On carbon footprints

The last several paragraphs of the “Choke points” editorial imply that since a significant portion of electric power is currently generated from coal, the environmental impact of all-electric vehicles might not necessarily be good. This argument implies that coal-generated power is so inefficient that its presence on the power grid used to charge an EV makes the carbon footprint from an EV exceed that of an internal combustion vehicle. That is not the case.

The direct-drive capability of all-electric cars results in an estimated average 77 percent of the energy used to charge the car reaching the wheels versus only about 30 percent of energy in the fuel consumed by an internal combustion engine. This means that if the process used to generate electricity from fossil fuels is more than 39 percent efficient, then even if all the power used to charge an EV comes from fossil fuels, you still have an operational carbon footprint better than the average internal combustion car.

In April 2017 the average efficiency of coal-fired power plants in the U.S. was 37.4 percent, in the EU 38 percent, in China 38.6 percent, and in Japan 41.6 percent, all very close to or over that break-even point. China’s newest (April 2022) coal power plants run at 49 percent efficiency, and even in Arkansas the Turk coal-fired power plant runs at 42 percent. By now the average efficiency for coal-fired power in the U.S. is probably above the 39 percent threshold; but we are already considerably above the breakeven carbon footprint threshold when you consider that, by 2022, only 60 percent of U.S. electric power generation was from fossil fuels, with the rest coming from sources that do not contribute to greenhouse gases.

Even if increased electricity demand from EVs were completely satisfied by new high-efficiency coal-fired power plants, we would still come out ahead on the carbon footprint. Even better, the 2023 trend was that less than 20 percent of new electric power generation used fossil fuels. Every year the percentage of U.S. power generated by fossil fuels is decreasing. The carbon footprint for operation of an EV is smaller than for a non-EV today, and the environmental benefit for each EV will only get better as fossil-fuel-generated electric power continues to decline.

JOEL C. EWING

Bentonville