Beyond Coal: U.S. Energy in Historical Perspective

I just read a fascinating article 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 Sierra Club’s “Beyond Coal” campaign, funded by Michael Bloomberg).

The article is accompanied by a graph 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.

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 EIA web site and plotted it up as a stacked area chart, going back to 1950:

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.

The advantage of the stacked area chart is that it also shows the total 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) stopped growing 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.

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).

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):

On this graph, a straight, upward-sloping line corresponds to exponential growth (a fixed percentage 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!

I find it remarkable, though, that the log-scale graph of total 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.

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 “primary” energy, and EIA actually has estimates of primary energy use, 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:

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 energy flow chart from Lawrence Livermore National Lab.)

(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 other 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.)

Looking at the graph above, notice that coal provided more than half of all 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 heated with coal; 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.

Again it’s also useful to plot the same data on a logarithmic scale, with no stacking:

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.

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 BP Statistical Review of World Energy. The data in the BP Review goes back only to 1989, but at least it gives the big picture since then.

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 coal use in China, 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 not included in the graphs on this page.

Adopt-a-Weed Report, May 2012

It’s been a productive weed-pulling season in Ogden’s foothills.

Our most visible weed is dyer’s woad, with its upright stalks topped with a head of yellow during May. Ridding the foothills of this invasive plant may seem hopeless, but the Ogden Sierra Club has made a significant dent by “adopting” a 10-acre area above the 22nd Street trailhead and returning there to pull the dyer’s woad each spring. If I’ve counted correctly, this was our eighth year working in this area, and I’m delighted to report that we’ve made great progress. The plants do keep coming back, but they’re much thinner than before. This year it took only two hours for four of us to cover the entire area. (I went back for another half hour, a week later, to get the late bloomers.) In coming years we should be able to expand our adopted area to the north and/or south.

Most of Ogden’s trail users now seem to be aware of the dyer’s woad problem, and many will pause along a hike to pull a few plants. But to make real headway against this weed, our “adoption” method—spending a few hours working the same area each year—seems to be the key. I hope more groups will try it.

Meanwhile, two years ago I learned about myrtle spurge, a weed that’s still far less widespread than dyer’s woad but well established in a few dense infestations. One of those is at the 27th Street trailhead, and I personally adopted it two years ago. The strategy was to start pulling plants at the perimeter of the infestation and gradually work inward, containing and reducing the affected area.

Follow-up is also crucial with myrtle spurge, but it’s much easier because the plant grows more slowly than dyer’s woad. It’s taken me only about an hour each season to pull the small plants that are trying to come back in the areas that are already purged of mature plants. Now, after three seasons of work, the infestation is reduced to a single patch between the westernmost trail and a resident’s fence.

Skiing Wheeler Creek

Without a doubt, Ogden’s best easy ski touring is on the Wheeler Creek trails, below Snowbasin. While the better skiers are risking their lives on higher, avalanche-prone slopes, I find plenty of challenge--and great exercise--on twisting, narrow trails over gentler terrain.

My favorite tour, when snow conditions allowed, was to ascend the East Fork of Wheeler Creek from the Art Nord trailhead to Green Pond. After an initial 1.5-mile climb, the terrain opens out and you’re suddenly rewarded with an expansive view of Mt. Ogden and its satellite peaks. The photo above was taken from that magical spot on my very first trip up this trail, 15 years go. (That’s Jock up ahead.)

The final leg of the three-mile trail to Green Pond is now crossed by the new Snowbasin highway, which has ruined several of the old routes in the Green Pond area. So now the best option is to stop just short of the highway and descend the lovely trail along the Middle Fork of Wheeler Creek, closing a five-mile loop either on the old highway (now unplowed and groomed for skate skiers) or on the more challenging trail that parallels the highway just to the north. Ten of us went on a Sierra Club outing around this loop last Sunday, enjoying it as much as ever.

Fifteen years ago, navigating any of these trails in winter required good route-finding skills and a high tolerance for oak brush. But the Forest Service rebuilt all the trails shortly before the 2002 Olympics, clearing the brush and building excellent bridges across the many tributary creeks. Now the trails get packed down by snowshoers soon after each storm, so navigation is rarely a challenge.

