An underground power station is a type of hydroelectric power station constructed by excavating the major components from rock, rather than the more common surface-based construction methods.
Cushman Dam No. 1 is a hydroelectric dam on the North Fork of the Skokomish River in Mason County, Washington, which in derogation of the natural and treaty rights of the Native inhabitants impounded and enlarged the formerly natural Lake Cushman, leading to damage claims in excess of $5 billion and an eventual settlement agreement with the Skokomish tribe that terminates the right to operate the dam(s) after 2048. It was built by Tacoma City Light in 1924–1926. Tacoma's demand for electricity grew rapidly after World War I. Tacoma City Light's Nisqually River Hydroelectric Project, built in 1912, could not meet the demand and the utility decided to build a new hydroelectric project on the North Fork Skokomish River. The dam and powerhouse first began to deliver electricity on February 12, 1926.
The Petty Harbour Hydro Electric Generating Station is a hydroelectric generating station in Petty Harbour–Maddox Cove, Newfoundland and Labrador. It was constructed in 1898 and it was the first hydroelectric generating station in Newfoundland. It was built by the St. John's Street Railway Company, a company established by Robert Reid. Operation commenced on 19 April 1900.
The Bull Run Hydroelectric Project was a Portland General Electric (PGE) development in the Sandy River basin in the U.S. state of Oregon. Originally built between 1908 and 1912 near the town of Bull Run, it supplied hydroelectric power for the Portland area for nearly a century, until it was removed in 2007 and 2008. The project used a system of canals, tunnels, wood box flumes and diversion dams to feed a remote storage reservoir and powerhouse. The entire project was removed because of rising environmental costs. Marmot Dam on the Sandy River was demolished in 2007, and the Little Sandy Dam on the Little Sandy River was taken down in 2008.
Lake Chelan Dam officially known as the Lake Chelan Hydroelectric Project is located approximately 32 miles (51 km) north of the city of Wenatchee in Chelan County. The dam is located at the lower or southeasterly end of 50.4 miles long Lake Chelan, and is within the limits of the city of Chelan. The powerhouse is located near the community of Chelan Falls. The reservoir has 677,400 acre-feet (835,600,000 m3) of usable water storage. The 10-year average generation for the Project is 365,000 megawatt hours.
Spruce Falls was the local name for a small waterfall where the Swan River empties into Duck Lake in northeastern Saskatchewan, near the Manitoba boundary. It is at 55°37′ N and 102°7′ W.
Theodore Roosevelt Dam is a dam on the Salt River located northeast of Phoenix, Arizona. The dam is 357 feet (109 m) high and forms Theodore Roosevelt Lake as it impounds the Salt River. Originally built between 1905 and 1911, the dam was renovated and expanded in 1989–1996. The dam is named after President Theodore Roosevelt. Serving mainly for irrigation, water supply, and flood control, the dam also has a hydroelectric generating capacity of 36 megawatts.
Folsom Powerhouse State Historic Park is a historical site preserving an 1895 alternating current (AC) hydroelectric power station—one of the first in the United States.
Croton Dam is an earth-filled embankment dam and powerplant complex on the Muskegon River in Croton Township, Newaygo County, Michigan. It was built in 1907 under the direction of William D. Fargo by the Grand Rapids - Muskegon Power Company, a predecessor of Consumers Energy. The 40-foot-high (12 m) dam impounds 7.2 billion U.S. gallons (6 billion imp. gal/27 billion L) of water in its 1,209-acre (489 ha) reservoir and is capable of producing 8,850 kilowatts at peak outflow. It was listed on the National Register of Historic Places in 1979.
James Delmage Ross was the superintendent of lighting for Seattle for 28 years and was the first administrator of the Bonneville Power Administration. He was instrumental in developing the Cedar Falls and Skagit River hydroelectric power plants. A self-taught engineer, Ross advocated for public utilities and regional power networks. He also later served as a member of the Securities and Exchange Commission.
Hauser Dam is a hydroelectric straight gravity dam on the Missouri River about 14 miles (23 km) northeast of Helena, Montana, in the United States. The original dam, built between 1905 and 1907, failed in 1908 and caused severe flooding and damage downstream. A second dam was built on the site in 1908 and opened in 1911 and comprises the present structure. The current Hauser Dam is 700 feet (210 m) long and 80 feet (24 m) high. The reservoir formed by the dam, Hauser Lake, is 25 miles (40 km) long, has a surface area of 3,800 acres (1,500 ha), and has a storage capacity of 98,000 acre-feet (121,000,000 m3) of water when full.
