California’s grid operator has adopted an accounting change that could unlock more than 2 gigawatts of behind-the-meter batteries and aggregated distributed energy resources for participation in CAISO’s wholesale markets, a development advocates say removes a structural barrier that has long limited DER revenue potential. The adjustment, confirmed by regulatory experts tracking the proceeding, redefines how aggregated resources are measured against market participation thresholds, effectively expanding the pool of eligible assets without requiring new hardware or interconnection upgrades. A parallel rulemaking at the California Public Utilities Commission could amplify the impact, though a final decision is not expected until 2025.
The accounting shift addresses a persistent mismatch between how DER aggregators operate and how CAISO’s legacy market rules count capacity. Under the previous framework, resources behind a single meter were often evaluated individually against minimum size and performance requirements, disqualifying many smaller storage systems and flexible loads that operate as a coordinated portfolio. By allowing aggregation at the portfolio level for accounting purposes, the change aligns market eligibility with the operational reality of virtual power plants and demand response providers, potentially bringing thousands of residential and commercial batteries into the wholesale energy and ancillary services markets.
The CPUC’s companion proceeding focuses on compensation mechanisms and utility procurement targets for DERs, which would determine how much of this newly eligible capacity actually gets deployed and monetized. Regulatory observers note that the commission’s timeline reflects the complexity of aligning investor-owned utility distribution planning with CAISO’s transmission-level markets, particularly around issues of double-counting, locational value, and cost allocation. Until those rules are finalized, aggregators face uncertainty about revenue stacks, though the CAISO change alone enables immediate market registration for qualifying portfolios.
For the broader Western grid, the move signals a maturation of DER integration from pilot programs to structural market design. California’s scale means its rule changes often become de facto templates for other ISOs and state regulators grappling with similar integration challenges. The 2-gigawatt figure — roughly equivalent to a large nuclear plant — represents not just capacity but a shift in grid architecture: distributed assets becoming dispatchable, price-responsive resources that can reduce peak demand, provide frequency regulation, and defer transmission investment. Implementation details, including telemetry standards and settlement processes, will determine how quickly that potential translates into operational reality.
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