Every year the Hetch Hetchy Water and Power System produces 1.7 billion kilowatt-hours of clean renewable hydropower - equivalent to the power generated from burning 39 million gallons of oil.
Early Intake Powerhouse was built in 1918, twelve miles downstream from O'Shaughnessy Dam. It supplied power for the tools and equipment used in building the dam. It also powered lighting for nighttime construction - a visionary innovation at the time.
Moccasin Powerhouse was built in 1925; Holm and Kirkwood Powerhouses were built decades later to increase power generation capacity.
Hydropower from the Hetch Hetchy Water and Power Project supplies electricity to the Modesto and Turlock Irrigation Districts, in accordance with the Federal Raker Act, and to San Francisco for the airport, hospitals, libraries, schools, streetlights, electric buses and other municipal facilities.
(caption) San Francisco City Hall, San Francisco General Hospital and non-polluting electric railcars use renewable energy from the Hetch Hetchy Water and Power Project.
(caption) Early Intake Powerhouse, completed in 1918, provided a dependable source of clean power at the beginning of the Hetch Hetchy Water and Power Project construction.
(caption) Worker next to a Pelton Wheel, one of the most efficient water turbines for producing hydropower.
(inset diagram captions) Reservoir // A penstock is a pipeline or tunnel which delivers water from a higher elevation to the turbines located at the powerhouse. // A Pelton turbine is turned by the force of the water on their cups. // Generators are rotated by the turbines to generate electricity. // Transmission lines conduct electricity to the cities.