPgI/AAAAAAAAB6c/gEaYxuWoCGsKx5oHgZ2A_gF0zBlD7_wTQCLcBGAs/s320/MeterPhoto.jpg" width="320" /></a></div>
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The number on the display, 24362 in this case, is the number of kWh of electricity used since some time far in the past—probably whenever the meter was first installed. (The number may blink off and back on every few seconds, in which case you may need to wait a moment to see it.)<br />
<br />
So all you need to do is write down the number from the meter (and the time when you read it), then read it again an hour or a day or a week later, and subtract the two values to get the electrical energy usage during that time period. It’s a great exercise to read your meter once a day for a few weeks or months, and to keep a log of the readings, like this:<br />
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<div class="separator" style="clear: both; text-align: center;">
<a href="https://1.bp.blogspot.com/-mtV4_4iXm4s/Wh9tgy4ALjI/AAAAAAAAB9M/2cxXdXD1Ew4y-epwD7VUTbPwfCQraqdxACLcBGAs/s1600/FakeMeterLog.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="272" data-original-width="452" height="192" src="https://1.bp.blogspot.com/-mtV4_4iXm4s/Wh9tgy4ALjI/AAAAAAAAB9M/2cxXdXD1Ew4y-epwD7VUTbPwfCQraqdxACLcBGAs/s320/FakeMeterLog.png" width="320" /></a></div>
<span style="text-align: center;"><br /></span>
<span style="text-align: center;">From this kind of data you can get a very good idea of what kinds of activity use the most electricity: When did you run your air conditioner? When did you do laundry? How much energy does your house use on days when nobody is home?</span><br />
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<b>3. Multiply power by time.</b><br />
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<a href="https://1.bp.blogspot.com/-_S-uHjAtXz0/Wh9pwLQG3LI/AAAAAAAAB8o/o231DD5RoJ8JeHnJtiIpeWA2Nh3l9LoGwCLcBGAs/s1600/LEDbulb.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="500" data-original-width="329" height="320" src="https://1.bp.blogspot.com/-_S-uHjAtXz0/Wh9pwLQG3LI/AAAAAAAAB8o/o231DD5RoJ8JeHnJtiIpeWA2Nh3l9LoGwCLcBGAs/s320/LEDbulb.jpg" width="210" /></a></div>
Some electrical devices always use energy at the same rate, whenever they’re turned on. The most familiar example is an ordinary (non-dimmable) light bulb. The rate of energy use is what scientists call <i>power</i>, and we measure it in units of watts. Old incandescent light bulbs commonly used 60 or 100 watts, but modern LED bulbs put out just as much light while using only 10 or 15 watts.<br />
<br />
To determine the amount of energy used by a device, you multiply its rate of energy use (that is, the power, in watts) by the amount of time that it’s on:<br />
<blockquote class="tr_bq">
Energy = Power × Time.</blockquote>
If we measure the power in watts and the time in hours, then we get the energy in units of watt-hours. A <i>kilo</i>watt-hour is 1000 watt-hours, so we divide by 1000 to get the energy in kWh. For example, the energy consumed by a 10-watt bulb left on for 24 hours would be<br />
<blockquote class="tr_bq">
Energy = (10 watts)(24 hours) = 240 watt-hours = 0.24 kWh,</blockquote>
where I divided by 1000 in the last step. You can similarly estimate the energy use of a 40-watt ceiling fan running for six hours, or of a 1500-watt hairdryer that’s turned on for 10 minutes. Look for power consumption ratings printed on the backs of appliances, or in the owner’s manuals or on the manufacturers’ web sites. Or consult an <a href="http://solarpanelsphotovoltaic.net/power-consumption-101-typical-household-appliances/">online list</a> of typical power consumption values. The only catch is that many appliances use less than their nominal power rating under most conditions, or they cycle on and off automatically so that it’s hard to measure exactly how long they’re actually on.<br />
<br />
<b>4. Get a plug-in appliance meter.</b><br />
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<a href="https://4.bp.blogspot.com/-wL9psVWsOd0/Wh9kf9hKnKI/AAAAAAAAB74/SCIrqvz-J2A8aTnoFW2Xr3t53lpdWLGHgCLcBGAs/s1600/KillAWatt.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="600" data-original-width="391" height="320" src="https://4.bp.blogspot.com/-wL9psVWsOd0/Wh9kf9hKnKI/AAAAAAAAB74/SCIrqvz-J2A8aTnoFW2Xr3t53lpdWLGHgCLcBGAs/s320/KillAWatt.jpg" width="208" /></a></div>
For a mere $20 or so, you can buy a <a href="http://www.p3international.com/products/p4400.html">Kill A Watt P4400 meter</a>, which makes it easy to measure the energy use of any plug-in 120-volt appliance. Use it for a few days to track down unnecessary energy use, and it can easily repay your investment many times over. (There are a number of <a href="https://www.amazon.com/dp/B0716WQW79/ref=sspa_dk_detail_1?psc=1">competing</a> <a href="https://www.amazon.com/dp/B071GTVFG4?ref_=ams_ad_dp_ttl">products</a> on the market, but the Kill A Watt is the most common, and is very affordable, so that’s the one I’ll describe. I’ve never seen one in a store, but you can purchase it through <a href="https://www.homedepot.com/p/Kill-A-Watt-Electricity-Monitor-P4400/202196386">many</a> <a href="http://www.acehardware.com/product/index.jsp?productId=3799219">online</a> <a href="https://www.amazon.com/P3-P4400-Electricity-Usage-Monitor/dp/B00009MDBU">retailers</a>.)<br />
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To use the Kill A Watt meter you simply plug it into a wall outlet (through an extention cord if necessary), then plug your appliance into the meter. Initially it just displays the line voltage (120 or so), but if you press the rightmost button once, it will display the total energy used since you plugged it in, in kWh. Press the same button again and it displays the time since you plugged it in, so you don’t even need to write that down.<br />
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You’ll definitely want to use the meter to test your refrigerator(s), preferably for a day or longer. Other good candidates for testing include televisions, computers, washing machines, and electric blankets.<br />
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For some devices you may also want to try pressing the meter’s middle button. Then the display will show the instantaneous rate of energy use (power), in watts or kilowatts. This number will probably fluctuate, especially for something like a refrigerator that periodically cycles on and off. But if the power is reasonably steady and you already know how long the device will be in use, then a quick power reading can save you from having to wait for the energy measurement to build up. Just multiply the power by the time, as described above in method 3.<br />
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Don’t forget to test low-power devices that are on all the time, such as clocks and WiFi routers and televisions that never go completely off.<br />
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<b>5. Time the little blinking squares.</b><br />
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The main drawback of a plug-in meter is that you can’t use it to measure hard-wired devices or 240-volt appliances. For these, and for those times when you’re caught without a plug-in meter within reach, you can go back out to the power company’s meter, equipped with a stopwatch (probably the one on your smartphone).<br />
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This time, instead of looking at the numbers on the display, you want to watch the little blinking squares at the bottom. They should go on and off following a six-step pattern:<br />
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<a href="https://3.bp.blogspot.com/-u68v2YW3nGA/Wh5ae2nhiII/AAAAAAAAB6I/xIhaNMAO4HE97Qicim4EBPEbUaeMb7gcQCLcBGAs/s1600/MeterAnimation.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="204" data-original-width="400" height="100" src="https://3.bp.blogspot.com/-u68v2YW3nGA/Wh5ae2nhiII/AAAAAAAAB6I/xIhaNMAO4HE97Qicim4EBPEbUaeMb7gcQCLcBGAs/s200/MeterAnimation.gif" width="200" /></a></div>
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(The pattern is meant to mimic the horizontal rotating disk in an old mechanical meter, as if half the disk’s edge is dark and the other half is light, with the front turning from left to right.) Each change in the pattern—a square going on or off—indicates one watt-hour of energy usage. Use your stopwatch to time how long it takes between one change and the next. Or, if the pattern is changing quickly, measure the time for the entire six-step cycle and divide by six. Either way, you can now calculate the power being used in your home as follows:<br />
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Power in watts = 3600 / (measured time in seconds).</blockquote>
Explanation: The energy used during your measured time interval was one watt-hour, or 3600 watt-seconds (since an hour is 3600 seconds). But energy = power × time, so to calculate the power, you divide the energy by the measured time.<br />
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You’ve now measured the rate at which all the electrical devices in your home are using energy at a particular moment. The trick, then, is to make this measurement with everything except the device(s) you care about turned off. Try it once with all the major appliances turned off, and the refrigerator unplugged or turned off at the breaker panel, to get a power value for all the little stuff in the home that’s using a small amount of power 24 hours a day. Then turn on a major appliance like the furnace or air conditioner or electric dryer, and make another measurement.<br />
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Once you know the power of some device of interest, calculate its total energy use by multiplying by how long it’s on, as in method 3.<br />
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<b>6. Install a fancy monitoring system.</b><br />
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The five simple methods described above are more than enough to give you the big picture of your home electricity use, including the information you need to save a lot of money (and help save the planet). But if you want to understand every detail of what’s going on in your home, and you’ve exhausted what you can reasonably learn from the first five methods, then the next step is to install a home energy monitoring system. These systems start at about $150, and the installation process is nontrivial.<br />
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Electricity monitoring systems are available in several varieties, from several vendors. I have the <a href="http://efergy.com/us/energy-monitors/online-access/manage-energy-online/engageelitehub">Efergy Engage Elite Hub System</a> (recommended by <a href="http://www.mrmoneymustache.com/2015/03/25/cut-your-power-bill/">Mr. Money Mustache</a>), which is one of the most affordable and easy to use. But I wish I had spent a little more for Efergy’s <a href="http://efergy.com/us/energy-monitors/online-access/manage-energy-online/elite-true-power-meter-engage-hub">True Power Meter</a>, which would be more accurate.<br />
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The main components of these systems are a pair of clamp-around sensors that you install on the main feed wires coming into your breaker panel. To install them you need to turn off the electricity (otherwise <b>you may die!</b>), open up the panel, and then hope that there’s enough room to fit the clamps around the stiff wires. (I had a tough time with one of them, but finally managed.) If you have any doubts about your ability to do this installation safely, you should hire an electrician.<br />
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For a true power meter there would also be a wire to make an electrical connection inside the panel. Either way, the Efergy sensors connect to a transmitter just outside the panel, which beams the data wirelessly to one or two receivers. The data is simply an instantaneous power measurement for your whole house (or at least as much as is powered by this particular panel), equivalent to what you measured in method 5 above. But the monitoring system makes these measurements continually, day and night, with no need for you to use a stopwatch or a calculator.<br />
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One type of Efergy receiver contains a digital display for immediate readout, updating every ten seconds. This can sometimes be handy, but in my opinion it’s not worth the price or the installation effort by itself. The other type of receiver, though, is a “hub” that uploads the data over your internet router to Efergy’s web site, where you can look up (and even download) minute-by-minute power levels at any later time, from any location, through your web browser. It’s a data junkie’s dream. Here’s a sample of my own data as viewed on the Efergy web site, showing a steady base load, the refrigerator and furnace cycling on and off, and a big spike from cooking breakfast on my electric stovetop:<br />
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As I mentioned above, my basic Efergy sensor isn’t always accurate. Specifically, it’s accurate for “resistive loads” like the stove and other heating appliances, but it reads too high a value for anything with a motor in it, like a furnace blower or a washing machine. The reason has to do with the <a href="https://en.wikipedia.org/wiki/Power_factor">intricacies of alternating current</a>, and the best solution would be to use a slightly more sophisticated system such as the Efergy True Power Meter or <a href="http://www.theenergydetective.com/tedprohome.html">The Energy Detective</a> (a competing product that costs a bit more). The power company’s meter also makes accurate measurements, as does a Kill A Watt meter, so I’ve simply used those to calibrate my interpretation of the Efergy data.<br />
<br />Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com0tag:blogger.com,1999:blog-1233073253115884208.post-19935584221072743352017-04-15T09:10:00.001-06:002023-09-21T23:27:35.424-06:00Qubits or Wave Mechanics?A few days ago Sean Carroll tweeted a poll:<br />
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What's the best way to introduce physics undergrad students to quantum mechanics for the first time?</div>
— Sean Carroll (@seanmcarroll) <a href="https://twitter.com/seanmcarroll/status/851484675042230273">April 10, 2017</a></blockquote>
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As someone who’s been wrestling with this question for 30 years, I perked up at this tweet, and not only voted but even tweeted a <a href="https://twitter.com/dvs1444/status/851490557004136448">couple</a> of <a href="https://twitter.com/dvs1444/status/851542227666968576">responses</a>. It’s a fascinating question! </div>
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The second answer is the traditional one, and there are many good arguments for it: a solid experimental basis in phenomena that are easy to demonstrate; vivid images of wavefunctions for building intuition from classical waves; and a huge array of practical applications to atomic physics, chemistry, and materials science. The down-side is that the mathematics of partial differential equations and infinite-dimensional function spaces is pretty formidable. Mastering all this math takes up a lot of time and tends to obscure the logical structure of the subject. Especially if your main interest is in the new field of quantum information science, this is a long and indirect road to take.</div>
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Hence the alternative of starting with two-state systems, which are mathematically simpler, logically clearer, and directly applicable to quantum information science. The difficulty here is the high level of abstraction, with an almost complete lack of familiar-looking pictures and, inevitably, no direct connection to most of the traditional quantum phenomena or applications.<br />
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A fundamental challenge with teaching quantum mechanics is that it’s like the proverbial <a href="https://en.wikisource.org/wiki/The_poems_of_John_Godfrey_Saxe/The_Blind_Men_and_the_Elephant">Elephant of Indostan</a>, with many dissimilar parts whose connections are difficult for novices to discern. From various angles, quantum mechanics can appear to be about Geiger counters and interference patterns, or differential equations and their boundary conditions, or matrices and their eigenvalues, or abstract symbol-pushing with kets and commutators, or summing over all possible histories, or unitary transformations on entangled qubits. Stepping back to get a view of the whole beast is challenging even for experts, and bewildering for “blind” beginners.</div>
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I think most physicists would agree that an undergraduate degree in physics should include some experience with <i>both</i> wave mechanics and two-state systems. Carroll’s Twitter poll, though, asks not what a degree program should <i>include</i>, but how we should <i>introduce</i> physics students to quantum mechanics. That’s a hard question, and one’s answer could easily depend on any number of further assumptions:</div>
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<li>Who exactly are these “physics students”? Students taking an introductory course, which may be their last course in physics? Typical undergraduate physics majors? Undergraduate physics majors at Caltech? What’s their math background?</li>
<li>How long an introduction are we talking about here? A single lecture, or a few weeks, or an entire course?</li>
<li>Will this introduction be followed by further study of quantum mechanics? In other words, is the question <i>merely</i> about the order in which we cover topics, or is it also about the totality of what we should teach, and what we can justifiably omit, when we design a course or a curriculum?</li>
<li>Are we constrained to use existing resources, including textbooks, instructor expertise, and locally available lab equipment? Or are we dreaming about an ideal world in which any resources we might want are magically provided?</li>
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Due to all these ambiguities, we should interpret the poll results with caution. <a href="https://twitter.com/seanmcarroll/status/851526197108396033">Carroll’s interpretation</a> was that the winning second option “probably benefits from familiarity bias. I’ll call it a tie”—so I infer that his own preference is to start with two-state systems. I agree that some respondents were probably biased in favor of what’s familiar, but I also suspect that Carroll’s Twitter followers have more interest in fundamental theory, and less interest in atoms and molecules, than would a random sampling of physicists. I also wonder if some respondents weren’t biased in favor of what’s <i>un</i>familiar: it’s easy to suggest a radical curricular change if you’ve never actually tried it out and had to live with the unintended consequences. Carroll himself is currently teaching an <a href="https://www.preposterousuniverse.com/activities/physics125c/">advanced quantum course</a> that emphasizes two-state systems, but <a href="https://www.preposterousuniverse.com/activities/">as far as I can tell</a> he has never taught a first course in quantum mechanics for undergraduates.</div>
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No professional quantum mechanics teacher should be completely unfamiliar with the two-state-systems-first approach, because it’s used, more or less, in Volume III of the <a href="http://www.feynmanlectures.info/"><i>Feynman Lectures on Physics</i></a>, published in 1965 (thirty years before Schumacher and Wootters <a href="https://doi.org/10.1103/PhysRevA.51.2738">coined the term qubit</a>!). I say “more or less” because Feynman actually starts with two-slit interference and other wave phenomena, and then he introduces a <i>three</i>-state system (spin 1) before settling into a lengthy treatment of spin 1/2 and other two-state systems.</div>
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There are also some well-known graduate-level texts that begin with two-state systems: Baym’s <i><a href="https://books.google.com/books/about/Lectures_on_Quantum_Mechanics.html?id=1125sVZ2_GcC">Lectures on Quantum Mechanics</a></i> (1969) and Sakurai’s <i><a href="https://www.pearsonhighered.com/program/Sakurai-Modern-Quantum-Mechanics-2nd-Edition/PGM160720.html">Modern Quantum Mechanics</a></i> (1985).</div>
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At the upper-division undergraduate level, the earliest text I know of that takes the two-state-systems-first approach is <a href="http://www.uscibooks.com/townsend3.htm">Townsend</a>, which first appeared in 1992. Several others have appeared more recently: <a href="http://www.cambridge.org/catalogue/catalogue.asp?isbn=0511345569">Le Bellac</a> (2006), <a href="http://www.cambridge.org/catalogue/catalogue.asp?isbn=9780521875349">Schumacher and Westmoreland</a> (2010), <a href="https://global.oup.com/academic/product/quantum-mechanics-9780199798124?cc=us&lang=en&">Beck</a> (2012), and <a href="https://www.pearsonhighered.com/program/Mc-Intyre-Quantum-Mechanics/PGM64990.html">McIntyre</a> (2012). Instructors who want to take this approach in such a course can no longer complain about the lack of suitable textbooks.</div>
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But at the lower-division level, where most students <i>first</i> encounter quantum mechanics, the pickings are still slim. Nobody actually teaches out of the <i>Feynman Lectures</i>. You could try to use a few chapters out of one of the more advanced books (McIntyre would probably work best), or you could use Styer’s slim text <i><a href="http://www.cambridge.org/catalogue/catalogue.asp?isbn=1316097471">The Strange World of Quantum Mechanics</a></i> (2000, written for a course for non-science majors), or you could use the new (2017) edition of Moore’s introductory <i><a href="http://www.physics.pomona.edu/sixideas/index.html">Six Ideas</a></i> textbook (which inserts three short chapters on spin and “quantum weirdness” in between electron interference and wavefunctions), or you could try Susskind and Friedman’s <i><a href="http://www.basicbooks.com/full-details?isbn=9780465062904">Theoretical Minimum</a></i> paperback (2014, an insightful tour of the formalism with little mention of applications—see Styer’s review <a href="http://dx.doi.org/10.1119/1.4890980">here</a>).</div>
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I suspect that the time is ripe for someone to write an otherwise-conventional sophomore-level “modern physics” textbook that introduces quantum mechanics via two-state systems and qubits before moving on to wave mechanics. I really wish Moore would expand his Units R and Q into a more complete “modern physics” text!</div>
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Personally, I’ve had a soft spot for spin ever since I took a quantum class from Tom Moore in 1982, at the end of my sophomore year (after a conventional “modern physics” class) at Carleton College. This half-term class was mostly based on Gillespie’s <a href="https://www.amazon.com/Quantum-Mechanics-Primer-Daniel-Gillespie/dp/0700222901">marvelous little book</a>, which lays out the logic of quantum mechanics for a single spinless particle in one dimension. But Moore departed from the book to introduce us to two-state and three-state spin systems as well, even writing a simple computer simulation of successive spin measurements for us to use in a homework exercise. The following year I saw more spin-1/2 quantum mechanics in the philosophy of science course that I took from David Sipfle, using notes prepared by Mike Casper, probably inspired by the <i>Feynman Lectures</i>. So when I took Casper’s senior-level quantum course after another year, I was well prepared.</div>
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A few years later, while procrastinating on my thesis work during graduate school, I converted and expanded Moore’s computer simulation into a graphics-based Macintosh program. Moore and I published a <a href="https://arxiv.org/abs/1502.07036">paper</a> about this program, and how to use it at various levels, in 1993. From there the concept made its way into Moore’s Six Ideas course, and also into the Oregon State <a href="http://physics.oregonstate.edu/paradigms">Paradigms curriculum</a> and McIntyre’s book. Last year I ported the program to a <a href="http://physics.weber.edu/schroeder/software/Spins.html">modern web app</a>.</div>
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I recount this history mainly to establish my credentials as an experienced advocate for, and contributor to, the teaching of quantum mechanics via two-state (and three-state) spin systems. So you may be surprised to know that on Carroll’s quiz I actually voted <i>against</i> this approach and in favor of starting with the traditional wave mechanics. And in my own teaching I’ve actually never started with spin systems: I’ve always started with one-dimensional wave mechanics in both upper-division quantum mechanics and sophomore-level modern physics. In calculus-based introductory physics I teach a little about wave mechanics and don’t really cover two-state systems at all. My reasoning is simply that for these students, in these courses, the balance of the pros and cons listed above seems to weigh in favor of starting with wave mechanics.</div>
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Meanwhile, I think there are opportunities to improve on the way we teach wave mechanics. One serious drawback with most wave mechanics text materials is their relative neglect of systems of more than one particle. As a result, students tend to develop some misconceptions about multiparticle systems, and don’t hear about entangled states—an important and trendy topic—as early as they could. I’ve recently written a <a href="https://arxiv.org/abs/1703.10620">paper on how to address this deficiency</a>, with some <a href="http://physics.weber.edu/schroeder/software/EntanglementInBox.html">accompanying</a> <a href="http://physics.weber.edu/schroeder/software/CollidingPackets.html">software</a> to help students visualize entangled wavefunctions.</div>
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My bottom-line opinion, though, is that the best answer to Carroll’s question depends on both the students’ needs and the instructor’s inclinations. Back in 1989, Bob Romer published an <a href="http://dx.doi.org/10.1119/1.16019">editorial</a> in the <i>American Journal of Physics</i> titled “Spin-1/2 quantum mechanics?—Not in <i>my</i> introductory course!” But he hastened to clarify: “not in <i>my</i> course, thank you, but maybe in yours”—enthusiastically encouraging instructors to innovate and to follow whatever teaching plan they believe in. I wholeheartedly agree.</div>
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Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com0tag:blogger.com,1999:blog-1233073253115884208.post-26026204940951308082016-10-09T08:53:00.001-06:002017-01-27T09:12:52.111-07:00Could Clinton Win Utah?There’s been <a href="http://www.sltrib.com/home/4173439-155/could-donald-trump-turn-utah-blue?fullpage=1">plenty</a> of <a href="http://www.vox.com/2016/8/12/12425122/donald-trump-utah-polls">speculation</a> this election season that Utahns’ distaste for Donald Trump might drive them so far as to “turn the state blue” in November, giving Hillary Clinton a plurality of the vote. I never took this speculation seriously, figuring that however much they dislike Trump, most Utahns are deeply loyal to the Republican Party and would therefore rationalize their way to hating Clinton even more.<br />
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But the fallout from Trump’s <a href="https://www.washingtonpost.com/politics/trump-recorded-having-extremely-lewd-conversation-about-women-in-2005/2016/10/07/3b9ce776-8cb4-11e6-bf8a-3d26847eeed4_story.html">latest scandal</a> has changed the landscape incredibly fast: his bragging in vulgar terms about habitually committing sexual assault has pushed many Utahns over the edge. Governor Herbert and several other prominent Utah Republicans have <a href="http://www.sltrib.com/news/4444721-155/after-video-huntsman-says-it-is">withdrawn their endorsements</a>, and several who were on the fence have finally taken a stand against Trump, joining Mitt Romney, who has been a never-Trumper all along. Senator Hatch and my own Rep. Bishop are still <a href="http://www.sltrib.com/news/4445886-155/the-trump-tape-not-all-utah">supporting Trump</a>, but they’re undoubtedly feeling a bit lonely at the moment. Most remarkable of all, the Deseret News has just published an <a href="http://www.deseretnews.com/article/865664336/In-our-opinion-Donald-Trump-should-resign-his-candidacy.html">editorial</a> calling on Trump to drop out of the race, while expressing the hope that Congress will keep President Clinton in check.<br />