The East Fork / Middle Fork loop outlines a small peninsula of public land, bordered by private land on the east, west, and south. It’s just a matter of time before those private lands will be developed with trophy homes and golf courses. The solitude and sense of remoteness will then be nearly gone, but at least the trails themselves will remain.

Last Printed Edition of the Outings Guide?

The Ogden Sierra Club Outings Guide is now being printed. If anyone out there is waiting to buy a copy, we should have them in a week or two.

The changes since the last (2004) edition are numerous but minor. I’ve squeezed in descriptions of three new trails, tweaked the descriptions of many others, and updated several of the maps. The length is unchanged (112 pages), as are the illustrations and most of the page layout.

Shown here is one of the delightful chapter-opening cartoons, which were drawn before my time (1980s or perhaps earlier) by someone I’ve never met (Richard Hogue). It’s an honor to work on a project that so many others have lovingly contributed to over the decades.

Since the Guide went to press, one person has already requested an electronic version of it. This leads me to ponder its future, and the future of books more generally, as the world rushes into the internet age.

Technology has already had a big impact on the production and appearance of the Outings Guide. The first three editions were produced with typewriter, scissors, and tape. Some of the maps were hand-drawn, while others were copied (with permission) from newspaper clippings. A copy shop then reproduced the pages using an analog photocopier.

When I took over as editor in 1998, the production process went digital. I typeset the text (using TeX, the same software I use to write physics books and class handouts), scanned the line drawings, and produced new shaded-relief maps based on digital elevation data. I recall delivering that edition to the copy shop on a Zip disk, from which they uploaded it to their digital copier. In the 2004 edition we switched to FTP and offset printing.

To the end user, however, the format of the Guide is still unchanged: a pocket-sized soft-cover black-and-white booklet, printed on dead trees.

An electronic final version would be environmentally preferable, and would make my life easier in several ways. No more agonizing over the locations of page breaks, or over how much information to try to squeeze onto a tiny black-and-white map. No more running around town making deliveries. No more having to wait until the inventory is depleted before making updates.

On the other hand, the initial creation of a usable electronic version would be a major challenge, in terms of both programming and design. Sure, it’s easy to brainstorm about full-color zoomable maps with links to and from a searchable database of trail descriptions and photos. But I’ve done enough programming and web design to know that producing such a software package wouldn’t be easy.

To their credit, Weber Pathways has put an electronic version of their trail map on the web. As you roll the cursor over an alphabetical list of trail names, the trails are highlighted on the map. You can click on a trail name to see a text description of the trail, and you can restrict the list to trails of a chosen difficulty level if desired. With a bit of patience I can even view this map on my iPhone, if I’m in a location that has service.

But the Weber Pathways electronic map isn’t perfect. The map is extremely small and can’t be zoomed. Nor can you identify a trail by pointing at it on the map. You can’t access the map while exploring the more remote parts of the county. And notably, the electronic version of the map is now out of date, compared to the latest printed edition. 

Are there better examples of electronic trail maps? If so, I’d love to see them. But I’m doubtful, because solving one problem would probably create others. A fancier web site could be prohibitively expensive to create and maintain. A stand-alone mobile app could have a slicker user interface, but would be unavailable to anyone who doesn’t have the right gadget.

The long-term maintenance issue is especially troubling. Already, the production process for our Outings Guide has become so technical that I would have a lot of trouble finding another volunteer to take it over. Switching to an electronic Guide would ratchet up the geek level a couple more notches, and might require hiring a professional programmer. And while it’s easy in principle to update an electronic document, in practice it can become a burden and even an expensive necessity, as hardware and software quickly evolve.

Then there’s the question of money. Selling Outings Guides has been our group’s main source of income over the years. But nobody is willing to pay to access a web site, and at least for now, the market for a mobile app of this type isn’t large enough to cover the cost of hiring someone to produce it. (Weber Pathways operates on a much different business model, raising money from charitable contributions and mostly staying out of politics. We need organizations like that, but they can’t do everything.)

The good news is that we’re printing enough paper copies of the Outings Guide to last another four or five years. By then technology will have progressed, and perhaps the right way to do an electronic Guide will be obvious.

I’ll promise one thing now, though: As long as I’m the editor, the Guide will continue to include Richard’s cartoons.