The Story on Storage

Energy storage has been a significant topic and a rapidly growing sector within the sustainable energy landscape for several years. Utilities, regulators, and consumers recognize the value of various energy storage types, including electrochemical storage in batteries, thermal storage using ice or water, and mechanical storage systems. Additionally, stakeholders consider the “duration” of storage, which refers to how long a system can continuously deliver its rated power.

As of February 2025, twelve states have established energy storage targets, with New York leading the way with a goal of 6,000 MW by 2030. In mid-2024, lawmakers in Rhode Island set a target of 600 MW to be achieved by 2033. In Massachusetts, a new bill signed by the Governor in late 2024, known as S.B. 2967, mandates that all utilities jointly solicit proposals for up to 5,000 MW of energy storage capacity. This statute requires the contracting of storage with varying durations by July 31, 2030: 3,500 MW of mid-duration storage, 750 MW of long-duration storage, and 750 MW of multi-day storage. In Massachusetts, storage durations are defined as follows: short-duration is 2 to 4 hours of continuous output, mid-duration is 4 to 10 hours, long-duration is 10 to 24 hours, and multi-day storage must be capable of dispatching a system’s full rated output for more than 24 hours.

State Energy Storage Targets (February 2025)

In the past year, several state legislatures have proposed new actions or amendments to existing energy storage targets. A bill codifying the New Jersey Energy Master Plan is currently pending in the State Senate, aiming for 2,000 MW of energy storage capacity that can discharge for at least 24 hours by 2035. In Illinois, multiple bills introduced in mid-2024 included energy storage procurement targets, with one pair aiming for 7,500 MW by 2030 and another set proposing 9,000 MW by 2030 and 15,000 MW by 2038. New York legislators proposed bills to double the state’s storage targets from 3 GW to 6 GW, although these bills did not progress during the legislative session. Nonetheless, the New York Public Service Commission adopted an energy storage roadmap setting the 6 GW target.

Utilities often propose new storage deployments, even in states and regions without legislative mandates, emphasizing the essential services that energy storage can provide, such as load balancing, frequency regulation, and peaking capacity. Idaho Power and the Public Service Company of New Mexico include dispatchable balancing assets, like energy storage, in their capacity procurement plans. As coal plants and other large generators become less economical and are retired, the role of energy storage in providing balancing services will be critical for maintaining the reliability of the electric grid.

As of February 2025, utilities had active or pending procurements for energy storage assets in states without specific mandates. If all requests for proposals (RFPs), applications, and other utility proposals active at the end of 2024 are fulfilled, utilities could add over 18.5 GW of energy storage capacity in states including Arkansas, Louisiana, Georgia, Iowa, Indiana, Puerto Rico, Texas, Washington, and Wisconsin. Notably, there is strong participation in many storage solicitations regardless of geographic location. For instance, Puget Sound Energy recently sought 29 MW of storage in a request for proposals but received offers totaling 229 MW.

Recent Energy Storage Procurement Activity

Several proposals have recently aimed to utilize thermal energy storage to manage peak demand. Utilities in Georgia, Kentucky, Indiana, Iowa, and Wisconsin have either launched requests for proposals or sought regulatory approval for energy storage that encompasses both thermal and electrical solutions. Thermal storage can effectively offset energy use for heating or cooling by storing the necessary energy type for future needs. For example, chilled water storage can operate electric chillers overnight when electricity is more affordable, allowing for the distribution of chilled water during hot afternoons to avoid higher power costs.

For more information on current energy storage initiatives, DSIRE Insight offers quarterly and annual reports on energy storage regulations and deployment in the 50 States of Grid Modernization Report, along with notes on energy storage targets, procurement, and resource plans in the 50 States of Power Decarbonization Report. Visit our Publications and Subscriptions for additional details.