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Of course Utah won’t be the state that tips the balance of the Electoral College. But it’s still fun to consider whether Clinton could actually win Utah, so let’s take a look at the polling data. Here’s a screen capture from FiveThirtyEight.com, listing the nine Utah polls that weigh most heavily in that site’s <a href="http://projects.fivethirtyeight.com/2016-election-forecast/utah/">Utah forecast</a>:<br />
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<a href="https://3.bp.blogspot.com/-Dz1YKMPuXe8/V_n7tAwkCfI/AAAAAAAABu4/qNg7jombvZ8lxeLJHMQYJqd_mgLd6dCBwCLcB/s1600/Screen%2BShot%2B2016-10-08%2Bat%2B9.58.17%2BPM.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="322" src="https://3.bp.blogspot.com/-Dz1YKMPuXe8/V_n7tAwkCfI/AAAAAAAABu4/qNg7jombvZ8lxeLJHMQYJqd_mgLd6dCBwCLcB/s640/Screen%2BShot%2B2016-10-08%2Bat%2B9.58.17%2BPM.png" width="580" /></a></div>
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The polls are listed in descending order by their FiveThirtyEight-assigned weights, based on the quality of the pollster, the sample size, and how recently the poll was conducted. The range of polling results is remarkably wide, but notice that the overall quality of the polling is poor: all of the polls are substandard in at least one of the three respects. Even the highest-weighted poll is by a pollster (Dan Jones) with only a C+ grade, and is now more than two weeks old. The <a href="https://www.scribd.com/document/315450242/Salt-Lake-Tribune-President-Poll">highest-quality poll</a>, conducted by SurveyUSA for the Salt Lake Tribune and the Hinckley Institute, is now <i>four months</i> old.<br />
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Nevertheless, FiveThirtyEight has combined all the Utah polls into a weighted average, then done some further processing to obtain a predicted most-likely outcome. Here’s a summary of the calculation:<br />
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The first four adjustments made to the polling average are small and, in my opinion, should be uncontroversial. One of these, the “trend line” adjustment, tries to update the older results based on trends in other states (and the nation as a whole) for which there is abundant recent polling. In principle, this adjustment should account for Clinton’s rise in the polls since the September 26 debate, up to but not including the events of the past two days.<br />
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But the adjusted polling average allocates only 81.9% of the vote to Clinton, Trump, and Johnson. The next step then assumes that nearly all of the remaining 18.1% will end up split evenly between Clinton and Trump, and here’s where I think the FiveThirtyEight model makes a Utah-specific error. The problem is Utah-based minor candidate Evan McMullin, who <a href="http://www.sltrib.com/home/4209714-155/provo-native-byu-grad-joins-race">entered the race</a> only two months ago yet seems to be polling almost as well as Johnson: 12% in the top-weighted <a href="https://www.scribd.com/document/325174301/WEB-Presidential-Poll#fullscreen&from_embed">Dan Jones poll</a>, and 9% in the second-place <a href="http://www.publicpolicypolling.com/pdf/2015/PPP_Release_UT_82316.pdf">PPP poll</a>. It seems to me that if Johnson is allowed to retain his 12.6% share at this stage of the calculation, then McMullin should also retain his 10% or so.<br />
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FiveThirtyEight’s final adjustment is to mix in a prediction based not on polls but on a demographic regression model, which uses past voting patterns (broken down by region, race, religion, and educational level) to try to compensate for inadequate polling in states like Utah. (This is done even for the site’s “polls only” model, which is the one I’m working from.) But this adjustment could also be problematic, because of Utah’s (and Mormons’) peculiar affinity for Romney in 2012 and distaste for Trump in 2016.<br />
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So let’s back up to the “adjusted polling average” but tentatively give McMullin a share that’s 2% behind Johnson:<br />
<ul>
<li>Clinton 28.8%</li>
<li>Trump 40.5%</li>
<li>Johnson 12.6%</li>
<li>McMullin 10.6%</li>
<li>Other/undecided 7.5%</li>
</ul>
And now let’s ask how these numbers are likely to change over the next month, in light of the events of the last two days.<br />
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My guess is that a certain fraction of Trump’s 40.5% will follow Gov. Herbert’s lead and withdraw their support—some in direct reaction to the recent news and others because they now have “permission” from authorities they trust. Also, I doubt that Trump can now gain from any defections of Johnson, McMullin, or other/undecided voters. So unless there are further unexpected developments, it looks to me like Trump will end up with only 30% to 35% of the Utah vote.<br />
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Can Clinton’s share exceed this? If Trump gets only 30% then the answer is almost certainly yes: Clinton would then have to gain only a tiny fraction of the undecideds, Trump defectors, and perhaps defectors from minor candidates. If Trump can keep his vote share near 35% then it will be harder for Clinton, but still not out of the question. Let’s also remember that the percentages listed above are pretty uncertain, and you could make a case for discarding the weird outlying CVOTER International poll results; then Trump’s support would have already been below 40% even before the latest scandal.<br />
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Is there any chance that Johnson or McMullin could win? I think that would be a long shot, because they seem to be splitting the conservative anti-Trump vote so evenly. Only if one of them drops out, or otherwise implodes, would the other have a decent chance of surpassing Clinton.<br />
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The bottom line, in my opinion, is that Clinton is now a slight favorite to defeat Trump in Utah and carry the Beehive State. I say “slight” because of the large uncertainties in the past polling data, in the impact of the recent developments, and in what could still happen during the next 30 days. In any case, I can hardly wait to see what upcoming polls of Utah show, and to see how Utahns actually vote in such an extraordinary election.<br />
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<b>Update, 16 Oct 2016:</b> During the week since I wrote this article we’ve gotten three new Utah polls, and FiveThirtyEight has updated its <a href="http://projects.fivethirtyeight.com/2016-election-forecast/utah/">Utah model</a> to include Evan McMullin. Here’s their summary table of the polls that include McMullin, which are the only ones the model now uses:<br />
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<a href="https://4.bp.blogspot.com/-CkfjTsGU-ec/WAOnsQNgksI/AAAAAAAABvw/jQ24eUXrH90s4PCEfQUWUm4hE77RrdcKwCLcB/s1600/Screen%2BShot%2B2016-10-16%2Bat%2B10.09.40%2BAM.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="https://4.bp.blogspot.com/-CkfjTsGU-ec/WAOnsQNgksI/AAAAAAAABvw/jQ24eUXrH90s4PCEfQUWUm4hE77RrdcKwCLcB/s640/Screen%2BShot%2B2016-10-16%2Bat%2B10.09.40%2BAM.png" width="600" /></a></div>
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The <a href="https://www.dropbox.com/s/1p9dm1e1w184c3s/UT%20Statewide%20Presidential%20Polling%20October%202016%20Memo%20-%20Y2.pdf?dl=0">Y2 Analytics poll</a>, first <a href="http://www.deseretnews.com/article/865664606/Poll-Trump-falls-into-tie-with-Clinton-among-Utah-voters.html?pg=all">reported</a> late on the night of the 11th, caused a flurry of excitement because it shows Clinton and Trump tied at only 26%. Equally remarkable is that McMullin is just behind at 22%, even though only 52% of respondents were aware of his candidacy. This result immediately made me question my earlier dismissal of McMullin’s chances. It also prompted articles covering the race in the <a href="http://www.nytimes.com/2016/10/15/us/politics/evan-mcmullin-campaign-utah.html">New York Times</a>, <a href="https://www.washingtonpost.com/news/powerpost/paloma/daily-202/2016/10/14/daily-202-trump-really-is-in-danger-of-losing-utah/58002271e9b69b059243020f/">Washington Post</a>, and <a href="http://fivethirtyeight.com/features/how-evan-mcmullin-could-win-utah-and-the-presidency/">FiveThirtyEight</a>.<br />
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The subsequent polls from Monmouth and YouGov confirm that McMullin’s support is around 20%, but contradict the earlier indication that his gain has come entirely at the expense of Trump, whose support remains in the mid-30s. If these polls are a reasonably accurate predictor of the final results, then Trump will still win Utah by a safe margin.<br />
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After combining all six polls and making the minor adjustments described above, FiveThirtyEight now obtains the following “adjusted polling averages”:<br />
<ul>
<li>Clinton 24.1%</li>
<li>Trump 33.8%</li>
<li>Johnson 10.7%</li>
<li>McMullin 19.4%</li>
<li>Other/undecided 12.0%</li>
</ul>
Although Trump’s support has fallen about as much as I predicted a week ago, he remains comfortably ahead of Clinton because her support has also fallen somewhat (or at least is lower in polls that include McMullin). Could she or McMullin still win? Yes, because the uncertainty in these numbers is fairly large and the situation in Utah still seems pretty volatile. On the other hand, many Utahns will receive mail-in ballots during the coming week, so the clock is starting to run out. For what it’s worth, the <a href="https://www.predictit.org/Market/2230/Which-party-will-win-Utah-in-the-2016-presidential-election">PredictIt</a> betting market, as translated by <a href="https://electionbettingodds.com/">ElectionBettingOdds</a>, currently has the odds of winning Utah at Trump 71.5%, Clinton 20.0%, and Other (presumably McMullin) 8.5%.<br />
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<b>Update, 8 Nov 2016:</b> Polls of Utah have been coming thick and fast over the last three weeks, but the picture hasn’t changed much over this time. Here’s another screen capture from FiveThirtyEight showing nearly all of the polls that include McMullin:<br />
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<a href="https://4.bp.blogspot.com/-_q2R53uaBDQ/WCHm6-TMu2I/AAAAAAAABwo/wgJlEXMkIaI5xyk_nWN-0UDefEbjBGucACLcB/s1600/UtahPolls8Nov2016.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://4.bp.blogspot.com/-_q2R53uaBDQ/WCHm6-TMu2I/AAAAAAAABwo/wgJlEXMkIaI5xyk_nWN-0UDefEbjBGucACLcB/s1600/UtahPolls8Nov2016.png" /></a></div>
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The general picture here is pretty clear: Trump is ahead in almost every poll, though there’s disagreement over whether his lead is by single or double digits. McMullin is the frontrunner in just one poll, and Clinton in none. Johnson has collapsed. Here are FiveThirtyEight’s averages and adjustments, to obtain its final prediction for the Utah presidential election:</div>
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<a href="https://2.bp.blogspot.com/--lwzY3C_6Ng/WCHoUNxkJ5I/AAAAAAAABw0/PrygLSlJnUMpg4qPcgGqq__aZykyJ0GVgCLcB/s1600/UtahPollingAverage8Nov2016.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://2.bp.blogspot.com/--lwzY3C_6Ng/WCHoUNxkJ5I/AAAAAAAABw0/PrygLSlJnUMpg4qPcgGqq__aZykyJ0GVgCLcB/s1600/UtahPollingAverage8Nov2016.png" /></a></div>
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In the adjusted polling average, Trump comes out ahead of Clinton by nearly ten percentage points, while McMullin is behind Clinton by a point and a half. But then FiveThirtyEight assigns most of the remaining undecided voters to McMullin (presumably there’s a precedent for this), so McMullin ends up in second place in the final projection. The calculated win probabilities are Trump 82.9%, McMullin 13.5%, and Clinton 3.6%.</div>
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Meanwhile, <a href="https://electionbettingodds.com/">Election Betting Odds</a> has Trump at 87% likely to win, Clinton at 7%, and Other at 6%. Clinton’s higher odds here may reflect a <a href="http://www.sltrib.com/news/4548510-155/utah-dems-hold-edge-in-early">recent report</a> that she is ahead among early voters. It wouldn’t especially surprise me if Clinton beats her polls by a few points due to the early vote advantage, especially because many Utahns haven’t gotten used to Utah’s new mostly-by-mail voting system, and the number of physical polling locations has been greatly reduced since the last presidential election. Republicans who have hesitated this long because they’re unenthusiastic about all the candidates may have little motivation to find their polling locations and wait in the <a href="http://www.sltrib.com/news/politics/4556123-155/utah-prepares-for-long-lines-and">potentially long lines</a>.</div>
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Still, it seems highly unlikely that either Clinton or McMullin will make up the roughly ten-point polling deficit to catch Trump, who will probably win Utah with less than 40% of the vote.</div>
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Just as Trump’s potential national victory <a href="http://www.vox.com/policy-and-politics/2016/11/7/13532178/donald-trump-american-democracy-weakness">says a lot</a> about the state of American politics, so also his ability to win Utah tells us that our state isn’t as different as many would like to believe. Although many prominent Utah politicians have denounced Trump, Reps. Chaffetz and Stewart ultimately backtracked and <a href="http://www.deseretnews.com/article/865665751/Chaffetz-Stewart-now-voting-for-Trump-after-disavowing-GOP-nominee.html?pg=all">said they would vote for him</a> anyway. Governor Herbert and Mitt Romney have remained silent about whom they’re voting for. (A McMullin endorsement from either of them, which I was half expecting four weeks ago, might have put McMullin in the lead.) The bottom line is that even though most Utahns fully understand that Trump is a lying, bigoted, asshole who’s absolutely unqualified for the job, their allegiance to the Republican Party drives them to dislike Clinton even more. Many Utahns will explain that at least Trump will (he says) appoint anti-abortion justices to the Supreme Court. Few of them, I suppose, have carefully thought through the risks that America and the world will face if Trump actually wins.</div>
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<b>Update, 19 January 2017:</b> Before the inauguration of President Trump I suppose I should finish this saga with the actual <a href="https://elections.utah.gov/Media/Default/2016%20Election/2016%20General%20Election%20-%20Statewide%20Canvass%203.pdf">Utah election results</a>:</div>
<ul>
<li>Trump 45.5%</li>
<li>Clinton 27.5%</li>
<li>McMullin 21.5%</li>
<li>Johnson 3.5%</li>
<li>Others 2.0%</li>
</ul>
<div>
Comparing to the final FiveThirtyEight polling averages above, we see that not only did essentially all of the undecided voters apparently end up voting for Trump, but he also picked up a fair number of McMullin and Johnson defectors in the final days before the vote. This result fits in nicely with the <a href="https://www.washingtonpost.com/news/the-fix/wp/2016/11/17/how-america-decided-at-the-very-last-moment-to-elect-donald-trump/?utm_term=.3607821ea458">conventional</a> <a href="http://www.vox.com/the-big-idea/2017/1/11/14215930/comey-email-election-clinton-campaign">wisdom</a> about what happened in the decisive swing states, with the further complication that a larger percentage of Utah voters was up for grabs. Of course, it’s also possible that there was a systematic polling error in Utah, such as an <a href="https://fivethirtyeight.com/features/pollsters-probably-didnt-talk-to-enough-white-voters-without-college-degrees/">under-sampling of white voters without college degrees</a>. In any case, I was obviously wrong to predict that Trump would end up with under 40% of the vote. As for Clinton, she did over-perform her polls as I more or less predicted, but only by about a point.</div>
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Despite my poor numerical predictions, I think the overall tone of my final election-day paragraph holds up pretty well. Of course the important question now is what will happen during Trump’s presidency. The nation is headed into uncharted territory, with a vast range of possible outcomes ranging from reasonably normal to absolutely catastrophic. I don’t see how anyone could possibly predict what will happen.</div>
Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com0tag:blogger.com,1999:blog-1233073253115884208.post-18002166230357251192016-09-12T00:57:00.000-06:002017-06-03T20:08:46.403-06:00A Year of Solar DataMy solar panels were <a href="http://dvschroeder.blogspot.com/2015/09/solar-system-installation.html">installed</a> in August of last year, and two months later I <a href="http://dvschroeder.blogspot.com/2015/10/solar-system-first-look-at-data.html">reported</a> on how they were performing. Now, after a full year of operation, it’s time for a more comprehensive report.<br />
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The bottom line is that the panels produced a little less electrical energy than the <a href="http://www.gardner-energy.com/">installer</a> predicted, but still quite a bit more than I used over the course of the year. Here’s a diagram showing the overall energy flows:<br />
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<a href="https://1.bp.blogspot.com/-zyw2MkjAUzc/V9ZKbn2MhlI/AAAAAAAABsE/9_UY1jpz7ncAXRH5WaxaMiA6sfniov-bwCLcB/s1600/FirstYearEnergyFlow.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="251" src="https://1.bp.blogspot.com/-zyw2MkjAUzc/V9ZKbn2MhlI/AAAAAAAABsE/9_UY1jpz7ncAXRH5WaxaMiA6sfniov-bwCLcB/s400/FirstYearEnergyFlow.png" width="400" /></a></div>
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Here and throughout this article I’ll present data from the year that began on 1 September 2015 and ended on 31 August 2016. During that time the panels produced 1558 kilowatt-hours (kWh) of electrical energy, and I used 349 kWh of that energy directly. The other 1209 kWh went onto the grid for my neighbors to use. But I also pulled 813 kWh of energy off the grid, at night and at other times when I needed more power than the panels were producing. My total home usage from both the panels and the grid was 1162 kWh. (I got the solar production amount from my Enphase solar monitoring system, and the amounts going to and from the grid by reading my electric meter. From these three numbers I calculated the other two.)<br />
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Because I used less energy than my panels produced, I’ve paid no usage charges on my electric bills since the system was installed; I pay only the monthly minimum charges, which come to about $9.00 per month including taxes. Under Utah’s net-metering policy (which could change in the future), each kWh that I push onto the grid can offset the cost of a kWh that I pull off of the grid at some other time. But I don’t get to make a profit from the 396 kWh excess that I pushed onto the grid over the course of the year; that was effectively a donation to Rocky Mountain Power, worth about $40 at retail rates.<br />
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<b>Monthly and daily details</b><br />
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So much for the yearly totals. But the picture varies quite a bit with the seasons, as shown in this graph of my panels’ monthly output:<br />
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<a href="https://3.bp.blogspot.com/-dVoNdB-RuYo/V9ZKvLG_PsI/AAAAAAAABsI/LdvDmoEJLFI5awFtDCEZzy9a4Lw1ib-NgCLcB/s1600/MonthlySolarAndEstimates.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://3.bp.blogspot.com/-dVoNdB-RuYo/V9ZKvLG_PsI/AAAAAAAABsI/LdvDmoEJLFI5awFtDCEZzy9a4Lw1ib-NgCLcB/s1600/MonthlySolarAndEstimates.png" /></a></div>
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The total energy generated in July (165 kWh) was twice as much as in January (81 kWh), with a pretty steady seasonal rise and fall in between. On the other hand, my installer estimated significantly higher production in winter and spring, plotted on the graph as green squares. (I get a similar over-estimate of the winter and spring production, relative to summer and fall, when I use the NREL <a href="http://pvwatts.nrel.gov/index.php">PVWatts calculator</a>, with weather data from the Ogden airport. So maybe my location is cloudier than the airport, and/or maybe last winter was cloudier than the 30-year average that the calculator uses.) The actual annual production of 1558 kWh was 91% of the estimated total of 1713 kWh. (An earlier, less formal estimate from the installer was 1657 kWh for the year, and not broken down by month; my annual production was 94% of that estimate.)<br />
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You might think the factor-of-2 seasonal variation in my solar energy production was a direct result of the varying length of the days and/or the varying solar angles. In fact, however, it was mostly due to varying amounts of cloud cover. You can see this in a plot of the <i>daily</i> energy generated:<br />
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<a href="https://1.bp.blogspot.com/-feFOx-CvJCg/V9ZK73FZysI/AAAAAAAABsM/xnoZ6UIoSgYk8JoC2NUFNhDZ09Ulpr4WQCLcB/s1600/DailySolarEnergy.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://1.bp.blogspot.com/-feFOx-CvJCg/V9ZK73FZysI/AAAAAAAABsM/xnoZ6UIoSgYk8JoC2NUFNhDZ09Ulpr4WQCLcB/s1600/DailySolarEnergy.png" /></a></div>
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The energy output on sunny days varied only a little with the seasons, and was actually lowest in the summer. But summer days in northern Utah are <i>consistently</i> sunny, whereas a full day of sunshine can be uncommon in mid-winter. Incidentally, my best day of all was February 23 (6.7 kWh), while my worst day was January 30 (0.0 kWh, because it snowed throughout the day).<br />
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Although the seasonal variations among sunny days are relatively small, they’re still interesting. The output drops off in mid-winter because the days are shorter, and also because the mountains block the early morning sunlight. On the other hand, the output drops off in the summer because of the steep angle of my roof. The panels face the noon sun almost directly throughout the fall and winter, but they face about 37 degrees too low for the mid-summer noon sun, reducing the amount of solar power they receive by about 20% (because the cosine of 37° is 0.8). The following plot shows all these effects:<br />
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<a href="https://1.bp.blogspot.com/-PjKuBoBVL8M/V9ZLNuy5W8I/AAAAAAAABsQ/LLR4R-gPCsQZRW4xbgkkQf9qyB8enw6agCLcB/s1600/SunnyDaysDifferentSeasons.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://1.bp.blogspot.com/-PjKuBoBVL8M/V9ZLNuy5W8I/AAAAAAAABsQ/LLR4R-gPCsQZRW4xbgkkQf9qyB8enw6agCLcB/s1600/SunnyDaysDifferentSeasons.png" /></a></div>
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Notice that the vertical axis on this plot is <i>power</i>, or the <i>rate</i> of energy production. To get the total energy generated you need to multiply the power by the time elapsed, which is equivalent to calculating the area under the graph. As you can see, the June graph is lowest at mid-day but extends farther into the early morning and late afternoon, while the December graph is highest but narrowest. The total energy (area) is largest for the March graph. The asymmetry in the December graph, and in the lowest part of the March graph, is from the mountains blocking the rising sun. The smooth “shoulders” on either side come from the shadow of the pointy gable in the middle of my roof.<br />
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With all of these effects in mind, as well as the day-to-day variations in cloud cover, let me now show <i>all</i> of my solar data for the year in a single image. Here the day of the year is plotted from top to bottom, and the time of day from left to right. The power level in watts is represented by color, with brighter colors indicating higher power levels:<br />
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<a href="https://1.bp.blogspot.com/-Hstqyg7G6wg/V9ZLfcbWCrI/AAAAAAAABsU/Qzg5Nntcvo46wSGsuXWld31G9bPeZlMhACLcB/s1600/AllDataMap.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://1.bp.blogspot.com/-Hstqyg7G6wg/V9ZLfcbWCrI/AAAAAAAABsU/Qzg5Nntcvo46wSGsuXWld31G9bPeZlMhACLcB/s1600/AllDataMap.png" /></a></div>
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In the upper-left portion of this image you can more or less see the shape of the mountains, with a reflection at the winter solstice. The dark stripes are cloudy days, with the exception of a power outage during the wind storm of May 1 (that’s right—a standard grid-connected photovoltaic system produces no power when the grid goes out). Subtle astronomical effects cause some further asymmetries from which, with enough analysis, you could probably extract the shape of the <a href="https://en.wikipedia.org/wiki/Analemma">analemma</a>.<br />
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Details aside, the big picture is that the steepness of my roof is almost ideal for the winter months. It even ensures that snow slides off the panels as soon as the sun comes out. But the steep angle hurts my solar production more in the summer than it helps in the winter, mostly because so many winter days are cloudy anyway.<br />
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<a href="https://1.bp.blogspot.com/-bLq63hkXAu8/V9cDlgQlFKI/AAAAAAAABtc/oJyV_6gucrQCuHjHMx0Nb_mOfW7zKk8OgCLcB/s1600/MorningAfterSnowSmaller.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="306" src="https://1.bp.blogspot.com/-bLq63hkXAu8/V9cDlgQlFKI/AAAAAAAABtc/oJyV_6gucrQCuHjHMx0Nb_mOfW7zKk8OgCLcB/s400/MorningAfterSnowSmaller.jpg" width="400" /></a></div>
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<b>Effect of temperature</b><br />
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Looking back at the previous graph for the three sunny days in different seasons, you might have noticed that the noon power level drops from winter to summer by <i>more</i> than the 20% predicted by the solar geometry. The discrepancy on any particular day could be due to variable amounts of haze, but there’s another important effect: temperature.<br />
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To isolate the effect of temperature, I took the noon power level for every day of the year and divided it by the (approximate) cosine-theta geometrical factor to get what the power would have been if the panels were directly facing the sun. Then I plotted this adjusted power level vs. the ambient temperature (obtained from Ogden-area weather reports) to get the following graph:<br />
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<a href="https://4.bp.blogspot.com/-Re6r6wIEBSM/V9ZL3tnyJQI/AAAAAAAABsY/ULVTu0KUfHYQGo1SkJicov2VFGyOq_tqwCLcB/s1600/TemperatureDependence.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://4.bp.blogspot.com/-Re6r6wIEBSM/V9ZL3tnyJQI/AAAAAAAABsY/ULVTu0KUfHYQGo1SkJicov2VFGyOq_tqwCLcB/s1600/TemperatureDependence.png" /></a></div>
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The data points cluster along a line or curve with a negative slope, confirming that the panels produce less power at higher temperatures. Very roughly, it appears that the power output is about 15% less at 90°F than at 20°F. For comparison, the <a href="http://www.solarworld-usa.com/technical-downloads/datasheets#Sunmodule_Plus_&_Protect">data sheet</a> for the solar panels indicates that the power should drop by 0.43% for each temperature increase of 1 degree Celsius, or about 17% for an increase of 70°F. But this specification is in terms of the temperature of the <i>panels</i>, which I wouldn’t expect to vary by the same amount as the ambient temperature.<br />
