Chart

America's biggest power plant made under half the power of No. 2

Two pairs of tanks on one scale. Run at full power all year, Grand Coulee Dam could make 59.6 billion kilowatt-hours and the Vogtle nuclear plant 40.8, so the dam is 18.8 bigger. What each actually made in 2025: Grand Coulee 16.2, Vogtle 37.1, so the dam fell 20.9 short. — Grand Coulee Dam in Washington is the largest U.S. power plant by capacity: run at full power every hour of the year, it could make 59.6 billion kilowatt-hours, against 40.8 for Georgia's Vogtle nuclear plant, the No. 2 plant. But in 2025 Grand Coulee made 16.2 billion kilowatt-hours and Vogtle made 37.1, so the biggest plant made less than half (43%) as much. A nuclear plant runs near full power almost all year; a dam runs on the water the river brings.

Grand Coulee Dam in Washington has the most generating capacity of any U.S. power plant. In 2025 it made 16.2 billion kWh, less than half the 37.1 billion kWh made by Georgia's Vogtle nuclear plant, the No. 2 plant by capacity.

Credit: FactHub Research Team; data from the U.S. Energy Information Administration (Forms EIA-860 and EIA-923)

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What this chart asks

Does the largest U.S. power plant by capacity also make the most electricity?

Why it is shown this way

The surprise is that size and output rank the two plants in opposite order, so the same pair of plants is shown both ways, side by side, on one shared scale.
Capacity is converted to the most each plant could make in a year (capacity x 8,760 hours) so both panels use the same unit, billion kilowatt-hours.

Data and accessibility

Download chart data · Open accessible table · Download PNG · Download SVG

Dataset wa-electricity-generation-by-source, analysis grand-coulee-vs-vogtle-ceiling-vs-output

Sources

This chart draws on the sources of the dataset versions it visualizes.

Washington Electricity Generation by Source and the Largest U.S. Power Plants, 2001-2025

U.S. Energy Information Administration, State Historical Tables: Net Generation by State by Type of Producer by Energy Source, 1990-2025 (Final, released September 2026) Primary source for annual Washington net generation by energy source and for the state hydro ranking (EIA-923 and predecessor forms).
Retrieved October 9, 2026. U.S. federal government work (public domain). Linked as a public record; the source file is not redistributed. Its SHA-256 is recorded here and in source-manifest.json.

Reliability: Government. EIA, the U.S. Department of Energy's statistical agency, compiles state generation from the mandatory EIA-923 survey of power plants. It is federally funded and has no stake in which plant or state ranks first.
U.S. Energy Information Administration, State Electricity Profile tables for Washington (data year 2024) Table 10 (supply and disposition: retail sales, international trade, net interstate trade) and cross-check of Table 5 generation totals.
Retrieved October 9, 2026. U.S. federal government work (public domain). Linked as a public record; the source file is not redistributed. Its SHA-256 is recorded here and in source-manifest.json.

Reliability: Government. EIA's State Electricity Profiles compile supply and disposition from mandatory EIA surveys of utilities and plants. Federally funded, with no stake in the comparison.
U.S. Energy Information Administration, Form EIA-860 Annual Electric Generator Report, 2025 final data (eia8602025.zip, file 3_1_Generator_Y2025.xlsx, sheet Operable) Generator-level nameplate, summer and winter capacity used to rank U.S. plants by capacity.
Retrieved October 9, 2026. U.S. federal government work (public domain). Linked as a public record; the source file is not redistributed. Its SHA-256 is recorded here and in source-manifest.json.

Reliability: Government. Form EIA-860 is a mandatory annual survey of U.S. generators at plants of 1 MW or more, reporting nameplate and seasonal capacity. EIA is federally funded and has no stake in the ranking.
U.S. Energy Information Administration, Form EIA-923 Power Plant Operations Report, 2025 final data (f923_2025.zip, Schedules 2-5, Page 1 Generation and Fuel Data) Plant-level 2025 net generation used to rank U.S. plants by annual output.
Retrieved October 9, 2026. U.S. federal government work (public domain). Linked as a public record; the source file is not redistributed. Its SHA-256 is recorded here and in source-manifest.json.

Reliability: Government. Form EIA-923 is a mandatory survey of U.S. power plants' monthly and annual generation and fuel use. EIA is federally funded and has no stake in the ranking.
Washington State Department of Commerce, Fuel Mix Disclosure Consumption-side check: the aggregate 2024 fuel mix of electricity Washington utilities reported delivering to Washington customers.
Retrieved October 9, 2026. Washington State public record. Linked as a public record; the source file is not redistributed. Its SHA-256 is recorded here and in source-manifest.json.

Reliability: Government. Washington's Department of Commerce publishes the fuel mix that state law requires each utility to disclose. It reports what utilities filed and has no stake in the comparison.
Washington State Department of Commerce, chart "Washington electric utilities aggregate 2024 fuel mix" (image on the Fuel Mix Disclosure page) The labeled percentages transcribed into the wa-utility-fuel-mix-2024 table.
Retrieved October 9, 2026. Washington State public record. Linked as a public record; the source file is not redistributed. Its SHA-256 is recorded here and in source-manifest.json.

Reliability: Government. A chart on the Department of Commerce's Fuel Mix Disclosure page summarizing utilities' mandatory filings. The agency has no stake in the comparison.
U.S. Bureau of Reclamation, Grand Coulee Dam: About Operator statement of Grand Coulee generating capacity (6,809 MW) and typical output (up to 21 billion kWh), used as a replication check.
Retrieved October 9, 2026. U.S. federal government work (public domain). Linked as a public record; the source file is not redistributed. Its SHA-256 is recorded here and in source-manifest.json.

Reliability: Government. Has a stake in this finding. The Bureau of Reclamation owns and operates Grand Coulee Dam, so its description of the dam's size and output is the operator's own account. Its capacity figure matches EIA's survey data.
U.S. Energy Information Administration, Today in Energy, "Drought conditions reduce hydropower generation, particularly in the Pacific Northwest" (November 7, 2024) Context on 2023-2024 Pacific Northwest hydro conditions; states Grand Coulee net summer capacity as 6.7 GW.
Retrieved October 9, 2026. U.S. federal government work (public domain). Linked as a public record; the source file is not redistributed. Its SHA-256 is recorded here and in source-manifest.json.

Reliability: Government. An EIA analysis article based on its own survey data. Federally funded, with no stake in which plant or state ranks first.
Washington State Department of Ecology, news release, April 16, 2024 drought declaration Dates the 2024 statewide drought emergency and the 2023 emergency covering 12 watersheds.
Retrieved October 9, 2026. Washington State public record. Linked as a public record; the source file is not redistributed. Its SHA-256 is recorded here and in source-manifest.json.

Reliability: Government. A news release from Washington's Department of Ecology, the agency that declares drought emergencies under state law. It has no stake in the power-plant comparison.

Limitations

Full power all year is a ceiling no plant reaches. A dam is limited by river flow; Reclamation says Grand Coulee can make up to 21 billion kWh a year.
One year. Grand Coulee's output depends on the Columbia River's flow, which varies from year to year.
Capacity is nameplate capacity at the end of 2025 (EIA-860); output is 2025 net generation (EIA-923). Values are rounded to 0.1 billion kWh.

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