US storage update: Maine’s 350 MWh battery and Sierra Pinta 450 MWh system begin operations

Plus Power’s Cross Town Energy Storage, a 175 MW / 350 MWh standalone BESS in Gorham, Maine, is now online and is the largest battery facility on the ISO New England grid, with an interconnection at Central Maine Power’s 115 kV Moshers substation. Cross Town includes 156 Sungrow PowerTitan units and follows Plus Power’s 150 MW / 300 MWh Cranberry Point facility that came online in Massachusetts in 2025.

“Today, Maine welcomed the largest energy storage project of its kind in New England,” said Governor Janet Mills at the ribbon cutting, noting the project’s role in lowering electricity costs and enhancing regional reliability. The press release indicated the facility’s location will benefit from wind power in Northern Maine to meet demand in Southern Maine and Boston.

Plus Power CEO Naveen Abraham added that the company will continue working with ISO New England to demonstrate “the unique capabilities of battery energy storage systems.”

In Yuma County, Arizona, Leeward Renewable Energy’s (LRE) Sierra Pinta Battery Energy Storage System has also entered commercial service. The standalone facility is rated at 112.5 MW / 450 MWh — a four-hour duration project — and is part of a six-phase build-out in Yuma Country that now brings LRE’s installed capacity in the region to over 291 MW.

“With a 112.5 MW interconnection, the facility underscores our ability to deliver large-scale, dispatchable power when and where it is needed most. We are proud to support PG&E and the broader energy market by meeting growing energy demand while creating long-term economic opportunities in the region,” said Sam Mangrum, Executive Vice President of Project Execution at LRE.

Aside from local job support, the project listed a fact not always seen in battery press, with LRE noting the project will contribute “an estimated $12.4 million in property tax revenue” over its lifetime.