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(In the preceding plot, the outlying data points below the cluster are from days when clouds reduced the solar intensity; most such points lie below the range shown in the graph. I’m pretty sure that the outliers above the cluster are from partly cloudy days when the panels were getting both direct sunlight and some reflected light from nearby clouds.)<br />
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<b>Electricity usage</b><br />
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Now let’s look at the seasonal variation in my home electricity usage, compared to the solar panels’ output. Here’s a graph of the monthly data, with the solar data now plotted as blue squares and the usage plotted as columns, divided into direct-from-solar usage and from-the-grid usage:<br />
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Unfortunately, my electrical usage peaks in mid-winter, when the solar production is at a minimum! But even during the bulk of the year when the solar production exceeds my total use, well over half of the electricity I use comes off the grid, not off the panels.<br />
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The good news is that I’ve actually reduced my total electricity use by about 15% since the panels were installed. I did this through several small changes: <a href="http://dvschroeder.blogspot.com/2016/08/the-ecobee-smart-thermostat-data-junkie.html">running the furnace less</a> when I was away from home; cooling my house in the summer with a super-efficient <a href="http://dvschroeder.blogspot.com/2016/08/who-needs-air-conditioning.html">whole house fan</a> instead of smaller fans sitting in windows; and unplugging an old computer and a portable “boom box” stereo that were drawing a few watts even when turned off. I’m still using more electricity than I did a decade ago, when I had no home internet service and no hard-wired smoke detectors. But if you look just at what I’m using off the grid, it’s slightly lower even than back in those simpler times. Here’s an updated plot of my average daily usage during every month since I bought my house 18 years ago (as explained more fully in <a href="http://dvschroeder.blogspot.com/2015/05/home-energy-use.html">this article</a> from last year):<br />
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<b>What would it take to live off the grid?</b><br />
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I’ve repeatedly emphasized the electrical energy that I continue to draw from the grid, because I want readers to understand that virtually all of the solar panels being installed these days are <i>part</i> of the electrical grid—not an alternative to it. Even though my panels generate more electrical energy than I use over the course of a year, they will not function without a grid connection and of course they generate no power at all during most of the times when I need it.<br />
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But what would it take to live off the grid entirely? The most common approach is to combine an array of solar panels with a bank of batteries, which store energy for later use when the sun isn’t shining. For example, there’s been a lot of talk recently about the new <a href="https://www.tesla.com/powerwall">Tesla Powerwall battery</a>, which stores 6.4 kWh of energy—enough to power my home for about two days of average use. A Tesla Powerwall sells for $3000, which is somewhat more than the net cost (after tax credits) of my solar panels. If I were to make that further investment, could I cut the cord and live off the grid?<br />
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To answer this question, I combined my daily solar generation data with a data set of nightly readings of my electric meter. (The latter data set is imperfect due to inconsistent reading times, missed readings when I was away, and round-off errors, but day-to-day errors cancel out over longer time periods so it should give the right picture overall.) I then calculated what the charge level of my hypothetical Tesla Powerwall would be at around sunset on each day, and plotted the result:<br />
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For most of the year the battery would hold more than enough energy to get through the nights, but in this simulation there were 42 evenings in the late fall and winter when the level dropped to zero, and several more evenings when it dropped low enough that it would surely be empty by morning. Simply getting a Tesla Powerwall is not enough to enable me, or most other households with solar panels, to disconnect from the grid.<br />
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What if I added a second Tesla battery? Unfortunately, that would reduce the number of zero-charge nights by only eight, from 42 to 34. In fact, it would take <i>thirteen</i> Tesla batteries, in this simulation, to completely eliminate zero-charge nights, because there is a period of a few weeks during mid-winter when the average output of my solar panels is barely over half what I’m using.<br />
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The better solution, therefore, would be to add more solar panels. For example, if I were to double the size of my solar array <i>and</i> install two Tesla Powerwalls, then the simulation predicts that I would run out of electricity just one night during the year. Of course this scenario is still extremely wasteful, because I’d be using less than half the capacity of the panels and only a small fraction of the capacity of the batteries during most of the year. That’s why people who actually live off the grid tend to have backup generators that run on chemical fuels, and don’t rely on electricity for most of their heating or cooking.<br />
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Similar calculations would apply to our society as a whole. A massive investment in both solar panels and batteries could conceivably get us to the point where most of our electricity, for most of the year, is coming from the sun. But it will never be economical to get that “most” up to 100%, because so much over-building would be needed to get through periods of cloudy weather, and it will be much less expensive to use other energy sources at those times.Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com9tag:blogger.com,1999:blog-1233073253115884208.post-67763894948521774102016-08-29T21:03:00.000-06:002016-08-29T21:03:39.264-06:00Who Needs Air Conditioning?As I write these words the temperature outside is 91 degrees Fahrenheit, and the August sun has been beating down on my house for several hours, yet the inside temperature is an extremely comfortable 76.<br />
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That would hardly be remarkable in this day and age, except that my house has no air conditioning. I don’t even have an evaporative (“swamp”) cooler, which is a great alternative to air conditioning in the arid interior West.<br />
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Instead I rely on another benefit of Utah’s low humidity: the nights are almost always quite cool, so I can open windows and run fans to cool off the house at night. Then I shut everything up in the morning as the sun is rising over the mountains, and rely on my house’s thermal inertia to keep it comfortable for most or all of the day.<br />
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Of course, this old-fashioned, low-tech way of keeping cool is technically inferior to the modern method of just leaving the thermostat set at your preferred temperature. For one thing, opening and closing windows is hard work! Also, during the course of a typical summer day and night, while the outdoor temperature swings up and down by 30°F, I experience indoor temperature swings of as much as 15°F. Here’s some data (logged by my <a href="http://dvschroeder.blogspot.com/2016/08/the-ecobee-smart-thermostat-data-junkie.html">smart thermostat</a>) from a recent two-week period:<br />
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The indoor temperature swings mean that I might need to wear a sweatshirt in the early morning, take it off after a couple of hours, and perhaps sit in front of a small fan on the hottest late afternoons, when it climbs above 85°F. When I go to bed at night I rarely want more than a sheet over me, but after a few hours, as the house continues to cool, I usually reach for the blankets.<br />
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Maybe I’m a fanatic for happily enduring these needless, though minor, discomforts. But I can honestly say that a bit of discomfort makes me feel much more alive and connected to the surrounding world—in the same way as riding a bicycle instead of driving a car. As the late, great Tom Magliozzi <a href="http://www.cartalk.com/blogs/staff-blog/quotable-tom-magliozzi">said</a>, “I mean, before you know it, you're going to spend plenty of time sealed up in a box anyway, right?”<br />
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And, of course, using windows and fans for “air conditioning” saves massive amounts of energy, greenhouse gas emissions, and money.<br />
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“But wait!,” you ask, “Don’t you have solar panels on your roof?” <a href="http://dvschroeder.blogspot.com/2015/09/solar-system-installation.html">Indeed I do</a>, but I would need at least twice as many of them to offset the electricity needed by a modest central air conditioning system in regular use. Also, there’s a time lag of several hours between peak solar generation (high noon) and peak air conditioner use (late afternoon), so solar panels by themselves cannot meet all of America’s air conditioning demand. Yes, we could envision massively expensive battery storage systems, but it’s vastly more practical, at least here in Utah, to just <a href="http://www.mrmoneymustache.com/2011/07/18/how-not-to-use-your-air-conditioning/">forgo the technology and open the windows at night</a>.<br />
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Let me say a bit more about fans. Until this summer my arsenal included a basic 12-inch oscillating fan, which I typically placed on a bedroom windowsill at night, and a similarly inexpensive plastic window fan, containing two 7-inch fan units, which I typically placed in the kitchen window. At their highest speeds these fans use 40 and 110 watts, respectively, and they do a pretty good, but not great, job of cooling off the house. The window fan is pretty noisy, so I would usually close a door between it and the bedroom.<br />
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<span style="text-align: center;">In June, however, I invested some money in a </span><i style="text-align: center;">major</i><span style="text-align: center;"> upgrade: an </span><a href="http://www.airscapefans.com/products/Shop/Natural-Cooling/Whole-House-Fans/AirScape-2.5e-Whole-House-Fan" style="text-align: center;">AirScape 2.5e whole house fan</a><span style="text-align: center;">.</span><br />
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A whole house fan is mounted in the attic above a hole in the ceiling, so it pulls air upward into the attic from the living space while pushing the hot air out of the attic. You run it only at night, with your windows open, so cool air can come in the windows to replace the air pulled upward by the fan. You can choose which room(s) to cool off most quickly, simply by choosing which window(s) to open.<br />
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Some whole house fans can be awfully loud, but AirScape is the Rolls Royce of whole house fan manufacturers, and the model 2.5e is extremely quiet—especially toward the lower range of its five speed settings. The fan itself is suspended from chains a few feet above the attic floor, at the end of a seven-foot flexible duct that provides acoustic isolation. At the other end of the duct, immediately above the opening in the ceiling, is a box containing motorized damper doors. Here are some photos of the installed fan in the attic, the view looking up at the ceiling and the damper doors, and the wall switch (mounted next to my <a href="http://dvschroeder.blogspot.com/2016/08/the-ecobee-smart-thermostat-data-junkie.html">Ecobee thermostat</a>):<br />
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The motorized damper doors, in place of a simpler and less expensive back-draft damper, provide good insulation when closed and allow the fan to run at very low speeds, producing only the gentlest breeze. I usually run my fan all night long, choosing the speed based on how hot the house has gotten by evening.<br />
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The AirScape 2.5e is also extremely efficient: it draws only 25 watts on the lowest setting, and 200 watts on the highest (which I rarely use). Even on the lowest setting it’s about as effective as my two old inexpensive fans, which together use 150 watts and make much more noise. For comparison, a small central air conditioning system would use about 2500 watts while running.<br />
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As if the motorized damper doors aren’t already fancy enough, these AirScape fans can now also be connected to your home network router and then controlled through a smartphone app. This technological sophistication seems a little excessive to me, but the app, unlike the wall switch, tells you the current speed setting and even displays the attic temperature. You can only use it from home—not over the internet—but there would be little point to controlling it remotely unless you also had remote-control windows. Actually I wish AirScape would make a lower-tech damper assembly that you just open and close by hand with a lever, avoiding the complication and expense of all the electronics. This would also eliminate the continuous 8-watt electrical power draw from the electronics, even when the fan is turned off. (To avoid this small energy waste I’ll switch the fan off at the circuit breaker at the end of the summer.)<br />
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Of course, Rolls Royces don’t come cheap. With shipping I paid a little over $1500 for my AirScape 2.5e, and then I paid <a href="http://www.burrowsheating.net/">my favorite local HVAC contractor</a> a few hundred dollars more to install it. Even so, it cost less than any central air conditioning system I’ve ever heard of—and you could easily install the fan yourself if you have a helper and the right tools. But I don’t mind spending this money on a long-term improvement to my home, especially when I’m supporting a good company that makes such a useful product. AirScape fans are designed and made in Medford, Oregon.<br />
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Not every house is suitable for a whole house fan. It won’t be nearly as effective in a location where summer nights are warm. Your attic must be well ventilated, so the fan can push the air out (see the <a href="http://www.airscapefans.com/system-builder/attic-vent.php">AirScape web site</a> for detailed ventilation requirements). And for ducted models like the 2.5e, you need a reasonable amount of vertical space in the attic. But if your house meets these criteria and you have the money to invest, then I highly recommend this elegant alternative to air conditioning.Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com0tag:blogger.com,1999:blog-1233073253115884208.post-14608368414973698052016-08-28T01:35:00.000-06:002019-07-06T11:50:23.562-06:00The Ecobee Smart Thermostat: A Data Junkie’s Dream<a href="https://1.bp.blogspot.com/-mLXg340yuEQ/V8KClI9bquI/AAAAAAAABoI/DLDRUdczg5cQ1wjo_-kpB7qpu9jNkNaRwCLcB/s1600/EcobeePhoto.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="200" src="https://1.bp.blogspot.com/-mLXg340yuEQ/V8KClI9bquI/AAAAAAAABoI/DLDRUdczg5cQ1wjo_-kpB7qpu9jNkNaRwCLcB/s200/EcobeePhoto.jpg" width="182" /></a>In an attempt to reduce my <a href="http://dvschroeder.blogspot.com/2015/05/home-energy-use.html">heating bills and carbon footprint</a>, last September I installed an <a href="https://www.ecobee.com/">Ecobee 3 smart thermostat</a>.<br />
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Now, after using it through a full heating season and analyzing the results, I can report that it accomplished everything I hoped.<br />
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Should you buy one too? That depends.<br />
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<b>Why the Ecobee?</b><br />
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The idea behind a “smart” thermostat is to gather a whole bunch of data (past temperatures and settings, furnace and AC run times, outdoor weather, and times when you’re home and awake), then use this data to anticipate your heating and cooling needs and to keep you comfortable, automatically, without wasting energy. If you want a thermostat that does this then you can consult any number of <a href="https://www.google.com/?ion=1&espv=2#q=smart+thermostat+reviews">online reviews</a> for advice.<br />
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I <i>don’t</i> want my thermostat to set itself automatically. I’m fully capable of setting it myself, thank you very much, and I stubbornly cling to the notion that I’m still smarter than any thermostat.<br />
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But I decided to get a smart thermostat anyway, because I wanted the ability to remotely monitor the temperature in my house over the internet, and to remotely adjust the setting from time to time. Also, I wanted to get my hands on all that data. As usual, I take my mantra from <a href="http://www.mrmoneymustache.com/2015/03/25/cut-your-power-bill/">Mr. Money Mustache</a>: <i>Measure everything, then get angry at waste!</i><br />
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The most popular smart thermostat is the <a href="https://nest.com/thermostat/meet-nest-thermostat/">Nest</a>, but for my purpose it has a fatal flaw: They don’t let you download the data! You can view some daily summary data over the internet, and they send you monthly summaries by email, but the manufacturer has decided that you’re not even allowed to see the full minute-by-minute temperature and operation data, much less download it.<br />
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The Ecobee folks, on the other hand, treat their customers with respect. Through their web interface you can view a detailed chart of what’s happening in your house, and with a few clicks you can download the data as a CSV file for analysis in a spreadsheet or other software.<br />
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That feature was enough to earn my business, so I went ahead and ordered an Ecobee, directly from the manufacturer. The price was $249, but I got a $100 <a href="http://www.thermwise.com/home/ApplianceRebates.php">rebate</a> from my gas company. Installation was easy, although there can be complications depending on how your existing system is wired. With a couple of taps on the touch screen I configured it for fully manual operation.<br />
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My house has no air conditioning, so during the summer I use the Ecobee only as a remote-monitoring and data-logging device. It does, of course, use some electricity to accomplish these things: about 7 watts of continuous power, which adds up to 60 kilowatt-hours (about $6 worth here in Utah) of electrical energy per year. It also requires a continuously operating internet connection and wifi router.<br />
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One unique feature of the Ecobee 3 is that it comes with a wireless, battery-powered external sensor that you can use to monitor the temperature in another room, away from the thermostat. Their advertising suggests that this is almost as good as being able to heat different parts of your house independently, but of course that’s not the case; you merely have the flexibility to <i>control</i> the heat based on the temperature at one or another location. I put the external sensor in my basement laundry room, so I could make sure the pipes wouldn’t freeze when I was away during the winter. (Being a data junkie, I eventually purchased two more external sensors, for another $79, so I could also monitor the temperature in my living room and bedroom.)<br />
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<b>How I cut my gas use by 35% [see update below]</b><br />
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As it turned out, that external sensor in the basement is what saved me the most money. I was away from home quite a bit during the winter of 2015-16, and at those times I aggressively set the thermostat down, letting the temperature drop to 48 F upstairs and 40 F in the basement. Without the sensor next to the water pipes, and the ability to remotely monitor it and make adjustments if needed, I never would have taken the risk of turning the thermostat so low.<br />
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To put my savings in perspective, here’s a plot of my annual natural gas use ever since I bought my house in 1998:<br />
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The total for 2015-16 was 18.4 decatherms (MBtu), or 35% less than my average use from 2004 through 2015. When you consider that some of that (about 4 decatherms, I think) is for my hot water heater, the reduction is even more impressive. Gas is cheap here in Utah—about $8 per decatherm—so I saved only about $80 over the season, and it’ll take another year before the thermostat nominally pays for itself. On the other hand, not all of the reduction was a direct effect of the smart thermostat: my motivation to save energy was probably at an all-time high, and it’s possible that the winter was a little warmer than average [see update below].<br />
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<b>Getting the detailed data</b><br />
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And what about the detailed thermostat data? Here, to start with, is a screen capture showing what you can view through the Ecobee web interface:<br />
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The orange graph is the thermostat setting; the white graph is the temperature at the thermostat; the green graph is the outdoor temperature (obtained from public weather data for my local area, so it’s not literally the temperature right outside my house); and the orange bands at the top show when the furnace was running. On this particular day I kept the thermostat at 64 degrees when I was home, but set it down to 58 when I was at work. The furnace cycled on and off seven times between midnight and 8 am, didn’t run at all while I was away, ran for more than a half hour to warm the house up when I returned, and then cycled on and off four more times before midnight.<br />
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This web interface to the data is a wonderful thing, but I find it a little clunky and hope they’ll make some improvements in the future. Although you can scroll through the entire time period since your thermostat was installed, you can’t zoom out to view more than 24 hours of data at a time. Updating the graph with new incoming data requires multiple clicks and a delay of about 10 seconds. The graph always omits the most recent hour or so, and it won’t show the separate data from all your sensors, even though you can view all the current readings on a different web page.<br />
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To get a more comprehensive picture you need to download the data and plot it up yourself. Fortunately, the download process is easy and fast. As I mentioned above, you get a CSV file that you can open in a spreadsheet. The file contains a row for every five-minute time interval, and each row contains 20 or more data fields: date, time, thermostat settings, heating/AC/fan activity, outdoor temperature and wind speed, and, for the thermostat itself and each external sensor, the temperature and whether the motion detector was activated. You can download up to a month’s worth of data (more than 8000 rows) at a time.<br />
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The ways of plotting up all this data are endless. Here, for example, is a plot of my temperature data for the month of July. Can you guess which week I was out of town?<br />
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<a href="https://4.bp.blogspot.com/-g1hc8Azoo5w/V8KELa_RU6I/AAAAAAAABoc/ZV5T0vXsbLwUm-1VBttKA6ghiFcg8mfgACLcB/s1600/JulyTemperaturePlot.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://4.bp.blogspot.com/-g1hc8Azoo5w/V8KELa_RU6I/AAAAAAAABoc/ZV5T0vXsbLwUm-1VBttKA6ghiFcg8mfgACLcB/s1600/JulyTemperaturePlot.png" /></a></div>
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<b>Thermal properties of my house</b><br />
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One of my goals in obtaining all this data was to measure the thermal properties of my house. To do this I focused on the six-month heating season from November through April, and selected eight-hour-long periods at night (to avoid solar heating) when either the furnace was holding the indoor temperature steady, or the furnace didn’t run at all. (I didn’t use data from nights when neither of these conditions was met for eight consecutive hours.)<br />
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Working with the steady-temperature data, I used the furnace running time to calculate the rate at which the furnace had to supply heat to the house, to maintain the steady temperature. To calculate the heat rate I had to know that the furnace is rated to use 75,000 Btu per hour, at an efficiency of 92%; I’ve checked the Btu/hr value by reading my gas meter, but I have no good way to check the efficiency. Here is a plot showing the heating rate as a function of the average temperature difference between inside and outside:<br />
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<a href="https://2.bp.blogspot.com/-6yJ-Qq-mdT4/V8KMsM9bwfI/AAAAAAAABpA/VoUpKebgY1sli3PELxnoY7JhyiV1bRFIQCLcB/s1600/HeatRateVsTempDiff.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://2.bp.blogspot.com/-6yJ-Qq-mdT4/V8KMsM9bwfI/AAAAAAAABpA/VoUpKebgY1sli3PELxnoY7JhyiV1bRFIQCLcB/s1600/HeatRateVsTempDiff.png" /></a></div>
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You can immediately see from this plot that my 75,000 Btu/hr furnace (69,000 Btu/hr when you factor in the 92% efficiency) is much more powerful than necessary. Even on the coldest nights it needed to put out only about 14,000 Btu/hr to maintain a steady indoor temperature, so it was running only about one fifth of the time. Extrapolating, I conclude that my furnace could maintain a steady indoor temperature even if the outdoor temperature were as much as 200 degrees lower than indoors! How’s that for over-engineering?<br />
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A linear fit to the plotted data gives a slope of approximately 344 Btu per hour per degree Fahrenheit, meaning that for each additional degree in the temperature difference, the furnace had to supply additional heat at a rate of 344 Btu/hr. Of course that heat must also be escaping from the house (through the walls, windows, ceiling, and foundation) at the same rate, because the indoor temperature wasn’t changing. The value 344 Btu/hr/°F is therefore what is called the thermal <i>conductance</i> of the exterior envelope of my house.<br />
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There’s quite a bit of scatter in the data, so this measured conductance is somewhat uncertain. The standard error in the best-fit slope is only 6.4%, but when I plot subsets of the data (chosen by time of year or thermostat setting) I get a much wider range of values, so I would put the uncertainty very roughly at 20%.<br />
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You can also see from the plot that a best-fit line does not go through the origin; in fact the vertical intercept is at −2800 Btu/hr, with a rather large uncertainty (perhaps 40%). This means that on a typical winter night, heat from some other source must be entering my house at a rate of roughly 2800 Btu/hr, or about 800 watts. Some of that is from the refrigerator, electric blanket, and human bodies, but after slicing and dicing the data I’m convinced that there’s also a contribution from underground heat coming in through the basement floor and foundation.<br />
