California virtual power plants are receiving a clearer regulatory path after the state approved two electricity measures on Sept. 30. SB 913 sets a June 2028 deadline for updated grid participation rules, while SB 905 addresses utility planning and costs. The changes affect energy providers, battery owners and customers tracking electricity bills.
Key Takeaways
- California approved SB 913 and SB 905 on Sept. 30, 2026.
- SB 913 directs state regulators to update market pathways for aggregated energy devices by June 30, 2028.
- Sunrun and Tesla reported a 580-megawatt residential battery dispatch on Sept. 9.
- Neither measure guarantees lower bills or automatic payments to home battery owners.
SACRAMENTO, Calif. California virtual power plants could be counted more fully in grid reliability planning under a law that sets a June 30, 2028, deadline for regulatory changes. Senate Bill 913 directs the California Public Utilities Commission to refine existing rules for coordinated batteries and other smaller energy devices, including how their grid contributions are measured.
The Sept. 30 approval came after Sunrun and Tesla reported delivering 580 megawatts from residential batteries during a Sept. 9 heat wave. That company-reported output illustrates how widely separated devices can respond together when electricity demand rises. It does not mean the same output is available during every event.
The distinction matters because California’s electricity providers must demonstrate access to enough dependable capacity for periods of heavy use. Regulators will determine when aggregated resources can count toward those obligations and how their performance must be verified.
SB 913 Sets a Deadline for Measuring Home Battery Capacity
SB 913 addresses what grid planners call resource adequacy, the ability to meet expected electricity demand. It directs the Public Utilities Commission to coordinate with the California Energy Commission and California Independent System Operator to strengthen existing market pathways by June 30, 2028.
A virtual power plant groups equipment at different locations through software and an operator that can request a collective response. Depending on the program, devices may reduce electricity consumption, discharge stored power or send energy beyond a customer’s meter. The individual systems remain at homes or businesses rather than one central power station.
The law requires qualifying resources to be considered for capacity credit based on what they can deliver when needed. It addresses both reductions in demand and authorized electricity exports, rather than treating a battery’s advertised storage capacity as proof of available power.
Regulators must evaluate whether data collected from individual devices can measure their actual contribution accurately. The legislation also calls for standards covering data quality and equipment compatibility when device-level measurements are accepted. Separately, it allows multiple devices behind one utility connection to participate in different programs when the same response is not counted or compensated twice.
The commission must protect consumer data and reduce enrollment barriers. Electricity providers may then include eligible aggregated resources in their capacity filings, provided the resources meet the applicable requirements. The deadline concerns regulatory work, not a requirement for homeowners to buy or enroll batteries by 2028.
California Virtual Power Plants Dispatched More Than 580 Megawatts
Sunrun and Tesla said more than 140,000 residential batteries participated in a three-hour dispatch on Sept. 9 during a period of extreme heat. Their reported peak output exceeded 580 megawatts. The companies said Tesla Powerwalls accounted for 517 megawatts and other battery models supplied another 63 megawatts.
The event was coordinated through California’s Demand Side Grid Support program and Emergency Load Reduction Program. These programs existed before SB 913 became law, an important distinction between demonstrated operating activity and future regulatory changes.
Sunrun had separately reported more than 80,000 households enrolled in its California network in July, representing over 110,000 batteries. At that time, it estimated up to 425 megawatts of peak dispatchable capacity for its network. Those July figures describe Sunrun’s program, while the September total reflects a larger coordinated event involving Sunrun and Tesla.
The California Energy Commission reported that its wider Demand Side Grid Support program had more than 448,000 participants as of Nov. 30, 2025. Providers estimated more than one gigawatt of voluntary load-reduction capacity. That figure includes different forms of electricity demand management, not just home batteries or virtual power plants.
Unlike proposed large solar battery projects on San Joaquin Valley farmland, virtual power plants coordinate many smaller devices located where customers use electricity. Their reliability still depends on available charge, local network conditions and the ability to respond when called.
SB 905 Brings Grid Costs and Household Payments Into Focus
The companion law, SB 905, addresses how utilities plan and pay for electricity infrastructure. It requires the Public Utilities Commission to consider reduced shareholder returns on specified utility costs and examine alternative financing approaches. It also calls for public data about how fully distribution-grid segments are used and where capacity is constrained.
Utilities must assess whether flexible electricity use or distribution-connected storage could resolve identified grid needs at lower cost than conventional upgrades. The measure establishes an evaluation process, not a finding that batteries are always cheaper than new infrastructure.
Those decisions carry significance as California household electricity costs remain a concern for residents. The laws do not set retail electricity rates, reduce bills by a stated amount or create an automatic statewide rebate for owners of solar panels and batteries.
Existing participation payments depend on individual program terms. A household may receive compensation for making eligible stored electricity available, but the amount depends on enrollment conditions, dispatch schedules and the services delivered. Savings from using a battery during expensive hours are a separate calculation and can vary with utility rates and household consumption.
California’s Public Advocates Office has cautioned that virtual power plants should provide measurable additional benefits rather than receive duplicate payments for power that would have been supplied or demand that would have fallen anyway. It has also raised questions about battery availability and whether electricity can reach the parts of the grid where it is needed.
The state’s Self-Generation Incentive Program separately offers assistance for eligible storage systems. Eligibility, available funds and program obligations remain governed by that program rather than the new legislation. For participating households, the practical issues are whether equipment qualifies, how performance is measured and which payments are available under a particular provider agreement.
Frequently Asked Questions
What are California virtual power plants?
California virtual power plants are networks of smaller energy devices, such as home batteries, coordinated to support the electricity grid. Depending on the program, they can reduce demand or deliver stored electricity during designated periods.
When must California update the rules under SB 913?
SB 913 directs the Public Utilities Commission to enhance existing participation pathways by June 30, 2028. The deadline applies to regulatory work, not to individual homeowners purchasing equipment.
Do the new laws guarantee lower electricity bills?
No. The laws address grid participation and utility planning, while any household savings depend on rates, equipment use and applicable program arrangements.
Can home battery owners receive payments?
Some existing programs compensate eligible participants for grid services. Payment amounts and conditions depend on the specific provider or utility arrangement, and ownership alone does not guarantee eligibility.
