On October 19, 2023, the Federal Energy Regulatory Commission (FERC) accepted a proposal from ISO New England (ISO-NE) to allow for energy storage to “play an important role in ensuring a reliable transmission system.”[1] Storage as transmission-only assets (SATOAs), which may include a variety of storage resources like batteries and pumped hydro storage, would be owned and maintained by transmission companies, but ISO-NE system operators would control their use. Because they would be built only to serve a transmission reliability purpose, they will not compete in electricity markets and will have minimal effect on wholesale prices. These assets would used “under specific system conditions to prevent localized overloading after at least two unplanned equipment outages on the transmission system.” They may also be deployed as a last resort to help prevent or mitigate controlled outages if demand exceeds regionally available supply or to help with system recovery after an outage.

The new rules will not apply to or restrict other energy storage resources that already compete in the markets, which include almost 2,000 MW of pumped storage and more than 600 MW of new and existing battery storage resources. The rules would also not apply to or restrict the roughly 18,000 MW of battery resources proposed in ISO-NE’s Interconnection Request Queue or future projects looking to participate in the markets. Construction of SATOAs will depend on selection in ISO-NE’s open regional system planning process administered, similar to the way reliability-based system upgrades are handled today. FERC directed the ISO to submit a filing identifying the effective date of the SATOA revisions no less than 30 days prior to their implementation.

[1] https://isonewswire.com/2023/10/25/ferc-accepts-rules-allowing-storage-to-aid-transmission/?utm_source=isone&utm_medium=newsfeed