“Conservatively, over the next three years, renewables should expand from about a quarter of the nation’s generating capacity today to at least 30% and probably more,” says Ken Bossong, the non-profit research group's executive director.

Solar energy added 9,604 MW in the first 10 months of 2021 and wind added 8,580 MW, with growth significantly higher than the first 10 months of 2020, FERC said in a Dec. 20 update. Hydropower, geothermal and biomass added an additional 71 MW during the same time period.

New natural gas-fired capacity added 3,549 MW, while coal added 11 MW and oil-fired capacity added 19 MW, FERC said.

Solar generation during the first 10 months of 2021 rose about 28% and wind about 11% over the same period in 2020.

FERC also estimated the amount of wind and solar generation in the pipeline through 2024—deeming as “high probability" the addition of 52,692 MW of solar and 23,180 MW of wind.

The Energy Information Agency expects about 20,000 MW of new solar capacity to be added in 2022 alone.

But there are still bumps for states in deploying solar energy to meet ambitious carbon reduction goals.

Massachusetts in 2020 had high hopes of adding 3,200 MW of solar capacity to meet its climate goals by financially supporting small projects, but progress was mired in bureaucracy, say critics.

The state Dept. of Public Utilities on Dec. 30 cleared the way for faster project approval of solar capacity needed for Massachusetts to meet its goal to halve greenhouse gas emissions by 2030, the agency said. It needs to add 7,000 MW of clean energy to meet the goal. 

A spokesman for the state Executive Office of Energy and Environmental Affairs, said the agency order set "a runway to support twice as much solar capacity."

Advocates say delayed rooftop and small-scale solar projects can start claiming incentive awards by mid-January.

About 3.4 GW of solar, ranging from massive grid-scale projects to smaller distributed arrays, was generating power in Massachusetts as of third quarter 2021. Under the state's "most likely" capacity forecast for 2030, about 7 GW of new clean electricity will need to be built there, of which the expanded solar incentive program will deliver 3.2 GW.

California has had major success in adding solar generation under its net metering program that requires utilities to pay customers for excess power they generated and sent back into the grid.

But with growing pushback from utilities that say non-solar customers unfairly subsidize grid costs for solar customers, the state Public Utilities Commission has proposed to end the program it claims “disproportionately harms" low-income ratepayers.

Instead, it would offer payments to customers who add storage to their solar systems for excess capacity they generate in daytime for use at night. The new program would reduce demand for fossil fuel-generated power needed for homes and businesses during the peak evening time.

The revision was introduced by former Commissioner Martha Guzman Aceves, who was nominated in December by President Joe Biden to lead the U.S. Environmental Protection Agency region in San Francisco.

The proposal also creates a $600 million fund to support clean energy and energy storage programs for low-income residents.

Even so, solar companies and industry advocacy groups such as the Solar Energy Industries Association said higher costs under the proposal would hurt the state's solar growth by lengthening the time it takes for  customers to earn back their initial investments through lower electric bills. SEIA termed the new approach would create the “highest solar tax in the country and tarnish the state’s clean energy legacy.”

An agency vote is expected at the end of January.

Meanwhile, technology developments aim to lower deployment costs. The National Renewable Energy Laboratory and Sandia National Laboratories are working on a technology that could boost the U.S. solar panel manufacturing industry's competitive stance against cheaper Chinese imports, officials say.

Early next year “perovskite cells” will be deployed at Sandia’s solar testing site, to demonstrate in a field setting their touted improved ability to convert solar energy to power over typical photovoltaic silicon cells. Until now, the new cells have been subject to laboratory tests only.

In addition, a new solar roofing tile made by giant asphalt roofing shingle company GAF, called Timberline Solar, incorporates solar technology into standard roofing materials and procedures, according to the company.

“Timberline Solar installs like a regular roof, with only a nail gun required,” GAF says, adding that installation requires traditional roofing crews and supplies. The product is available in certain U.S. locations for the home construction market.