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<a href="https://4.bp.blogspot.com/-lcDs32mqegA/V8KNj-EIoqI/AAAAAAAABpI/sQ-wYLAYzYIIijwOjlXiF9UUAAhesF1gACLcB/s1600/ConductancePieChart.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="https://4.bp.blogspot.com/-lcDs32mqegA/V8KNj-EIoqI/AAAAAAAABpI/sQ-wYLAYzYIIijwOjlXiF9UUAAhesF1gACLcB/s1600/ConductancePieChart.png" /></a></div>
In principle, you can calculate the thermal conductance of a house without making any temperature measurements at all. You just need to know the sizes and thermal conductivities (R values) of the components of the exterior envelope. Add the R values for each layer of a given component (e.g., plaster, wood, brick, and air films for my uninsulated walls), then divide this total R value into the surface area to get that component’s contribution to the conductance. I had never before done this calculation for my house, because there’s a lot of guess-work involved and I had no good way to check the answer. But now I have done the calculation, and amazingly, I obtained a total conductance of 374 Btu/hr/°F, within ten percent of the measured value! The pie chart shows a breakdown of how each major component of my house’s envelope contributes to this calculated total.<br />
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The ceiling contribution is small because it’s the only place where my 81-year-old house has at least a little bit of insulation. Of course, these fractional contributions could still be pretty inaccurate. But I now have enough confidence in my calculations to start considering whether I should try to add insulation to my exterior walls and foundation.<br />
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By the way, people sometimes say that homeowners should focus on air infiltration as a major source of heat loss. That may be true for some homes, but I’ve always been skeptical in my own case. My calculations justify this skepticism because I was able to account for <i>more</i> than 100% of my house’s measured heat loss through conductance estimates alone, completely ignoring infiltration.<br />
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Meanwhile, as mentioned above, I’ve also looked at data from winter nights when the furnace didn’t run at all—so the indoor temperature dropped steadily. Here is a plot of the rate of temperature decrease as a function of the average temperature difference between inside and outside:<br />
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<a href="https://4.bp.blogspot.com/-AwpaBh54b6Y/V8KRKdHB6CI/AAAAAAAABpg/4MCnz8htXKAcggrq3nw8uBTXTeo-H8bGACLcB/s1600/CoolingRateVsTempDiff.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://4.bp.blogspot.com/-AwpaBh54b6Y/V8KRKdHB6CI/AAAAAAAABpg/4MCnz8htXKAcggrq3nw8uBTXTeo-H8bGACLcB/s1600/CoolingRateVsTempDiff.png" /></a></div>
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The slope of this graph is minus the thermal conductance divided by the effective heat capacity of the interior of my house. (So a high thermal conductance makes the graph steeper, because heat escapes faster, while a high heat capacity makes it shallower, because there’s more energy that needs to escape in order for the temperature to drop by a given amount.) The best-fit slope is −0.023 degrees per hour, per degree (or simply inverse hours if you prefer). Dividing this into the previously measured conductance of 344 Btu/hr/°F gives a heat capacity of approximately 15,000 Btu/°F. That’s equivalent to the heat capacity of 15,000 pints of water, or 1800 gallons, or enough to fill my bathtub up to the brim 26 times. So filling the bathtub wouldn’t make much of a dent in the total heat capacity!<br />
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An alternative way to estimate the heat capacity is simply to measure how long it takes the furnace to warm the house up after adjusting the thermostat upward. For example, on one winter evening it took my furnace two hours to warm the house by 14 degrees Fahrenheit. The furnace supplied 138,000 Btu of heat over that time, so the estimated heat capacity would be (138,000 Btu)/(14°F) = 10,000 Btu/°F. The effective heat capacity is smaller over this relatively short time period, because less of the house is actually being warmed up by the full amount.<br />
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In principle I could try to calculate a theoretical heat capacity, by adding up all the contributions of the materials and contents of my house. It would be interesting to know roughly what percentage comes from wood, plaster, concrete, and so on. But making reasonably accurate estimates would be quite a bit of work, so I’ll put that off to another day.<br />
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The more useful thing to know is that even on a very cold night (bottom-right corner of the graph), my house cools down at a rate of less than a degree Fahrenheit per hour. This means that setting the thermostat down for, say, eight hours at a time saves only a small amount of energy, because the <i>average</i> indoor temperature over that time will be no more than two or three degrees lower. This average drop is what matters, because it determines how much less heat the house loses to the outdoors—and therefore how much less heat the furnace must replace. Any further energy savings from not running the furnace during this time will be offset when you run it to heat the house back up afterwards. (You can see all this vividly in the screen-capture image above.)<br />
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So how did I save huge amounts of energy, cutting my gas bill by 35%? Partly by setting the thermostat somewhat lower even when I was home, but mostly by setting it way down when I was away for 24 hours at a time or longer. If your house is never unoccupied for more than half a day at a time, then you shouldn’t expect dramatic winter energy savings from a smart thermostat. Summer might be another matter if you use air conditioning, but I wouldn’t know. And if you own a vacation home that’s unoccupied for half the winter, then install a smart thermostat in it immediately!<br />
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<b>Update, July 2019</b><br />
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Honesty compels me to report that over the last three years I’ve failed to keep my gas use as low as it was during 2015-16. Here is an updated chart:<br />
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<a href="https://1.bp.blogspot.com/-G_N2iYOVW0U/XSDSL3vsP5I/AAAAAAAACN0/DwNf_2OQnlgT6BIiALgFYF2o6eBLBZ0kQCLcBGAs/s1600/AnnualGasUseChart2019.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="347" data-original-width="600" src="https://1.bp.blogspot.com/-G_N2iYOVW0U/XSDSL3vsP5I/AAAAAAAACN0/DwNf_2OQnlgT6BIiALgFYF2o6eBLBZ0kQCLcBGAs/s1600/AnnualGasUseChart2019.png" /></a></div>
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Over these last three years my annual gas use has averaged 23.6 decatherms, which is only 16% less (not 35% less!) than the average from 2004 through 2015 (before I installed the Ecobee thermostat). The most recent winter was the coldest of these three, so I’m not too worried about a continuing upward trend in gas use as the chart might suggest. Instead I think I’ve reached a new normal, after the anomalous one-time low during 2015-16.<br />
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The direct carbon emissions from burning 23.6 decatherms of natural gas come to 1.25 metric tons (2760 pounds), so this contribution to my personal carbon footprint is somewhat larger than any one of the contributions from <a href="http://dvschroeder.blogspot.com/2015/05/home-energy-use.html">electricity</a> <a href="http://dvschroeder.blogspot.com/2016/09/a-year-of-solar-data.html">use</a>, <a href="http://dvschroeder.blogspot.com/2019/05/five-years-of-driving.html">driving</a>, or <a href="http://dvschroeder.blogspot.com/2015/06/air-travel.html">flying</a>.<br />
<br />Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com8tag:blogger.com,1999:blog-1233073253115884208.post-69953238083920047782016-03-17T06:25:00.000-06:002016-03-17T06:33:54.835-06:00Ivory Tower<a href="https://4.bp.blogspot.com/-IQDl8IH6bjs/Vuqh_uKhWXI/AAAAAAAABl0/ywQljiZ-sIwGPnLie7JYUVP5aF4zQE3Qg/s1600/Ivory_Tower_poster.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="https://4.bp.blogspot.com/-IQDl8IH6bjs/Vuqh_uKhWXI/AAAAAAAABl0/ywQljiZ-sIwGPnLie7JYUVP5aF4zQE3Qg/s1600/Ivory_Tower_poster.jpg" /></a>Thanks to the <a href="http://www.utahfilmcenter.org/">Utah Film Center</a> and all its generous supporters, I just saw a free screening of <a href="https://en.wikipedia.org/wiki/Ivory_Tower_(2014_film)">Ivory Tower</a>, the 2014 documentary about the problems facing American higher education.<br />
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For the most part I thought the film was excellent. It focused on the crisis of <a href="http://dvschroeder.blogspot.com/2015/08/why-cost-of-college-has-tripled.html">rising tuition</a> and student loan debt, and touched on most of the reasons why this crisis has arisen: growing enrollments, shrinking state subsidies, and increased overhead costs for <a href="http://www.washingtonmonthly.com/magazine/septemberoctober_2011/features/administrators_ate_my_tuition031641.php?page=all">bloated administrations</a> and <a href="https://www.insidehighered.com/news/2015/06/15/are-lazy-rivers-and-climbing-walls-driving-cost-college">frivolous amenities</a>. The film also explored a variety of innovative variations on higher education, ranging from massive open online courses to the tiny <a href="https://en.wikipedia.org/wiki/Deep_Springs_College">Deep Springs College</a>. It came down heavily against impersonal, one-size-fits-all solutions, and emphasized the importance of one-on-one human interaction.<br />
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The film fell short, though, in its inadequate attention to profit motives. It didn’t even mention the for-profit college sector, which has played a <a href="https://www.insidehighered.com/news/2015/09/11/study-finds-profit-colleges-drove-spike-student-loan-defaults">disproportionate role</a> in the student debt crisis. It seemed to blame the federal government for pushing loans on students, when in fact it’s private banks and investors who are profiting from those loans. And although it highlighted the for-profit MOOC startups Udacity and Coursera (and the much-publicized <a href="http://www.npr.org/2013/12/31/258420151/the-online-education-revolution-drifts-off-course">collaboration</a> between Udacity and San Jose State University), it failed to mention the lower-profile infiltration of software for <a href="http://www.slate.com/articles/life/education/2014/09/online_college_classes_textbook_companies_offer_courses_with_minimal_university.html">canned courses</a> that’s coming from traditional textbook publishers.<br />
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To get to the bottom of a scandal, you need to <a href="https://en.wikipedia.org/wiki/Follow_the_money">follow the money</a>.Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com3tag:blogger.com,1999:blog-1233073253115884208.post-26510168880588933682015-12-12T21:42:00.000-07:002016-01-02T11:58:08.708-07:00Textbook Price Pandemonium<div>
Physics textbook prices have gotten crazier than ever. Just look:<br />
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<table cellpadding="1" cellspacing="0" style="border-collapse: collapse; margin-left: auto; margin-right: auto;">
<tbody>
<tr>
<th style="border-bottom: 1px solid black; text-align: left;">Author</th>
<th style="border-bottom: 1px solid black; text-align: left;">Subject</th>
<th style="border-bottom: 1px solid black; text-align: left;">Publisher</th>
<th style="border-bottom: 1px solid black;">List price</th>
</tr>
<tr><td>Serway</td><td>Modern physics</td><td>Cengage</td><td style="text-align: right;">$368.95</td></tr>
<tr><td>Thornton and Rex</td><td>Modern physics</td><td>Cengage</td><td style="text-align: right;">$355.95</td></tr>
<tr><td>Tipler and Llewellyn</td><td>Modern physics</td><td>Macmillan</td><td style="text-align: right;">$182.99</td></tr>
<tr><td>Ohanian</td><td>Modern physics</td><td>Pearson</td><td style="text-align: right;">$179.00</td></tr>
<tr><td>Taylor et al.</td><td>Modern physics</td><td>Univ. Sci. Books </td><td style="text-align: right;">$98.50</td></tr>
<tr><td style="padding-top: 12px;">Fowles and Cassiday</td><td style="padding-top: 12px;">Mechanics</td><td style="padding-top: 12px;">Cengage</td><td style="padding-top: 12px; text-align: right;">$404.95</td></tr>
<tr><td>Marion and Thornton</td><td>Mechanics</td><td>Cengage</td><td style="text-align: right;">$401.95</td></tr>
<tr><td>Hamill</td><td>Mechanics</td><td>Jones & Bartlett</td><td style="text-align: right;">$303.95</td></tr>
<tr><td>Taylor</td><td>Mechanics</td><td>Univ. Sci. Books</td><td style="text-align: right;">$124.50</td></tr>
<tr><td style="padding-top: 12px;">Wangsness</td><td style="padding-top: 12px;">Electrodynamics</td><td style="padding-top: 12px;">Wiley</td><td style="padding-top: 12px; text-align: right;">$205.95</td></tr>
<tr><td>Griffiths</td><td>Electrodynamics</td><td>Pearson</td><td style="text-align: right;">$174.60</td></tr>
<tr><td>Ohanian</td><td>Electrodynamics</td><td>Jones & Bartlett</td><td style="text-align: right;">$164.95</td></tr>
<tr><td>Cook</td><td>Electrodynamics</td><td>Dover</td><td style="text-align: right;">$34.95</td></tr>
<tr><td style="padding-top: 12px;">Gasiorowicz</td><td style="padding-top: 12px;">Quantum mechanics </td><td style="padding-top: 12px;">Wiley</td><td style="padding-top: 12px; text-align: right;">$224.95</td></tr>
<tr><td>Griffiths</td><td>Quantum mechanics</td><td>Pearson</td><td style="text-align: right;">$193.20</td></tr>
<tr><td>McIntyre</td><td>Quantum mechanics</td><td>Pearson</td><td style="text-align: right;">$135.20</td></tr>
<tr><td>Townsend</td><td>Quantum mechanics</td><td>Univ. Sci. Books</td><td style="text-align: right;">$98.50</td></tr>
<tr><td>Beck</td><td>Quantum mechanics</td><td>Oxford</td><td style="text-align: right;">$89.00</td></tr>
<tr><td style="padding-top: 12px;">Carter</td><td style="padding-top: 12px;">Thermal physics</td><td style="padding-top: 12px;">Pearson</td><td style="padding-top: 12px; text-align: right;">$187.20</td></tr>
<tr><td>Kittel and Kroemer</td><td>Thermal physics</td><td>Macmillan</td><td style="text-align: right;">$154.50</td></tr>
<tr><td>Reif</td><td>Thermal physics</td><td>Waveland Press</td><td style="text-align: right;">$111.95</td></tr>
<tr><td>Baierlein</td><td>Thermal physics</td><td>Cambridge</td><td style="text-align: right;">$105.00</td></tr>
<tr><td>Schroeder</td><td>Thermal physics</td><td>Pearson</td><td style="text-align: right;">$71.60</td></tr>
<tr><td style="padding-top: 12px;">Hecht</td><td style="padding-top: 12px;">Optics</td><td style="padding-top: 12px;">Pearson</td><td style="padding-top: 12px; text-align: right;">$209.40</td></tr>
<tr><td>Pedrotti et al.</td><td>Optics</td><td>Pearson</td><td style="text-align: right;">$204.40</td></tr>
<tr><td>Guenther</td><td>Optics</td><td>Oxford</td><td style="text-align: right;">$98.50</td></tr>
<tr><td>Peatross and Ware</td><td>Optics</td><td>Lulu/self</td><td style="text-align: right;">$21.30</td></tr>
<tr><td>Fowles</td><td>Optics</td><td>Dover</td><td style="text-align: right;">$19.95</td></tr>
<tr><td style="padding-top: 12px;">Ashcroft and Mermin </td><td style="padding-top: 12px;">Solid state</td><td style="padding-top: 12px;">Cengage</td><td style="padding-top: 12px; text-align: right;">$398.95</td></tr>
<tr><td>Kittel</td><td>Solid state</td><td>Wiley</td><td style="text-align: right;">$203.95</td></tr>
<tr><td>Snoke</td><td>Solid state</td><td>Pearson</td><td style="text-align: right;">$165.20</td></tr>
<tr><td>Myers</td><td>Solid state</td><td>Taylor & Francis</td><td style="text-align: right;">$87.95</td></tr>
</tbody></table>
<div>
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Here I’ve tried to list a representative sample of textbooks, including the most popular ones, for seven standard physics courses at the sophomore through senior level. The list prices came from the publishers’ web sites, accessed during November and December 2015. To see a more complete list, <a href="https://docs.google.com/spreadsheets/d/1--Gs54yREqxm1guqsG3iYL0gfBxeVS0Zs_PRp_1pPWQ/edit?usp=sharing">click here</a>.</div>
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How did the average price of such books climb to nearly $200? And what are we to make of the fact that Cengage now gouges students for $350 to $400 per book, even while other publishers sell competing books for under $100?</div>
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Nearly 18 years ago I wrote a <a href="http://physics.weber.edu/schroeder/bookprices.html">web article</a> about physics textbook prices, showing how they generally tracked inflation from 1960 through the early 1980s but then began rising steadily, outpacing inflation by about 50% by 1998. At that time there was much less variation in prices, and the average price for books at this level was about $80. But the <a href="http://data.bls.gov/cgi-bin/cpicalc.pl">cost of living</a> in the U.S. has increased by nearly 50% since then, so in today’s dollars the 1998 average would be about $120. Before 1985 the average price, in today’s dollars, was about $75. So on average, after inflation, these types of textbooks now cost about two and a half times what they did 30 (or 50) years ago. </div>
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I won’t repeat every explanation I offered in that earlier article, or in a <a href="http://dvschroeder.blogspot.com/2010/08/textbook-prices.html">more recent post</a> on this blog, but the most important factor behind high textbook prices hasn’t changed: The people <i>buying</i> the books (students) aren’t the same as the people <i>choosing</i> the books (professors). This system effectively eliminates most of the price competition you would otherwise expect.</div>
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A secondary factor, though, has been the bewildering series of mergers, acquisitions, spin-offs, and rebrandings of the major commercial textbook publishers. Addison-Wesley and Prentice Hall are now Pearson; Freeman is now Macmillan; Saunders, Harcourt Brace, Brooks Cole, and others are now Cengage. And the bigger a publishing company gets, the more separated the corporate decision makers become from the people who are affected by their decisions.</div>
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Meanwhile, the major commercial publishers are devoting more and more resources to frequent revisions of mass-market introductory textbooks and, especially, to the online homework and tutorial systems that accompany these textbooks. Their ultimate goal seems to be to <a href="http://www.slate.com/articles/life/education/2014/09/online_college_classes_textbook_companies_offer_courses_with_minimal_university.html">take over the teaching</a> of these courses entirely, making faculty superfluous.</div>
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But software development is expensive, so such a program is out of the question for courses that enroll under ten thousand students a year nationwide. Publishing textbooks for these smaller markets is really no different from the way it was 30 years ago, but when it happens inside a huge company whose main business is mass-market course materials, the small-market books seem to be taxed to pay for all the overhead.</div>
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Physics textbooks beyond the introductory level have become a mere afterthought for most of the big commercial publishers, and have been completely abandoned by others. McGraw-Hill, once a major publisher of advanced physics textbooks, got out of that business 10 or 15 years ago. Pearson sold the Addison-Wesley Advanced Book Program to Perseus/Westview in the late 1990s, but has remained the dominant publisher of undergraduate and beginning graduate texts; yet despite this success, it is now telling authors that it will no longer publish any new upper-division physics titles. Wiley, as far as I can tell, is the only big commercial publisher that is still whole-heartedly in the upper-division (and beyond) physics textbook business.</div>
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On the other hand, more and more undergraduate textbooks are now being published by the Cambridge, Oxford, and Princeton university presses, and by small publishers like University Science Books. These publishers demonstrate that high-quality textbooks for small-market courses can still be published at about the same (inflation-adjusted) prices as during the 1960s, 70s, and early 80s.</div>
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At still lower prices, Dover has reprinted a few classic undergraduate physics textbooks, to add to its much more extensive collection of classic graduate-level textbooks. And a small but growing number of <a href="http://www.amazon.com/Computational-Physics-Mark-Newman/dp/1480145513">high-quality</a> <a href="http://www.amazon.com/Numerical-Methods-Physics-Alejandro-Garcia/dp/1514136686">textbooks</a> are now being self-published through services like CreateSpace and Lulu.</div>
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Of course it must be pointed out that fewer and fewer students are paying the full list prices for their textbooks. Online retailers typically sell new textbooks at discounts of around 20%, and it’s easier than ever to buy used textbooks at deeper discounts. The lowest prices of all are on international editions that are intended for sale in Asia but, thanks to a <a href="https://en.wikipedia.org/wiki/Kirtsaeng_v._John_Wiley_%26_Sons,_Inc.">2013 Supreme Court decision</a>, legally available in the U.S. Traditionally these editions have been inferior in their print and paper quality, and now Pearson, at least, is also abridging their content to deliberately lower their value.</div>
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Let me end with a few notes regarding some particular books in the list above. <i>Modern Physics</i> by Taylor, Zafiratos, and Dubson was published by Prentice Hall and then Pearson until 2013, when Pearson took it out of print and the authors took it to University Science Books—resulting in a significantly lower price. Similarly, Reif’s <i>Fundamentals of Statistical and Thermal Physics</i> was formerly published by McGraw-Hill but has now found a new lower-overhead home at Waveland Press. Snoke’s <i>Solid State Physics</i> apparently went out of print around the time I was writing this article, because it was available from Pearson when I compiled the list but isn’t any more. The self-published optics textbook by Peatross and Ware, available in hard copy through Lulu, can also be downloaded for free from the <a href="http://optics.byu.edu/textbook.aspx">authors’ web site</a>. And my own book, <i>An Introduction to Thermal Physics</i>, costs much less than Pearson’s other textbooks <a href="http://physics.weber.edu/thermal/production.html">because</a> I did all the typesetting, artwork, and layout myself, and insisted on a clause in our contract to limit the book’s price. I’m now more glad than ever that I did it that way.<br />
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<b>Update, 2 January 2016:</b> Here’s a plot of all the price data in <a href="https://docs.google.com/spreadsheets/d/1--Gs54yREqxm1guqsG3iYL0gfBxeVS0Zs_PRp_1pPWQ/edit?usp=sharing">my spreadsheet</a>, grouped by publisher. This plot not only highlights what an outlier Cengage is, but also shows that there are only four other publishers with multiple books priced above $150. However, this handful of publishers produces some of the most widely used textbooks.<br />
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<a href="http://3.bp.blogspot.com/--ylUbUIx7LI/VogbrhB4f2I/AAAAAAAABko/jmwVInplzSo/s1600/TextbookPricesByPublisherDec2015.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="358" src="http://3.bp.blogspot.com/--ylUbUIx7LI/VogbrhB4f2I/AAAAAAAABko/jmwVInplzSo/s400/TextbookPricesByPublisherDec2015.png" width="400" /></a></div>
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Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com0tag:blogger.com,1999:blog-1233073253115884208.post-19703798470547478862015-10-22T23:53:00.002-06:002015-10-23T09:52:49.101-06:00Solar System: A First Look at the DataMy <a href="http://dvschroeder.blogspot.com/2015/09/solar-system-installation.html">new solar panels</a>, installed two months ago, have been working hard during the beautiful days of late summer and early fall.<br />
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Although the days have gotten shorter, the noon sun faces the panels most directly at this time of year—thanks to my steep roof. I can now report that under a clear sky and direct sunlight, the output of my system is typically about 950 watts. That’s the alternating current coming out of the microinverters, as reported by the monitoring system. For comparison, the nameplate rating on the panels themselves is 280 watts each, or 1120 watts total. I’m not sure how much of the difference between 1120 and 950 is due to atmospheric conditions, and how much is due to the losses in the DC-to-AC conversion.<br />
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To get an idea of the variability of the power output, you can look at the data on the <a href="https://enlighten.enphaseenergy.com/pv/public_systems/pyng712374">Enphase Enlighten site</a>. Here’s a plot of all the data from September on a single horizontal axis (click to enlarge):<br />
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<a href="http://4.bp.blogspot.com/-PjD1x6gZ_uY/VimdTe0_2fI/AAAAAAAABg8/QgWq_217qRs/s1600/SolarMonitorData2015Sep.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="163" src="http://4.bp.blogspot.com/-PjD1x6gZ_uY/VimdTe0_2fI/AAAAAAAABg8/QgWq_217qRs/s400/SolarMonitorData2015Sep.png" width="400" /></a></div>
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This graph shows instantaneous power in watts. To calculate the total energy produced, you need to multiply the power by the time elapsed and then add that up for each time interval (the system records data in five-minute intervals). If the time is expressed in hours, then the energy will be in watt-hours; divide by 1000 to convert to kilowatt-hours (kWh), the power company’s billing unit.<br />
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On my system’s best day so far, September 18, its total energy output was 6.5 kWh. On its worst day, just two days earlier, the output was only 0.3 kWh. Fortunately, I live where the skies are not cloudy all day—at least not very often—so the system is averaging about 5 kWh per day.<br />
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I use some of that solar-generated electricity as it comes off the panels, but most of it gets pushed onto the grid for my neighbors to use. Then, at night and at other times when I need more power than the panels are producing, I pull what I need off the grid. The power company’s meter, on the back of my house, separately measures the power flowing in both directions, records both amounts of cumulative energy, and blinks between displaying the two amounts:<br />
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<a href="http://4.bp.blogspot.com/-Dvr0Z84bluM/VimiD2OJX4I/AAAAAAAABhI/5Tki2gDfPHs/s1600/NetMeterPhotos17Oct2015compressed.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="258" src="http://4.bp.blogspot.com/-Dvr0Z84bluM/VimiD2OJX4I/AAAAAAAABhI/5Tki2gDfPHs/s400/NetMeterPhotos17Oct2015compressed.jpg" width="400" /></a></div>
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I took these photos on the morning of October 17, when the incoming energy (since the meter was installed on August 27) had reached 100 kWh (left) and the outgoing energy had reached 200 kWh (right).<br />
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By combining the solar monitor data with the net meter readings, I can construct a comprehensive picture of the energy flows through my house. Here’s the picture for the calendar month of September:<br />
