Somerset Plant — United States of America

Somerset Plant is a 107.1 MW biomass power station in Maine, United States of America. It is operated by Sappi Fine Paper North America-Somerset. Based on reported annual generation of 532 GWh, it can supply roughly 152k homes. It ranks #2651 of 10,884 United States of America power plants by installed capacity. Commissioned in 1984, it is around 42 years old — long-established. In context, biomass supplies about 1.0% of United States of America's electricity; the national grid averages 384 gCO₂/kWh (43.0% low-carbon) (2025).

Plant data: WRI Global Power Plant Database (CC BY 4.0), id USA0050406.

Data provenance

Source of the capacity and fuel values:

capacity: Wikidata P2109; fuel: WRI GPPD

In context: how this plant compares

At 107.1 MW, Somerset Plant is well above the median biomass plant in United States of America (17.9 MW). Biomass plants burn organic material such as wood, residues or waste-derived fuel to raise steam; they are dispatchable and counted as low-carbon where the feedstock is sustainably sourced.

Capacity comparison computed from the WRI Global Power Plant Database; fuel-type context is general engineering background.

Key facts

Load factor

57%, from 532 GWh of reported generation; the median for 144 biomass plants in United States of America that report generation is 53%

Generation trend

567 GWh in 2013 and 532 GWh in 2019 (−6%)

Highest and lowest year

2014: 585 GWh; 2016: 508 GWh

Share of United States of America biomass capacity

1.7% of 6,324 MW across 184 plants in this dataset

Age among peers

39 of 153 dated biomass plants in United States of America are older

Calculated from the capacity and generation records in this dataset (WRI Global Power Plant Database (CC BY 4.0)).

Reported generation trend

Annual generation (GWh), WRI Global Power Plant Database (CC BY 4.0).

Owner

Operated by Sappi Fine Paper North America-Somerset.

Local climate & thermal context

This biomass plant burns organic material (wood, residues) to raise steam for a turbine. It sits in a warm-summer humid continental climate (Köppen Dfb) — Northern Hemisphere, latitude 44.7°N — which shapes how much energy it can produce and how its output varies through the year.

Monthly mean temperature

Heating degree-days here run 71% above the median power plant in this dataset — a proxy for how much extra energy heated equipment must replace through its surfaces in winter.

Climate heat-demand index: 87/100 — this site sits in the top third of the power plants we cover by heating degree-days.

Climate normals: WorldClim 2.1 (1970–2000 monthly normals, 10 arc-min, CC BY 4.0); zone: Köppen-Geiger world climate classification (Kottek et al. 2006, 0.5° grid). Degree-days & heat-demand index computed by PowerAtlas — a modelled heat-demand proxy, not a measured site figure.

Site climate & environmental severity

This site sits in a moderately corrosive environment (estimated ISO 9223 class C3 — Medium), with thermal cycling the leading environmental stress.

Indicative estimate via the ISO 9223:2012 informative method (atmospheric corrosivity from temperature, time-of-wetness and airborne salinity), using WorldClim climate normals, the Köppen-Geiger class and coast distance. Indicative, not a measured corrosion rate.

How it compares & nearby plants

The #12 largest biomass power plant of 184 in United States of America by capacity.

United States of America has 184 biomass power plants in this dataset, together about 6,324 MW of capacity.

Nearby power plants

• Weston Hydro · Hydro · 12 MW · Maine
• Shawmut · Hydro · 8.8 MW · Maine
• Waste Management Crossroads LFGTE · Waste · 3.2 MW · Maine
• Messalonskee 3 · Hydro · 1.6 MW · Maine
• Benton Falls Associates · Hydro · 4.2 MW · Maine
• Hydro Kennebec Project · Hydro · 15.4 MW · Maine

Location

Coordinates 44.7035, -69.6474 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions