Top 10 hydroelectric dams in the world
Generating electricity via hydroelectric facilities is certainly evocative; the primordial rush of water driving turbines is perhaps the most visual example of nature being harnessed to satiate our relentless demand for electricity. Not only does hydropower spark the imagination, it is also one of the most effective means of power generation. According to the International Energy Agency, hydropower accounts for around 17% of total global electricity production. Hydroelectric generation is clearly prolific, and it produces minimal pollution, will be renewable as long as rain replenishes reservoirs, and poses limited maintenance and operations costs. With generator-equipped dams being the most effective vector for this power generation, we’ve taken a look at the world’s ten largest hydroelectric dams by megawattage (MW).
10 | Sayano-Shushenskaya, Russia
The 6,400MW hydroelectric station, located near Sayanogorsk in Russia, was the subject of a disaster in 2009 that claimed the lives of 75 people and brought the plant’s output to a complete halt. Following the failure of one of the plant’s turbines that triggered an explosion, the respective building flooded and a section of the turbine hall’s roof collapsed. Five years later, in 2014, the dam had been restored to full operations at a cost of US$89.3mn.
9 | Longtan, China
Beginning full operations in 2009, the Longtan dam cost around US$4.2bn to construct and has an installed capacity of 6,426MW. It is one of the tallest gravity dams in the world, standing at over 700ft tall with its power station situated underground.
8 | Xiangjiaba, China
Operated by China Yangtze Power Company (CYPC), itself owned by China Three Gorges, Xiangjiaba boasts a capacity of 6,448MW. Found on the Jinsha River, the dam offers a shipping route, sediment retention and flood control along the famed Yangtze alongside with its significant power generation capabilities. According to CYPC’s website, the dam’s reservoir houses a river basin area of around 458,800 sq km.
7 | Grand Coulee, USA
Located on the Columbia River in Washington, USA, the Grand Coulee Dam has an installed capacity of 6,809MW. The dam is the lead component of the Columbia Basin Project, focused on providing irrigation, electricity, flood control, recreation, streamflow regulation along with metropolitan, navigator and environmental water supply across 671,000 acres in east central Washington. The dam, comprised of three hydroelectric plants and a pump generating plant, provides an average of 21bn kWh annually for distribution across Washington, Idaho, Oregon, California, Colorado, New Mexico, Wyoming, Nevada, Arizona and Utah.
6 | Tucuruí, Brazil
Tucuruí Dam is the largest ever built in a rainforest, situated in the Amazon Basin of northeastern Brazil with a capacity of 8,370MW. According to the WWF, 90% of Brazil’s power is hydroelectric – harnessing the Amazon’s aquatic force facilitates this whilst offering the opportunity to sell power abroad. Unfortunately, the dam’s virtues come at the cost of ethical and environmental sustainability. The WWF noted that 40,000 people were displaced by the dam’s construction, and rotting vegetation at the bottom of the reservoir accounts for a sixth of the country’s total GHG emissions.
5 | Belo Monte, Brazil
The Belo Monte Dam is currently under construction, but nonetheless has an operational capacity, as of August 2019, of 9,166.65MW. Set for completion in 2020, the dam is expected to have a total capacity of 11,233MW. The dam, situated on Brazil’s Xingu River, has been beset with design and legislative impediments since it was originally pitched in the 1970s. Along with Brazil’s strong economic growth over the past decade and need for energy security, the dam’s construction was approved and accelerated to cater to this demand.
4 | Guri, Venezuela
Guri Dam, located on the Caroní River in Venezuela, boasts a generating capacity of 10,235MW. The dam’s official name is Embalse Raúl Leoni, with Guri referring to the name of the village and river, both now submerged, upon which the dam was originally built. The plant was originally devised as a means to minimise fossil fuel-powered electricity in Venezuela, thereby enabling it to export as much oil as possible. Venezuela’s grid relies primarily on hydroelectricity, with the power source accounting for 67,633GWh in 2016.
3 | Xiluodu, China
At 13,860MW, Xiluodu Dam is China’s second largest hydroelectric dam by capacity. Found on the Jinsha River in Yunnan Province, the dam encroaches on Sichuan Province on the side of the river opposite to Xiluodu Town. The dam is operated by CYPC and began operations in 2013, and its reservoir houses up to 12.67bn cubic metres of water. Xiluodu is instrumental in flood control on the Yangtze River.
2 | Itaipu, Brazil and Paraguay
Located on the Brazil-Paraguay border, the Itaipu dam and its 20 turbine generators carry a capacity of 14,000MW. Built between 1975 and 1982 as a joint venture between the Brazilian and Paraguayan governments, the dam’s reservoir stretches 160km north while the structure itself spans 8km across the Alto Paraná River. While it generates massive amounts of electricity each year, the dam sadly submerged the river’s famed Guaíra Falls which, according to Britannica, likely represented the world’s largest volume of falling water.
1 | Three Gorges, China
According to USGS, China’s Three Gorges Dam spanning the Yangtze River houses by far the world’s largest MW capacity. The dam overtook Itaipu in 2012 when the last of its 32 generators were activated, realising a total capacity of 22,500MW. Known as one of the greatest feats of Chinese engineering, the CYPC-operated dam’s reservoir is comprised of the submerged Qutang, Wu and Xiling gorges, stretching over 600km upstream.