Hydroelectric power is a form of hydropower to produce electricity. Most hydroelectric power comes from the potential energy of dammed water driving a water turbine and generator. Hydroelectric plants tend to have longer lives than fuel-fired generation. Hydroelectric plants generally have small to negligible emissions of carbon dioxide and methane due to reservoir emissions, and emit no sulphur dioxide, nitrogen oxide, dust, or other pollutants associated with combustion. The hydroelectric plants may have several purposes including electricity generation, flood control, navigation, irrigation, public water supply, and recreation. A hydroelectric power plant has the following components: reservoir, dam, turbine, penstock, valve, tailrace, transformer, and alternator. The construction of diversion and storage dams for hydroelectric power plants requires suitable topography and other site conditions, and a steep drop in the elevation of the river. Construction of hydroelectric plant is capital intensive but the operating costs are low since there are no fuel costs associated with a hydroelectric plant. The operation and maintenance cost of hydroelectric plants are low, and they have a long lifetime.
