Sunrun sells home-battery capacity into Voltus's data center program, skipping the queue

Sunrun has agreed to supply capacity from a portion of its thousands of residential storage-plus-solar systems in the PJM and MISO regions to Voltus's Bring Your Own Capacity program, which markets capacity to AI data center developers ^[1][2]. The interesting part is procedural rather than technical: a developer that cannot get a utility approval on its own schedule can instead assemble accredited capacity that already sits on other people's roofs ^[3].

Voltus launched BYOC in October last year, positioning it as an alternative pathway to interconnection built on existing grid flexibility, with its virtual power plant platform delivering market-accredited capacity ^[4][3]. Voltus claims developers using the model can bring their own capacity stack to utilities and secure approvals and build-outs years ahead of schedule ^[5]. That claim is the whole commercial proposition, and it is the company's own. What is verifiable is the customer list: Voltus has signed a 100MW BYOC agreement with Google covering operations across PJM, and has partnered with Octopus Energy US to build flexible capacity portfolios for data center firms under the same framework ^[6][7].

Sunrun CEO Mary Powell said the capacity from home batteries is "supported by funding from hyperscalers" ^[8]. Read that literally and the direction of the money is the story: data center balance sheets are now underwriting hardware installed in houses, because the houses are already interconnected and a new substation is not. Voltus CEO Dana Guernsey framed BYOC as turning distributed resources into capacity the grid can count on ^[9].

This is the second Voltus-Sunrun deal. In June the two companies, with Tesla, signed an agreement to aggregate more than 16GW of residential capacity across the US for sale to hyperscalers and utilities, drawing on home batteries, smart thermostats and vehicle-to-grid devices already installed ^[10][11]. Voltus says it connects distributed resources to all nine North American wholesale markets and has more than 7.5GW of DERs in operation ^[12]. So the June ambition is roughly 2.1 times the fleet Voltus currently operates ^[1], and the Google contract, the largest BYOC deal disclosed, is about 1.3 percent of that operating fleet ^[2]. Sunrun, founded in 2007, is the largest US provider of residential photovoltaic and battery systems, which makes it the most plausible single source of that incremental volume ^[13].

The announcement withholds the numbers an operator would need to size this. There is no megawatt figure for Sunrun's contribution, no contract term, no price, and no statement of what participating homeowners receive ^[3]. "A portion of its thousands of systems" is a range wide enough to cover almost anything ^[2].

Watch three things. First, how much of the 16GW aggregation converts into capacity that clears market accreditation, since accredited megawatts and installed megawatts are different quantities and only the former is sellable under BYOC ^[3][11]. Second, whether utilities in PJM and MISO actually treat a delivered capacity stack as grounds for faster approval, which is the specific claim Voltus is making rather than a demonstrated outcome ^[5]. Third, the homeowner side of the ledger: batteries dispatched for a data center's capacity obligation are batteries not available for the household, and neither company has published those terms ^[3].