Power generated by natural gas-fired plants saw the steepest declines on record last year, as coal-fired power continued to slump and power from renewable energy sources continued to rise.
Nationally, natural gas remains the top fuel for electricity, a spot it has held for three years as coal-fired power plants shut down. But power from natural gas fell by 7.7 percent in 2017, a bigger drop than coal-fired power, which fell 2.5 percent, according to the U.S. Department of Energy.
The drop is partially due to decreased electricity demand in 2017.
It has been a decade since natural gas and coal-fired generation both saw declines, and for the first time in a decade no new coal plants were added last year, according to the Energy Department. Coal plants accounted for half of the plant retirements nationally, and more natural gas plants were put online than were retired.
Meanwhile, wind and solar power hit record numbers for power generation -- wind accounted for 6.3 percent of the nation's energy mix, while solar accounted for 1.3 percent.
Hydroelectricity also had a strong year in 2017, thanks so record-breaking precipitation in California, and hydro power generated 7.5 percent of the nation's electricity. But wind is expected to become the dominant renewable energy source in 2019.