Callaway — United States of America

Callaway is a 1,275 MW nuclear power station in Missouri, United States of America. It is operated by Union Electric Co - (MO). Based on reported annual generation of 9,190 GWh, it can supply roughly 2.6 million homes. It ranks #428 of 10,884 United States of America power plants by installed capacity. Commissioned in 1985, it is around 41 years old — long-established. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, nuclear supplies about 17.4% 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 USA0006153.

Data provenance

Source of the capacity and fuel values:

capacity: GEM Global Nuclear Power Tracker September 2025 operating-unit sum (location L100000500053); fuel: WRI GPPD

In context: how this plant compares

At 1,275 MW, Callaway is around the median nuclear plant in United States of America (1,350 MW). Nuclear plants split uranium to raise steam with no direct CO₂; they run as steady baseload with very high capacity factors and the longest operating lifetimes of any thermal plant.

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

Key facts

Load factor

82%, from 9,190 GWh of reported generation; the median for 57 nuclear plants in United States of America that report generation is 89%

Generation trend

8,367 GWh in 2013 and 9,190 GWh in 2019 (+10%)

Highest and lowest year

2018: 10,655 GWh; 2017: 8,304 GWh

Share of United States of America nuclear capacity

0.5% of 270,415 MW across 176 plants in this dataset

Age among peers

68 of 111 dated nuclear 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 Union Electric Co - (MO). All plants by this company →

Local climate & thermal context

This nuclear plant uses heat from nuclear fission to raise steam for a turbine-generator. It sits in a humid subtropical climate (Köppen Cfa) — Northern Hemisphere, latitude 38.8°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 7% 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: 53/100 — 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 mild atmospheric environment (estimated ISO 9223 class C2 — Low), with humidity / wetness 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 #95 largest nuclear power plant of 176 in United States of America by capacity.

United States of America has 176 nuclear power plants in this dataset, together about 270,415 MW of capacity.

Nearby power plants

• Chamois · Coal · 59 MW · Missouri
• Fulton (MO) · Gas · 33.2 MW · Missouri
• Ameresco Jefferson City · Waste · 3 MW · Missouri
• Moreau · Oil · 60.8 MW · Missouri
• Fairgrounds · Oil · 68.3 MW · Missouri
• Mexico · Oil · 60.7 MW · Missouri

Location

Coordinates 38.7589, -91.7788 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

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