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A bill advancing through California’s legislature would create pathways for virtual power plants to compete with fossil-fueled peaker plants — a move that could help the state curb its fast-rising utility rates.
Virtual power plants are aggregations of small-scale batteries, electric vehicles, smart thermostats, and other customer-owned devices that can be called upon to provide cheap capacity to the grid. VPP programs already exist in California, but the state’s utility and grid regulatory structures don’t offer a clear way for VPPs to replace peaker plants.
Senate Bill 913, introduced by state Sen. Josh Becker, a Democrat, would allow VPPs to “compete on a level playing field with traditional power sources to provide grid reliability at the lowest cost.” The bill, which lays out a slew of policy changes, passed out of the California Senate Energy, Utilities, and Communications Committee earlier this month, a first step on the way to a potential vote before the full state Senate and Assembly.
Gas-fired peaker plants are a major driver of California’s rising electricity bills. Most of the state’s aging peaker plants are used only during a handful of hours each year when electricity demand is particularly high, but utility customers are required to pay for them to be available year-round in case of emergency.
VPPs can accomplish this job at a much lower cost, their advocates say, because customers have already paid to install these devices in their homes and businesses. The potential is vast: Millions of homes across California have devices that can turn down power use, and hundreds of thousands have batteries that can inject power onto the grid — all of which can be used to reduce the need for those “peaker” power plants.
Still, SB 913 may face an uphill climb, even in California’s Democratic-controlled government.
Pacific Gas & Electric, Southern California Edison, and San Diego Gas & Electric, the state’s major utilities, haven’t openly opposed the legislation. But VPP advocates say the utilities have quietly pushed back against programs that might undermine their ability to invest in — and earn guaranteed profits on — grid infrastructure to serve peak electricity demand.
The California Public Utilities Commission, whose five members have all been appointed by Democratic Gov. Gavin Newsom, has taken a number of actions in recent years that have reduced the ability of customer-owned resources to serve grid needs. Newsom also vetoed a slate of pro-VPP legislation last year.
But Becker and SB 913’s supporters are hopeful that mounting concerns about energy affordability could push the VPP legislation over the finish line this year. The bill is backed by clean energy companies, environmental groups, and consumer advocates.
“This is part of a nationwide effort that you’re starting to see, which is all about making better use of the clean energy resources that people already have in their homes to both lower cost and to improve reliability and to reduce pollution,” Becker, who’s authored several utility cost-containment and VPP bills in the past few years, told Canary Media. “I’m hopeful that now that more and more folks are focused on these things, we can move the ball forward.”
At its core, SB 913 is aimed at answering a fundamental question: How can VPPs reduce our reliance on gas-fired power plants that rarely ever run?
In California, the state’s aging peaker plants are paid to be available through a program called resource adequacy. In recent years, resource adequacy has become an increasingly larger part of customers’ bills, according to the community energy providers that are having to pay higher and higher prices to secure it.
The state’s growing fleet of utility-scale batteries is starting to become available for resource adequacy, but storage can’t meet these requirements on its own. For now, aging gas power plants remain the primary last resort for this critical service, which is meant to prevent blackouts.
Becker estimated that Californians are spending about $1 billion per year to “keep expensive peaker plants available for short-term demand,” both through resource adequacy payments and via state emergency funding to extend the lifespan of three coastal power plants, which were slated to close years ago to reduce their harmful impact on marine life.
“At the same time, we have underutilized assets like home batteries and EVs and smart thermostats,” he said.
SB 913 would order the California Public Utilities Commission to design clearer pathways for those assets to count toward resource adequacy.
That could allow VPPs to help displace gas peaker plants. Overall, VPPs could provide more than 15% of the state’s peak grid demand by 2035 and deliver $550 million in annual utility customer savings, according to a 2024 analysis conducted by the energy consultancy The Brattle Group for GridLab. About $417 million of those savings would come from deferring the need for generation capacity, the report found — a category of costs that includes resource adequacy.
Home batteries have already proved that they’re ready and able to meet these peak grid needs, Becker said. In particular, the Demand Side Grid Support program, one of California’s most successful VPP programs to date, has grown to more than a gigawatt of capacity as of last year.
DSGS has shown that its fleet of home batteries can be relied on much like a traditional power plant. In a test of the program over two consecutive hours during a late afternoon in July 2025, roughly 100,000 home batteries delivered about 476 megawatts of energy — enough power to match the output of a typical gas peaker plant.
Despite this performance, the DSGS program has been severely underfunded over the past two years and is now facing the threat of being disbanded entirely. VPP proponents are pushing legislators and the Newsom administration to keep it alive.
SB 913 largely uses the DSGS program as a model for how the California Public Utilities Commission should order the state’s three major utilities to design broader VPP programs.
