For all the hype surrounding virtual power plants, they’re still a niche player on the U.S. electric grid. A new partnership between three of the biggest residential energy companies in the country — Tesla, Sunrun, and Renew Home — aims to recast VPPs into a leading role.
The companies announced on Wednesday that they have more than 16 gigawatts of dispatchable VPP capacity available today to deliver to utilities and data center developers throughout the country. That’s about the same as 16 nuclear reactors, except instead of generating power round the clock from a central plant, the companies aggregate unused electricity capacity from thousands of individual home solar and battery systems and programmable thermostats, and can make it available for several hours at a time.
Today, the companies bid these resources into electricity markets as a sort of bespoke grid service. A few times per year — often in the summer months when demand spikes — the grid operator in California might ask Sunrun to switch on its VPP to prevent a blackout. That means Sunrun’s rooftop solar and battery customers all either begin exporting excess power to the grid or rely more on their energy storage systems for their own power needs, reducing strain on the grid. Tesla operates similar programs, some in partnership with Sunrun. Renew Home, which spun out of Google Nest, does the same thing but with thermostats and water heaters, nudging temperatures on thousands of devices up or down during peak demand hours.
“A lot of our assets are enrolled in a contract where they can be used up to 20 times per year,” Paul Dickson, the president and chief revenue officer of Sunrun, told me. Now the company, along with its partners, are making the pitch to utilities and hyperscalers to view VPPs as 365-day resources, and more fully integrate them into their grid planning.
It’s a “turnkey” solution, the companies wrote in a press release, “deployable in months, not years,” that requires “no additional hardware, software, interconnection, water, or land usage for offtaking parties.”
VPPs also typically kick back some of the proceeds they earn from the electricity market to the residential customers hosting the solar panels, batteries, and programmable thermostats providing the power, meaning they can meet growing energy demand while helping to lower household energy bills. Sunrun and Renew Home paid out a combined $67 million in customer rewards last year.
About 60% of the 16 gigawatts the companies have available are tied to Renew Home’s enrolled devices, with the remaining 40% coming from Sunrun and Tesla’s solar and battery assets, Dickson told me. The capacity is also spread out geographically. There’s about 1.7 gigawatts available in Texas — the second largest data center market in the country, Dickson pointed out. There’s 300 megawatts available in Virginia, which the companies expect to grow to 500 megawatts by 2030.
“Unlike a traditional power plant that's fixed in size, this number grows every single day as the combined three companies continue to add additional capacity,” Dickson said. Sunrun alone plans to more than double its energy storage capacity by the end of 2028.
If utilities and large industrial customers buy the VPP pitch, the companies will be able to expand even more quickly, he added. If regulators or utilities come back and say, we’ll take your existing capacity today, and if you can add another gigawatt in the next year, here’s what we’ll pay, Sunrun could potentially reduce the upfront cost to customers to host the solar and battery installations, driving faster adoption.
The new partnership follows a similar announcement earlier this month from the VPP company Voltus, which signed a three-year agreement with Google. Voltus will provide up to 100 megawatts per year of capacity for Google in PJM, the country’s largest (and most constrained) electricity market covering much of the Midwest and mid-Atlantic. In that case, however, Voltus is using the deal with Google to finance the VPP, with the capacity set to come online by 2027.
The Tesla/Sunrun/Renew Home group is simply announcing they are open for business — they haven’t signed up any offtakers yet. Dickson told me the companies wanted to “make everybody aware that there is this uncontracted capacity, and make sure that it goes to the place that it can be most impactful.” Wednesday’s announcement is accompanied by a live map that shows where the capacity is. The companies did, however, already bid over a gigawatt of capacity into PJM, the larger energy market that Virginia is a part of, as part of its emergency procurement to meet near-term load growth in the region, and are waiting to hear if they were selected.
Last year, the electrification advocacy group Rewiring America published a paper arguing that hyperscalers could free up grid capacity for at least a third of the load growth expected from data centers if they paid for residential households to get heat pumps. All of that capacity would simply be the result of swapping inefficient appliances for more efficient versions, reducing the overall energy use of the homes. If hyperscalers also financed residential solar and storage upgrades, they could more than meet data center demand, the report posited.
That’s not how these VPP proposals are going to work — residential customers will still have to pay something to Sunrun and Tesla for their solar panels and batteries. But Ari Matusiak, the executive director of Rewiring America, told me he viewed these new VPP partnerships as a step in that direction. Today, energy markets are largely bifurcated between residential market activity and large industrial customers. “Where we are going is toward a world where we think about the household as actual energy infrastructure and not simply an end of the line billpayer,” he said. “Once you start doing that, it changes the economics of how those household upgrades are treated and what the opportunities are.”
