- Renewables accounted for 60.2% of the new U.S. electricity generation capacity for the first three quarters of 2015, according to the "Energy Infrastructure Update" from the Federal Energy Regulatory Commission (FERC) Office of Energy Projects.
- The cumulative installed capacity of biomass, geothermal, hydropower, solar, and wind from Jan. 1 through Sept. 30 was 7,276 MW. It included 2,966 MW of new wind capacity, 40.76% of the total, as well as 1,137 MW of solar, 205 MW of biomass, 45 MW of geothermal steam, and 27 MW of hydropower. Natural gas generation capacity grew by 2,884 MW in the same period.
- In the month of September, wind topped the new generation capacity list with 448 MW, natural gas was second at 346 MW, and solar was third with 20 MW of new capacity.
- Critics point out the renewables numbers — especially those for solar — are underestimated because FERC does not fully account for distributed generation in its reports.
FERC puts renewables at 17.4% of total installed U.S. generating capacity, including 8.59% hydro, 5.91% wind (68,830 MW), 1.43% biomass, 1.13% solar (13,180 MW), and 0.34% geothermal steam. No new nuclear capacity was added in 2015, and only 9 MW of oil and 3 MW of coal.
Because of differing capacity factors, the U.S. Energy Information Administration (EIA) distinguishes between installed generation capacity and actual generation. Its July 2015 report put renewables’ share of net generation at 13.6%.
Renewables advocates say FERC and EIA do not fully account for distributed energy resources (DERs) in their measurements, meaning that actual renewable energy penetration is higher than the figures suggest. Nationwide, rooftop solar is estimated at about 45% of installed solar capacity.
Wind and solar industry policy experts are concerned about sustaining growth. Wind advocates are lobbying Congress to extend or gradually phase out wind’s now-expired $0.023/kWh federal production tax credit. Solar advocates are lobbying to keep Congress from letting its 30% federal investment tax credit revert to 10% for commercial solar and zero for residential solar on December 31, 2016.