Medway Grid, LLC - Norfolk County - ISONE
Medway Grid is an operating 250 MW / 500 MWh standalone battery in Medway, Massachusetts. The project uses 141 Tesla Megapack 2 XL units and connects to Eversource's West Medway substation through a 1,465-foot underground 345 kV line.
Canonical EIA plant baseline.
plant-69720
Answers use this researched asset profile with live ISO-NE data. Ask about ownership, equipment, project history, or current grid context.
Live ISO-NE public data · answers can be wrong, verify against source data or the ISO.
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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 |
Monthly EIA generation history and recent market-resource behavior where linked telemetry is available.
EIA-923 reports gross generation and net grid exchange for storage plants. Gross generation is shown as a discharge proxy; it is not a cycle count or conventional capacity factor.
Deterministic links to ERCOT market resources, price records, outage disclosures, queue records, and nearby infrastructure. Candidate joins remain labeled until corroborated.
Source-backed project transactions, agreements, land records, permits, and environmental disclosures. Portfolio and adjacent-project facts remain explicitly scoped.
Parties, market resources, and identifiers tied to this asset, with owner, operator, developer, EPC, compliance provider, and interconnecting entity roles kept separate.
Portfolio membership follows the latest EIA-860 reporting entity. It does not imply ultimate ownership.
Project milestones and public references behind the asset profile.
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.
EIA-860 lists generator MEDWA with this operating date.
Advantage Capital closed a $158 million tax-equity investment in the Medway Grid Energy Battery Storage project, leveraging federal Investment Tax Credits.
Answered from the published record above. Questions whose inputs this profile does not carry are omitted rather than estimated.
Medway Grid has a reported capacity of 250 MW. Source: EIA Form 860M.
Medway Grid is a batteries facility in Norfolk County, MA, participating in the ISO-NE market.
Medway Grid is in Norfolk County, MA, inside the ISO-NE balancing area.
Medway Grid reported 25.4 GWh over the twelve months to 2026-04. For a storage plant this is reported gross generation — a discharge proxy, not a cycle count or a conventional capacity factor.
By capacity, Medway Grid ranks #27 of 962 operating plants of the same technology nationally. It ranks #1 of 129 in MA.
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.