Granite Ridge is a 790 MW operating natural-gas-fired combined-cycle power station located at 21 North Wentworth Avenue in Londonderry, Rockingham County, New Hampshire.
Mapped infrastructure geometry associated with this asset.
EIA plant 55170 · Inventory for Aug 2026.
| Generator | Technology | Status | Power (MW) | Energy (MWh) |
|---|---|---|---|---|
| CT11 | Natural Gas Fired Combined Cycle | Operating | 260 | Unknown |
| CT12 | Natural Gas Fired Combined Cycle | Operating | 260 | Unknown |
| STG | Natural Gas Fired Combined Cycle | Operating | 270 | Unknown |
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Operating generator records and technology attributes reported through EIA-860.
| Generator | Capacity | Technology | Operation | Status |
|---|---|---|---|---|
| CT11 | 260 MW 218 MW summer | Natural Gas Fired Combined Cycle Natural Gas · CT | Mar 2003 | Operating |
| CT12 | 260 MW 218 MW summer | Natural Gas Fired Combined Cycle Natural Gas · CT | Mar 2003 | Operating |
| STG | 270 MW 232 MW summer | Natural Gas Fired Combined Cycle Natural Gas · CA | Mar 2003 | Operating |
Monthly EIA generation history and recent market-resource behavior where linked telemetry is available.
Monthly generation is reported through EIA-923. Capacity factor uses the current EIA nameplate capacity and is shown only for complete calendar years.
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.
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Portfolio membership follows the latest EIA-860 reporting entity. It does not imply ultimate ownership.
Project milestones and public references behind the asset profile.
Construction began on a 47.7-acre site near Manchester Airport in Londonderry, New Hampshire
Combustion turbine CT11 (Siemens Westinghouse 501G, serial 37A9010-1) achieved startup
Combustion turbine CT12 (Siemens Westinghouse 501G, serial 37A9011-1) achieved startup
EIA-860 lists generator CT11, generator CT12, generator STG with this operating date.
Ownership of AES Londonderry LLC (project company) was transferred from AES Londonderry Holdings LLC to Granite Ridge I SPE LLC through consensual foreclosure; the project company was renamed Granite Ridge Energy LLC and came under new management controlled by the project's lenders
Calpine Corporation announced an agreement to acquire Granite Ridge Energy Center from Granite Ridge Holdings LLC for approximately $500 million, subject to working-capital adjustments; capacity stated as 745 MW
Answered from the published record above. Questions whose inputs this profile does not carry are omitted rather than estimated.
Granite Ridge reports 790 MW natural gas of operating nameplate capacity. These technology ratings do not establish a common export limit. Source: EIA Aug 2026.
Granite Ridge is a Natural Gas Fired Combined Cycle facility in Rockingham County, NH, participating in the ISO-NE market.
Granite Ridge is in Rockingham County, NH, inside the ISO-NE balancing area.
Granite Ridge is operated by Granite Ridge Energy LLC according to the EIA generator inventory. Reporting membership does not by itself establish ultimate ownership.
Granite Ridge reported 3,814.1 GWh over the twelve months to 2026-07. Figures are net generation as filed to EIA-923.
By capacity, Granite Ridge ranks #148 of 540 operating plants of the same technology nationally. It ranks #1 of 2 in NH.
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.
