Medway Grid — 250 MW battery storage, Norfolk County, MA

Medway Grid — 250 MW battery storage, Norfolk County, MA · Ask the Grid

Generation and physical site

EIA plant 69720 · Inventory for Aug 2026.

Reported operating nameplate by technology

Battery storage: 250 MW

Operating generators only. Battery power is in MW; stored energy is in MWh. These ratings do not establish a shared export limit.

Generator records (1)

EIA generator status and nameplate capacity for Medway Grid
Generator	Technology	Status	Power (MW)	Energy (MWh)
MEDWA	Batteries	Operating	250	500

Physical map location · OpenStreetMap: 42.14441, -71.44741
Filed location · EIA: 42.14537, -71.44737

Sources and observation dates

Inventory source: EIA-860M workbook (preliminary)
EIA reporting month: Aug 2026
EIA retrieved: Oct 10, 2026
OSM extract: Oct 9, 2026
OSM last mapped edit: Sep 18, 2026
Map prepared: Oct 10, 2026
Field verification: Not reported

Reporting month describes the inventory. Retrieval and map preparation describe processing; an OSM edit does not establish an in-service date.

EIA source inventory

Units and generators

Operating generator records and technology attributes reported through EIA-860.

Generator	Capacity	Technology	Operation	Status
MEDWA	250 MW 250 MW summer	Batteries Electricity used for energy storage · BA	Mar 2026	Operating

Timeline and sources

Project milestones and public references behind the asset profile.

Project timeline

Apr 26, 2023
Apr 26, 2023
Massachusetts siting and permitting approvalmass.gov
Massachusetts Energy Facilities Siting Board and Department of Public Utilities issued tentative decision on consolidated proceedings EFSB 22-02, D.P.U. 22-18, and D.P.U. 22-19 concerning Medway Grid's battery energy storage system, zoning exemptions, and 345 kV interconnection approval.
Mar 2026
Mar 2026
Generator enters operationEIA-860
EIA-860 lists generator MEDWA with this operating date.
Mar 31, 2026
Mar 31, 2026
Tax-Equity Investment Closedadvantageca...
Advantage Capital closed a $158 million tax-equity investment in the Medway Grid Energy Battery Storage project, leveraging federal Investment Tax Credits.

Sources

PublisherReferenceType

U.S. Energy Information AdministrationEIA-860 generator inventoryFederal registry

U.S. Energy Information AdministrationEIA-923 generation filingsFederal filing

advantagecap.comadvantagecap.compublic_source

Common questions about Medway Grid

Answered from the published record above. Questions whose inputs this profile does not carry are omitted rather than estimated.

How big is Medway Grid?

Medway Grid reports 250 MW battery storage of operating nameplate capacity. These technology ratings do not establish a common export limit. Source: EIA Aug 2026.

What kind of plant is Medway Grid?

Medway Grid is a batteries facility in Norfolk County, MA, participating in the ISO-NE market.

Where is Medway Grid located?

Medway Grid is in Norfolk County, MA, inside the ISO-NE balancing area.

Who operates Medway Grid?

Medway Grid is operated by Medway Grid LLC according to the EIA generator inventory. Reporting membership does not by itself establish ultimate ownership.

How much electricity does Medway Grid generate?

Medway Grid reported 44.3 GWh over the twelve months to 2026-07. For a storage plant this is reported gross generation — a discharge proxy, not a cycle count or a conventional capacity factor.

How does Medway Grid compare to other plants?

By capacity, Medway Grid ranks #33 of 1,061 operating plants of the same technology nationally. It ranks #1 of 131 in MA.

Co-located assets

Plants within 25 km, nearest first, regardless of technology. Proximity is straight-line distance between mapped plant coordinates; it does not by itself establish a shared point of interconnection.

Exelon Medway LLCPetroleum LiquidsPetroleum Liquids135 MW494 m Exelon West Medway II LLCNatural Gas Fired Combustion TurbineNatural Gas Fired Combustion Turbine264 MW831 m Holliston Solar CSGSolar PhotovoltaicSolar Photovoltaic1 MW3.3 km Bourne (MA) - Holliston ISolar PhotovoltaicSolar Photovoltaic

Overview

Infrastructure record

Overview

Infrastructure record

Explore related directories

Explore related directories

Structured profile

Generation and physical site

Reported operating nameplate by technology

Related assets

Cranberry Point Energy Storage

Cross Town Energy Storage

Outer Cape Community Battery

Holden BESS 1

Ocean State BTM

Wakefield MA BESS 1

Units and generators

Performance

Peer context

Monthly generation

Grid and market context

Nearby substations

Commercial, land, and environmental record

Financing

Transactions and agreements

Related parties and identifiers

Parties and identifiers

Reporting portfolio