Where is Mousam River Solar?

In York County, Maine (ME). The map on this page is placed at the coordinates EIA files for the plant, which locate the site rather than any individual unit.

How big is Mousam River Solar?

20 MW of nameplate capacity across 1 unit, as of the EIA-860M release for 2026-07.

Who owns Mousam River Solar?

EIA-860M names Walden Renewables Development LLC as the reporting entity. That is the operator of record on the survey, which is not always the ultimate owner.

Is this the same as Mousam River Solar LLC?

Probably, but EIA-860M does not say. The survey records a plant name and a reporting entity — Walden Renewables Development LLC here — not the project company that holds the asset. Project companies are commonly registered as an LLC carrying the plant's name, so a search for "Mousam River Solar LLC" usually means this site. This page shows only what EIA files, and does not assert a corporate structure it cannot see.

Is Mousam River Solar still running?

EIA-860M files it as "Operating" for 2026-07. Statuses change monthly, and this page follows the monthly release.

Mousam River Solar

Mousam River Solar is a 20 MW solar farm in York County, Maine, operated by Walden Renewables Development LLC. EIA-860M lists 1 generating unit here, inside ISO New England. Its unit entered service in 2025.

As of 2026-07 (inventory dated 2026-07-31) · EIA-860M Preliminary Monthly Electric Generator Inventory · eia.gov/…/july_generator2026.xlsx · eia.gov/…/eia860m

Nameplate capacity: 20 MW; 20 MW net summer
Generating units: 1
In service: 2025
EIA plant ID: 69499

Where it is

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County: York County, Maine
Coordinates: 43.4322, -70.7273
Balancing authority: ISNE
Sector: IPP Non-CHP

Units, technology and status

Operator of record: Walden Renewables Development LLC
Primary energy source: Solar
Technologies: Solar Photovoltaic
Status: Operating

Every plant Walden Renewables Development LLC reports to EIA →

Mousam River Solar: FAQ

Where is Mousam River Solar?: In York County, Maine (ME). The map on this page is placed at the coordinates EIA files for the plant, which locate the site rather than any individual unit.
How big is Mousam River Solar?: 20 MW of nameplate capacity across 1 unit, as of the EIA-860M release for 2026-07.
Who owns Mousam River Solar?: EIA-860M names Walden Renewables Development LLC as the reporting entity. That is the operator of record on the survey, which is not always the ultimate owner.
Is this the same as Mousam River Solar LLC?: Probably, but EIA-860M does not say. The survey records a plant name and a reporting entity — Walden Renewables Development LLC here — not the project company that holds the asset. Project companies are commonly registered as an LLC carrying the plant's name, so a search for "Mousam River Solar LLC" usually means this site. This page shows only what EIA files, and does not assert a corporate structure it cannot see.
Is Mousam River Solar still running?: EIA-860M files it as "Operating" for 2026-07. Statuses change monthly, and this page follows the monthly release.