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<a href="http://1.bp.blogspot.com/-6pbZdfayIV0/Vimoy9rX-oI/AAAAAAAABhs/mEmJGkBlhao/s1600/September2015EnergyFlowWithTitle.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="252" src="http://1.bp.blogspot.com/-6pbZdfayIV0/Vimoy9rX-oI/AAAAAAAABhs/mEmJGkBlhao/s400/September2015EnergyFlowWithTitle.png" width="400" /></a></div>
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During this time period the solar system produced 151 kWh of energy, while the net meter reported that I pushed 114 kWh onto the grid. Therefore I must have used the other 37 kWh directly, as it was being produced. Meanwhile, the net meter reported that I pulled another 58 kWh off the grid, so my total household use was 95 kWh. (My <a href="http://dvschroeder.blogspot.com/2015/05/home-energy-use.html">usage</a> is lowest in spring and fall, higher in the summer, and highest in the winter.)<br />
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Fortunately, the power company (under direction from the Utah Public Services Commission) lets me accumulate credits for energy pushed onto the grid, and apply them toward future months when I’ll use more energy than I produce. Here’s a copy of my first net-metering bill, covering the end of August and the beginning of September:<br />
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<a href="http://2.bp.blogspot.com/-UOhleJajfTo/VimjzFSIK8I/AAAAAAAABhU/d9pLwfJdXOQ/s1600/FirstNetMeteringBill.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="247" src="http://2.bp.blogspot.com/-UOhleJajfTo/VimjzFSIK8I/AAAAAAAABhU/d9pLwfJdXOQ/s400/FirstNetMeteringBill.png" width="400" /></a></div>
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As you can see, they actually applied 32 kWh of my credits to the final reading off the old meter (which couldn’t distinguish incoming from outgoing energy, so it “charged” me for some of the energy I produced from August 19-27). Even so, I ended the billing month with 16 kWh of credits, and I have quite a bit more than that now.<br />
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I’m still getting billed the $6 “basic charge” that everyone pays for being connected to the grid, plus a $2 “minimum charge” for not using any (net) electricity. (So in effect, the basic charge is really $8 and they give you your first $2 worth of electricity for free. That’s not much electricity, but this practice still bugs me.) Add on the taxes and surcharges and my total bill comes to just over $9.<br />
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It’s only fair that I have to pay to be connected to the grid, because I really do depend on it. Here, for example, is a detailed plot of my solar production on the best day so far, with my “typical” electricity use superimposed:<br />
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<a href="http://4.bp.blogspot.com/-nGKd_bjbhyo/VimmOqZONBI/AAAAAAAABhg/GrpRUIlG2EM/s1600/SolarAndUse24hourPlot.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="278" src="http://4.bp.blogspot.com/-nGKd_bjbhyo/VimmOqZONBI/AAAAAAAABhg/GrpRUIlG2EM/s400/SolarAndUse24hourPlot.png" width="400" /></a></div>
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The big spikes are from cooking: a pancake breakfast, toasting bread for the lunch I packed in the morning, and a pretty big meal in the evening. The little bumps that repeat about once an hour are from the refrigerator cycling on and off. There’s a bunch of miscellaneous activity in the evening, mostly from lights and my computer. Last but not least, there’s a baseline of about 40 watts that I'm using 24/7, for my modem, router, clock, smoke alarms, smart thermostat, solar monitor, and the electricity monitor that took this data.<br />
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(That electricity monitor is the <a href="http://efergy.com/us/products/energy-gateways/engageelitehub#.Vimt4WSrT1o">Efergy Elite Classic and Engage hub system</a>, which I installed soon after the solar panels. It’s a <a href="http://www.mrmoneymustache.com/2015/03/25/cut-your-power-bill/">marvelous tool</a>, and I really wish I had installed it earlier. But I also wish I had paid another $25 for the <a href="http://efergy.com/us/products/energy-gateways/elite-true-power-meter-engage-hub#.VimucmSrT1o">version that measures true power</a>, because my microinverters have a nontrivial <a href="https://en.wikipedia.org/wiki/Power_factor">power factor</a> that fools the Efergy Elite Classic, especially at night. Unfortunately, even Efergy’s “true power” meter apparently can’t measure the direction of energy flow, so it would give confusing data when my solar panels are active during the day. There are <a href="http://www.theenergydetective.com/">competing</a> <a href="https://www.egauge.net/">brands</a> that lack this drawback but I haven’t tried them. In any case, I’ve had to manipulate my Efergy data quite a bit to produce the “typical” usage graph shown above.)<br />
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Because I use so much electricity when sunlight is scarce or absent, I can hardly claim that my home is 100% solar powered. I still depend very much on Rocky Mountain Power’s <a href="http://www.pacificorp.com/es/thermal.html">coal- and gas-fired power plants</a>, which are steadily pumping carbon dioxide into the atmosphere and contributing to global warming. Consequently, I don’t consider my solar panels to be a <a href="http://www.theonion.com/video/scientists-continue-developing-alternative-energy--51011">license to waste electricity</a>. Rather, they’ve inspired me to better understand and minimize my electricity use.<br />
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Here, then, is an estimated breakdown of my daily household electricity use, averaged over the seasons:<br />
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<a href="http://3.bp.blogspot.com/-g7BBYCTbhTs/VinGFRAB3-I/AAAAAAAABiQ/KiGZ3R6FBRk/s1600/HomeElectricityPieChart.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="305" src="http://3.bp.blogspot.com/-g7BBYCTbhTs/VinGFRAB3-I/AAAAAAAABiQ/KiGZ3R6FBRk/s400/HomeElectricityPieChart.png" width="400" /></a></div>
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I obtained these estimates through a variety of measurements using my power company’s meter, my Efergy monitor, and a few handy <a href="http://www.p3international.com/products/p4400.html">Kill-a-watt meters</a>. Even so, there’s a lot of guess-work involved in getting these annual averages, especially for seasonal contributions like heating and fans. I’ll have better data on heating after my first winter with the new <a href="https://www.ecobee.com/">smart thermostat</a>.<br />
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My total household electricity use, <a href="http://dvschroeder.blogspot.com/2015/05/home-energy-use.html">as reported earlier</a>, averages about 4 kWh per day. That’s quite a bit lower than the per-capita average here in the U.S., but not so different from <a href="http://www.wec-indicators.enerdata.eu/household-electricity-use.html">most other industrialized countries</a>. Notably absent from my household are such unnecessary luxuries as air conditioning, a second refrigerator or freezer, an electric clothes dryer, a television, or a hot tub.<br />
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Not everyone is in a position to invest in rooftop solar panels, but everyone <i>can</i> work to cut their unneeded electricity use—and save money in the process. As Mr. Money Mustache <a href="http://www.mrmoneymustache.com/2015/03/25/cut-your-power-bill/">says</a>, “<b><i>Measure everything, then get angry at waste.</i></b>”<br />
<br />Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com1tag:blogger.com,1999:blog-1233073253115884208.post-9995668892922306472015-09-06T12:01:00.000-06:002015-09-06T13:18:19.070-06:00Solar System InstallationUntil very recently I never considered myself a candidate for a rooftop solar photovoltaic system, because my electricity use is <a href="http://dvschroeder.blogspot.com/2015/05/home-energy-use.html">so low</a> by U.S. standards. Surely, I figured, there are fixed costs that are the same for PV systems of any size, so a system that produces only four kilowatt-hours a day wouldn’t be economical. Better to just pay the power company a few extra dollars a month for <a href="https://www.rockymountainpower.net/bluesky">wind-generated electricity</a>. Besides, my greater home energy need is for <a href="http://dvschroeder.blogspot.com/2015/05/home-energy-use.html">heat</a>—not electricity—so if anything, my steep south-facing roof should (I thought) be used for solar thermal panels that feed some kind of space-heating system.<br />
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But nobody in Utah seems to be in the business of retrofitting old houses with practical solar space-heating systems (and designing such a system from scratch, though tempting, would be incompatible with holding down a day job for a clumsy tinkerer like me). Meanwhile, PV keeps getting cheaper, and Utah has a generous 1:1 <a href="http://www.weberstatesolar.org/solar-101/connecting-to-the-grid">net-metering policy</a>, plus a 25% <a href="http://www.weberstatesolar.org/solar-101/solar-pv-incentives">state tax credit</a> on top of the 30% federal tax credit. The last straw was the <a href="http://www.weberstatesolar.org/">Susie Hulet Community Solar</a> program, which offers attractive pricing that scales down linearly (except for the city permit fee) to arbitrarily small installations. With the encouragement of my colleague John Armstrong and the good people at <a href="http://utahcleanenergy.org/">Utah Clean Energy</a>, I signed up as soon as the program got up and running, at the end of May.<br />
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(At about the same time, I also got a bid from <a href="http://www.cesolar.com/">another reputable installer</a> who apologized for not being able to offer me a decent price on such a small system, and suggested I look into the Susie Hulet program instead.)<br />
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Apparently I wasn’t the only one who signed up as the program began, because it took the contractor (<a href="http://www.gardner-energy.com/">Gardner Energy</a>) several weeks to process all the applications, conduct site visits, and prepare contracts. On July 9 they gave me my installation date: August 19. Then I patiently waited while the summer sun beat down on my roof.<br />
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Finally the day arrived, and the Gardner truck pulled up to my curb with four solar panels strapped to the bed and a trailer full of tools in tow:<br />
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<a href="http://2.bp.blogspot.com/-iAk42H9jDKw/Veu-G76WLuI/AAAAAAAABbY/HXT3Y32kBas/s1600/IMG_9737.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="222" src="http://2.bp.blogspot.com/-iAk42H9jDKw/Veu-G76WLuI/AAAAAAAABbY/HXT3Y32kBas/s400/IMG_9737.JPG" width="400" /></a></div>
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The crew of three wasted no time getting to work. Chad and Chase got up on the roof, tied themselves to the chimney, and began installing mounting brackets:<br />
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Meanwhile Patrick, the electrician and crew leader, ran the wires from the attic down to my electrical panel:<br />
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Back on the roof, the mounting rails came next:<br />
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<a href="http://2.bp.blogspot.com/-lxjq4l8l5UI/VevBHpO59sI/AAAAAAAABb8/BcOJL-d5pII/s1600/IMG_9747.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="298" src="http://2.bp.blogspot.com/-lxjq4l8l5UI/VevBHpO59sI/AAAAAAAABb8/BcOJL-d5pII/s400/IMG_9747.JPG" width="400" /></a></div>
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By lunch time the mounting hardware was all in place, along with most of the electrical components:<br />
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<a href="http://1.bp.blogspot.com/-UkSvuwuL_ro/VevBi2QQC2I/AAAAAAAABcI/dZ9pflbcCBc/s1600/IMG_9755.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="298" src="http://1.bp.blogspot.com/-UkSvuwuL_ro/VevBi2QQC2I/AAAAAAAABcI/dZ9pflbcCBc/s400/IMG_9755.JPG" width="400" /></a></div>
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Each of the four panels gets its own <a href="https://enphase.com/en-us/products-and-services/microinverters">Enphase M250 microinverter</a>:<br />
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<a href="http://3.bp.blogspot.com/-dcxu3IRkgZg/VevB3rHx3OI/AAAAAAAABcQ/qcoGbylC-kw/s1600/IMG_9754.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="239" src="http://3.bp.blogspot.com/-dcxu3IRkgZg/VevB3rHx3OI/AAAAAAAABcQ/qcoGbylC-kw/s320/IMG_9754.JPG" width="320" /></a></div>
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After lunch, Patrick installed the second electrical box:<br />
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<a href="http://1.bp.blogspot.com/-KfkoPxHWXa4/VevCStOcKDI/AAAAAAAABcY/PiSMfRoXoYI/s1600/IMG_9758.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="300" src="http://1.bp.blogspot.com/-KfkoPxHWXa4/VevCStOcKDI/AAAAAAAABcY/PiSMfRoXoYI/s400/IMG_9758.JPG" width="400" /></a></div>
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And before long it was time to hoist up the first of the four <a href="http://www.solarworld-usa.com/">SolarWorld</a> <a href="http://www.solarworld-usa.com/technical-downloads/datasheets">Sunmodule Plus 280-watt mono black</a> panels:<br />
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The three remaining panels quickly followed:<br />
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With all four panels installed and connected, the crew’s work was done before 4 pm. Hooray for Chase, Patrick, and Chad!<br />
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The system came with this cool monitoring unit, which reads data from the inverters off the power line, displays the current power level, and beams it via wifi onto the internet:<br />
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<a href="http://3.bp.blogspot.com/-uSqlWWZ_6WU/VexuB51aZOI/AAAAAAAABeI/ukCJ6GFlKD8/s1600/IMG_9816.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="221" src="http://3.bp.blogspot.com/-uSqlWWZ_6WU/VexuB51aZOI/AAAAAAAABeI/ukCJ6GFlKD8/s320/IMG_9816.JPG" width="320" /></a></div>
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But I had to get a new wifi router, because we couldn’t figure out how to get the Enphase monitor to talk to my Apple Airport Express. I’ll try to post some of the data later. Meanwhile, you can view it <a href="https://enlighten.enphaseenergy.com/pv/public_systems/pyng712374">here</a>.<br />
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The solar system connects to a new 240-volt breaker in my electrical panel:<br />
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<a href="http://4.bp.blogspot.com/-PQCSm0d1XUk/VevXtjPLuZI/AAAAAAAABdo/hFR8xTQ42h0/s1600/IMG_9815.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="http://4.bp.blogspot.com/-PQCSm0d1XUk/VevXtjPLuZI/AAAAAAAABdo/hFR8xTQ42h0/s320/IMG_9815.JPG" width="320" /></a></div>
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The city inspector came to check the wiring just five days after the installation. Then, after three more days, Rocky Mountain Power installed my new net meter:<br />
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<a href="http://3.bp.blogspot.com/-duWbxFigRMM/VevYH3z7TsI/AAAAAAAABdw/KN2ccL_k8EQ/s1600/IMG_9784.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="298" src="http://3.bp.blogspot.com/-duWbxFigRMM/VevYH3z7TsI/AAAAAAAABdw/KN2ccL_k8EQ/s400/IMG_9784.JPG" width="400" /></a></div>
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The meter’s LCD display blinks between showing the energy I’ve pulled off the grid and the energy I’ve pushed onto it. So far, after ten days, those numbers are 25 and 37 kilowatt-hours, respectively. But the Enphase monitor data says I’ve generated a total of 51 kWh during this time, so I must have used another 14 kWh as it came off the solar system, which the meter never saw.<br />
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Gardner predicts that this system will generate a total of 1657 kWh per year, and I’ve been using only about 1400 kWh/year, so in a sense I can now claim that “all” of my home’s electricity is solar. But only a fraction of the solar energy is being produced when I need it, so I’m still very much dependent on the grid, and on the coal- and gas-fired power plants that power that grid through the nights and cloudy days.<br />
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What about cost? The sticker price of my solar system came to $4251.41, including $260.61 for the Ogden City permit. But I expect to recover 55% of the cost through the federal and state tax credits, so my net up-front cost should be a little over $1900. Under the current rates and net-metering policy I should save about $10/month on my electricity bill (I’ll still pay the $8 minimum monthly fee), so the system would pay for itself in 16 years if rates and policies don’t change. Inevitably the rates and policies will change over that time, so my $1900 investment is rather risky.<br />
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If you’re thinking of installing your own solar system, be aware that the return-on-investment calculation depends on all sorts of details that will vary from one installation to another. In all cases, however, we’re talking about thousands of dollars. Before you even consider spending that kind of money, I would strongly urge you to invest the effort to find and eliminate wasteful electricity uses in your home. Mr. Money Mustache has a <a href="http://www.mrmoneymustache.com/2015/03/25/cut-your-power-bill/">great article</a> on how to do that. Get yourself a <a href="http://www.p3international.com/products/p4400.html">Kill-a-Watt meter</a> at the very least!<br />
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Finally, from a broader perspective, let me point out that it’s not very efficient to pay young men to risk their lives up on roofs, installing solar panels a few at a time. At least in Utah where electricity is cheap, the rooftop solar business is viable only because of the tax incentives—and even then, it works only for homeowners with suitable, unshaded roofs and cash to invest (or at least good credit). If the goal is to reduce carbon emissions, it would be far more efficient for society to invest in utility-scale solar farms. Then the economy of scale, ease of installation, and optimized siting would make government subsidies superfluous. But here in Utah our elected officials don’t even believe global warming is real, while they’re happy to provide government subsidies to well-off rugged individualists. So for now, rooftop is the only solar game in town.<br />
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<br />Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com1tag:blogger.com,1999:blog-1233073253115884208.post-45367076198407605622015-08-30T06:46:00.002-06:002021-06-03T07:39:55.394-06:00Why the Cost of College Has TripledIt’s back-to-school time, so again people are talking about the rising cost of college. I <a href="http://dvschroeder.blogspot.com/2013/08/college-tuition-has-outpaced-inflation.html">wrote about this issue</a> two years ago, and produced a plot showing how college tuition has increased faster than virtually any other component of the U.S. Consumer Price Index. Here’s an updated version of that plot, showing the relative cost of various types of goods and services compared to the overall CPI, since 1978 (the first year for which college tuition has its own CPI category):<br />
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<a href="http://1.bp.blogspot.com/-rLlUEZOIFpQ/VeLy_nfB3gI/AAAAAAAABaA/l-EfdRFs-fY/s1600/CPI.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://1.bp.blogspot.com/-rLlUEZOIFpQ/VeLy_nfB3gI/AAAAAAAABaA/l-EfdRFs-fY/s400/CPI.png?imgmax=960" width="480" /></a></div>
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As I said before, it’s not hard to understand the basic economics shown in this plot. Manufactured goods have become cheaper over time, as manufacturing has been automated and outsourced. The cost of professional services has therefore risen in comparison. College is often the ticket into high-paying service professions, so the demand for college and the willingness to pay for it have risen even more.<br />
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But even if we understand why people are <i>willing</i> to pay ever-higher tuition, this fact doesn’t tell us where all that money is going. Has the actual cost of educating a student more than tripled since 1978 and if so, how is that possible?<br />
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The answer to this question depends on whether we’re talking about public or private colleges (and universities). We can separate the two sectors, and also look 15 years farther back in time, by going to the Education Department’s <a href="http://nces.ed.gov/programs/digest/d14/tables/dt14_330.10.asp?current=yes">Digest of Education Statistics</a>. Here’s the Digest’s tuition data in constant (2013-14) dollars:<br />
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<a href="http://1.bp.blogspot.com/-boCafbOlOnM/VeLzWb2AFzI/AAAAAAAABaI/GOIpkr5ZWyY/s1600/TuitionHistory.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://1.bp.blogspot.com/-boCafbOlOnM/VeLzWb2AFzI/AAAAAAAABaI/GOIpkr5ZWyY/s400/TuitionHistory.png?imgmax=960" width="480" /></a></div>
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Obviously the private colleges charge much higher tuition than the public ones. Notice also that tuition gradually <i>decreased</i>, in real dollars, from the mid-1970s through the early 1980s, probably because colleges lagged in keeping up with the double-digit inflation of that era.<br />
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If you look closely at this second graph, you’ll see that since the 1970s tuition has increased slightly faster, in percentage terms, at the public schools than at the private ones. And even at the public schools the increase has been only about 200%, slightly less than what’s shown on the CPI graph. I don’t know the reason for this slight discrepancy, but the fact remains that tuition has roughly tripled over the last 35 years. Again, where is all this money going?<br />
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Let me first answer the question for the public colleges, which currently enroll <a href="http://nces.ed.gov/programs/digest/d14/tables/dt14_303.10.asp?current=yes">72% of all students</a> and <a href="http://nces.ed.gov/programs/digest/d14/tables/dt14_307.10.asp?current=yes">69% of full-time students</a>. Based on the data I’ve found (described below), it appears that the cost of an education at these schools <i>has</i> increased since the late 1970s, but only by about 20% (after accounting for inflation). However, these schools receive a great deal of their revenue from state appropriations, and that revenue, on a per-student basis, has declined by about 25%. Amazingly, the combination of these two 20-25% effects has resulted in a tuition increase of roughly 200%.<br />
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To show how this is possible, let me present a grossly simplified “toy” model that uses rounded numbers and ignores a variety of complications as well as all the little bumps and dips in the actual data:<br />
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<a href="http://2.bp.blogspot.com/-C1CaQGm7oD4/VeL3D5_b-fI/AAAAAAAABaY/KIhEYtKeVXQ/s1600/ToyModel20-25.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://2.bp.blogspot.com/-C1CaQGm7oD4/VeL3D5_b-fI/AAAAAAAABaY/KIhEYtKeVXQ/s400/ToyModel20-25.png?imgmax=1000" width="500" /></a></div>
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In today’s dollars, the actual annual cost of educating a full-time student was about $10,000 back around 1980 and has increased about 20%, to about $12,000 today. Meanwhile, state funding of higher education has declined, on a per-student basis, by about 25%, from $8000 to $6000. This means that the average tuition has had to triple, from about $2000 to $6000. Simple arithmetic has combined 20% and 25% to yield 200%.<br />
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To construct this toy model I relied on the tuition data shown above, along with data from The College Board’s annual <a href="http://trends.collegeboard.org/college-pricing">Trends in College Pricing</a> reports. Figure 18A of the latest Trends report shows that state and local appropriations currently cover about half the cost of education at public colleges (more at two-year schools but less at four-year schools), and that this share has been decreasing in recent years. Figure 16B shows the history of state appropriations in more detail back to 1983-84, and the corresponding figure in the 2010 Trends report goes back to 1979-80. Here I’ve plotted state funding <i>relative</i> to its value in 1979-80, comparing the total amount to the amount per student:<br />
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<a href="http://1.bp.blogspot.com/-BGhlfBGBefI/VeL3gAE1J8I/AAAAAAAABag/dquZQlb_7SU/s1600/StateFunding.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://1.bp.blogspot.com/-BGhlfBGBefI/VeL3gAE1J8I/AAAAAAAABag/dquZQlb_7SU/s400/StateFunding.png?imgmax=960" width="480" /></a></div>
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The decrease in per-student funding from 1979-80 to 2013-14 was almost exactly 25%, so that’s the number I used in my toy model. But the bumps in the data (caused mostly by economic ups and downs) have been large, so you can get very different overall changes by choosing slightly different starting and ending years.<br />
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It’s important to note, meanwhile, that <i>total</i> state funding of higher education has <i>increased</i> over time, even after allowing for inflation. As you can see, the increase since 1980 has been about 25%. The decrease in <i>per-student</i> funding has been caused by a combination of two further effects. First, the U.S. population has grown by about 40% since 1980, and the working-age population has grown by about the same amount, so state funding for higher education has not kept up with the growth in the population or the tax base. Second, college enrollments have grown faster than the overall population (and also faster than the college-age population). Here is a graph of full-time-equivalent enrollments as a percentage of the total population, since 1950:<br />
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<a href="http://2.bp.blogspot.com/-AxKJ6dmV2Zo/VeL3_-30YTI/AAAAAAAABao/10iW3dS1o2o/s1600/EnrollmentPercentage.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://2.bp.blogspot.com/-AxKJ6dmV2Zo/VeL3_-30YTI/AAAAAAAABao/10iW3dS1o2o/s400/EnrollmentPercentage.png?imgmax=960" width="480" /></a></div>
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Whereas attending college was once the privilege of a small elite fraction of Americans, it is now commonplace among the middle class. And while most of us celebrate this <a href="http://www.bestcollegesonline.com/blog/2011/08/08/a-timeline-of-college-tuition/">transformation</a>, we need to realize that it doesn’t come for free. The increasing number of college students has caused the total cost of educating these students to grow to become a substantial chunk of the U.S. economy. <a href="http://www.npr.org/sections/ed/2014/06/19/322563525/free-college-for-all-dream-promise-or-fantasy">Somehow</a> society has to pay that cost.<br />
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In any case, the toy model shown above is based on actual (rounded) data for the current levels of tuition and state funding, the decline in state funding per student, and the observed growth in tuition. From those numbers it’s a simple matter to calculate that state funding provided about 80% of the total cost in 1980, and that the total per-student cost of education has increased by about 20% since then. (It would be nice, of course, to corroborate these results with independent data, but I don’t know where to find such data.)<br />
