Hydropower, also known as water power, 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. Hydropower is an attractive alternative to fossil fuels as it does not directly produce carbon dioxide or other atmospheric pollutants and it provides a relatively consistent source of power. Nonetheless, it has economic, sociological, and environmental downsides and requires a sufficiently energetic source of water, such as a river or elevated lake. International institutions such as the World Bank view hydropower as a low-carbon means for economic development.
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. The method 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. Although the losses of the pumping process make the plant a net consumer of energy overall, the system increases revenue by selling more electricity during periods of peak demand, when electricity prices are highest. If the upper lake collects significant rainfall or is fed by a river then the plant may be a net energy producer in the manner of a traditional hydroelectric plant.
Hydroelectricity, or hydroelectric power, is electricity generated from hydropower. Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, 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 McAlpine Locks and Dam are a set of locks and a hydroelectric dam at the Falls of the Ohio River at Louisville, Kentucky. They are located at mile point 606.8, and control a 72.9 miles (117.3 km) long navigation pool. The locks and their associated canal were the first major engineering project on the Ohio River, completed in 1830 as the Louisville and Portland Canal, designed to allow shipping traffic to navigate through the Falls of the Ohio.
Hartwell Dam is a concrete and embankment dam located on the Savannah River at the border of South Carolina and Georgia, creating Lake Hartwell. The dam was built by the U.S. Army Corps of Engineers between 1955 and 1962 for the purposes of flood control, hydropower and navigation. The concrete and earthen structure spans 15,840 feet (4,828 m). The concrete section is 1,900 feet (579 m) long and rises 204 feet (62 m) above the riverbed at its apex. The Hartwell Dam currently produces 468 million KWh of electricity annually, has prevented over $40 million in flood damage since completion and also provides recreation, water quality, water supply, along with fish and wildlife management.
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).
The Kajaki Dam is one of the two major hydroelectric power dams of Helmand province in southern Afghanistan. The dam is located on the Helmand River 100 miles (161 km) north-west of Kandahar and is operated by the Helmand and Arghandab Valley Authority. It has a dual function, to provide electricity and to irrigate some 650,000 acres (1800 km2) of an otherwise arid land. Water discharging from the dam traverses some 300 miles (500 km) of downstream irrigation canals feeding farmland. As of July 2022 it produces up to 151 megawatts (MW) of electricity.
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, thus 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.
Tenom Pangi Dam is the hydroelectric plant in Tenom, Sabah, Malaysia. It is located 120 km (75 mi) south of Kota Kinabalu on the Padas River. The project is a run-of-river hydroelectric power plant. Tenom Pangi Dam is the only major hydroelectric dam in Sabah.
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.
Kaligandaki A Hydroelectric Power Station is situated near Mirmi of Syangja District about 300 km to the west of Kathmandu and 100 km from Pokhara in the same direction in Nepal. The hydropower project is also the biggest hydropower project of Nepal. The dam and headworks are situated on the Gandaki River at the confluence of the Andhikhola whereas the power house is located downstream, around a bend in the river, in Beltari. A 5.9 km (3.7 mi) long headrace tunnel connects the reservoir to the power station which contains three 48 MW Francis turbine-generators. Owner and operator of the power plant is Nepal Electricity Authority.
The Dix Dam is a dam on the Dix River located between Mercer and Garrard County, Kentucky. It was constructed to generate hydroelectricity and prevent flooding of the Kentucky River but is better known for creating Herrington Lake.
Hydroelectricity is, as of 2019, the second-largest renewable source of energy in both generation and nominal capacity in the United States. In 2021, hydroelectric power produced 31.5% of the total renewable electricity, and 6.3% of the total U.S. electricity.
Richard B. Russell Dam is a concrete-gravity and embankment dam located on the Savannah River at the border of South Carolina and Georgia, creating Richard B. Russell Lake. The dam was built by the U.S. Army Corps of Engineers between 1974 and 1985 for the purposes of flood control, hydroelectricity, recreation, additional stream flow regulation, water supply, and fish and wildlife management. The concrete structure of the dam spans 1,904 feet (580 m) and rises 210 feet (64 m) above the riverbed, housing a hydro-power plant with an installed 600 megawatts (800,000 hp) capacity. The Richard B. Russell Dam is the final large dam completed by the U.S. Army Corps in the Savannah River Basin and lies 30 miles downstream from the Hartwell Dam (1962) and 37 miles (60 km) upstream from the J. Strom Thurmond Dam (1954).
The Shin-Takasegawa Pumped Storage Station (新高瀬川発電所) uses the Takase River to operate a pumped storage hydroelectric scheme about 12 kilometres (7.5 mi) west of Ōmachi in Nagano Prefecture, Japan. Part of the system is within Chūbu-Sangaku National Park.
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.
