SACRAMENTO, Calif. — It’s a common sight across the state: suburban homes covered in solar panels.
But as California moves toward its ambitious clean energy vision, an almost counterintuitive challenge has emerged: The state is at times generating more solar energy than it can handle, to the point where vast amounts of clean energy are being wasted.
The phenomenon that other states are likely to encounter as they increase their solar production has been dubbed the “duck curve.” The duck’s belly is the time of day when solar production can exceed demand. Because solar energy relies on the sun, the curve is usually more pronounced on sunny days in the spring, when not as many people are using electricity or running their air conditioners.
“When we get to certain times of the year, particularly in the spring, when the demand for electricity is not as high, and under certain conditions, we have quite a bit of solar generation that we have more than California can really use,” said Elliot Mainzer, CEO of the California Independent System Operator, which manages 80% of the state’s electricity.
“Under these conditions, we benefit from significant transmission connectivity to other parts of the West and we export much of that energy to other utilities in the Western United States,” he said.
“And under some extreme circumstances, we actually have to restrict it and shut it down,” he added.
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In recent years, the amount of renewable energy constrained or wasted, both by oversupply and so-called congestion—when some areas have more electricity than transmission lines can handle—has skyrocketed, according to Independent System Operator data. So far this year, the state has lost about 2.6 million megawatt-hours of renewable energy, mostly solar—enough to power all homes in San Francisco for a year.
Mainzer argues that adding transmission lines will help increase the flow of electricity across the state, and permitting reform is needed to make that happen
“When you build a new solar project or a new battery or a new wind project or a new geothermal resource, if you don’t have transmission lines to access it and get it to customers, that generation is basically an island. It’s stranded,” he said.
Gov. Gavin Newsom’s administration is also pushing to add more batteries to store that excess energy for use during peak demand times. And state regulators at the California Public Utilities Commission have taken a more controversial approach: They’ve drastically cut financial incentives for homeowners who want to install solar.
The move has angered many in the rooftop solar industry, such as Ed Murray, president of the California Solar and Storage Association, which operates Aztec Solar outside Sacramento. He said the changes were devastating to his business. He said he laid off 10 employees in the past year.
“Sales stagnated because nobody wanted it anymore,” Murray said. “It wasn’t productive or cost-effective to do solar, and now we had to try to figure out what to do.”
According to the California Solar and Storage Association, residential solar installations are down 66% in the first quarter of 2024 compared with the same period in 2022. The trade group estimates that 17,000 green jobs have been lost statewide since the state changed its incentive structure, known as net metering.
To make it more cost-effective with the state’s new incentives, homeowners now have to install batteries in addition to solar panels, but that can cost an additional $10,000 to $20,000 or more.
“It’s an easy solution, but it’s an expensive solution,” Murray said, “because people don’t want it or can’t afford batteries, unfortunately.”
Newsom defended the state’s policies in a statement, saying the state has had about 100 days this year where clean energy exceeded 100 percent of demand for part of the day.
“No state in America comes close to the solar production of California,” he said. “We are producing nearly twenty times more solar than we did a decade ago, providing clean energy to millions of homes. And now we are adding more batteries faster than ever to help capture that energy for use at night.”
Supporters of the state’s change in incentives also point to equity concerns, arguing that switching to solar power could increase the cost of energy for those who don’t have or can’t afford it.
Net metering “has left an incredible legacy and brought solar power to hundreds of thousands of Californians, but it has also been prohibitively expensive for non-solar customers and is long overdue for reform,” Public Utilities Commission member John Reynolds said in a 2022 announcement.
Murray disagrees, saying most of his clients have annual salaries between $50,000 and $60,000, many of which are financed with loans at a time when interest rates are skyrocketing.
Given California’s leadership role in solar energy, Murray believes other states could follow suit.
“I’m hearing from Florida, Arizona, Minnesota, Massachusetts that they’re thinking about copying the rules, changing the rules of the game,” he said. “They’re upset because it’s going to hurt all parties.”
“As we move forward, so does California, and so does the rest of the country generally,” he added.
As California enters full steam ahead with its historic clean energy transition, with a goal of reaching 100% clean energy by 2045, it’s an example of how new challenges are casting a shadow on the path to a renewable future.
“There’s no way we’re going to get there without rooftop solar,” Murray said. “Electric vehicles, heat pumps, electric stove tops — these things are not going to happen without solar. Period.”
This article was originally published on NBCNews.com