Former Vice President Dick Cheney once said that “Conservation may be a sign of personal virtue, but it is not a sufficient basis for a sound, comprehensive energy policy.” But in the US, increased energy efficiency has helped drive a drop in total electricity use. That, combined with the rise of renewable power, caused the use of both coal and natural gas to decline last year.

The changes, according to the Energy Information Agency, are relatively small. Total electric generation last year was down 1.5 percent compared to the year before, a drop of 105,000 GigaWatt-hours. But both coal and natural gas saw declines that were even larger. Coal use was down by 2.5 percent, a smaller decline than it has seen in many recent years. But the numbers for its future aren’t promising; no new coal plants were opened, and 6.3 Gigawatts of coal capacity were retired in 2017.