Coal is the dirtiest of the fossil fuels, both for its contribution to the standard pollutants like particulates and sulfur, but also because it emits more carbon per unit of energy produces than natural gas or petroleum. Thus, it’s good environmental news that, in the last couple of decades, US coal has declined to just 9% of total US primary energy consumption. The US Energy Information Administration reports: “In terms of coal’s total primary energy content, annual U.S. coal consumption peaked in 2005 at about 22.80 quads and production peaked in 1998 at about 24.05 quads.”

(For the curious, “primary” energy consumption refers to the original source of the energy. “Electricity” is not included, because electricity needs to be generated from something else like a natural gas power plant or a solar panel–electricity is not a primary source of energy by itself.)

(For those still more curious, NGPL refers to “Natural Gas Plant Liquids,” which are hydrocarbons like propane, which are separated from natural gas at processing plants.)

(For the additionally curious, the “renewable” energy category here includes hydropower, wind, solar, and biofuels like ethanol and wood. Of the 9% of total US energy consumption that traces to renewable energy in 2023, about three-fifths is biomass, like ethanol and wood. Not quite one-third of the 9% of US energy consumption from renewable energy in 2023 traces to wind and solar.)

But there was a time a half-century ago, when promoting coal use was a primary energy policy for the US government. Karen Clay, Akshaya Jha, Joshua Lewis, and Edson Severnini provide the background as part of their overall history in “Carbon Rollercoaster: A Historical Analysis of Decarbonization in the United States,” in the Summer 20205 issue of the Journal of Economic Perspectives (where I work as Managing Editor). 

If you flash back to a half-century ago, you may know that in 1973, the members of OPEC, the Organization of the Petroleum Exporting Countries, embargoed oil exports to the United States and any other countries that had supported Israel during the Yom Kippur War.  As Clay, Jha, Lewis and Severnini write: “The real price of imported oil rose dramatically, from $10.67 per barrel in 1972 (in 2007 US dollars) to $36.05 in 1974 (Seiferlein 2007, p. 171). Turbulence in the Middle East kept prices high. Unrest in Iran and the Iran-Iraq War caused further disruption, driving oil prices to $62.71 per barrel in 1980.”

In response, one policy goal of the time was to shift US energy use away from oil. The authors report:

Various regulations passed during and after the crisis reinforced the continued use of coal in electricity and other sectors. The first major piece of legislation was the Energy Supply and Environmental Coordination Act of 1974, which required that, if feasible, electric power plants burning oil and natural gas would have to convert to coal (Meltz 1975). This law was then largely superseded by the Fuel Use Act of 1978. Edward Lublin, Acting Deputy Assistant General Counsel for Coal Regulations in the Department of Energy, wrote: “The Fuel Use Act prohibits new facilities and allows DOE to prohibit existing facilities, from using petroleum or natural gas as a primary energy source unless DOE determines to grant to such facility an exemption from the Fuel Use Act’s prohibitions (Lublin 1981, p. 355).” This pro-coal legislation was often justified in terms of energy independence, given the abundant US reserves of coal. The legislation covered both electric utilities and major industrial fuel-burning installations …

The Three Mile Island nuclear powerplant meltdown happened in March 1979. Thus, an additional policy goal at this time was to shift away from nuclear. The authors write:

After Three Mile Island, no new nuclear power plant construction was authorized until 2012. Because nuclear plants displaced coal-fired electricity generation—one gigawatt-hour of nuclear generation resulted in a roughly 0.8 gigawatt-hour decrease in coal-fired generation historically (Adler, Jha, and Severnini 2020)—the nuclear upheaval kept coal consumption higher than it would otherwise have been.

One additional step was that the anti-pollution efforts of the original Clean Air Act had the useful effect of reducing “conventional” pollutants like ozone, particulate matter, carbon monoxide, and others. However, reducing carbon emissions was not yet on the policy agenda. Reducing these other pollutants had a tradeoff that coal was burned with lower efficiency–which meant that more carbon was emitted.

[E]fforts to cut local air pollution often increased carbon emissions. The 1970 Clean Air Act and subsequent amendments in 1977 coincided with less efficiency in converting coal to electricity sold and higher carbon emissions … The aggregate implications of this shift from 1970 to 1990 are meaningful: annual total carbon emissions in 1990 from coal-fired generation was 1,607 million tons, but would have been 1,415 million tons if the same amount of coal-fired electricity had been generated at 1970 levels of carbon emissions per gigawatt-hour. Similarly, the aggregate kilowatt hours of electricity sold per ton of coal burned decreased from 2,529 in 1970 to 2,065 in 1990. Thus, regulation increased coal consumption and carbon emissions.

Putting all of these together, “By 2005, coal consumption was five times what it had been in 1960.”

One of my complaints about the world, which I’m confident will never really be addressed, is that those who advocated for policies that turned out to have undesireable tradeoffs pretty much never acknowledge that reality. The US economy doesn’t really start getting off coal until the fracking revolution greatly expanded the supply of natural gas (as shown by the light blue area in the figure above). But what if it had been possible to move to natural gas sooner? Or France reacted to the OPEC oil embargo of 1973 by building nuclear power plants, which means that France’s carbon emissions have been quite low since then. Perhaps the worst thing about the US stepping away from nuclear is that several decades went by without intensive research on how to make the technology safer. What if solar and wind technology could have been accelerated as well? The carbon from the additional coal that was burned from, say, 1975 to 2005 is still in the atmosphere now, and will remain there for a very long time.

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