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And why has the per-student cost of education increased, even if only by 20%? Probably for many reasons, which I hope to explore more carefully in a later article. In brief, it appears that expenditures for faculty salaries have been <a href="http://nces.ed.gov/programs/digest/d14/tables/dt14_316.10.asp?current=yes">almost unchanged</a> (on a per-student basis, after allowing for inflation), although there has been a <a href="http://nces.ed.gov/programs/digest/d14/tables/dt14_315.10.asp?current=yes">significant rise</a> in the number of part-time faculty. Meanwhile, there has also been a <a href="http://www.washingtonmonthly.com/magazine/septemberoctober_2011/features/administrators_ate_my_tuition031641.php?page=all">steep rise in the number of professional staff</a>, as well as a steep rise in the cost of medical insurance for all full-time employees. Other possible factors are non-staff expenses such as academic and nonacademic buildings, library books, journals, computers, software, and student financial aid. The important thing to remember is that even small increases in any of these expenses have had amplified effects on tuition (or on <a href="http://www.sltrib.com/home/2386525-155/utah-students-pay-hundreds-in-fees">mandatory student fees</a>, which are included in the tuition statistics), because state funding has not increased to absorb any of the increases.<br />
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Finally, what about the private colleges and universities? Given that they never had any state funding to begin with, you might expect their tuition to have increased by only about 20%, to absorb the same increased expenses as at the public schools. Yet they’ve actually raised tuition nearly as much as the public schools: about 150% (above inflation) since the late 1970s. Where is all <i>that</i> money going?<br />
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There’s <a href="http://nces.ed.gov/programs/digest/d14/tables/dt14_316.10.asp?current=yes">good data</a> to show that faculty salaries <i>have</i> been increasing faster than inflation at the private colleges, so that’s one difference. It also seems likely that the private schools have been spending increasingly more than the public ones on almost everything else: <a href="http://www.washingtonmonthly.com/magazine/septemberoctober_2011/features/administrators_ate_my_tuition031641.php?page=all">professional staff</a>, buildings, computers, and so on. It would be interesting (but difficult) to explore whether these disparate expenditures have affected the relative quality of private vs. public education over the years.<br />
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A critical difference, meanwhile, is that the more expensive private colleges tend to provide large amounts of need-based financial aid to many of their students. In other words, the advertised “sticker price” applies only to those who can afford to pay it, and these wealthy families subsidize students who are more needy. Perhaps one could construct a toy model of the interplay between this practice and rising costs and tuition over time.<br />
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But let’s not lose sight of the big picture here. Private colleges enroll only 30% of all college students, and they couldn’t get away with raising tuition by 150% if the public colleges weren’t raising it by 200%. That increase is being driven by a variety of modest cost increases, amplified and greatly exacerbated by the decline in state funding per student.<br />
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Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com11tag:blogger.com,1999:blog-1233073253115884208.post-70873426604078334432015-07-15T20:06:00.000-06:002015-07-17T21:28:45.924-06:00Beyond Coal: U.S. Energy in Historical PerspectiveI just read a <a href="http://www.politico.com/agenda/story/2015/05/inside-war-on-coal-000002">fascinating article</a> on the so-called “war on coal” that has shut down a significant fraction of U.S. coal-fired power plants over the last several years. What was almost unthinkable just a few years ago has become a reality, thanks to a confluence of technology (shale gas extraction, wind power, and efficiency), economics (the great recession), government regulations (thanks, Obama!), and environmental activism (the <a href="http://content.sierraclub.org/coal/">Sierra Club’s “Beyond Coal” campaign</a>, funded by <a href="http://www.bloomberg.org/program/environment/clean-energy/beyond-coal/">Michael Bloomberg</a>).<br />
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The article is accompanied by a <a href="http://www.politico.com/agenda/story/2015/05/what-energy-powers-your-house-chart-000009">graph</a> that shows all the sources of U.S. electricity over the last 30 years, highlighting the dramatic (roughly 20%) decline of coal since 2007—even while coal remains larger than any other electricity source.<br />
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I love graphs like that, but I wanted a longer-term perspective and I also wanted to visualize the data a little differently. So I pulled the data from the <a href="http://www.eia.gov/electricity/data.cfm">EIA web site</a> and plotted it up as a stacked area chart, going back to 1950:<br />
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<a href="http://2.bp.blogspot.com/-QKv9CFRwDRE/VacFK_JQ0pI/AAAAAAAABXk/L7rdG5RJLvQ/s1600/USElectricityStackedAreaPlot.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="340" src="http://2.bp.blogspot.com/-QKv9CFRwDRE/VacFK_JQ0pI/AAAAAAAABXk/L7rdG5RJLvQ/s400/USElectricityStackedAreaPlot.png" width="500" /></a></div>
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The recent decline of coal is all the more striking when juxtaposed with its remarkably steady rise over more than 50 years. Though if you look closely, you’ll see that the rise had already flattened out before 2007.<br />
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The advantage of the stacked area chart is that it also shows the <i>total</i> electricity generation at a glance—and the behavior of the total is also striking. After an almost uninterrupted rise from 1950 through 2007 (with just a couple of hiccups due to the oil price spikes of the 70s and early 80s), U.S. electricity generation (and consumption) <i>stopped growing</i> in 2008. Even though our economy has recovered in most respects since 2009, our electricity use hasn’t quite regained its pre-recession peak. I won’t try to predict whether it will do so in the coming years.<br />
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Meanwhile, there’s so much more to notice on that graph. Look at the rise and fall of petroleum as an electricity source. Marvel at the rapid rise of nuclear power and how steady it has remained in recent decades. And don’t overlook that expanding sliver of green at the top, which now comes mostly from wind energy (4.5% of total U.S. electricity in 2014).<br />
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To get a better view of wind energy and the other minor contributors, here I’ve plotted the same data on a logarithmic scale (with no stacking):<br />
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<a href="http://4.bp.blogspot.com/-LrKBNVybKw8/VacFaIZqfGI/AAAAAAAABXs/Ly0qBTkI2jQ/s1600/USElectricityLogPlot.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="343" src="http://4.bp.blogspot.com/-LrKBNVybKw8/VacFaIZqfGI/AAAAAAAABXs/Ly0qBTkI2jQ/s400/USElectricityLogPlot.png" width="500" /></a></div>
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On this graph, a straight, upward-sloping line corresponds to <i>exponential</i> growth (a fixed <i>percentage</i> increase each year). It’s interesting to look at how each electricity source has experienced a period of approximately exponential growth at some time in the past, but these periods always end when that growth runs up against practical limits. The exponential growth of wind has recently slowed, but now solar-generated electricity is in a period of dramatic exponential growth. Let’s hope this period lasts a little longer!<br />
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I find it remarkable, though, that the log-scale graph of <i>total</i> U.S. electricity generation is almost entirely concave-down. The very rapid exponential growth of the early 1950s slowed somewhat in the 60s, then slowed a lot more after 1973, then slowed to a crawl after 2000, and has now more or less stopped.<br />
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Of course, electricity isn’t the same as energy. For a bigger-picture view we should also include fuels used for heating and transportation and industrial machinery. The energy sources used for all these things, including electricity generation, are called <a href="http://www.eia.gov/totalenergy/data/monthly/">“primary” energy</a>, and EIA actually has <a href="http://www.eia.gov/totalenergy/data/annual/archive/038400.pdf">estimates of primary energy use</a>, by source, going back to the founding of the American colonies. For the first 200 years the only important source (besides muscle power, which EIA doesn’t count) was wood. I’ve started the following graph in 1850, when coal makes its first appearance:<br />
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<a href="http://1.bp.blogspot.com/-sgLZrVsEijU/VacFjZFxtrI/AAAAAAAABX0/9Jh5tfNo8Bo/s1600/USEnergyStackedAreaPlot.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="327" src="http://1.bp.blogspot.com/-sgLZrVsEijU/VacFjZFxtrI/AAAAAAAABX0/9Jh5tfNo8Bo/s400/USEnergyStackedAreaPlot.png" width="500" /></a></div>
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The units on this graph are quadrillions of British thermal units, or “quads” for short. One quad equals 293 billion kilowatt-hours, but the inherent inefficiency of heat engines means that a quad can generate only about 100 billion kWh of electricity. Roughly, therefore, the current annual total of about 4000 billion kWh on the electricity graphs requires about 40 quads of primary energy. The other 60 or so quads of primary energy go toward transportation, heating, and industry. (To see a careful breakdown of how each of these energy sources is used, look at the latest <a href="https://flowcharts.llnl.gov/">energy flow chart</a> from Lawrence Livermore National Lab.)<br />
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(A couple of technical notes on the primary energy data: First, the numbers from before 1949 are estimated from various sources and are provided by EIA at only 5-year intervals, so there could be important details that are missing. Second, for non-thermal electricity sources like hydro, wind, and photovoltaic solar cells, EIA defines the “primary” energy to be the amount of some <i>other</i> fuel that would produce (on average) the same amount of electricity. This fictitious accounting allows for fair comparisons between thermal and non-thermal electricity sources.)<br />
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Looking at the graph above, notice that coal provided more than half of <i>all</i> U.S. energy from about 1885 through 1940. During that era our cities were badly polluted with soot. My own house, built in 1935, was originally <a href="https://sunhomedesign.wordpress.com/2007/10/26/a-brief-history-of-heating-and-cooling-americas-homes/">heated with coal</a>; the coal room in the basement now stores assorted outdoor equipment and other hardware. Nowadays, coal burning occurs almost exclusively at electric power plants, mostly outside major cities.<br />
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Again it’s also useful to plot the same data on a logarithmic scale, with no stacking:<br />
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<a href="http://2.bp.blogspot.com/-lW5_JagxpRA/VacFn2Q8hMI/AAAAAAAABX8/PqWDKLHsc7Q/s1600/USEnergyLogPlot.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="348" src="http://2.bp.blogspot.com/-lW5_JagxpRA/VacFn2Q8hMI/AAAAAAAABX8/PqWDKLHsc7Q/s400/USEnergyLogPlot.png" width="500" /></a></div>
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Here you can see the early growth of each major energy source in detail, notice how they were affected by the Great Depression and the 1970s, and mentally extrapolate to the right to envision a variety of possible energy futures. Petroleum remains our largest single energy source, a distinction it has held since 1950. Biomass is making a bit of a comeback, thanks mostly to ethanol added to motor fuels. Wind and solar are tiny in comparison to the fossil fuels, but their extremely rapid growth is encouraging. The recent flattening of total energy use is even more apparent than for electricity alone, extending back to the late 1990s when all forms of energy are included.<br />
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For an even bigger picture I should really plot energy use for the entire world, rather than just the United States. One of the best sources of worldwide energy data is the <a href="http://www.bp.com/en/global/corporate/about-bp/energy-economics/statistical-review-of-world-energy.html">BP Statistical Review of World Energy</a>. The data in the BP Review goes back only to 1989, but at least it gives the big picture since then.<br />
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According to the BP Review, Europe’s coal use was on the decline already in 1989, though it has been fairly stable in recent years. Far outweighing the declines in Europe and the U.S., however, has been the phenomenal increase of <a href="http://qz.com/405059/chinas-on-track-for-the-biggest-reduction-in-coal-use-ever-recorded/">coal use in China</a>, especially during the 2000s. China now uses approximately half of the world’s coal, and its per-capita use is now about the same as in the U.S. (although its per-capita use of petroleum and natural gas are much less than ours). Even China’s use of coal, however, was fairly stable for the last couple of years and now seems to be decreasing. And it should be pointed out that a significant fraction of energy use in the developing world goes toward manufacturing products for export to wealthier countries. The coal used to make your iPhone is <i>not</i> included in the graphs on this page.Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com0tag:blogger.com,1999:blog-1233073253115884208.post-61688205919287289172015-06-27T16:47:00.000-06:002015-06-28T16:24:24.575-06:00Air TravelAfter carefully tallying up my <a href="http://dvschroeder.blogspot.com/2015/05/home-energy-use.html">home energy use</a> and the associated carbon emissions, I realized that for context (and out of curiosity) I should do the same for my personal travel.<br />
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For daily commuting and most short errands I pedal a bicycle: no fossil fuels used there, and no more carbon emissions than if I were merely exercising for health and enjoyment.<br />
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For most longer trips (and some short ones) I drive, and I’ve kept track of the odometer readings and approximate fuel economy of all 2.5 of the <a href="http://dvschroeder.blogspot.com/2014/03/little-blue-and-big-blue.html">cars</a> I’ve ever owned. But I usually don’t drive alone, and I’ve never kept records of exactly how often I do, so it would be tricky to figure out my personal share of the associated gasoline and CO<sub>2</sub>. I’ll try to make an estimate anyway, but not today.<br />
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I’ve occasionally ridden on buses and trains, but not often enough for either to have made a significant contribution to my energy/carbon footprint.<br />
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That leaves air travel, which in many ways is the most interesting. It didn’t take me long to go through old credit card statements and other records, to reconstruct a list of every trip I’ve ever taken by plane. With just a bit of guess-work I count 71 trips over 35 years. Here’s a plot of my air travel history:<br />
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<a href="http://2.bp.blogspot.com/-H8bMuSyppHo/VY8QPqfLtII/AAAAAAAABW0/fJ54lmsQxb8/s1600/AirTravelGraph.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="265" src="http://2.bp.blogspot.com/-H8bMuSyppHo/VY8QPqfLtII/AAAAAAAABW0/fJ54lmsQxb8/s400/AirTravelGraph.png" width="400" /></a></div>
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I never flew at all as a child; my first four flights were trips home from college (to St. Louis from Minnesota). Then in 1984 I flew to visit graduate schools on both coasts, and chose to attend one in California. That choice left me making regular flights back east to visit family and friends over the next seven years (including one year in my first full-time job). In 1991, after three flights for job interviews, I moved to Iowa—within driving distance of my immediate family but now a long flight from professional collaborators back in California. In 1993 there were more job interviews, plus my longest trip ever, to a conference in Hawaii. But I ended up in Utah, from which I’ve regularly flown to visit family and to attend professional conferences and workshops. Recently, since my <a href="http://dvschroeder.blogspot.com/2009/10/happy-birthday-dad.html">dad</a>’s final illness in 2011, my personal air travel has declined.<br />
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The mileages in the chart are somewhat uncertain because I don’t remember the locations of all the intermediate stops and transfers. But by my best estimate I’ve flown a little under 200,000 miles, in a little over 200 separate up-and-down flight legs. Over the last ten years I’ve averaged 3800 miles per year, and my lifetime average (since birth) is about the same. But as you can see from the chart, I was averaging twice that amount during grad school and for several years afterwards.<br />
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So is 3800 miles/year a lot or a little? The answer is both, depending on the standard of comparison:<br />
<ul>
<li>The total number of <a href="http://www.rita.dot.gov/bts/sites/rita.dot.gov.bts/files/publications/national_transportation_statistics/html/table_01_40.html">passenger-miles</a> for all U.S. domestic flights is about 600 billion per year. If we divide that by the U.S. population (320 million), we get an average of about 1900 miles/year per person. So my 3800 miles/year is about <i>twice</i> the national average. (If you include <a href="http://web.mit.edu/airlinedata/www/2013%2012%20Month%20Documents/Traffic%20and%20Capacity/International/International%20Revenue%20Passenger%20Miles.htm">international flights</a>, then the average American probably flies somewhat more than 1900 miles/year—but nowhere near twice as much.)</li>
<li>World-wide, annual air traffic comes to about <a href="http://www.icao.int/sustainability/pages/eap_fp_forecastmed.aspx">4 trillion passenger-miles</a>, or about 550 miles per person. So my 3800 miles/year is nearly <i>seven times</i> the world average.</li>
<li>Among my friends, on the other hand, 3800 miles/year seems to be on the low side. Most of my friends are well-educated, upper-middle-class professionals who, like me, travel for professional reasons and to visit families and friends scattered across the U.S. Unlike me, however, most of them also travel overseas occasionally. And many of them just seem to fly more often than I do. My guess is that most of my friends fly about twice as much as I do today, or about as much as I did 20-30 years ago. A few of them fly significantly more than that. One of my acquaintances has accumulated nearly two million frequent-flyer miles on a single airline.</li>
</ul>
And what about my CO<sub>2</sub> emissions from flying? The most helpful resource I’ve found for calculating this is a 2008 report from the Union of Concerned Scientists titled <a href="http://www.ucsusa.org/clean_vehicles/what_you_can_do/greentravel/getting-there-greener.html">Getting There Greener: The Guide to Your Lower-Carbon Vacation</a>. This report compares the carbon emissions from flying, driving, and riding buses and trains, for trips of different lengths and for different numbers of travelers. Appendix B, in particular, lists average per-passenger emissions for two dozen types of commercial aircraft, broken down into per-flight and per-mile contributions. The numbers include an additional 20% to account for emissions associated with the production and distribution of jet fuel.<br />
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Based on these numbers, I calculate that for my typical mode of flying (coach class on a narrow-body jet with an average flight leg of 950 miles), the average emission rate is 0.415 pounds of CO<sub>2</sub> per mile. Multiplying by 3800 miles/year, I find that my flying contributes 1600 pounds of CO<sub>2</sub> to the atmosphere in an average year. (It was much higher 20-30 years ago, when I was flying twice as much and planes were less efficient—mostly because they tended to be less full.)<br />
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As always with such estimates, this result is rather fuzzy because of all the approximations and assumptions that went into it. Even if all of my calculations are perfectly “accurate,” I haven’t included the emissions associated with manufacturing the aircraft, or operating the airports, or ground transportation. Also, aircraft have <a href="http://www.co2offsetresearch.org/aviation/RF.html">other climate impacts</a> besides CO<sub>2</sub> emissions, and I’ve applied no enhancement factor to account for these effects.<br />
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In any case, 1600 pounds per year is a significant contribution to my <a href="http://shrinkthatfootprint.com/what-is-a-carbon-footprint">total carbon footprint</a>—probably about 10% of the total—but not as large as the contributions from driving or <a href="http://shrinkthatfootprint.com/shrink-your-food-footprint">food production</a> or <a href="http://dvschroeder.blogspot.com/2015/05/home-energy-use.html">heating my home</a>. For the average American, who flies only half as much as I do but uses much more gasoline and electricity, flying is actually a pretty small fraction of the total carbon footprint. And the same is true <a href="https://en.wikipedia.org/wiki/Environmental_impact_of_aviation#Total_climate_effects">worldwide</a>, because most people fly so much less than Americans do.<br />
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Although air travel may not currently seem like the biggest carbon concern, it will inevitably become a bigger issue in the future. Global passenger air transportation is currently growing at a rate of about <a href="http://www.icao.int/sustainability/pages/eap_fp_forecastmed.aspx">6% per year</a>, five times as fast as the population growth rate. Further efficiency gains in air transportation will be small, and there’s currently no alternative to petroleum-based jet fuel.<br />
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The real issue with flying is that it’s so unequal. Rich people tend to fly <a href="http://e360.yale.edu/feature/toward_sustainable_travel/2280/">a great deal</a>, and increasing numbers of the middle class are becoming wealthy enough to fly 10,000 miles a year if they want to. If the world average ever gets close to that level, petroleum prices will soar and the impact on earth’s climate will be catastrophic.<br />
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Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com1tag:blogger.com,1999:blog-1233073253115884208.post-31605103149332202692015-05-25T07:37:00.001-06:002023-08-21T19:56:58.941-06:00Home Energy Use<div style="margin-top: 10px;">Several of my friends have been receiving <a href="https://rmp.opower.com/">home energy use reports</a> for the last few months, comparing their electricity and natural gas use to the average of their neighbors. I wasn’t selected to participate in this program/study, but I’m glad it has generated so many discussions about energy conservation. Meanwhile, folks are talking more and more about <a href="http://www.weberstatesolar.org/">rooftop solar photovoltaic systems</a>, which are now more or less paying for themselves even in Utah where electricity is <a href="http://www.eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_5_6_a">cheap</a>.<br />
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As a numbers guy, I’ve always paid attention to my own utility bills, trying to understand (at least in broad outline) how much energy I was using and how I could use less. And I’ve saved my utility bills for many years, so I can document exactly what I’ve used.<br />
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Here’s a plot of my monthly electricity use for the last 16 and a half years, since I bought my house. The vertical scale is in kilowatt-hours per day, plotted for each billing month, so multiply by 30.4 to get the typical monthly use, or divide by 24 to get the average power in kilowatts:<br />
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<a href="http://2.bp.blogspot.com/-OPK_n7LNIF0/VWKaXl4GaQI/AAAAAAAABUg/2qHfldunC7E/s1600/ElectricityUsageHistory.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="275" src="http://2.bp.blogspot.com/-OPK_n7LNIF0/VWKaXl4GaQI/AAAAAAAABUg/2qHfldunC7E/s400/ElectricityUsageHistory.png" width="400" /></a></div>
There’s quite a bit of information in this graph:<br />
<ul>
<li>The three highest spikes are from when I had renters or guests (one to three at a time) living in my basement.</li>
<li>Soon after the first of these renters moved in, in September 2001, I bought a new refrigerator for the kitchen and moved the old refrigerator into the basement for the renter to use. The old fridge used about 3 kWh/day and the new one uses only 1 kWh/day (as measured with a <a href="http://www.p3international.com/products/p4400.html">handy power meter</a>), so when the renter moved out in early 2002 and I unplugged the old fridge, my household electricity use dropped by about 2 kWh/day from what it had been before. (The new fridge cost $650, but it saves me about $70 a year, so it paid for itself in nine years.)</li>
<li>There are some pretty reliable seasonal cycles. I use the most electricity in the winter, thanks to the furnace fan, a space heater, an electric blanket, and having more lights on. I also use somewhat more in July and August than in the spring and fall, because the refrigerator works harder then and I use fans to keep cool.</li>
<li>Finally, there’s been a gradual increase in my electricity use over the last 13 years. I need to make some measurements to figure out exactly why, but I suppose I’m using the fans and heaters more as I become old and soft, and my laptop computers have gotten greedier for power over time. Also, since the beginning of 2012 I’ve been spending about half of every work week at home, helping to edit the <a href="http://scitation.aip.org/content/aapt/journal/ajp">American Journal of Physics</a>.</li>
</ul>
At present, my electricity use averages just under 4 kWh/day, or about 160 watts. For comparison, the average U.S. household uses about <a href="http://www.eia.gov/tools/faqs/faq.cfm?id=97&t=3">30 kWh/day</a>, or 12 kWh/day per person. I use less than average because my house has no air conditioning, and because my refrigerator and lights and computer are all pretty efficient. I do cook with electricity, but I hang my clothes (indoors) to dry. And I don’t indulge in power-hungry extravagances like a second refrigerator or freezer or hot tub.<br />
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Still, my home electricity use is far from negligible. It’s pretty close to the <a href="http://www.wec-indicators.enerdata.eu/household-electricity-use.html">household average</a> (counting only electrified households) in China and Mexico; it’s nearly twice the <a href="http://en.wikipedia.org/wiki/List_of_countries_by_electricity_consumption"><i>total</i> per-capita use</a> (including all commercial and industrial uses) in India; and it’s a hundred times greater than the total per-capita use in some African countries.<br />
