Data through June shows that renewable generation has surpassed levels from previous years in every month so far this year, the U.S. Energy Information Administration (EIA) reports.
Non-hydro renewable sources, including rooftop solar, collectively exceeded 10% of the monthly electricity generation mix for the first time in March and again in April, both months that typically have low electricity demand because of relatively moderate weather.
Non-hydro renewable generation also exceeded hydro generation in each month since February 2016, but after a lengthy drought West Coast hydro generation has moved closer to historical levels.
Non-hydro renewable generation has steadily increased over the past several years, reflecting booming installations of wind and solar farms.
Earlier this month, the EIA, a division of the Department of Energy, projected that carbon-free power generation, which includes nuclear power, in North America will rise to 45% in 2025, from 38% in 2015.
Generation from non-hydro renewable sources first surpassed hydro generation in 2013, according to EIA data.
As renewable energy capital costs have come down, capacity additions from non-hydro renewable sources have accounted for most of the capacity additions in the U.S. over the past three years.
EIA defines renewable sources as both conventional hydro and non-hydro sources such as wind, geothermal, biomass, and solar, larger than 1 MW, except for rooftop solar, which is counted as a renewable resources but does not have to be larger than 1 MW. Hydro and wind facilities under 1 MW are much less common than small solar installation and would contribute only a small amount of generation to the total tally.
Annual hydro generation in 2015 was at the lowest level since 2007, largely because of drought conditions in the Pacific Coast states. Those three states—California, Oregon, and Washington—encompass 50% of all U.S. conventional hydro capacity. But increased rain from the El Nino weather pattern has helped to fill reservoirs in Washington and northern California, bringing hydro generation back closer to historical levels in 2016.