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Solar + storage
Solar + storage: how rooftops became California’s newest power plant
Solar panels make power when the sun shines; batteries let that power show up when the grid needs it. Together they built the biggest residential VPPs in the country.
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The short answer
- Solar alone isn’t a VPP asset — it can’t be turned up on command at 6 p.m. Paired with a battery, it becomes the core of the largest VPPs in the country.
- California proved it on Sept. 9, 2026: more than 140,000 batteries delivered over 580 MW during a heat wave, and Brattle estimates 700 MW of enrolled capacity saved $206 million (pv magazine USA).
- Per-battery pay is modest — roughly $50 to $450 a year — but it stacks on top of solar bill savings, and some fleets average more (Lunar Energy).
- Policy risk is high. California’s DSGS program depends on annual state funding, and new VPP bills await the governor’s signature.
What a solar-paired battery earns in California
Published annual or seasonal payments per battery. Ranges reflect event count and battery size.
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How solar companies became power plant operators
Sunrun reports more than 56,000 customers enrolled in CalReady, paid $50–$150 per battery a year while Sunrun keeps a 20% reserve for outages (Sunrun). Lunar Energy’s Gridshare software manages about 130,000 Sunrun batteries and reports an average of $464 a year per battery (Lunar Energy). Enphase points to Massachusetts ConnectedSolutions customers averaging about $1,500 a year (Enphase).
Outside California, the Department of Energy highlights San Diego Community Power’s Solar Battery Savings program ($0.10 per kWh discharged on peak, with a budget used up in three months) and Puerto Rico’s LUMA program, which pays $1.25 per kWh through aggregators and has more than 7,000 participants (DOE Liftoff).
Does a battery pay on time-of-use rates?
Solar plus storage savings before any VPP payment, by utility rate.
Method and caveats
Figures are from program operators and trade press and are not independently audited. Lunar’s average reflects its fleet’s mix of programs. Checked October 1, 2026.