Long-Duration Energy Storage
Hull Street Energy Expanded Pumped Hydro Storage in New England
mursal rahman — May 19, 2026
Hull Street Energy is acquiring FirstLight USA’s portfolio of hydroelectric and pumped storage assets, including Northfield Mountain in Massachusetts, the largest energy storage facility in New England. The 1,168 MW pumped hydro system stores electricity by moving water between reservoirs, allowing energy to be released during periods of high demand. Alongside hydroelectric stations and solar-plus-storage facilities, the portfolio supports grid flexibility as renewable energy adoption continues to expand across the Northeast.
The acquisition reflects growing interest in long-duration energy storage as utilities and investors search for reliable ways to balance intermittent renewable power generation. Pumped hydro systems can help stabilize electricity grids, improve energy reliability, and reduce dependence on fossil-fuel-based backup generation during demand spikes. As power demand rises from electrification and data infrastructure growth, existing hydroelectric assets may become increasingly valuable components of regional clean-energy strategies and grid modernization efforts.
