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Data

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

Annual EIA data on Washington in-state net generation by energy source (2001-2025), the state's hydro share and national hydro rank, generation versus retail sales and net interstate trade, Washington utilities' 2024 delivered fuel mix, and EIA-860/EIA-923 rankings of the largest U.S. power plants by capacity and by 2025 generation. FactHub-curated; not an official EIA, Reclamation or Washington State publication.

Coverage: 2001-2025 (state generation); 2001-2024 (supply and disposition); 2024 (utility fuel mix); 2025 (plant capacity and generation)

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What this dataset measures

Tests two common claims: that hydropower supplies most of Washington's electricity, and that Grand Coulee is the largest U.S. power plant. Both depend on the measure used (in-state generation versus delivered power; capacity versus annual output), so the release keeps each measure separate.

Geography
Washington State, United States
Unit of observation
Mostly one state-year; plant tables are one EIA plant in 2025.
Update cadence
Immutable research release; EIA annual data for 2026 would be published as a new version.
Curator
FactHub Research Team

Curated data tables

These related tables form this versioned dataset release. Each table has its own downloadable file and field definitions.

Washington net generation by energy source, 2001-2025

Annual in-state net generation by energy source as published by EIA, with each source's share of the state total.

Unit of observation: One year and one EIA energy-source category for Washington, all producer types (Total Electric Power Industry).

View this table

wa-generation-by-source.csv text/csv · 11.4 KB (11,623 bytes)
5 field definitions
FieldTypeMeaningUnitsValue type
year integer Data year. calendar year observed
source string Short code for the EIA energy source (hydro, natural_gas, nuclear, wind, coal, solar, wood, other_biomass, other_gases, petroleum, pumped_storage, other). — derived
eia_energy_source string EIA ENERGY SOURCE label exactly as published. — observed
net_generation_mwh integer Net generation. Pumped storage can be negative because pumping consumes more than it generates. A source absent from EIA's file for a year has no row (not zero). megawatthours (MWh) observed
share_of_total_pct number net_generation_mwh divided by EIA's Washington Total for the year. percent derived

Washington conventional hydro share and national rank, 2001-2025

Hydro share of in-state net generation and Washington's rank among the 50 states and DC for conventional hydroelectric generation.

Unit of observation: One year for Washington.

View this table

wa-hydro-annual.csv text/csv · 1.8 KB (1,894 bytes)
10 field definitions
FieldTypeMeaningUnitsValue type
year integer Data year. calendar year observed
total_net_generation_mwh integer Washington total net generation, all sources and producer types. megawatthours (MWh) observed
hydro_net_generation_mwh integer Conventional hydroelectric net generation (excludes pumped storage). megawatthours (MWh) observed
hydro_share_pct number Hydro share of in-state net generation. percent derived
non_hydro_net_generation_mwh integer Total minus conventional hydro. megawatthours (MWh) derived
wa_hydro_rank_among_states integer Rank of Washington's conventional hydro generation among the 50 states and DC. rank (1 = most) derived
us_hydro_net_generation_mwh integer Sum of conventional hydro across the 50 states and DC. megawatthours (MWh) derived
wa_share_of_us_hydro_pct number Washington share of U.S. conventional hydro generation. percent derived
second_ranked_state string State with the second-largest conventional hydro generation that year. USPS state code derived
second_ranked_state_hydro_mwh integer That state's conventional hydro generation. megawatthours (MWh) observed

Top 10 states by conventional hydro generation, 2025

The ten states with the most conventional hydroelectric net generation in 2025.

Unit of observation: One state in 2025.

View this table

state-hydro-rank-2025.csv text/csv · 290 bytes
5 field definitions
FieldTypeMeaningUnitsValue type
year integer Data year (2025). calendar year observed
rank integer Rank among the 50 states and DC. rank (1 = most) derived
state string State. USPS state code observed
hydro_net_generation_mwh integer Conventional hydro net generation. megawatthours (MWh) observed
share_of_us_hydro_pct number Share of U.S. conventional hydro. percent derived

Washington electricity supply and disposition, 2001-2024

EIA State Electricity Profile Table 10 rows: generation, retail sales, direct use, losses, international trade and EIA's computed net interstate trade, with two derived ratios.

Unit of observation: One year for Washington.

