Renewables could make up 30% of the US’ energy capacity mix within the next four years, according to new analysis by the non-profit Sun Day Campaign.

Solar PV power capacity installations outstripped that of natural gas last year, according to new data from the Federal Energy Regulatory Commission (FERC), accounting for close to a third (29.7%) of all new additions.

The FERC said in its latest monthly infrastructure report that more than 8.5GW of solar capacity was installed across the country last year, exceeding the additional 6,259MW generating capacity of natural gas. More wind power was installed last year than any other energy source, the federal agency said, with 13,626MW accounting for almost half (47.4%) of new capacity in 2020.

A handful of high-profile US solar projects were connected to the grid at the end of last year, including ENGIE’s 225MW Long Draw Solar Project in Borden County, Texas, and five solar plants operated by Florida Power & Light totalling 372.5MW. December saw a rebound in project completion across the country, following a year of supply chain disruption and construction delays brought on by COVID-19. More than 1.1GW (1,113MW) of new solar capacity was installed in December alone, according to the agency’s data, making it the second fastest-growing energy source in the US behind wind.

Although utility-scale solar capacity grew by 28.9% last year compared with 2019, it still accounts for just 4.32% of the nation’s energy mix, according to FERC, compared with 9.83% for wind and 44.3% for natural gas.

However, US President Joe Biden has signalled strong support for the renewables sector’s growth, signing an executive order last month instructing all federal agencies to procure “carbon pollution-free electricity” alongside zero-emission vehicles, as well as pause new leases for oil and natural gas projects on public lands and offshore waters. The Sun Day Campaign predicts that, with renewables making up just under a quarter (24.1%) of the US’ energy capacity mix today, they are “on track to reach – and likely exceed – 30% of the nation’s total generating capacity by 2025.”

Ken Bossong, the executive director of the Sun Day Campaign, noted that wind and solar combined exceed the generation capacity of nuclear power, which has a 8.6% share of the market.

Bossong said that wind and solar “dominated new capacity additions for yet another year, continuing the nearly unbroken pattern of the past half-decade.”

“Now, with a very supportive Biden Administration and Democratic majorities in the U.S. Senate and House of Representatives, renewables are clearly on course to become the foundation of the nation’s electricity supply.”

FERC’s latest report predicts that an additional 58,629MW of both solar and wind capacity will be added to the grid by December 2023, taking a 27.9% share of the market. Bossong, however, believes this share “could, and probably will, be even higher”.

A statement from the Sun Day Campaign noted that FERC has regularly increased its renewable energy projections in its monthly infrastructure reports over the past few years. “FERC’s first such projection – provided in its March 2019 report,” the statement said, “forecast the addition of 36,608MW of wind and solar during the ensuing three years. In its most recent report, those forecasts had grown to 58,629MW of new solar and wind capacity by December 2023.”