Solar energy will play a significant role in decarbonising the US power grid and has potential to provide at least 37% of the nation’s electricity by 2035 and 44% by 2050, versus 3% today, according to a new study released by the Department of Energy (DoE).

Achieving the mid-century target, however, would require America to end its longstanding reliance on fossil fuels to generate most electricity and some $562bn in spending by the federal and state governments, consumers, and industry over the next three decades.

The cumulative savings, the report concluded, could be triple that amount – $1.7trn – from avoided climate change damages and health benefits from air quality improvements.

“The study illuminates the fact that solar, our cheapest and fastest-growing source of clean energy, could produce enough electricity to power all the homes in the US by 2035 and employ as many as 1.5 million people in the process,” said Secretary of Energy Jennifer Granholm.

Getting there requires a “massive and equitable deployment of renewable energy and strong decarbonization policies,” she added. The 310-page Solar Future Study was prepared by DoE’s National Renewable Energy Laboratory (NREL).

The study noted that the US is the largest source of cumulative carbon emissions and the second-largest annual emitter after China. On its current trajectory, the US is unlikely to meet its targets for keeping global temperature rise below 2°C as specified under the 2015 Paris Agreement.

“To help remedy the situation,” President Joe Biden’s administration has set ambitious goals to produce carbon-free electric power by 2035 and shift the US onto an “irreversible path to a 100% clean energy economy, reaching net-zero emissions by 2050,” the study’s authors wrote.

They said reaching this transition would result in an “unprecedented transformation of the grid and broader energy system over the next few decades—a challenging, but achievable, task”.

In 2020, the US installed a record 15GW (on an alternating current basis) of solar and had 76GW at the start of this year – 46GW of utility PV, 28GW of distributed PV and 2GW of concentrating solar power. The study shows that by 2035, the US would need quadruple its annual solar capacity additions.

By 2050, solar energy would provide 1.6TW on a zero-carbon grid – producing more electricity than consumed in all residential and commercial buildings now in the country.

“Decarbonising the entire energy system could result in as much as 3TW of solar by 2050 due to increased electrification in the transportation, buildings, and industrial sectors, according to the study, which lays out a blueprint for solar and wind providing 75% of the nation’s electricity by 2035 and 90% by 2050.

A dramatic ramp of solar energy will require new tools that increase grid flexibility, like storage and advanced inverters, as well as transmission expansion to tap abundant, lowest-cost resources in the desert southwest and West Texas.

The report estimates the 2050 solar target could require use of as much as 10.34 million acres (41,844km2) of land, effectively removing it for other uses in most cases.