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If all my electricity <a href="http://www.eia.gov/tools/faqs/faq.cfm?id=105&t=3">came from</a> <a href="http://www.eia.gov/tools/faqs/faq.cfm?id=667&t=3">coal</a>, the resulting CO<sub>2</sub> <a href="http://www.eia.gov/environment/emissions/co2_vol_mass.cfm">emissions</a> would be about 3000 pounds per year. The actual carbon footprint is less than this by an amount that’s ambiguous, because of the way electricity from natural gas and renewables is mixed into Utah’s grid. I actually pay Rocky Mountain Power an extra $3.90 per month to participate in their <a href="https://www.rockymountainpower.net/bluesky">Blue Sky program</a>, nominally buying 200 kWh of wind-generated electricity—enough to cover 170% of what I use. For <a href="http://www.solarsimplified.org/solar-resources/calculate-your-solar-savings">about $1500</a>, after <a href="http://www.weberstatesolar.org/solar-101/solar-pv-incentives">federal and state tax incentives</a>, I could install enough rooftop solar panels to cover my household use, and thereby reduce each of my monthly bills by about $10. Neither wind nor sunshine, however, is always available at the times when I’m using electricity, so neither provides complete freedom from the fossil fuels that dominate Utah’s electrical grid.<br />
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Meanwhile, there’s a carbon-emitting elephant in the room that I haven’t yet mentioned: natural gas, which my house uses for space heating and water heating. Here is a plot of my monthly gas use over the last 16 and a half years:<br />
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<a href="http://3.bp.blogspot.com/-VexSnQvM_m8/VWKzlyRPwJI/AAAAAAAABUw/ylTyD3nwyGk/s1600/GasUsageHistory.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="275" src="http://3.bp.blogspot.com/-VexSnQvM_m8/VWKzlyRPwJI/AAAAAAAABUw/ylTyD3nwyGk/s400/GasUsageHistory.png" width="436" /></a></div>
I’ve again plotted my average daily use for each billing month, in millions of BTUs (the gas company’s billing unit, also called decatherms, and often abbreviated MMBtu). Along the right side I’ve multiplied by 300 to convert this unit to approximate kilowatt-hours (the more accurate conversion factor would be 293), to facilitate comparison to my electricity use. Notice the following:<br />
<ul>
<li>Nearly all of my natural gas use is in the winter. Water heating in the summer is small by comparison.</li>
<li>My 2001-2002 renter produced a significant spike, as we kept the basement warmer than usual. My other renters/guests don’t show up on this graph because they weren’t around in the winter.</li>
<li>In December 2003 my old (from 1980 or so) furnace died, and the house was without heat for a week or two before I had a new one installed. The new one is a “condensing” furnace, rated at 92% efficiency because it sends less heat up the chimney. At the same time, I moved the thermostat from the front room to the back of the house, so I could close off the front room and avoid heating it for most of the winter. These changes reduced my gas use by more than 40%. The new furnace has just about paid for itself in the 11 years since it was installed, so it would have been a good investment even if the old one hadn’t died.</li>
<li>Any other changes or trends (such as the new storm windows that I got in 2011) are indiscernible due to the weather-caused variations.</li>
<li>Even with the new furnace, my average daily gas use is about 0.08 million BTU, or 23 kWh: <i>six times</i> as much energy as I use from electricity.</li>
</ul>
I use a lot of natural gas because my house, though small, is 80 years old and poorly insulated. But the factor of 6 is somewhat misleading, because when electricity is generated from fossil fuels (or nuclear fuel, for that matter), only <a href="http://www.eia.gov/tools/faqs/faq.cfm?id=667&t=3">about a third</a> of the energy in the fuel is actually converted to electricity. (The rest is given off as waste heat at the power plants, and the second law of thermodynamics says there’s <a href="http://dx.doi.org/10.1119/1.10023">not much we can do about it</a>.) So instead of a factor of 6, we could say that my natural gas use is only about <i>twice</i> the amount of fuel that I cause to be burned for electricity. Perhaps coincidentally, the amount that I pay for natural gas is also close to twice what I pay for electricity (about $20/month on average vs. $10), if you neglect the flat fees that are charged just for being hooked up to these utilities.<br />
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Burning one million BTU of natural gas emits <a href="http://www.eia.gov/environment/emissions/co2_vol_mass.cfm">117 pounds</a> of CO<sub>2</sub>, so my annual CO<sub>2</sub> emissions from burning natural gas come to 3370 pounds—unambiguously more than the emissions from my electricity use. Thus, even if I reduce my electricity-related carbon emissions to zero, I shouldn’t feel too proud of myself unless I also reduce gas use. Unfortunately, I may have no good cost-effective ways to do that. One option might be to turn the thermostat down and rely more heavily on electric heating pads and blankets and space heaters—and then invest in a rooftop solar system that’s big enough to offset the electricity used by these appliances.<br />
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Before wrapping up this article, I should mention that my overall <a href="http://www.carbonfootprint.com/calculator.aspx">carbon footprint</a> includes quite a few other contributions besides home energy use. There are significant emissions from <a href="http://www.fueleconomy.gov/feg/Find.do?action=sbs&id=34234#tab2">driving</a>, from <a href="http://shrinkthatfootprint.com/shrink-your-travel-footprint">flying</a>, from growing and transporting the <a href="http://shrinkthatfootprint.com/shrink-your-food-footprint">food</a> that I eat, and from making the <a href="http://shrinkthatfootprint.com/shrink-your-product-footprint">stuff</a> that I buy. Perhaps I’ll detail my estimates of these in a future article. For now I’ll just say that each of these four is very roughly comparable to the footprint of my electricity or natural gas use; no one of them seems to be so large that it makes my home energy use negligible in comparison.<br />
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In any case, the graphs above make it pretty clear that the new furnace and new refrigerator were the “low-hanging fruit” for reducing my utility bills and the associated carbon emissions. I hope others can learn from these examples, even as I ponder which fruit to reach for next.<br />
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</div>Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com0tag:blogger.com,1999:blog-1233073253115884208.post-54304490128611681492015-04-18T15:11:00.000-06:002015-04-25T16:01:58.549-06:00How Grad School Made Me RichFirst let me be clear: I did not go to graduate school in order to get rich. I went because I loved physics and wanted to learn more physics and wanted to have a career in physics.<br />
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Besides, how could anyone get rich by going to grad school? Even if, as in my case, you have teaching and research assistantships that pay your tuition plus a stipend, that stipend is far less than what a college graduate “should” be earning.<br />
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And yet, as a side effect, grad school made me rich. It did so partly by enabling me to get good-paying academic jobs ever since. But far more important was the way grad school taught me how to happily live on a grad student’s stipend.<br />
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I’ve come to appreciate this fact so much that I went back through my old check registers and credit card statements, to see in detail how I did it. My average annual stipend while in grad school, from 1984 to 1990, was about $12,000 (less for the first couple of years and more later on, after I got a research assistantship). Meanwhile, my annual expenses averaged only about $10,500, so I actually accumulated a five-figure bank balance over those six years. (The <a href="http://data.bls.gov/cgi-bin/cpicalc.pl">consumer price index</a> has approximately doubled since then, so double these numbers to convert to today’s dollars.)<br />
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Here’s a breakdown of where that $10,500 went:<br />
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<a href="http://4.bp.blogspot.com/-HSTjxWhSxQk/VTLALaJ517I/AAAAAAAABRs/PRiHSOcLfXA/s1600/GradSchoolExpenseChart.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://4.bp.blogspot.com/-HSTjxWhSxQk/VTLALaJ517I/AAAAAAAABRs/PRiHSOcLfXA/s1600/GradSchoolExpenseChart.png" height="293" width="320" /></a></div>
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I kept my housing expenses down by living in <a href="http://stanforddailyarchive.com/cgi-bin/stanford?a=d&d=stanford19881018-01.2.2&srpos=52&e=30-08-1980-30-06-1993--en-50--51--txt-txIN-%22manzanita+park%22------">on-campus</a> <a href="http://web.stanford.edu/dept/rde/cgi-bin/drupal/housing/housing/liliore-green-rains-houses">apartments</a>, shared with one to three other grad students. The apartments were furnished, and the rent included utilities.<br />
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I kept my other expenses down by eating home-cooked meals (my roommates and I usually took turns cooking dinners) and by not owning a car (a choice that put me in the minority among my classmates).<br />
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These savings freed up substantial sums to spend on extravagant luxuries: more books than I would ever make time to read; two Macintosh computers that allowed me to work from home much of the time; a $900 Miyata touring bike; all sorts of other “toys” including backpacks, tents, other outdoor equipment, two nice pairs of binoculars, a telescope, and a new camera; and roughly two trips a year back east to visit family and friends. (The “miscellaneous” category in the chart includes small amounts for clothes and household items, but consists mostly of cash expenditures that I didn’t keep track of, probably including some groceries, plus occasional restaurant meals, concerts, movies, and cash spent while traveling.)<br />
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The fact is, I could have lived on 30% less if I’d had to. Or I could have blown that discretionary 30%, and more, on rent or cars or eating out, and ended up feeling like I had no spending money at all.<br />
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I did enter grad school with several advantages. My student loans from college totaled only $4500, with payments and interest deferred until after I was out of school. My parents never spoiled me with big-ticket gifts or large sums of cash, but they did make sure I got started with enough clothes and kitchen utensils. My health was always very good, and health insurance (my only significant medical expense) was cheap back then.<br />
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The moral of the story, for today’s grad students and anyone else who’s interested, is simple: Minimize your major expenses (housing, meals, transportation), try to avoid other expensive habits (smoking, drugs, debts, children), and you can live extremely well on a graduate student’s stipend.<br />
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After I got my degree my take-home pay instantly doubled, and it has continued to rise steadily ever since. But my expenses remained flat, because I was already living an extravagant lifestyle and never had the least desire to spend more. My spending shifted away from books and outdoor toys, since my need for those things was pretty much saturated. I spent less on computers as their prices dropped. I <a href="http://dvschroeder.blogspot.com/2014/03/little-blue-and-big-blue.html">bought a used car</a> in 1991 and bought one and a half new cars (a <a href="http://www.mrmoneymustache.com/2011/11/28/new-cars-and-auto-financing-stupid-or-sensible/">massive extravagance</a>) more recently. I eventually bought a house, and quickly paid off the mortgage, so my biggest housing expenditures are now for major maintenance and upgrades. I still ride around town on my Miyata touring bike, and I still prefer home-cooked meals to eating out.<br />
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My current living expenses, as near as I can figure them, look like this:<br />
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<a href="http://2.bp.blogspot.com/-ww8alHK07sI/VTLFVtCWo_I/AAAAAAAABSE/2CGgqRB2kus/s1600/2015expenseChart.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://2.bp.blogspot.com/-ww8alHK07sI/VTLFVtCWo_I/AAAAAAAABSE/2CGgqRB2kus/s1600/2015expenseChart.png" height="293" width="320" /></a></div>
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The total comes to a little over $20,000 per year, or slightly less than what I spent in grad school when you account for inflation. However, the chart doesn’t include health insurance premiums, which are paid by and through my employer. If I didn’t have employer-provided insurance I would probably buy a “bronze” Obamacare plan and end up paying roughly an additional $4000 a year for premiums and deductibles.<br />
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The “miscellaneous” category in this chart includes clothes, household items, books, subscriptions, toys, entertainment, and bike accessories. I’ve tried to average big-ticket expenditures, like car purchases and home improvements, over a suitable number of years. And I’ve mostly tried to separate my own expenses from those of my better half, which isn’t too hard since she has her own financial accounts and her own house.<br />
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And where does the rest of my income go? Three places: income tax, savings, and donations to a long list of good causes that I’m proud to support. I won’t detail the breakdown among these three categories, but with a little arithmetic you can safely infer that I could have afforded to retire years ago. I’ve become wealthy without ever trying, and, although I know everyone’s situations and priorities are different, I hope my example can help others do the same.<br />
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[For more advice on living a happy life on not much money (or “financial freedom through badassity,” as he puts it), I highly recommend <a href="http://www.mrmoneymustache.com/">Mr. Money Mustache</a>.]<br />
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Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com0tag:blogger.com,1999:blog-1233073253115884208.post-21956952458516712382014-12-05T14:07:00.000-07:002014-12-05T15:59:24.054-07:00First Step to Mars?<a href="http://1.bp.blogspot.com/-CGqNeO8cyro/VIH8HbRRHHI/AAAAAAAABNE/F8jiFlVYHoI/s1600/OrionLiftoffSmall.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="http://1.bp.blogspot.com/-CGqNeO8cyro/VIH8HbRRHHI/AAAAAAAABNE/F8jiFlVYHoI/s1600/OrionLiftoffSmall.jpg" height="320" width="252" /></a>My Facebook and Twitter feeds are currently flooded with news of this morning’s flight of the Orion space capsule, echoing NASA’s claim that this is the “<a href="http://www.nasa.gov/content/successful-launch-of-orion-heralds-first-step-on-journey-to-mars/#.VIH7Y2TF-OM">first step on the journey to Mars</a>.”<br />
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Baloney. That claim, and the whole propaganda campaign that it’s a part of, constitutes outright fraud.<br />
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Sure, there’s a chance that someday a version of the same space capsule will play some role in carrying people to Mars. I’d put the chance below 5%, but who knows? It could happen.<br />
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The claim is still fraudulent, because NASA has no plans for most of the <a href="http://www.orlandosentinel.com/news/space/os-nasa-mission-to-mars-20141202-story.html">remaining steps to Mars</a>:<br />
<ul>
<li>The Orion capsule is far too small for a months-long mission. You can find <a href="http://en.wikipedia.org/wiki/Deep_Space_Habitat">drawings on the internet</a> of proposed larger modules that Orion could attach to, but they’re just drawings. </li>
<li>The Orion capsule can’t actually land on Mars. In fact, no technology that NASA has ever developed is capable of <a href="http://www.universetoday.com/7024/the-mars-landing-approach-getting-large-payloads-to-the-surface-of-the-red-planet/">landing humans on Mars</a>. NASA has some ideas on how to do it, but it’s not clear whether any of these ideas will even work.</li>
<li>There is no consensus on what risk level would be acceptable for a human Mars mission. Is NASA willing to send people on a one-way suicide trip? If not, it also needs to develop a system for getting people back off the Martian surface (not easy!). To increase the chance of survival above 50%, even with reasonably reliable spacecraft, NASA will have to deal with the poorly understood <a href="http://en.wikipedia.org/wiki/Effect_of_spaceflight_on_the_human_body">hazards</a> of radiation, long-term weightlessness, and human psychology. Matching the 98% success rate of Space Shuttle missions is completely out of the question for the foreseeable future.</li>
</ul>
Moreover, even if NASA solves all these problems and actually takes all these further steps to Mars, the Orion capsule will not have been the <i>first</i> step. It is merely another incremental advance, adding to the accomplishments of Mariner, Viking, Spirit, Opportunity, Phoenix, Curiosity, ISS, Mir, Salyut, Skylab, Apollo, Soyuz, Gemini, Mercury, and Vostok.<br />
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The “first step to Mars” claim is fraudulent not only in its promises, but also in its intent. The reason NASA uses this language is because it knows that an honest one-line explanation of the Orion space capsule (“slightly larger version of Apollo with <a href="http://www.scientificamerican.com/article/nasa-s-plan-to-visit-an-asteroid-faces-a-rocky-start/">no definite destination</a>”) wouldn’t grab headlines and generate the public support that it needs to maintain its funding levels.<br />
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Even my well-meaning colleagues who are repeating the “first step to Mars” slogan will usually admit, when pressed, that NASA’s robotic science missions are more important than its human space flight efforts. But, these folks argue, NASA has to keep doing human space flight because otherwise the public—and Congress—would lose interest in space, and funding for the science missions would dry up. And, they continue, human space flight gets kids interested in science, which is always a good thing.<br />
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I know I’ll be called a cynic for writing this essay, but to me it’s the attitude I’ve just described that seems cynical. Why can’t we trust the public by telling them the straight truth about what NASA is and isn’t doing? Misleading people is not only morally wrong—it’s also a bad strategy over the long term, because people will eventually stop believing what you say. Skepticism toward scientists is already at <a href="http://www.huffingtonpost.com/2013/12/21/faith-in-scientists_n_4481487.html">epidemic levels</a> in the U.S., and NASA’s credibility, in particular, has plummeted during the <a href="http://discovermagazine.com/2011/jul-aug/22-how-to-avoid-repeating-debacle-of-space-shuttle">Space Shuttle</a> era. Making empty promises about future Mars missions will only hurt this credibility further, whatever cheering it might stimulate today.<br />
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Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com0tag:blogger.com,1999:blog-1233073253115884208.post-14589801950798034392014-04-16T20:46:00.000-06:002014-04-16T21:08:04.146-06:00Fuel Economy vs. PowerThe recent experience of <a href="http://dvschroeder.blogspot.com/2014/03/little-blue-and-big-blue.html">buying a new car</a> left me angry and bewildered over the meager choices for those of us who care about fuel economy. Here we are in 2014, more than 40 years after the <a href="http://en.wikipedia.org/wiki/1973_oil_crisis">OAPEC oil embargo</a>, and in the U.S. you still can’t buy a liquid-fueled car with an EPA combined rating above 50 miles per gallon. Only a <a href="http://www.fueleconomy.gov/feg/PowerSearch.do?action=Cars&year1=2014&year2=2014&minmsrpsel=0&maxmsrpsel=0&cbftreggasoline=Regular+Gasoline&cbftmidgasoline=Midgrade+Gasoline&cbftprmgasoline=Premium+Gasoline&city=0&combined=40&highway=0&mpgType=0&minMPGSel=&maxMPGSel=&YearSel=2014&MakeSel=&MarClassSel=&FuelTypeSel=Regular+Gasoline%2C+Midgrade+Gasoline%2C+Premium+Gasoline&VehTypeSel=&TranySel=&DriveTypeSel=&CylindersSel=&MpgSel=0400&sortBy=Comb&Units=&url=SearchServlet&opt=new&minmsrp=0&maxmsrp=0&minmpg=0&maxmpg=0&rowLimit=25&pageno=1&tabView=0">handful of cars</a> exceed 40 mpg, and your selection is pretty limited until you get down to mpg ratings in the low 30s. The most efficient <a href="http://www.fueleconomy.gov/feg/PowerSearch.do?action=PowerSearch&year1=2014&year2=2014&minmsrpsel=0&maxmsrpsel=0&cbmcpickupTrucks=Pickup+Trucks&city=0&combined=0&highway=0&mpgType=0&minMPGSel=&maxMPGSel=&YearSel=2014&MakeSel=&MarClassSel=Pickup+Trucks&FuelTypeSel=&VehTypeSel=&TranySel=&DriveTypeSel=&CylindersSel=&MpgSel=000&sortBy=Comb&Units=&url=SearchServlet&opt=new&minmsrp=0&maxmsrp=0&minmpg=0&maxmpg=0&rowLimit=10">pickups</a> and <a href="http://www.fueleconomy.gov/feg/PowerSearch.do?action=PowerSearch&year1=2014&year2=2014&minmsrpsel=0&maxmsrpsel=0&cbmcminivans=Minivans&city=0&combined=0&highway=0&mpgType=0&minMPGSel=0&maxMPGSel=0&YearSel=2014&MakeSel=&MarClassSel=Minivans&FuelTypeSel=&VehTypeSel=&TranySel=&DriveTypeSel=&CylindersSel=&MpgSel=&sortBy=Comb&Units=&url=SearchServlet&opt=new&minmsrp=0&maxmsrp=0&minmpg=0&maxmpg=0&rowLimit=10">minivans</a> get 23 and 24 mpg, respectively. (Throughout this article I’m using city/highway “combined” fuel economy values under the current, less generous, EPA rating system.)<br />
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To some extent the limitations on fuel economy are due to basic physics: air and rolling resistance, braking losses, and thermodynamic limits on engine efficiency. But the existence of the 50 mpg Prius and of <a href="http://en.wikipedia.org/wiki/Volkswagen_Polo">high-efficiency cars sold outside the U.S.</a>, not to mention the 47 mpg Geo Metro from <a href="http://www.fueleconomy.gov/feg/PowerSearch.do?action=PowerSearch&year1=1990&year2=1990&minmsrpsel=0&maxmsrpsel=0&city=0&combined=0&highway=0&mpgType=0&minMPGSel=0&maxMPGSel=0&YearSel=1990&MakeSel=&MarClassSel=&FuelTypeSel=&VehTypeSel=&TranySel=&DriveTypeSel=&CylindersSel=&MpgSel=&sortBy=Comb&Units=&url=SearchServlet&opt=new&minmsrp=0&maxmsrp=0&minmpg=0&maxmpg=0&rowLimit=10">a generation ago</a>, raises the question of why more cars aren’t comparably efficient. The short answer is that most American car buyers don’t care. Or rather, they care much more about other factors such as size, price, appearance, and power. The most interesting of these is power.</div>
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Each year the EPA publishes a <a href="http://www.epa.gov/otaq/fetrends-complete.htm">report</a> under the cumbersome title <i>Light-Duty Automotive Technology, Carbon Dioxide Emissions, and Fuel Economy Trends</i>. All 135 pages of the latest <i>Trends</i> report are informative, but I’ll highlight just Figure 2.3, which shows some trends in fleet-wide averages for new vehicles sold in the U.S.:</div>
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<a href="http://4.bp.blogspot.com/-39CWP2DjY60/U0qzbpQE_oI/AAAAAAAABDY/5KPwe-6c70U/s1600/TrendsGraph.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://4.bp.blogspot.com/-39CWP2DjY60/U0qzbpQE_oI/AAAAAAAABDY/5KPwe-6c70U/s1600/TrendsGraph.png" height="317" width="400" /></a></div>
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First look at the line for weight, which decreased sharply by 20% in the late 1970s (as more people bought small cars), then began creeping upward in the late 1980s (as SUVs became popular). By 2004 the average vehicle weight was back to its 1975 value, and it has stayed there since.</div>
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Simple physics predicts that fuel economy should increase by about the same percentage that weight decreases, all other things being equal. But all other things have not been equal. Since 1975 we’ve seen steady improvements in engine and drive train efficiency, as well as in aerodynamics. Today’s new vehicles are 80% more efficient than in 1975, with essentially no change in average weight.</div>
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My point, though, is that the efficiency gain could have been significantly more than 80%, even with the same weights and the same technologies. Look at the trend in horsepower, which has been rising <i>much faster than weight</i> for the last 30 years. A higher power/weight ratio translates into faster acceleration, but (other factors being equal) lower fuel economy. Let’s quantify these effects.</div>
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A thorough statistical analysis of the acceleration performance of U.S. vehicles was published a couple of years ago (in both <a href="http://web.mit.edu/sloan-auto-lab/research/beforeh2/files/MacKenzie%20&%20Heywood%20-%20TRB%20-%2012-1475.pdf">report</a> and <a href="http://cta.ornl.gov/TRBenergy/trb_documents/2012_presentations/541_MacKenzie%20and%20Heywood%2012-1475%20Poster.pdf">poster</a> formats) by MacKenzie and Heywood of MIT. Their data set of 1500 cars and light trucks came from tests done by Consumer Reports, and was representative of the U.S. auto fleet as a whole. The results are striking:<br />
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<a href="http://2.bp.blogspot.com/-1gBujLbNzzc/U0rLA7JoHMI/AAAAAAAABDo/g3uKmmjjP_M/s1600/MacKenzieHeywoodPlot.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://2.bp.blogspot.com/-1gBujLbNzzc/U0rLA7JoHMI/AAAAAAAABDo/g3uKmmjjP_M/s1600/MacKenzieHeywoodPlot.png" height="288" width="400" /></a></div>
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Whether you look at the median (black curve), the slowest vehicles (red curve), or the fastest vehicles (green curve), 0-60 mph acceleration times are barely over half what they were in the early 1980s. To quote from MacKenzie and Heywood, “Acceleration performance that was typical in the early 1990s would put a vehicle among the slowest on offer today. Even the slowest end of the market (95th percentile) today delivers performance that was reserved for the fastest vehicles (5th percentile) in the mid-1980s.” Some of this increased performance has come from improvements in drive trains and aerodynamics, but most of it is a direct result of higher power/weight ratios. MacKenzie and Heywood found that with other factors held fixed, each 1% increase in power reduces the 0-60 mph acceleration time by about 0.7% for lower-power vehicles and about 0.58% for higher-power vehicles. (I think these values are less than 1% because limited traction prevents a vehicle from using its full power at low speeds.)</div>
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But why should engine power affect fuel economy? The answer lies not so much in basic physics as in the practicalities of engine operation. My amateur’s understanding is that running a gasoline engine at less than its full power means filling the cylinders at less than atmospheric pressure. You then get less force during the power stroke, with a proportional reduction in fuel consumption, while there’s no reduction in the friction between the piston and the cylinder wall—and that friction lessens the efficiency. In other words, a smaller engine running closer to full throttle is more efficient than a larger engine that’s being throttled back to produce the same power output.</div>
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So much for qualitative understanding. What about some numbers? </div>
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I couldn’t easily find a quantitative analysis of the effect of engine power on fuel economy, so I did a quick empirical analysis of my own. Lacking the time to study every vehicle on the U.S. market, I started with a <a href="http://www.examiner.com/slideshow/sales-charts-of-the-top-30-best-selling-cars-of-2013#slide=2">list of the 30 best-selling models</a> in 2013. I then looked up each of these models in the <a href="http://www.fueleconomy.gov/feg/download.shtml">2014 EPA database</a>, and picked out those that come with more than one engine option. I further pruned the list down to pairs of vehicles with different engines but the same (or nearly the same) transmission and drive type, and I eliminated duplicate pairs (e.g., same two engine options with different drive trains, or similar vehicles sold under different names). I also eliminated vehicles with turbocharged engines, which are generally more efficient but add a lot of noise to the data. Finally I was left with 14 vehicle pairs (5 cars, 3 SUVs, and 6 pickups) to compare, and I looked up the engine power for each on the manufacturers’ web sites. Here’s the final list:</div>