View this table

wa-supply-disposition.csv text/csv · 1.9 KB (1,991 bytes)
10 field definitions
FieldTypeMeaningUnitsValue type
year integer Data year. calendar year observed
total_net_generation_mwh integer Table 10 Total net generation. megawatthours (MWh) observed
retail_sales_mwh integer Table 10 Total electric industry sales to ultimate customers in Washington. megawatthours (MWh) observed
direct_use_mwh integer Table 10 Direct use. megawatthours (MWh) observed
estimated_losses_mwh integer Table 10 Estimated losses (allocated by EIA from utility-level reports). megawatthours (MWh) estimated
international_imports_mwh integer Table 10 Total international imports (Canada). megawatthours (MWh) observed
international_exports_mwh integer Table 10 Total international exports. megawatthours (MWh) observed
net_interstate_trade_mwh integer Table 10 Net interstate trade; positive = net exporter to other states, negative = net importer. EIA computes it as a residual. megawatthours (MWh) estimated
generation_to_retail_sales_ratio number Total net generation divided by retail sales. ratio derived
hydro_to_retail_sales_pct number In-state conventional hydro generation as a percent of in-state retail sales. A volume ratio, not the share of hydro in what customers bought. percent derived

Ten largest U.S. power plants by nameplate capacity, end of 2025

Plant capacity summed over all operable generators in EIA-860 2025, ranked by nameplate capacity, with rank by net summer capacity.

Unit of observation: One EIA plant (plant code).

View this table

largest-plants-capacity-2025.csv text/csv · 1 KB (1,049 bytes)
11 field definitions
FieldTypeMeaningUnitsValue type
rank_by_nameplate integer Rank among all U.S. plants by summed nameplate capacity. rank (1 = largest) derived
rank_by_summer_capacity integer Rank among all U.S. plants by summed net summer capacity. rank (1 = largest) derived
plant_code integer EIA plant code. — observed
plant_name string EIA plant name. — observed
state string Plant state. USPS state code observed
operator string Utility name on the first listed generator. — observed
primary_technology string EIA technology with the most nameplate capacity at the plant. — derived
operable_generators integer Count of operable generator records. generators derived
nameplate_capacity_mw number Sum of generator nameplate capacity. megawatts (MW) derived
summer_capacity_mw number Sum of generator net summer capacity. megawatts (MW) derived
winter_capacity_mw number Sum of generator net winter capacity. megawatts (MW) derived

Ten largest U.S. power plants by net generation, 2025

Plant net generation for 2025 from EIA-923, summed over all prime mover and fuel rows, ranked.

Unit of observation: One EIA plant (plant ID).

View this table

largest-plants-generation-2025.csv text/csv · 663 bytes
8 field definitions
FieldTypeMeaningUnitsValue type
rank_by_net_generation integer Rank among all U.S. plants in EIA-923 2025 Page 1. rank (1 = most) derived
plant_code integer EIA plant ID. — observed
plant_name string EIA plant name. — observed
state string Plant state. USPS state code observed
primary_technology string Technology with the most nameplate capacity in EIA-860 2025. — derived
net_generation_2025_mwh integer Sum of Net Generation (Megawatthours) over the plant's rows. megawatthours (MWh) derived
nameplate_capacity_mw number Summed EIA-860 nameplate capacity. megawatts (MW) derived
capacity_factor_pct number Net generation divided by nameplate capacity times 8,760 hours. percent derived

Washington utilities' aggregate 2024 fuel mix (Commerce)

Share of electricity delivered by Washington utilities to Washington customers in 2024, by fuel, as labeled on the Department of Commerce chart.

Unit of observation: One fuel category in the 2024 statewide utility fuel mix.

View this table

wa-utility-fuel-mix-2024.csv text/csv · 193 bytes
3 field definitions
FieldTypeMeaningUnitsValue type
year integer Fuel-mix year (2024). calendar year observed
fuel string Commerce fuel category; Unspecified is power whose source the utility could not identify (mostly market purchases). — observed
share_pct number Share of the statewide aggregate fuel mix, as printed on the chart. percent observed

Supporting files

Source snapshots, manifests, quality reports, documentation, and other materials used to produce or review this release.

  • dataset-parts.json Documentation · application/json · 71.3 KB (73,000 bytes)

    Sources, tables, events, saved analyses and replications of this dataset version, as JSON.

  • source-manifest.json Source manifest · application/json · 2 KB (2,088 bytes)

    URL, byte length and SHA-256 of every downloaded source file.

  • README.md Documentation · text/markdown · 2.1 KB (2,149 bytes)

    Contents, definitions and reproduction steps.

  • quality-report.md Quality report · text/markdown · 1.3 KB (1,311 bytes)

    Cross-checks and data-quality notes.

  • build.js Transformation manifest · text/javascript · 15.1 KB (15,416 bytes)

    Reads the EIA and Commerce source files and writes every table (Node.js 20 + SheetJS).

  • build_payload.js Transformation manifest · text/javascript · 40.7 KB (41,716 bytes)

    Writes the release files and this dataset's FactHub content.

Saved analyses

Hydro share of Washington in-state net generation, 2001-2025

Question: What share of electricity generated in Washington came from conventional hydropower each year?

Result: Hydro supplied 59.3% (2024) to 79.7% (2011) of in-state net generation; 59.7% in 2023, 59.3% in 2024 and 63.6% in 2025.

