By Shelby Fleig

WASHINGTON — Solar power is now the third most popular renewable energy source, behind water and wind, according to a new report by the U.S. Energy Information Administration.

The latest example of its continued growth came on May 9, when the California Energy Commission voted unanimously to require builders to install solar power systems on all new homes. As the American power grid grapples with aging infrastructure, cybersecurity threats and a reliance on fossil fuels, solar offers homeowners a cheaper and cleaner option, according to supporters of the law.

Commissioner Andrew McAllister said the “modestly sized” solar systems will be designed based on the needs at each home to reduce the possibility of creating wasted energy. Homeowners will be less reliant on the traditional grid, he said, and could further reduce their need by investing in panels with storage capability.

“The emergence of super-smart photovoltaic systems is expected to enable owners to participate in” the renewable energy markets “that will strengthen the ability of the grid to help achieve climate change goals,” McAllister said in an email.

If the homes do produce extra solar energy, it could also be transferred directly to the grid, McAllister explained.

However, John Twitty, executive director of the Transmission Access Policy Study Group, told a House subcommittee on May 10 that merging existing and alternative energy sources is a worthy idea, but difficult to implement.

“Making sure it works as it relates to the total grid is one of the challenges today of intermittent resources,” Twitty said at the hearing. “Wind and solar are wonderful and we’re all trying to figure out ways to harness them properly, but when the wind doesn’t blow or the sun doesn’t shine, it’s a real challenge.”

Rep. Kathy Castor, D-Fla., took it one step further, stressing the importance of non-transmission alternatives, such as solar-powered microgrids that run completely independently of a larger grid.

Like California, Florida is increasing its commitment to renewables, completing eight solar projects already this year, according to a separate EIA report released this week.

“Non-transmission alternatives not only have significant environmental benefits but they can help prevent long-term, area-wide blackouts after natural disasters like we saw in Texas and Florida and Puerto Rico this summer,” Castor said.

The California law – the first in the U.S. to mandate solar power in building construction – will reduce greenhouse gas emissions by the same amount as eliminating 115,000 gas-powered cars, according to the California Energy Commission.

Homeowners will also save money in the long run, McAllister said. The Commission estimates that, based on a 30-year mortgage, residents will pay $40 more each month for the panels, but save $80 each month on heating, cooling, and lighting bills.

“These standards help to deliver the clean energy and air that Californians want,” McAllister said. “Nationwide, renewable energy is on the rise. We expect that trend to continue.”

In 2017, Solar power generated 77 million megawatt hours, exceeding biomass power — which involves burning wood, solid waste, and landfill gas — for the first time. Hydropower, the most popular renewable, generated 300 million megawatt hours — about four times as much as solar.