The renewable energy sector in the United States generated more energy than coal-fired plants for the month of April, according to data released by the U.S. Energy Information Administration (EIA). That's the first time this has happened, and according to projections from the Institute for Energy Economics and Financial Analysis (IEEFA), it may have happened again in May. Renewables include hydroelectricity, biomass, wind, solar and geothermal.
Renewable energy generated more than 68 million megawatt-hours of power in April, according to the EIA data, surpassing the 60 million megawatt-hours produced by coal that month. As Bloomberg News reports, that's the most clean energy the U.S. has ever produced, and the least coal the country has consumed in years.
In an earlier report, the EIA projected renewable energy will "sporadically" top coal this year and again in 2020.
Coal was replaced by natural gas in April 2015 as the most popular source of power in the U.S., according to the IEEFA.
Some of the renewables' impact, however, is due to seasonal issues. Some coal plants are taken off-line for maintenance in spring and fall when demand is low. Spring also is a peak time for hydro power.
The EIA forecasts renewable energy will produce 18% of U.S. electricity in 2019 and nearly 20% in 2020. The agency expects wind power to surpass hydroelectricity as the leading source of renewable energy this year and next.
"Five years ago this never would have been close to happening," Dennis Wamstead, research analyst at IEEFA, tells CNN. "The transition that's going on in the electric sector in the United States has been phenomenal."
Editor's note: This article has been updated with new information since it was originally published in May 2019.