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<tr><th style="border-bottom: 1px solid black; text-align: left;">Vehicle (transmission)</th> <th style="border-bottom: 1px solid black;"> Engine 1 </th> <th style="border-bottom: 1px solid black;">HP</th> <th style="border-bottom: 1px solid black;"> MPG </th> <th style="border-bottom: 1px solid black;"> Engine 2 </th> <th style="border-bottom: 1px solid black;">HP</th> <th style="border-bottom: 1px solid black;"> MPG </th> <th style="border-bottom: 1px solid black;"> ΔHP </th> <th style="border-bottom: 1px solid black;">ΔMPG</th> </tr>
<tr><td style="text-align: left;">Chevrolet Impala (auto 6)</td> <td>2.5L 4cyl</td> <td>195</td> <td>24.5</td> <td>3.6L 6cyl</td> <td>305</td> <td>21.4</td> <td>56%</td> <td>−13%</td>
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<tr><td style="text-align: left;">Honda Accord (manual 6)</td> <td>2.4L 4cyl</td> <td>185</td> <td>27.7</td> <td>3.5L 6cyl</td> <td>278</td> <td>21.6</td> <td>50%</td> <td>−22%</td>
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<tr><td style="text-align: left;">Hyundai Elantra (auto 6)</td> <td>1.8L 4cyl</td> <td>145</td> <td>31.5</td> <td>2.0L 4cyl</td> <td>173</td> <td>27.9</td> <td>19%</td> <td>−11%</td>
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<tr><td style="text-align: left;">Nissan Altima (auto CVT)</td> <td>2.5L 4cyl</td> <td>182</td> <td>31.2</td> <td>3.5L 6cyl</td> <td>270</td> <td>25.3</td> <td>48%</td> <td>−19%</td>
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<tr><td style="text-align: left;">Toyota Camry (auto 6)</td> <td>2.5L 4cyl</td> <td>178</td> <td>28.7</td> <td>3.5L 6cyl</td> <td>268</td> <td>24.8</td> <td>51%</td> <td>−14%</td>
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<tr><td style="text-align: left;">Chevrolet Equinox AWD (auto 6)</td> <td>2.4L 4cyl</td> <td>182</td> <td>23.5</td> <td>3.6L 6cyl</td> <td>301</td> <td>18.9</td> <td>65%</td> <td>−19%</td>
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<tr><td style="text-align: left;">Jeep Grand Cherokee 4WD (auto 8) </td> <td>3.6L 6cyl</td> <td>290</td> <td>19.5</td> <td>5.7L 8cyl</td> <td>360</td> <td>15.9</td> <td>24%</td> <td>−18%</td>
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<tr><td style="text-align: left;">Jeep Grand Cherokee 4WD (auto 8)</td> <td>5.7L 8cyl</td> <td>360</td> <td>15.9</td> <td>6.4L 8cyl</td> <td>470</td> <td>14.9</td> <td>31%</td> <td>−7%</td>
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<tr><td style="text-align: left;">Chevrolet Silverado 2WD (auto 6)</td> <td>4.3L 6cyl</td> <td>285</td> <td>19.8</td> <td>5.3L 8cyl</td> <td>355</td> <td>18.6</td> <td>25%</td> <td>−6%</td>
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<tr><td style="text-align: left;">Chevrolet Silverado 2WD (auto 6)</td> <td>5.3L 8cyl</td> <td>355</td> <td>18.6</td> <td>6.2L 8cyl</td> <td>420</td> <td>17.0</td> <td>18%</td> <td>−9%</td>
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<tr><td style="text-align: left;">Ford F150 4WD (auto 6)</td> <td>3.7L 6cyl</td> <td>302</td> <td>17.5</td> <td>5.0L 8cyl</td> <td>360</td> <td>15.9</td> <td>19%</td> <td>−9%</td>
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<tr><td style="text-align: left;">Ford F150 4WD (auto 6)</td> <td>5.0L 8cyl</td> <td>360</td> <td>15.9</td> <td>6.2L 8cyl</td> <td>411</td> <td>13.4</td> <td>14%</td> <td>−16%</td>
</tr>
<tr><td style="text-align: left;">Ram 1500 2WD (auto 8)</td> <td>3.6L 6cyl</td> <td>305</td> <td>19.7</td> <td>5.7L 8cyl</td> <td>395</td> <td>17.3</td> <td>30%</td> <td>−12%</td>
</tr>
<tr><td style="text-align: left;">Toyota Tacoma 4WD (manual 5/6)</td> <td>2.7L 4cyl</td> <td>159</td> <td>19.2</td> <td>4.0L 6cyl</td> <td>236</td> <td>17.0</td> <td>48%</td> <td>−11%</td>
</tr>
</tbody></table>
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The last two columns show the differences in power and fuel economy, respectively, between the first and second engine options. Here’s a plot of these two columns, showing that there’s quite a bit of scatter in the data but the decreasing trend is clear:<br />
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<a href="http://2.bp.blogspot.com/-ZswBI3jvPgU/U0sWvPKJwgI/AAAAAAAABD4/Nc_u4ohqYh8/s1600/PowerAndMPG.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://2.bp.blogspot.com/-ZswBI3jvPgU/U0sWvPKJwgI/AAAAAAAABD4/Nc_u4ohqYh8/s1600/PowerAndMPG.png" height="290" width="400" /></a></div>
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On average, the percentage decrease in fuel economy is about 1/3 of the percentage increase in engine power. So, for example, a 30% increase in power typically results in a 10% decrease in fuel economy.<br />
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On one hand, these results help explain why consumers are so inclined to choose power over fuel economy: In percentage terms, you typically get about <i>three times</i> the added power for every bit of fuel economy you’re willing to sacrifice! On the other hand, MacKenzie and Heywood’s analysis shows that your 0-60 mph acceleration time drops by only about 2/3 as much as the power gain (in percentage terms), or about <i>twice</i> the percentage that the fuel economy drops. And of course, bigger engines are also more expensive. Given that Americans were happy to buy much less powerful vehicles only a generation ago, it’s hard to believe that most consumers are behaving rationally when they choose more powerful vehicles.<br />
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(In some places you’ll read that cars with slower acceleration are less safe—though I’ve never seen any actual evidence for this claim. Leaving aside the likelihood that powerful cars encourage stupid people to drive stupidly, I suppose the argument is that you need fast acceleration to safely merge onto a freeway where traffic is moving rapidly. Yet somehow we still share freeways with heavy trucks and buses and RVs and vehicles towing trailers and quite a few <a href="http://dvschroeder.blogspot.com/2014/03/little-blue-and-big-blue.html">25-year-old economy cars</a>, all with accelerations much slower than that of any of today’s light-duty vehicles. In practice, slow acceleration just means you sometimes need to wait a little longer before it’s safe to merge. It’s really a question of incremental convenience, not safety.)<br />
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Hypothetically, if Americans were willing to go back to the acceleration performance of vehicles made in 1985, we could immediately increase the average fuel economy of new cars by more than 30%. Realistically, that’s not going to happen unless there’s another oil crisis or similar shock to the economy. The most we can probably hope for is that acceleration performance (and vehicle weight) will plateau, so future technological improvements will translate fully into better fuel economy.<br />
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Meanwhile, I wish the auto makers would offer just a few more extra-efficient vehicles of various designs, to give consumers more choice. By combining power levels that were typical of the early 1990s with the best current technologies for engines, transmissions, hybrid systems, and aerodynamics, it shouldn’t be hard to produce a 40 mpg small SUV, a 35 mpg minivan, a 30 mpg pickup, and a 60 mpg subcompact. They might not become the instant market leaders, but they would still get plenty of attention, sell to the niche market of sane consumers, and perhaps raise everyone’s expectations for the future.</div>
Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com5tag:blogger.com,1999:blog-1233073253115884208.post-64794743098339293082014-03-05T19:20:00.000-07:002014-03-06T08:33:08.991-07:00Little Blue and Big BlueI don’t especially like cars. They’re too big and too fast and too <a href="https://www.census.gov/compendia/statab/2012/tables/12s1104.pdf">dangerous</a> and too polluting and too isolating and too <a href="http://www.mrmoneymustache.com/2013/04/22/curing-your-clown-like-car-habit/">seductively comfortable</a> and especially too <a href="https://www.google.com/search?q=too+many+cars&espv=210&es_sm=91&tbm=isch&tbo=u&source=univ&sa=X&ei=Mo4TU9yJHND_oQSoroCYDw&ved=0CCUQsAQ&biw=933&bih=803#q=%22too+many+cars%22&tbm=isch">ubiquitous</a>. For everyday commuting and most errands I’ll stick to my trusty bicycle.<br />
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Still, I have to admit that cars are useful. I bought my first one in 1991 when I moved to a small town in Iowa, because I knew I would occasionally need a way to escape. And I still have that car: a 1989 Toyota Tercel hatchback, now known affectionately as Little Blue. I’m a bit embarrassed to admit that I’ve grown attached to it.<br />
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<a href="http://4.bp.blogspot.com/-uS4KSKjrmrQ/UxfafaddK5I/AAAAAAAABC4/-a2essVNtfs/s1600/LittleBlue.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="http://4.bp.blogspot.com/-uS4KSKjrmrQ/UxfafaddK5I/AAAAAAAABC4/-a2essVNtfs/s1600/LittleBlue.jpg" height="125" width="200" /></a>My parents helped me pick out Little Blue from the classified ads: automatic transmission, 17,460 miles, $6000. A nice practical car for a young single visiting assistant professor, and an easy car to drive and maneuver and park, for someone who didn’t have much experience behind the wheel.<br />
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Oh, the places I went in Little Blue. During my two years in Iowa there were monthly supply runs to Iowa City, occasional trips to St. Louis to see the folks, a canoe outing with five students who all had to squeeze in for the return drive after the other car broke down, a big camping vacation to southern Utah after school was out in 1992, and a spring break (1993) hiking trip to Arkansas (anywhere warmer than Iowa!) when, on the way home near Joplin, Missouri, the differential somehow ran dry and ground itself into smithereens.<br />
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After the move to Utah there were road trips all around the West, mostly to hike and camp in the mountains. I made some of these trips alone, but more often brought a friend or two. Little Blue still reminds me of companions from long ago, including the greatly missed friend who put that big dent near the left front wheel.<br />
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<a href="http://1.bp.blogspot.com/-CcULjWkIhdc/Uxfat2tPe7I/AAAAAAAABDA/tPaMKj_PST4/s1600/BumperStickers.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="http://1.bp.blogspot.com/-CcULjWkIhdc/Uxfat2tPe7I/AAAAAAAABDA/tPaMKj_PST4/s1600/BumperStickers.jpg" height="140" width="200" /></a></div>
Little Blue has accumulated several bumper stickers over the years: <a href="http://www.krcl.org/">Radio Free Utah</a>, <a href="http://saveourcanyons.org/">Save Our Canyons</a>, Kill Your Television, <a href="http://en.wikipedia.org/wiki/Patrick_Shea_(Utah_lawyer)">Down the Hatch (24 years is too long!)</a>, <a href="http://utahnsforbettertransportation.org/">Transit First</a>, Obama ’08, <a href="http://thinkprogress.org/election/2012/05/01/474507/right-wing-claims-obamas-new-campaign-slogan-reveals-his-secret-communist-andor-fascist-allegiances/">FOrward</a>, and <a href="http://www.hrc.org/">=</a>. But the rear bumper faces the noon sun from Little Blue’s parking space, so the stickers that haven’t completely disintegrated are well on their way.<br />
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Since we bought a Prius at the end of 2004, Little Blue hasn’t gotten much use. I no longer feel very safe in such a small car without airbags, and of course the Prius gets much better fuel economy. (Its nickname is the Patriot Car, since you don’t have to attack Iraq to get enough gasoline to run it.) So Little Blue’s odometer has only gradually crept beyond 100,000, even as the passage of time has taken a toll on more and more of its parts. Still, we do occasionally need a second car around town, and the Patriot Car is pretty lousy on snow and on Utah’s unpaved back roads.<br />
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So I’ve just taken the plunge and bought a replacement for Little Blue: a 2014 Subaru XV Crosstrek, known for the time being as Big Blue. It dwarfs Little Blue, even though by today’s standards it’s not especially big. But it’s about the most modest (and most efficient) vehicle you can buy that has high clearance, which I want for those trips into the backcountry. It also has all-wheel drive, so we’ll use it in town when the roads are icy.<br />
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<a href="http://1.bp.blogspot.com/-WDRwC4MVZfo/Uxfa2HdUR5I/AAAAAAAABDI/BfNJwM3SyHA/s1600/LittleBlueBigBlue.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://1.bp.blogspot.com/-WDRwC4MVZfo/Uxfa2HdUR5I/AAAAAAAABDI/BfNJwM3SyHA/s1600/LittleBlueBigBlue.jpg" height="170" width="400" /></a></div>
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I have extremely mixed feelings about buying a new car. It was a <a href="http://www.mrmoneymustache.com/2011/11/28/new-cars-and-auto-financing-stupid-or-sensible/">stupid decision financially</a>, especially since I don’t plan to drive it more than 5000 miles a year. It would have been far cheaper to fix up Little Blue, or to buy a used Subaru or perhaps a Ford Escape hybrid or some other small SUV. But the Crosstrek, which came out only a year ago, is closer to what I really want than any of those older models, in terms of capability and fuel economy. And I’m not enthusiastic about spending the time to shop for and maintain a used car. At this point in my life, my money is worth less than my time.<br />
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It’s fun and informative to compare some of the specifications of Little Blue, the Patriot Car, and Big Blue. Here for each is the curb weight, engine power (including the hybrid drive for the <a href="http://en.wikibooks.org/wiki/Toyota_Prius/Specifications">Prius</a>), and city/highway <a href="http://www.fueleconomy.gov/feg/Find.do?action=sbs&id=5492&id=20934&id=34234">fuel economy</a> under the current EPA rating system:<br />
<blockquote class="tr_bq">
1989 Tercel: 2085 lbs, 78 hp, 24/29 mpg<br />
2005 Prius: 2921 lbs, 110 hp, 48/45 mpg<br />
2014 Crosstrek: 3175 lbs, 148 hp, 25/33 mpg</blockquote>
Although the power/weight ratio is about the same for the two Toyotas, the Prius accelerates much faster—presumably because of its better transmission (CVT vs. three-speed automatic). In practice, both Little Blue and the Patriot Car have consistently beaten their EPA mpg ratings on the highway, but fallen short of them in the city. Probably the same will hold true for Big Blue, but we’ll see.<br />
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I have more to say about power and fuel economy, but that will have to wait for a future blog.Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com3tag:blogger.com,1999:blog-1233073253115884208.post-12517572856121742512013-10-19T11:28:00.002-06:002013-10-22T17:02:21.267-06:00Inventory of Physics Simulations in HTML5/JavaScriptWhen I <a href="http://dvschroeder.blogspot.com/2013/03/javascript-and-html5-for-physics.html">discovered last winter</a> how useful JavaScript and the HTML5 canvas element can be for physics simulations, I was astonished that there seemed to be so few examples of such simulations out there. That situation is rapidly changing. Here’s an inventory of the examples I’m aware of at this time.<br />
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My own <a href="http://physics.weber.edu/schroeder/software/">portfolio</a> of three simulations is unchanged, except for a few bells and whistles added to each of them:<br />
<ul>
<li><a href="http://physics.weber.edu/schroeder/software/demos/IsingModel.html">Ising model</a></li>
<li><a href="http://physics.weber.edu/schroeder/software/demos/MDv0.html">Molecular dynamics</a></li>
<li><a href="http://physics.weber.edu/schroeder/fluids/">Fluid dynamics</a></li>
</ul>
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<a href="http://4.bp.blogspot.com/-ksNnI6voyI8/UmLHpSSB_KI/AAAAAAAAA_E/CSYYq-mHWi8/s1600/MolecularSpeedsScreenShot.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="http://4.bp.blogspot.com/-ksNnI6voyI8/UmLHpSSB_KI/AAAAAAAAA_E/CSYYq-mHWi8/s1600/MolecularSpeedsScreenShot.png" /></a></div>
Over the summer, with support from the Weber State University Beishline Fellowship, our student Nathaniel Klemm ported five of the simulations that my colleague <a href="http://physics.weber.edu/amiri/">Farhang Amiri</a> uses in his general education physics course:<br />
<ul>
<li><a href="http://physics.weber.edu/amiri/director-dcrversion/newversion/ballma/BALLMA_2.1.1.html">One-dimensional projectile motion</a></li>
<li><a href="http://physics.weber.edu/amiri/director-dcrversion/newversion/airresi/AirResi_1.0.html">Two-dimensional projectile motion</a></li>
<li><a href="http://physics.weber.edu/amiri/director-dcrversion/newversion/kepler/Kepler_1.2.html">Kepler’s laws</a></li>
<li><a href="http://physics.weber.edu/amiri/director-dcrversion/newversion/maxwelldist/maxwellDist_1.0.html">Distribution of speeds in a gas</a></li>
<li><a href="http://physics.weber.edu/amiri/director-dcrversion/newversion/ohm/ohm_1.5.html">Ohm’s law</a></li>
</ul>
(The original versions of these simulations were written by Farhang Amiri and <a href="http://physics.weber.edu/carroll/">Brad Carroll</a> in Adobe Director, and runnable through the Shockwave browser plugin. These were part of a <a href="http://physics.weber.edu/amiri/director-dcrversion/movieslist.html">much larger collection of simulations</a> that they developed in the 1990s. Unfortunately, support for the Shockwave plugin is becoming problematic.)<br />
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<a href="http://physics.bu.edu/people/show/duffy">Andrew Duffy</a> of Boston University has created some simple mechanics simulations:<br />
<ul>
<li><a href="http://physics.bu.edu/~duffy/HTML5/">Duffy HTML5 directory</a></li>
</ul>
These would be good examples for a beginning HTML5 developer to learn from, since their code is short and straightforward. (Andrew and I will be giving a workshop on beginning HTML5 simulation development at the 2014 <a href="http://aapt.org/Conferences/meetings.cfm">AAPT</a> summer meeting next July.)<br />
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<a href="http://1.bp.blogspot.com/-QZ8ynlCDy1I/UmLHz63qkcI/AAAAAAAAA_M/TT3hKEVbWE0/s1600/ZeemanScreenShot.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="http://1.bp.blogspot.com/-QZ8ynlCDy1I/UmLHz63qkcI/AAAAAAAAA_M/TT3hKEVbWE0/s1600/ZeemanScreenShot.png" /></a></div>
<a href="http://www.haverford.edu/physics/dcross/">Dan Cross</a> of Haverford College has created two extremely elegant simulations that I especially recommend:<br />
<ul>
<li><a href="http://www.haverford.edu/physics-astro/dcross/projects/zcm">Zeeman’s catastrophe machine</a></li>
<li><a href="http://www.haverford.edu/physics-astro/dcross/projects/nm">Normal mode decomposition</a></li>
</ul>
<a href="http://www.av8n.com/jsd/">John Denker</a> has a simulation that draws hydrogen wavefunction scatter plots:<br />
<ul>
<li><a href="http://www.av8n.com/physics/wavefunctions.htm#sec-animation">Scatter plot of electron probability</a></li>
</ul>
<a href="http://www.oberlin.edu/physics/dstyer/">Dan Styer</a> and Noah Morris of Oberlin College have created a nice demonstration of two-slit interference:<br />
<ul>
<li><a href="http://www.oberlin.edu/physics/dstyer/InterferenceSimulator/">Interference simulator</a></li>
</ul>
This simulation uses the jQuery UI library for its slider controls, which unfortunately makes them unusable on devices that rely on touch events.<br />
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<a href="http://3.bp.blogspot.com/-xASzf5JRXhA/UmLH_kneNkI/AAAAAAAAA_U/XT73aJKDuO0/s1600/GlowScriptScreenShot.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="http://3.bp.blogspot.com/-xASzf5JRXhA/UmLH_kneNkI/AAAAAAAAA_U/XT73aJKDuO0/s1600/GlowScriptScreenShot.png" /></a></div>
<a href="http://www.glowscript.org/">GlowScript</a> is a 3D graphics library built on WebGL, created by David Scherer and Bruce Sherwood who modeled it on their earlier <a href="http://www.vpython.org/">VPython</a> system. GlowScript is accompanied by a web-based development environment that eliminates the need to write HTML, although it can also be used as an ordinary JavaScript library. Some collections of GlowScript examples are posted here:<br />
<ul>
<li><a href="http://www.glowscript.org/#/user/GlowScriptDemos/folder/Examples/">GlowScript examples</a></li>
<li><a href="http://www.glowscript.org/#/user/Bruce_Sherwood/folder/MI/">Bruce Sherwood’s GlowScript examples</a></li>
</ul>
Unfortunately, the use of WebGL makes GlowScript simulations runnable only under certain browsers. As of this writing they will not run on most mobile devices, although some mobile devices offer partial support.<br />
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<a href="http://www.um.es/fem/EjsWiki/Main/Author">Francisco Esqembre</a> of the University of Murcia has created a high-end development environment for quickly creating physics simulations, called <a href="http://fem.um.es/Ejs/">Easy Java Simulations</a>. Although EJS is a Java program, the new version 5 beta release can output stand-alone HTML5/JavaScript code. More than a dozen examples are now posted here:<br />
<ul>
<li><a href="http://www.compadre.org/osp/EJSS/">OSP EJSS page at comPADRE</a></li>
</ul>
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<a href="http://1.bp.blogspot.com/-W9w5-DGmzpI/UmLIGGV_L1I/AAAAAAAAA_c/uN23ZLDo0X4/s1600/PhetScreenShot.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="http://1.bp.blogspot.com/-W9w5-DGmzpI/UmLIGGV_L1I/AAAAAAAAA_c/uN23ZLDo0X4/s1600/PhetScreenShot.png" /></a></div>
The <a href="http://phet.colorado.edu/">PhET</a> group at Colorado has recently gone public with its first six HTML5 simulations for introductory physics and chemistry:<br />
<ul>
<li><a href="http://phet.colorado.edu/en/simulations/category/html">PhET HTML5 simulations</a></li>
</ul>
As you would expect from PhET, these simulations are extremely professional and hence the code, which relies on a vast collection of libraries, is unreadable by mortals.<br />
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All of the simulations listed above were created by (or under the supervision of) academic physicists, primarily for the purpose of physics education. But of course the vast majority of graphics-intensive HTML5 development is being done by game developers. Here are a couple of these efforts that contain good physics and are fun to play with:<br />
<ul>
<li><a href="http://thred.github.io/xkcd-time-catapult/#37b5">xkcd Time Catapult</a> by Manfred Hantschel</li>
<li><a href="http://nerget.com/fluidSim/">Oliver Hunt’s simple fluid dynamics simulator</a></li>
</ul>
And that’s my list for now. If any readers out there would like to add to this list, feel free to leave links (noncommercial, please) in the comments.Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com5tag:blogger.com,1999:blog-1233073253115884208.post-52000823541077325462013-08-27T16:34:00.000-06:002013-08-28T11:57:24.072-06:00College Tuition Has Outpaced Inflation by 237% Since 1978Everyone from <a href="http://www.nytimes.com/2013/08/22/education/obamas-plan-aims-to-lower-cost-of-college.html">President Obama</a> on down seems to be talking about how expensive college has become. Amidst all this talk you hear plenty of statistics, usually quoted without much context, by people who have a political agenda. The Democrats want to <a href="http://www.nytimes.com/2013/07/11/us/politics/democratic-rifts-stymie-senate-bill-on-student-loan-rates.html">make college more affordable</a> for the poor, while the Republicans want to <a href="http://www.nytimes.com/2012/07/30/education/harkin-report-condemns-for-profit-colleges.html">help the rich tap into</a> the tuition gravy train. College <a href="http://www.hastac.org/blogs/cathy-davidson/2013/08/24/why-does-college-cost-so-much-and-why-do-so-many-pundits-get-it-wron">professors</a> and <a href="http://www.tampabay.com/opinion/columns/column-colleges-are-more-than-sticker-prices-salaries/2137968">administrators</a> want to protect their own salaries and budgets. <a href="http://www.mlive.com/opinion/kalamazoo/index.ssf/2012/01/8_theories_on_why_college_cost.html">Everyone</a>, it seems, is an <a href="http://economix.blogs.nytimes.com/2011/02/18/why-does-college-cost-so-much/">expert</a>, and indeed, there is a vast body of <a href="http://trends.collegeboard.org/sites/default/files/college-pricing-2012-full-report-121203.pdf">literature</a> on the economics of higher education.<br />
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So, being a typical curious <a href="http://xkcd.com/793/">physicist</a>, I decided to ignore all this literature and try to get the big picture directly from the most obvious place: <a href="http://www.bls.gov/cpi/data.htm">Consumer Price Index data</a> from the U.S. Bureau of Labor Statistics. The CPI has included a <a href="http://www.bls.gov/cpi/cpifacct.htm">college tuition (and fees) component</a> since 1978, and it’s easy to download the data and compare it to the prices of other goods and services. The results are striking.<br />
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To visualize what has happened since 1978, I chose several other CPI data sets and divided each by its 1978 value to get a consistent baseline. Then, to more or less cancel out the effects of overall inflation, I divided each number for a specific CPI category by the “all items” value. Here, without further ado, are the results:<br />
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<a href="http://2.bp.blogspot.com/-Wm2D18yp7FU/Uh0YSRtkvCI/AAAAAAAAA-I/bZAtVaFJgQ0/s1600/CPIcomparisons.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="280" src="http://2.bp.blogspot.com/-Wm2D18yp7FU/Uh0YSRtkvCI/AAAAAAAAA-I/bZAtVaFJgQ0/s400/CPIcomparisons.png" width="400" /></a></div>
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College tuition has risen far more quickly than any other CPI component that I looked at, with the exception of <i>pre</i>-college tuition (which tracks college tuition very closely). You think medical care has gotten more expensive? In the last 35 years the medical care CPI has exceeded overall inflation by only 92%, while college tuition has outpaced inflation by 237%.<br />
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Shelter (buying or renting a home) has risen in price only a little faster than the overall CPI during this time. The price of energy has been quite volatile, also rising somewhat on average. Food prices have not quite kept pace with the overall CPI. Virtually all categories of manufactured goods, from apparel to household furnishings to new cars, have become much more affordable than they were in 1978.<br />
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In fact, this one graph tells much of the story of the U.S. economy over the last 35 years. Manufactured goods are now cheap because the manufacturing has been either outsourced or automated—and the retailers who sell these goods don’t pay high wages. The money is in professional services like law and finance and medicine and education that can’t easily be outsourced or automated. These professions require a college education, so the demand for college has risen, further driving up its price.<br />
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But where is all that tuition money going? That’s an excellent question, which I’ll try to address in a subsequent post.<br />
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[Addendum: Of course I’m not the first to produce a graph like the one above. <a href="http://www.bloomberg.com/news/2013-08-26/college-costs-surge-500-in-u-s-since-1985-chart-of-the-day.html">Here’s one</a> that appeared online just yesterday, although it doesn’t show as wide a variety of CPI categories and it doesn’t divide by the overall CPI as I did.]Dan Schroederhttp://www.blogger.com/profile/13437237801383466177noreply@blogger.com1