Browse
Log in / Register
Share
Washington, D.C., March 20, 2025 – The Federal Energy Regulatory Commission (FERC) is expected to unveil a draft rule requiring new solar and wind power plants to include on-site energy storage capable of holding at least 10% of the facility’s installed capacity for a minimum of two hours. The mandate, which would apply to projects commencing commercial operation after July 1, 2027, marks a significant shift in U.S. renewable energy policy, aiming to address the intermittent nature of wind and solar generation.
The proposal, modeled partly on similar initiatives in India and California, is designed to ensure that renewable energy can be dispatched reliably during peak demand periods or when the sun isn’t shining and the wind isn’t blowing. According to a FERC staff memo obtained by Reuters, the regulation would require developers to co-locate battery storage systems with their generating assets. For example, a 100-megawatt solar farm would need at least 10 megawatts of storage with a two-hour duration, or 20 megawatt-hours of usable capacity.
The rule is expected to be published in the Federal Register in the coming weeks, with a 60-day public comment period. Industry groups and utilities have been anticipating such a move, as grid operators increasingly struggle to balance supply and demand with rising renewable penetration. The North American Electric Reliability Corporation (NERC) reported last month that more than 20% of U.S. electricity now comes from variable renewables, and that number is projected to double by 2030.
Proponents argue that mandatory storage will improve grid stability and reduce the need for fossil fuel “peaker” plants. "Adding storage alongside renewable generation is the most cost-effective way to ensure that clean power is available when customers need it most," said Dr. Emily Torres, energy policy director at the Clean Grid Alliance. "This rule could accelerate the transition to a fully reliable, zero-carbon grid."
However, the proposal has drawn criticism from some renewable developers who warn that it will increase project costs by 15% to 25%, potentially slowing new capacity additions. The Solar Energy Industries Association (SEIA) has called for a more gradual phase-in and alternative compliance mechanisms, such as purchasing grid‑connected storage credits. "We support storage, but a one-size-fits-all mandate could stifle innovation and raise electricity prices for consumers," said SEIA president Abigail Ross Hopper.
Under the draft rule, projects commissioned between July 1, 2027, and June 30, 2029, would need to meet the 10% / 2-hour requirement. Starting July 1, 2029, the requirement would increase to 15% of capacity for a three-hour duration. These thresholds are similar to those adopted by the Central Electricity Authority of India in 2024, though FERC’s version includes broader flexibility for virtual power purchase agreements and off-site storage.
The scope of the rule covers all new utility-scale solar and wind facilities with a capacity of 20 megawatts or more. Smaller projects, as well as existing plants, are exempt. FERC also plans to allow developers to meet the storage requirement through a combination of on-site batteries and contracted storage from third‑party providers, provided the storage is committed to the project’s output profile.
The first public hearing on the proposal is scheduled for April 15, 2025, at FERC headquarters in Washington. Comments will be accepted until May 20. The commission is expected to finalize the rule by late 2025, with enforcement beginning in January 2026 for new projects that break ground after that date.
Industry analysts note that the policy could trigger a boom in battery storage manufacturing and deployment. The U.S. Energy Information Administration projects that utility‑scale battery storage capacity will need to grow from 15 gigawatts today to over 100 gigawatts by 2035 to meet grid reliability needs. The proposed mandate, if adopted, would add at least 20 to 30 gigawatts of additional storage demand by 2030, according to BloombergNEF.
The move also aligns with the Biden administration’s goal of a carbon‑free electricity sector by 2035. The White House National Climate Advisor, Ali Zaidi, declined to comment on the specific rule but said, "We support any policy that makes clean energy more reliable and affordable."
