A hydroelectric dam is a building constructed along the route of a river to constrict flow, with water under high pressure thereby driving turbines. The driving of these turbines is a way of creating electrical power. They can be combined with manmade reservoirs to increase the possible output. The main benefit of hydroelectric power is that it is a fairly cheap, renewable source of energy with no hazardous emissions or waste. In addition, with a significantly large amount of water, the energy output can be enormous (for example, at about the time of the First Tiberium War, hydroelectric stations at Niagara Falls had a production capacity of about 4,700 megawatts of electricity). However to provide a significant amount of usable power, hydroelectric plants need to be constructed near large bodies of water; limiting the places where they can be built.
During the Second Tiberium War, General Vega's island base in Central America depended partly on a hydroelectric dam for power, however, Vega failed to adequately defend them. GDI's Commander McNeil targeted this facility for destruction before attacking the Drug Lord's main base; severely undermining Vega's defences.