How many battery storage projects are in ISO-NE?

ISO-NE has 153 operating utility-scale battery storage projects with 1.0 GW of capacity, according to the EIA's monthly survey of power plants.

What is the largest battery storage project in ISO-NE?

Medway Grid in Norfolk County, Massachusetts is the largest, at 250 MW. It came online in 2026.

How many battery storage projects were built in ISO-NE in 2025?

10 battery storage projects came online in ISO-NE in 2025, with 348 MW of capacity.

Who is developing battery storage projects in ISO-NE?

Interconnection queues list each project under a project company, not the developer behind it. Cleanview researches the developer of every project and has them on paid plans.

Battery storage projects in ISO-NE

ISO-NE has 153 operating battery storage projects with 1.0 GW of capacity. 10 came online in 2025.

Operating153

See planned battery storage projects in ISO-NE

Updated monthly. Last updated November 2026.

Under 50 MW50–249 MW250 MW and up

Updated monthly. Last updated November 2026.

ISO-NE had 3 battery storage projects online in 2016 and 153 in 2026

112

126

142

152

153

2016’162017’172018’182019’192020’202021’212022’222023’232024’242025’252026’26

Battery storage projects online at the end of each year. Source: EIA-860M, compiled by Cleanview.

The 10 largest battery storage projects in ISO-NE

Operating, by capacity

#	Battery storage project	Location	Year online	Capacity
1	Medway Grid	Norfolk County, Massachusetts	2026	250 MW
2	Cross Town Energy Storage	Cumberland County, Maine	2025	175 MW
3	Cranberry Point Energy Storage	Plymouth County, Massachusetts	2025	150 MW
4	Outer Cape Community Battery	Barnstable County, Massachusetts	2022	25 MW
5	Great Lakes Hydro America - ME	Penobscot County, Maine	2020	20 MW
6	William F Wyman Hybrid	Cumberland County, Maine	2016	17 MW
7	Berlin Gorham	Coos County, New Hampshire	2023	14 MW
8	Rumford Falls Hydro Facility	Oxford County, Maine	2023	8 MW
9	Bonny Eagle	York County, Maine	2023	8 MW
10	Nantucket Hybrid	Nantucket County, Massachusetts	2019	6 MW

Battery storage projects that came online most recently in ISO-NE

Newest first

#	Battery storage project	Location	Year online	Capacity
1	Medway Grid	Norfolk County, Massachusetts	2026	250 MW
2	Milk Street Solar, LLC	Worcester County, Massachusetts	2025	1 MW
3	Cross Town Energy Storage	Cumberland County, Maine	2025	175 MW
4	NL MA - Division	Bristol County, Massachusetts	2025	1 MW
5	Wakefield MA BESS 1	Middlesex County, Massachusetts	2025	5 MW
6	Upland	Plymouth County, Massachusetts	2025	2 MW
7	Ring Road	Plymouth County, Massachusetts	2025	2 MW
8	Cranberry Point Energy Storage	Plymouth County, Massachusetts	2025	150 MW
9	Kearsarge Riverpark I LLC	Middlesex County, Massachusetts	2025	5 MW
10	Kearsarge Riverpark II LLC	Middlesex County, Massachusetts	2025	5 MW

The developer behind each project is on paid plans. See plans

How Cleanview tracks battery storage projects

Operating battery storage projects come from the EIA's monthly survey of power plants. Planned projects come from the grid operators' interconnection queues. We research who is developing each one, since a queue lists a project company, not its owner.

Questions about battery storage projects in ISO-NE

How many battery storage projects are in ISO-NE?: ISO-NE has 153 operating utility-scale battery storage projects with 1.0 GW of capacity, according to the EIA's monthly survey of power plants.
What is the largest battery storage project in ISO-NE?: Medway Grid in Norfolk County, Massachusetts is the largest, at 250 MW. It came online in 2026.
How many battery storage projects were built in ISO-NE in 2025?: 10 battery storage projects came online in ISO-NE in 2025, with 348 MW of capacity.
Who is developing battery storage projects in ISO-NE?: Interconnection queues list each project under a project company, not the developer behind it. Cleanview researches the developer of every project and has them on paid plans.