Sammis Plant — United States of America

Sammis Plant is a 2,455.6 MW coal power station in Ohio, United States of America. It is operated by Energy Harbor Generation LLC [100%]. Based on its capacity (estimated), it can supply roughly 3.1 million homes (estimated). It ranks #84 of 10,884 United States of America power plants by installed capacity. Commissioned in 1959, it is around 67 years old — an older, legacy facility. In context, coal supplies about 16.3% 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 GEM_coa_sammis_unite.

Data provenance

Capacity and fuel are the upstream open-dataset record, not yet matched to a 2026 registry or GEM entry.

capacity: GEM GCPT; fuel: GEM GCPT

In context: how this plant compares

At 2,455.6 MW, Sammis Plant is well above the median coal plant in United States of America (558 MW). Technically it is described as subcritical. Coal plants burn pulverised coal to raise high-pressure steam for a turbine; they run as baseload but are the most carbon-intensive mainstream source and the first targeted for retirement or efficiency retrofits.

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

Key facts

Share of United States of America coal capacity

0.4% of 621,194 MW across 802 plants in this dataset

Age among peers

152 of 745 dated coal 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)).

Capacity vs largest coal plants in United States of America

Installed capacity (MW), WRI Global Power Plant Database (CC BY 4.0).

Owner

Operated by Energy Harbor Generation LLC [100%].

Local climate & thermal context

This coal plant burns coal to raise high-pressure steam that spins a turbine-generator. It sits in a warm-summer humid continental climate (Köppen Dfb) — Northern Hemisphere, latitude 40.5°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 23% 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: 63/100 — this site sits in the mid 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 #31 largest coal power plant of 802 in United States of America by capacity.

United States of America has 802 coal power plants in this dataset, together about 621,194 MW of capacity.

Nearby power plants

• FirstEnergy W H Sammis · Coal · 2,468.1 MW · West Virginia
• South Field Energy power station · Gas · 1,210 MW · Ohio
• Shippingport nuclear power plant · Nuclear · 68 MW · Pennsylvania
• Beaver Valley · Nuclear · 1,917 MW · Pennsylvania
• Bruce Mansfield power station · Gas · 3,641.1 MW · Pennsylvania
• FirstEnergy Bruce Mansfield · Coal · 2,741.1 MW · Pennsylvania

Location

Coordinates 40.529167, -80.632083 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions