Hydroelectricity, or hydroelectric power, is electricity generated from hydropower. Hydropower supplies one sixth of the world's electricity, almost 4,500 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 electricity sector in Norway relies predominantly on hydroelectricity. A significant share of the total electrical production is consumed by national industry.
Hidroelectrica is a leader in electricity production and the main provider of technological services required in the National Energy System in Romania.
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 Tarnița–Lăpuștești Hydropower Plant is a proposed hydroelectric pumped-storage project on the Someșul Cald River in Cluj County, Romania. If built it would be the largest hydro-electric load balancing system in Romania. During the night, when the demand is low and electricity is cheap because of powerplants which generate electricity continuously, such as the Cernavodă nuclear power plant, it will use electricity to pump water up the hill, while during the day, it will use the hydro energy to generate electricity.
The Mingachevir Dam is an earth-fill embankment dam on the Kura River just north of Mingachevir in Azerbaijan. It serves several purposes to include 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, is located over Kur river and not far from Mingachevir city.
Two-thirds of energy in Azerbaijan comes from fossil gas and almost a third from oil. Azerbaijan is a major producer of oil and gas, much of which is exported. Most electricity is generated by gas-fired power plants. Energy is all types of energy products, including fuel, renewable energy, water energy, electrical and heat energy.
Azerenergy (Azerenerji Joint Stock Company (JSC)) is the largest electrical power producer in the Republic of Azerbaijan. It also maintains the largest distribution network in the country, although the regional power networks are being privatized. Azerenergy was recreated as a state-owned joint stock company in 1996, by decree of President Heydar Aliyev.
India is 5th globally for installed hydroelectric power capacity. As of 31 March 2020, India's installed utility-scale hydroelectric capacity was 46,000 MW, or 12.3% of its total utility power generation capacity. Additional smaller hydroelectric power units with a total capacity of 4,683 MW have been installed. India's hydroelectric power potential is estimated at 148,700 MW at 60% load factor. In the fiscal year 2019–20, the total hydroelectric power generated in India was 156 TWh with an average capacity factor of 38.71%.
Renewable energy in Russia mainly consists of hydroelectric energy. Russia is rich not only in oil, gas and coal, but also in wind, hydro, geothermal, biomass and solar energy – the resources of renewable energy. Practically all regions have at least one or two forms of renewable energy that are commercially exploitable, while some regions are rich in all forms of renewable energy resources. However, fossil fuels dominate Russia’s current energy mix, while its abundant and diverse renewable energy resources play little role.
In 2021, hydroelectricity generated 11% of Bulgaria’s electricity. As of 2020, the country's total installed electricity capacity was approximately 12,839 MW, with hydropower contributing 25%, or 3,213 MW.
Dariali Hydropower Plant, referred to as Dariali HPP, is a 108 MW run-of-the-river hydropower plant built in 2017 in Georgia. It is located on the Tergi River in Kazbegi Municipality, at less than 1 km from the Russian-Georgian border, 160 km far from Tbilisi.
Hydroelectricity is currently China's largest renewable energy source and the second overall after coal. According to the International Hydropower Association, China is the worlds largest producer of hydroelectricity as of 2021. China's installed hydroelectric capacity in 2021 was 390.9 GW, including 36.4 GW of pumped storage hydroelectricity capacity, up from 233 GW in 2011. That year, hydropower generated 1,300 TWh of power, an increase of 68 TWh over 2018 when hydropower generated 1,232 TWh of power, accounting for roughly 18% of China's total electricity generation.
Sevan–Hrazdan Cascade is a complex of hydroelectric power plants on the Hrazdan River and its tributaries between the Lake Sevan and Yerevan in Armenia. They use irrigation water flow from the Lake Sevan and streams waters of Hrazdan River. The cascade is owned by the International Energy Corporation (IEC), a subsidiary of Tashir Group owned by Samvel Karapetyan.
The Vorotan Cascade, or the ContourGlobal Hydro Cascade, is a cascade on the Vorotan River in Syunik Province, Armenia. It was built to produce hydroelectric power and provide irrigation water. The Vorotan Cascade consists of three hydroelectric power plants and five reservoirs with a combined installed capacity of 404.2 MW. It is one of the main power generation complexes in Armenia.
The Dzoraget Hydroelectric Power Station is situated in Dzoraget village, Lori Region, Armenia. The plant is located on the coast of Debed River, but it uses the flows of the waters of Dzoraget River. Construction of the Dzoraget HPP started in 1927 and it was launched on 15 November 1932 with the full installed capacity of 22.32 MW. As of 1980, the plant uses three generators with an installed capacity of 26.2 MW. The Dzoraget Hydro Power Plant is considered to be small size power plant. There is a little water storage behind the weir, as Dzoraget HPP is a run-of-the-river plant.
Utilities in Azerbaijan cover the topic of public utility services in the territory of Azerbaijani Republic. The utilities of Azerbaijan are provided by the government owned public utilities: “Azersu” for the water supply and waste management, “Azerishiq” and “Azerenerji” for electricity, “Azerigaz” for natural gas, “Azeristiliktechizat” for district heating.
Hydroelectricity in Ukraine is quite developed branch of power engineering. State operating company is Ukrhydroenergo and Energoatom. Design of main power plants is carried out by Ukrhydroproject.
Hydropower generates about 30% of Armenia's electricity but its share varies a lot from year to year.
