Grand Coulee Dam
The largest power plant in the United States by capacity
Location
History & Background
Grand Coulee Dam was authorized by President Franklin D. Roosevelt as a New Deal project in 1933 and completed in 1942. At the time of completion it was the largest concrete structure ever built, and electricity from its turbines powered the wartime production of aluminum for B-17 and B-29 aircraft and of plutonium at the Hanford Site for the Manhattan Project. Its capacity was expanded several times after the war, most significantly with the addition of the Third Powerplant (1975–1980) that added six new generators rated at over 800 MW each.
Why It Matters
Grand Coulee is the largest power plant in the United States and the fifth-largest in North America after several Brazilian, Canadian, and Mexican plants. It anchors the Federal Columbia River Power System operated by the Bonneville Power Administration, which provides roughly 40% of the electricity used in the Pacific Northwest. The dam also irrigates more than 670,000 acres of central Washington farmland via the Columbia Basin Project.
Environmental Impact
The dam permanently blocked salmon and steelhead migration to roughly 1,100 miles of upstream habitat in the upper Columbia River basin, including most of the Snake and Spokane River systems. No fish ladders were ever built. Tribes whose traditional fisheries depended on those runs—particularly the Colville Confederated Tribes and the Spokane Tribe—received no compensation until the 1990s. On the positive side, Grand Coulee produces low-cost, zero-carbon electricity that has helped keep Pacific Northwest emissions well below the US national average.
Fun Facts
- When completed in 1942, Grand Coulee was four times the size of the Boulder (Hoover) Dam and contained more concrete than was used in the entire pyramid of Cheops.
- Woody Guthrie wrote 26 songs about the dam in May 1941 while employed by the Bonneville Power Administration as a writer-in-residence.
- During WWII, Grand Coulee's output reportedly produced about a third of all the aluminum used in US warplanes.
- The dam's spillway is over a mile long—when active, it creates one of the largest manmade waterfalls in the world.
Frequently Asked Questions
Is Grand Coulee Dam the largest in the United States?▾
Yes. With 6,809 MW of installed capacity, Grand Coulee is the largest power plant in the United States by nameplate capacity. The next-largest is the Palo Verde Nuclear Generating Station in Arizona.
When was Grand Coulee Dam built?▾
Construction began in 1933 and the first generators came online in 1941. The dam was officially completed in 1942 and was significantly expanded with the Third Powerplant addition between 1975 and 1980.
What river does Grand Coulee Dam impound?▾
Grand Coulee is on the Columbia River in central Washington state. Its reservoir, Franklin D. Roosevelt Lake, stretches 151 miles upstream to the Canadian border.
About Hydroelectric Power
Hydroelectric power plants use the kinetic energy of flowing or falling water to generate electricity. They are renewable, produce no direct emissions, and can provide reliable baseload power or flexible peaking capacity.
Other Hydroelectric Power Plants in United States of America
| Name | Capacity | Owner |
|---|---|---|
| Chief Joseph Dam | 2.6 GW | U.S. Army Corps of Engineers |
| Robert Moses Niagara | 2.5 GW | NYPA |
| Hoover Dam | 2.1 GW | Bureau of Reclamation |
Related Reading
Data Information
Data Sources
Power plant data is based on the Global Power Plant Database by World Resources Institute, in collaboration with Google, KTH Royal Institute of Technology, Enipedia, and the Global Energy Observatory. Editorial content on this page is curated and reviewed by the StatsPanda team using publicly available reporting and operator filings.
Disclaimer
Information found on this page is for informational purposes only. Power plant specifications, ownership, and operational status may have changed since the data was last updated. Please verify critical information with official sources.