“DSGS has been a very successful program, and it’s the thoughtful design elements that have made it that way,” said Erik Lyon, an energy regulatory manager at Renew Home. “That’s the key thing to understand about SB 913. The latest version of the bill actually names DSGS as a model.”
Renew Home manages millions of Google Nest thermostats that control air conditioners and home heating systems to reduce energy use and relieve grid peaks across the country, including in California. But to date, California’s demand-response programs have severely limited the role of such assets in addressing resource adequacy.
There are a lot of reasons for these limitations. Most of the demand-response programs in California require customers and the VPP companies that are enlisting them to undergo complicated and time-consuming enrollment processes, Lyon said. They also impose problematic compensation structures that can penalize participants on the basis of what VPP companies say are inaccurate measurements of how much relief they’ve actually provided to the grid.
The design elements that SB 913 adopts from DSGS, by contrast, offer a lot more flexibility for participants, according to Lyon. The bill instructs the CPUC to “streamline the enrollment process to eliminate these common and well-documented problems” that have been cumbersome for customers participating in traditional demand response programs, he said. And it calls for pathways to allow customers to enroll individual batteries, EV chargers, smart thermostats, or other devices that are actively reducing energy use, he said.
SB 913 also instructs the CPUC to use “weather normalized” approaches to measuring customers’ contributions to grid relief, Lyon said. That could help solve a measurement problem often associated with weather-sensitive devices like thermostats, ensuring that household contributions are emphasized during peak days when they are using more air conditioning or heat but not penalized for low load reductions on mild days, he said.
The California Public Utilities Commission has been leery of relying on demand- response programs in the past. But VPP backers say that perspective is based on its analysis of traditional programs, with all their flaws and gaps in accurate measurement.
Renew Home has been working with other utilities in other states and the companies that manage their home thermostat programs to test and verify more modern approaches to measuring the impact of lots of home thermostats turning down their air-conditioning use in response to utility signals, Lyon pointed out.
This should give the CPUC more confidence that it’s getting the grid relief promised, he said. “You can have statisticians dig around in that data and show how it works in ways that are really hard to fake.”
SB 913 also takes on a key problem for households that are increasingly installing batteries alongside rooftop solar: getting compensation for the power they can feed back to the grid.
Today, almost none of the state’s VPP programs allow that, said Jonathan Hart, policy director at the trade group California Solar and Storage Association.
Instead, those programs only allow homes to reduce their grid consumption to zero, he said — which means “utilities are not really accounting for what could be tapped into.”
State regulators have created some rare exceptions to this “no export” rule — including for the DSGS program. Under those exceptions, companies are allowed to measure the power flowing from batteries to the grid using the battery inverters themselves, rather than the utility-owned smart meters.
What’s missing right now is a way to account for that flow of electrons to the grid for resource adequacy, he said.
SB 913 would explicitly order the CPUC to develop a methodology that will give credit for energy exported to the grid in consultation with the California Energy Commission, which currently manages the DSGS program, and the California Independent System Operator, which manages the state’s transmission grid and energy markets.
That won’t be a simple task. CAISO has traditionally required that any power exported from home batteries must be measured via special stand-alone meters, as is required for utility-scale energy resources.
But these rules designed for utility infrastructure don’t work for programs that need to be cost-effective for homes and businesses, said Kurt Johnson, community energy resilience director at The Climate Center, a nonprofit group that supports SB 913.
The “revenue-grade meters” that CAISO requires battery-equipped homes to install would add an extra $800 to $1,000 per home, Johnson said. “If you require that, you’re going to crush the economics” of VPPs. Modern home-battery inverters and smart thermostats can meter themselves at a fraction of that cost, he said.
Hart noted that CAISO is working on rule changes that could allow distributed energy resources like home batteries to be integrated into its markets.
The grid operator hasn’t yet accepted the idea that VPPs should be able to earn resource adequacy value for battery power that’s exported to the grid, Hart said. But recent proposals that might allow individual batteries to be credited for their exported power indicate that there’s room for compromise on that front, he noted.
Sunrun and Tesla Energy, which collectively manage by far the largest share of rooftop solar–charged home batteries enrolled in DSGS, agree that California is missing out under its current regulatory regime.
“Building on this success means creating long-term pathways for DERs to enter the resource adequacy and CAISO wholesale energy markets,” said Lauren Nevitt, Sunrun’s senior director of policy. “SB 913 endeavors to do just that.”
Colby Hastings, senior director of residential energy at Tesla, said that the company has roughly 3 gigawatts of distributed battery capacity deployed in the state. “Enabling these resources to provide grid value will put downward pressure on rates, but we are not seeing urgency on using them,” she said. “We need faster action.”
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