But today, the state and its grid manager are grappling with a strange reality: There is so much solar power on the grid that, on sunny spring days, when demand is lower, solar prices electricity become negative. Gigawatts of solar power are “diminished” – essentially thrown away.
In In response, California reduced incentives for rooftop solar and slowed the pace of panel installation. But dwindling economic returns could slow solar development in a state that has tried to transition to renewable energy. And as other states build more solar plants, they could soon face the same problems.
“These are not insurmountable challenges,” said Michelle Davis, global head of solar at energy research and consulting firm Wood Mackenzie Power and Renewables. “But these are challenges that many network managers have never had to face. »
Solar power has many wonderful properties: once built, it costs almost nothing to operate; it produces no air pollution and generates energy without burning fossil fuels. But it also has a major and obvious drawback: the sun doesn’t shine all the time.
More than 15 years ago, researchers at the National Renewable Energy Laboratory were modeling a future with widespread solar power when they noticed something strange. With lots of solar power on a given power grid, the net load – or electricity demand minus renewable energy – would take the shape of a “U”. Extremely high demand in the morning would be replaced by almost zero demand in the middle of the day, when solar power could produce virtually all of people’s electricity. necessary. Then, as the sun set, demand increased again.
California’s grid operator, known as CAISO, later dubbed this effect the “duck curve.” (If you squint, you can imagine the curve as a duck’s belly.) It’s greatest in spring, when solar panels get plenty of sunlight but there’s less demand for heating and cooling .
In recent years in California, the Duck Curve has become a huge, deep canyon – and solar power goes unused. In 2022, the state wasted 2.4 million megawatt hours of electricity, 95% of which comes from solar sources. (That’s about 1 percent of the state’s total electricity production in a year, or 5 percent of its solar production.) Last year, the state did this in just the first eight months .
Clyde Loutan, director of renewable energy integration at CAISO, says the state has long been prepared for more solar power on the grid. But, he added, “we significantly underestimated how quickly residential solar was going to happen.”
Limiting solar power isn’t technically difficult: According to Paul Denholm, a senior scientist at the National Renewable Energy Laboratory, it’s like flipping a switch for grid operators. But throwing away free electricity drives up electricity prices.
He also undermined the benefits of installing solar energy on the roof. Since the 1990s, California has paid rooftop solar panel owners when they export their energy to the grid. This meant that rooftop solar owners received between $0.20 and $0.30 for each kilowatt hour of electricity they sent.
But a year ago, the state changed that system, known as “net metering,” and now pays solar panel owners only based on the value of their energy to the grid. In the spring, when the duck curve is deepest, this number may drop close to zero. Customers can get more money if they install batteries and feed into the grid in the early evening or morning.
The change sparked a huge backlash from Californians and rooftop solar companies, which say their businesses are in trouble. Indeed, Wood Mackenzie predicts that residential solar installations in California will decline by about 40% in 2024. Some policymakers are now trying to overturn the rule.
“Under the leadership of the CPUC, California is responsible for the largest loss of solar jobs in our nation’s history,” Bernadette del Chiaro, executive director of the California Solar and Storage Association, said in a statement. reference to the California Public Utilities Commission.
But experts say it reflects how the economics of solar energy are evolving in a state that has fully invested in the technology.
“You don’t want the utility or grid operator to overpay for electricity when they don’t have to,” Davis said.
Other states that have been slower to adopt solar energy are starting to experience the same thing. Nevada, which generates 23 percent of its electricity from solar, has also seen steepening duck curves. Hawaii, which has thousands of homes with rooftop solar, has reduced the payments those households receive from the grid.
Beyond the sunny West, many states are still trying to expand rooftop solar and expand its reach beyond affluent households. The Biden administration this week announced $7 billion in grants to provide rooftop solar panels to 900,000 low-income households.
California’s grid operators hope their experience will teach other states what to expect as renewable energy expands. “The problem we’re seeing in the West — no one else has seen it,” Loutan said.
Solar energy can still grow in California. In summer, when heavy use of air conditioning puts a strain on the grid, solar power can be useful even in the middle of the day. Denholm says that as the price of solar continues to fall, installing steadily discounted solar can still be cost-effective. “Throwing away a certain amount of renewable energy can definitely make economic sense,” he said.
But the Californian network manager still hopes to avoid it as much as possible. Loutan called it “one of the last things we want to do.”
To cope, CAISO sells part of its excess electricity to neighboring states; California also plans to install additional storage systems and batteries to conserve solar energy until later in the afternoon. Transmission lines capable of carrying electricity to neighboring regions will also help: some of the lost energy comes from regions where there simply aren’t enough power lines to carry a sudden burst of solar energy .
Denholm says the state is starting to take the necessary steps to address the glut. “There are fundamental limits to how much solar we can put on the grid before we start needing a lot of storage,” Denholm said. “You can’t just sit around and do nothing. »
News Source : www.washingtonpost.com
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