10% of EVs Could Meet One-Third of Storage Needs
California’s electric vehicles could become a critical energy storage resource for the state. A report jointly released by GridLab, Kevala, and Energy and Environmental Economics estimates that if 10% of California’s projected EVs participate in vehicle-to-grid (V2G) programs by 2036, they could supply approximately 9 gigawatts (GW) of power for 12 hours, totaling 108 gigawatt-hours (GWh) of storage. This capacity would meet more than one-third of California’s long-duration energy storage target for that year.
V2G technology allows compatible electric vehicles to feed power back into the grid during peak demand periods, while owners recharge their vehicles when electricity prices are lower. The report highlights that effectively integrating these “mobile batteries” could significantly reduce California’s need for new power plants and grid upgrades. Ric O’Connell, executive director of GridLab, stated that the next generation of grid infrastructure already exists in driveways, homes, and businesses, emphasizing the importance of fully leveraging these resources.
Inconsistent Program Rules Hinder Expansion
Currently, demand flexibility programs across California’s utilities vary in rules, payment structures, and participation requirements, creating barriers to broader adoption. The report recommends that California standardize program designs, establish common technical standards, and adopt performance-based compensation models that reward participants based on verified grid contributions rather than fixed participation fees. This approach could increase engagement and ensure measurable program benefits.
The report also suggests that participant compensation should remain below the utility’s “avoided cost” to ensure savings are shared with non-participating customers, preventing cost shifts. This recommendation aligns with debates over California’s rooftop solar subsidies, which have faced criticism for potentially raising electricity bills for non-participants. In contrast, Vermont’s Green Mountain Power has demonstrated an alternative model through its virtual power plant program, which uses battery storage to lower costs for all customers.
Virtual Power Plants Could Meet 15% of Peak Demand
The report cites a 2024 study by GridLab and The Brattle Group, which found that virtual power plants (VPPs) could meet over 15% of California’s peak electricity demand and save utilities and customers approximately $550 million annually. However, these benefits remain modeled projections, contingent on EVs remaining connected to the grid during critical demand periods and requiring compatible vehicles, chargers, and utility programs.
The California Energy Commission noted that automated demand flexibility can reduce the need for costly grid upgrades and better align electricity use with renewable energy generation. The state’s challenge lies not in a lack of storage resources but in creating a statewide system to effectively integrate them. The report stresses that California must accelerate V2G infrastructure development and simplify participation processes to unlock the 9 GW storage potential by 2036.
As EV adoption grows, transforming these “mobile batteries” into grid assets will be a key focus of California’s energy transition. Research indicates that even one-way smart charging could deliver significant benefits, though full V2G implementation still faces technical, policy, and market hurdles.