Black Eagle Dam is a hydroelectric gravity weir dam located on the Missouri River in the city of Great Falls, Montana. The first dam on the site, built and opened in 1890, was a timber-and-rock crib dam. This structure was the first hydroelectric dam built in Montana and the first built on the Missouri River. The dam helped give the city of Great Falls the nickname "The Electric City." A second dam, built of concrete in 1926 and opened in 1927, replaced the first dam, which was not removed and lies submerged in the reservoir. Almost unchanged since 1926, the dam is 782 feet (238 m) long and 34.5 feet (10.5 m) high, and its powerhouse contains three turbines capable of generating seven megawatts (MW) of power each. The maximum power output of the dam is 18 MW. Montana Power Company built the second dam, PPL Corporation purchased it in 1997 and sold it to NorthWestern Corporation in 2014. The reservoir behind the dam has no official name, but was called the Long Pool for many years. The reservoir is about 2 miles (3.2 km) long, and has a storage capacity of 1,710 acre-feet (2,110,000 m3) to 1,820 acre-feet (2,240,000 m3) of water.
Stave Falls Dam is a dual-dam power complex on the Stave River in Stave Falls, British Columbia, Canada. The dam was completed in 1912 for the primary purpose of hydroelectric power production. To increase the capacity of Stave Lake, the dam was raised in 1925 and the Blind Slough Dam constructed in an adjacent watercourse 500 m (1,600 ft) to the north, which was the site of the eponymous Stave Falls. In 2000, the dam's powerhouse was replaced after a four-year upgrade. The original Stave Falls powerhouse was once British Columbia's largest hydroelectric power source, and is a National Historic Site of Canada.
The Enloe Dam, also known as the Similkameen Dam, and its powerplant are located on the Similkameen River about 4 miles (6.4 km) west-northwest of Oroville, Washington. Located just above Similkameen (Coyote) Falls, the concrete arch-gravity dam stands about 54 feet (16 m) high, with a crest length of about 290 feet (88 m), built between 1916 and 1923. The dam was named after the president of the Okanogan Valley Power Company, Eugene Enloe. The dam was operated to generate power at its powerplant, located about 850 feet (260 m) downstream from the dam. Lacking fish ladders, Enloe Dam blocks fish passage and completely extirpated anadromous fish migration into the upper reaches of the Similkameen River and its tributaries in Canada.
Cooke Dam is a hydro-electric dam on the Au Sable River in Michigan. It was listed on the National Register of Historic Places in 1996 as the Cooke Hydroelectric Plant.
The Devil's Gate-Weber Hydroelectric Power Plant was built in 1909–1910 on the Weber River in northeastern Utah, United States, about 10 miles (16 km) southeast of Ogden. It was built by the Utah Light and Railway Company under the direction of E.H. Harriman, a director of the Union Pacific Railroad. It was one of the first powerplants in Utah designed to feed an electrical grid rather than as a source of power of a single locality.
The Stairs Station Hydroelectric Power Plant was built in 1894-1895 in Big Cottonwood Canyon, about 8 miles (13 km) southeast of Salt Lake City, Utah. The plant comprises the powerhouse, switchyard, penstocks, and a pipeline. A dam next to the site is associated with the Granite Power Plant farther downstream, and is part of neither historic district. The powerhouse is the only remaining building associated with the plant. It is an example of an intact high-head generating plant from the late 19th century.
The Granite Hydroelectric Power Station was built in 1896–1897 at the mouth of Big Cottonwood Canyon, about 6 miles (9.7 km) southeast of Salt Lake City, Utah, United States(in what is now eastern Cottonwood Heights. The plant comprises the powerhouse, transformer house, a wooden conduit, penstocks, and a small dam. Like the Stairs Station upstream, it represents an intact high-head generating plant from the late 19th century.
The Eklutna Power Plant, also referred to as Old Eklutna Power Plant, is a historic hydroelectric power plant on the Eklutna River in Anchorage, Alaska. Located about 5 miles (8.0 km) downstream of the more modern new Eklutna Power Plant, it was built in 1928–29 to provide electrical power to the growing city, and served as its primary power source until 1956. The facilities include two dams, a tunnel and penstock, and a powerhouse. The main dam, Eklutna Dam, located at the northwestern end of Eklutna Lake, was built in 1941 to replace a series of temporary structures built after an earthen dam failed before the plant began operation. The diversion dam, a concrete arch dam, is located 7 miles (11 km) downstream from the lake, and provides facilities for diverting water into the tunnel. The tunnel is 1,900 feet (580 m) long, and is terminated in a penstock, a structure designed to raise the water pressure. The powerhouse is a concrete-and-steel structure completed in 1929. The diversion dam removal was completed in 2018 to allow for the passage of salmon.
The Snoqualmie Falls Hydroelectric Plant is located just north of Snoqualmie in King County, Washington state, US. It is situated about 22 mi (35 km) east of Seattle. Located just below the Snoqualmie Falls, the power plant consists of two power houses, Plant 1 and Plant 2. Plant 1 was completed in 1899 and is located underground. It is the first completely underground hydroelectric power plant ever built in the world. Plant 2 was built in 1910 and is located along the right bank of the Snoqualmie River. Both plants receive water from a small reservoir created by a weir atop the falls. Plant 1 has an installed capacity of 13.7 MW and Plant 2 a capacity of 40.2 MW for a total installed capacity of 53.9 MW, enough to power 40,000 homes.