Operation: ratio

Scope: Washington, calendar years 2001-2025 (EIA final data).

View this analysis

  • Net generation measures electricity produced by plants located in Washington, not the electricity Washington customers use; Washington trades large volumes with other states and Canada.
  • Conventional hydro excludes pumped storage, which EIA reports separately and which is near zero or negative in Washington.
  • Annual shares hide large seasonal swings in hydro output (spring runoff versus late summer and winter).

Robustness checks

Summary of the hydro share series

Question: How low has the hydro share fallen, and in which years was it below 60 percent?

Result: Mean 68.9% (2001-2010 mean 71%, 2016-2025 mean 65.1%); below 60% only in 2023 and 2024; never at or below 50%. 2025: 64.7 of 101.7 TWh.

Operation: summary-statistics

Scope: Washington, 2001-2025.

View this analysis

  • Net generation measures electricity produced by plants located in Washington, not the electricity Washington customers use; Washington trades large volumes with other states and Canada.
  • Conventional hydro excludes pumped storage, which EIA reports separately and which is near zero or negative in Washington.

Washington rank among states for conventional hydro, 2001-2025

Question: Is Washington the largest hydropower-producing state, and by how much?

Result: Washington ranked first every year 2001-2025, with 22.9% to 32.4% of U.S. conventional hydro generation; Oregon, California or New York ranked second.

Operation: rank

Scope: All states, 2001-2025.

View this analysis

  • State totals assign each plant to the state where it sits; output from rivers shared with Oregon and Canada is credited to the dam's location.

Top 10 hydro states, 2025

Question: Which states produced the most conventional hydropower in 2025?

Result: 1. WA 64.7 TWh (26.8%); 2. OR 28.7 TWh (11.9%); 3. CA 28.1 TWh (11.7%).

Operation: rank

Scope: 2025.

View this analysis

  • One year; hydro rankings below first place shift with precipitation.

Largest U.S. power plants by capacity, end of 2025

Question: Is Grand Coulee the largest U.S. power plant by generating capacity?

Result: Grand Coulee ranks first by nameplate (6,809 MW) and by net summer capacity (7,079 MW); second by nameplate is Vogtle (GA, 4,658 MW).

Operation: group-sum-and-rank

Scope: All operable U.S. generators reported on EIA-860 for 2025.

View this analysis

  • Plant boundaries follow EIA plant codes; a site reported under several codes would be split.
  • Net summer capacity exceeds nameplate at Grand Coulee because several units are rated above nameplate; other EIA publications have cited about 6.7 GW of summer capacity.

Largest U.S. power plants by net generation, 2025

Question: Is Grand Coulee also the largest U.S. power plant by electricity produced?

Result: No. Vogtle (GA) led 2025 with 37.1 TWh and Palo Verde (AZ) was second with 31.3 TWh; the top 10 were all nuclear. Grand Coulee produced 16.2 TWh and ranked 27th.

Operation: group-sum-and-rank

Scope: All U.S. plants on EIA-923 2025 Page 1.

View this analysis

  • One year. Hydro output varies with water supply; Reclamation says Grand Coulee can produce up to 21 billion kWh, still below the leading nuclear plants.
  • Battery and other energy-storage plants reported on a separate EIA-923 sheet are not included; none is near the top of the ranking.

Grand Coulee in 2025

Question: What were Grand Coulee's capacity, output and ranks in 2025?

Result: 6,809 MW nameplate, 7,079 MW summer, 16.2 TWh in 2025 (15.9% of Washington's in-state generation); rank 1 by capacity, 27 by generation.

Operation: lookup

Scope: Grand Coulee (EIA plant 6163), 2025.

View this analysis

  • Share of Washington generation uses the state total from EIA's State Historical Tables, which is built from the same EIA-923 reports.

Washington generation versus retail sales and net interstate trade, 2001-2024

Question: Does Washington generate more electricity than it sells to its own customers?

Result: Generation exceeded retail sales every year (ratio 1.04 to 1.34). EIA's residual net interstate trade shows Washington as a net importer only in 2001 (10,176,675 MWh), 2010 (1,279,785 MWh), 2023 (1,170,693 MWh), 2024 (385,768 MWh); it was a net exporter in every other year, including 21-29 million MWh a year in 2020-2022.

Operation: ratio

Scope: Washington, 2001-2024 (EIA State Electricity Profile Table 10; 2025 not yet published).

View this analysis

  • Because net interstate trade is a residual, it absorbs errors in estimated losses and is approximate.
  • Physical flows do not identify which generator served which customer.

Robustness check for: Hydro share of Washington in-state net generation, 2001-2025

Hydro share of electricity Washington utilities delivered in 2024

Question: What share of electricity delivered to Washington customers came from hydropower?

