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U.S. energy transitions in one graph

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


To understand what the future of United States’ energy mix will look like in the future, it’s useful to look back at its energy history. This one graph from the U.S. Energy Information Administration tells us a lot about how we have consumed energy in this country:

There are three themes that run through U.S.’s energy history:

  • We go through energy transitions regularly, largely out of necessity (running out of forests or whale oil (Peak Whale) or with the discovery of a better fuel source;

  • We tend to diversify our fuel mix as time goes on (again, finding new, better fuel sources) by adding new fuel sources more than we retire fuel sources;

  • We tend to decarbonize as time goes on (from carbon-intensive wood to coal to petroleum to natural gas).


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The twentieth century saw an explosion of fuels: natural gas was heavily developed, coal reemerged as an electric fuel source, nuclear fission was harnessed for electricity generation while renewables like solar, wind, and hydro grew as well.

We can make an informed guess about the future of the U.S. energy mix and assume that these three themes will continue. It’s likely that we will continue to decarbonize (which we are seeing some with fuel switching to natural gas from coal and an increase in renewables, notably wind generation).

As for the first bullet point, there is an important nuance between past transitions and present day. The impetus to fuel switch was more observable in many cases in the past; one could look out and see a dwindling supply of trees in a forest, or run out of whales.

Energy transitions driven by climate change and carbon emissions are based mostly on indirect observations or anticipated outcomes (rising sea levels, melting glaciers, insects and other biological proxies), rather than, say, stepping outside and “seeing” more carbon in the atmosphere.

David Wogan is an engineer and policy researcher who writes about energy, technology, and policy.

David's academic and professional background includes a unique blend of technology and policy in the field of energy systems. Most recently, David worked at Austin Energy, a Texas municipal utility, implementing a Department of Energy stimulus grant related to energy efficiency. Previously, David was a member of the Energy & Climate Change team at the White House Council on Environmental Quality for the Obama Administration.

David holds two Master's degrees from The University of Texas at Austin in Mechanical Engineering and Public Affairs. While at UT, David was a researcher in the Webber Energy Group, where his research focused on advanced biofuel production to offset petroleum use in the transportation sector. David holds a Bachelor's of Science degree in Mechanical Engineering from The University of Texas at Austin, where he researched nuclear non-proliferation measurement technology.

David is a 2013 Aspen Institute Journalism Scholar, joining a select group of journalists from Slate, ABC News, and The New York Times.

David lives in Austin, Texas. Follow along on Twitter or email him at david.wogan@me.com.

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