Low cost, reliable and renewable, hydroelectric power has become the world's largest source of renewable energy, accounting for a fifth of global electricity, according to the World Bank.
As our energy needs become more pressing, hydro-power will become increasingly important. Here, Energy Future takes a look at eight of the world's biggest and most spectacular hydro installations.
By Anmar Frangoul, special to CNBC.com
The Dalles Lock and Dam, United States:
Located nearly 200 miles from the mouth of the Columbia River The Dalles Lock and Dam has generated over 9.2 million megawatt hours of electricity since its first generators were installed in 1960.
Daily it provides enough electricity to power 800,000 homes, according to the dam's builders, the U.S. Army Corps of Engineers.
Rance Barrage, France:
The Rance Barrage was officially opened in 1966. Located on the Rance Estuary in Brittany, France, and with a capacity of 240 megawatts, it generates 540,000 MW hours of electricity every single year.
Annapolis Tidal Station, Canada:
The only tidal power plant in North America, the Annapolis Tidal Station, in Nova Scotia, Canada, has been operational since 1984.
The output of the installation is dependent on the tides, but on average it generates between 80-100 MW hours of electricity every day.
John Day Lock and Dam, United States:
Situated at the head of Lake Celilo near Rufus, Oregon, the John Day Lock and Dam was completed in 1971. Its powerhouse is 602 meters in length and has 16 generators with a capacity of 2,160 MW.
According to the U.S. Army Corps of Engineers, the dam's powerhouse can produce enough electricity, "to meet the electrical needs of two cities the size of Seattle."
Sayano-Shushenskaya hydropower plant, Russia:
Opened in 1978, the Sayano-Shushenskaya hydropower plant is situated in Khakassia, almost 2,000 miles east of Moscow. Its dam is 245 meters tall and 1,000 meters in length, and the plant has a capacity of 6400 MW.
In August 2009, tragedy struck when one of the plant's turbines broke apart, causing flooding and the collapse of the turbine room and killing 75 people. A reconstruction project of the power plant was completed this month.
Guri Dam, Venezuela:
Located on the Caroni River in the east of oil-rich Venezuela, the Guri Dam has been operational since 1969 and was fully completed in 1986.
One of the largest hydroelectric power stations on the planet with a capacity of over 10,000 MW, the dam is over 160 meters high and 11.4 kilometers in length.
Tucuruí Dam, Brazil:
One of the world's largest hydroelectric power stations, the Tucuruí Dam sits on the River Tocantins, in the Brazilian Amazon. Construction of Tucuruí began in 1975, and today it has a capacity of more than 8,370 MW.
A large proportion of Brazilian electricity is generated using hydropower, but this comes at a cost. According to the World Wide Fund for Nature, 40,000 people have been displaced as a result of Tucuruí.
Nurek Dam,Tajikistan :
One of the world's tallest dams, standing 300 meters in height, and over 700 meters wide Tajikistan's Nurek Dam is situated on the Vakhsh River, in the west of the country.
The Nurek Dam's hydro power plant has a capacity of more than 2,500 MW, while water from the dam is used to irrigate more than one million acres of land.
