Hydropower, also known as water power or water energy, is the use of falling or fast-running water to produce electricity or to power machines. This is achieved by converting the gravitational potential or kinetic energy of a water source to produce power. Hydropower is a method of sustainable energy production. Hydropower is now used principally for hydroelectric power generation, and is also applied as one half of an energy storage system known as pumped-storage hydroelectricity.
Small hydro is the development of hydroelectric power on a scale suitable for local community and industry, or to contribute to distributed generation in a regional electricity grid. Exact definitions vary, but a "small hydro" project is less than 50 megawatts (MW), and can be further subdivide by scale into "mini" (<1MW), "micro" (<100 kW), "pico" (<10 kW). In contrast many hydroelectric projects are of enormous size, such as the generating plant at the Three Gorges Dam at 22,500 megawatts or the vast multiple projects of the Tennessee Valley Authority.
Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing. A PSH system stores energy in the form of gravitational potential energy of water, pumped from a lower elevation reservoir to a higher elevation. Low-cost surplus off-peak electric power is typically used to run the pumps. During periods of high electrical demand, the stored water is released through turbines to produce electric power.
Hydroelectricity, or hydroelectric power, is electricity generated from hydropower. Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other renewable sources combined and also more than nuclear power. Hydropower can provide large amounts of low-carbon electricity on demand, making it a key element for creating secure and clean electricity supply systems. A hydroelectric power station that has a dam and reservoir is a flexible source, since the amount of electricity produced can be increased or decreased in seconds or minutes in response to varying electricity demand. Once a hydroelectric complex is constructed, it produces no direct waste, and almost always emits considerably less greenhouse gas than fossil fuel-powered energy plants. However, when constructed in lowland rainforest areas, where part of the forest is inundated, substantial amounts of greenhouse gases may be emitted.
The Robert Moses Niagara Hydroelectric Power Station is a hydroelectric power station in Lewiston, New York, near Niagara Falls. Owned and operated by the New York Power Authority (NYPA), the plant diverts water from the Niagara River above Niagara Falls and returns the water into the lower portion of the river near Lake Ontario. It uses 13 generators at an installed capacity of 2,525 MW (3,386,000 hp) with an average annual net generation of 15,897,000 MWh between 2014 and 2023, and a capacity factor of 71.9%.
Run-of-river hydroelectricity (ROR) or run-of-the-river hydroelectricity is a type of hydroelectric generation plant whereby little or no water storage is provided. Run-of-the-river power plants may have no water storage at all or a limited amount of storage, in which case the storage reservoir is referred to as pondage. A plant without pondage is subject to seasonal river flows, so the plant will operate as an intermittent energy source. Conventional hydro uses reservoirs, which regulate water for flood control, dispatchable electrical power, and the provision of fresh water for agriculture.
According to the International Hydropower Association, Canada is the fourth largest producer of hydroelectricity in the world in 2021 after the United States, Brazil, and China. In 2019, Canada produced 632.2 TWh of electricity with 60% of energy coming from Hydroelectric and Tidal Energy Sources).
The Mingachevir Dam is an earth-fill embankment dam on the Kura River just north of Mingachevir in Azerbaijan. It serves several purposes, including hydroelectric power production and water storage for irrigation. The Mingachevir reservoir, behind the dam, supplies water to the Upper Qarabag and Upper Sirvan channels which help irrigate about 1,000,000 ha of farmland in the country. Its six Francis turbine-generators were overhauled or replaced with 70 megawatts (94,000 hp) sets in 2000. Mingachevir reservoir has a storage capacity of 15.730 cubic kilometres (12,753,000 acre⋅ft), covering 605 km2 (234 sq mi). The length of the dam is 1,550 metres (5,090 ft), its width is 16 metres (52 ft) and height is 80 m (260 ft). It is the largest hydroelectric power station in the South Caucasus, and is located on Kura river, not far from Mingachevir city.
The Taltson River is a roughly 500 km (310 mi) river in the Northwest Territories of Canada that drains into the Great Slave Lake. There are three hydroelectric power control structures on the river, and one power station.
Ohio Falls Station is a hydroelectric power station owned by Louisville Gas & Electric (LG&E) and Kentucky Utilities (KU) which is located three miles west of Downtown Louisville, Kentucky. The generating station is located on Shippingport Island at the site of the McAlpine Dam and locks along the Ohio River in Kentucky. The plant was built in 1923 by Byllesby Engineering and Management Corporation and the U.S. Army Corps of Engineers. The plant featured eight 10.4 MW units operating at roughly 13,500 hp per unit. Each unit was composed of Allis-Chalmers turbines and General Electric generators. The plant is located inside the Ohio Natural Wildlife Conservation Area and is considered a large impoundment hydro power plant. The station was built after a canal and dam within the Ohio river in an attempt to allow boats to navigate the 8 ft vertical drop among the falls that spanned 2 miles wide. Production of the canal and dam began in 1825. It was not until a repair on the dam was needed that Louisville engineers had the idea of building a hydroelectric station to harvest the power of the falls.
The Uglich Hydroelectric Station or Uglich GES is a hydroelectric station on the Volga River in Uglich in Yaroslavl Oblast, Russia, and is the first of the Volga-Kama cascade of dams. It began operating on December 8, 1940, making it one of the oldest hydroelectric plants in Russia. The 120-MW plant is operated by RusHydro. There is also a Russian hydropower museum located at the hydroelectric plant dedicated to the development of hydropower.
The Broadlands Dam is a 35 MW run-of-the-river hydroelectric complex currently under construction in Kitulgala, Sri Lanka. The project is expected to be completed in 2020, and will consist of two dams, and a power station downstream.
The Moragolla Dam is a planned hydroelectric dam in Moragolla, Sri Lanka. The dam is to be 35 m (115 ft) high and is planned to create the 1,980,000 m3 (70,000,000 cu ft) Moragolla Reservoir with a maximum supply level at 548 m (1,798 ft) MSL. Upon completion, the Moragolla Power Station would have a gross installed capacity of 30 megawatts from two francis turbines, capable of generating approximately 85 GWh annually.
Pit 5 Dam is a run-of-the-river hydroelectric dam on the Pit River in Shasta County, northeastern California, about 2 miles (3.2 km) south of Big Bend. It is part of the Pit 3-4-5 hydroelectric project owned by Pacific Gas & Electric Company.
St. Anthony Falls in Minneapolis, Minnesota, is the only natural falls on the Mississippi River. Since almost the beginning of settlement in the area by European descendants, the St. Anthony Falls have been used for waterpower. The first allowed settlers were at Ft. Snelling, where construction began in 1820. A sawmill was operating 1821 and a flour mill in 1823. As soon as the land at the sides of the falls became available it was purchased with the intent of using the waterpower of the falls. First lumber mills covered the falls, cutting lumber floated down the Mississippi. After 1870 flour mills started to dominate the area. From 1880 to 1930 the area was the number one flour producer in the US. In later years, some of the power came from steam, but in 1923 half of the waterpower used was for flour milling. Other industries have also used the waterpower.
Daraundi A Hydropower Station is a 6 MW run-of-river hydro-electric plant located on the Daraundi River in the Gorkha District of Nepal.