Result: Hydro 48.73%, unspecified 15.44%, natural gas 13.33%, wind 9.6%, coal 5.91%, nuclear 5.13%.

Operation: transcription

Scope: Washington utilities, aggregate 2024 fuel mix (Commerce).

View this analysis

  • Unspecified power (mostly market purchases) has no fuel attribution and may itself be partly hydro, so 48.73% is a floor on the hydro share of delivered power, not an estimate of it.
  • Utility-reported resource claims, not physical flows; Commerce compiles but does not audit every claim.
  • Only 2024 is included.

Robustness check for: Hydro share of Washington in-state net generation, 2001-2025

Cross-check of two EIA generation tables

Question: Do EIA's State Historical Tables and the Washington State Electricity Profile agree on total generation?

Result: Agree within 4 MWh in every year (rounding).

Operation: difference

Scope: Washington, 2001-2024.

View this analysis

  • Both tables come from the same EIA survey data, so agreement checks transcription, not measurement.

Grand Coulee vs. Vogtle: most each could make in a year vs. what each made in 2025

Question: The largest U.S. power plant by capacity is Grand Coulee Dam. How does its electricity compare with the No. 2 plant, Vogtle, both at full power and in practice?

Result: At full power every hour of the year, Grand Coulee could make 59.6 billion kWh and Vogtle 40.8. In 2025 Grand Coulee made 16.2 billion kWh and Vogtle 37.1, so the biggest plant made less than half (43%) of what No. 2 made.

Operation: For Grand Coulee (EIA 6163) and Vogtle (EIA 649): ceiling = nameplate capacity (MW, from largest-plants-by-capacity-2025) x 8,760 hours; made = 2025 net generation (MWh, from grand-coulee-2025-summary and largest-plants-by-generation-2025). Both converted to billion kWh (TWh) and rounded to 0.1.

Scope: Two plants, end-of-2025 nameplate capacity and calendar-2025 net generation.

View this analysis

  • Full power every hour of the year is a ceiling no plant reaches. Nuclear plants come close; a dam is limited by how much water the river brings, and Reclamation says Grand Coulee can produce up to 21 billion kWh in a year.
  • One year. 2025 hydro output depends on that year's Columbia River flow.

Replication

FactHub's estimates beside published external estimates of the same quantity. The difference is FactHub's value minus the external value.

FactHub analysis External estimate External value FactHub value Difference Note
Grand Coulee in 2025 U.S. Bureau of Reclamation, Grand Coulee Dam: About
About page: "generating capacity of more than 6,809-megawatts" 		6809 MW (nameplate) 6809 MW (nameplate) 0 MW (nameplate) Reclamation's figure equals the EIA-860 nameplate total including the pump-generating units.
Grand Coulee in 2025 U.S. Energy Information Administration, Today in Energy, "Drought conditions reduce hydropower generation, particularly in the Pacific Northwest" (November 7, 2024)
Today in Energy, Nov 7 2024, paragraph on the Columbia River Basin: "net summer capacity of 6.7 gigawatts" 		6700 MW (net summer) 7079 MW (net summer) +379 MW (net summer) EIA's article gives a rounded, lower summer figure than the 2025 EIA-860 generator file sums to; the article does not say which units it counted. Either figure keeps Grand Coulee first: the next plant has 4,530 MW of summer capacity.

Sources

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

License: FactHub's selection, cleaning and combined tables are licensed under CC BY 4.0. Source data keeps the terms listed above (terms).

Limitations and reproducibility

Fully reproducible from public downloads with Node.js 20 and SheetJS.: source-manifest.json lists every downloaded file with URL and SHA-256; build.js regenerates every table from those files and build_payload.js regenerates the release. The Commerce fuel-mix percentages are transcribed from a chart and are typed into build.js.

  • Net generation measures electricity produced by plants located in Washington, not the electricity Washington customers use; Washington trades large volumes with other states and Canada.
  • Conventional hydro excludes pumped storage, which EIA reports separately and which is near zero or negative in Washington.
  • Washington's hydro output depends on Columbia River Basin water supply, so any single year can differ from the long-run pattern; 2023 and 2024 were drought years.
  • Plant rankings use EIA plant codes and 2025 data only; capacity rankings use year-end operable generators.
  • The consumption-side fuel mix covers 2024 only and includes 15.44% unspecified power.

Publications using this dataset

Version details

The exact citing versions, and the version of this dataset each cites.

  • Article wa-hydropower-grand-coulee — version 2 (published) cites version 1
  • Article wa-hydropower-grand-coulee — version 1 (published) cites version 1
  • Chart grand-coulee-biggest-plant-vs-output — version 2 (published) cites version 3
  • Chart wa-hydro-share-of-generation — version 2 (published) cites version 1

Node: dataset:wa-electricity-generation-by-source:3