The world's largest power plant is a hydroelectric dam on the Paraná River on the border between Brazil and Paraguay. It is a bi-national project, led by the company Itaipu Binacional. The power plant was named in honor of an island that was at the location of the construction site, Itaipu, which means "singing stones" in the native Guarani language. As the world's largest power plant, the Itaipu dam can produce as much as 17.6 gigawatts of power through its 18 installed hydroelectric generator units. In 1995, the dam was named one of the Seven Wonders of the Modern World by Popular Mechanics magazine.

The Itaipu dam was finished in May 5, 1984, but all 18 generators were not installed until 1991, meaning it didn't become the world's largest power plant until sometime around 1985. The dam took 14 years to built, with construction beginning in January 1970. Itaipu blows away all other competitors, including nuclear plants, for the title of world's largest power plant. The largest nuclear plants are in the 3GW range, and more recent projects, such as China's efforts towards a 6GW nuclear power plant, inevitably fall short. However, the Three Gorges Dam on the Yangtze River in China will eventually beat Itaipu when all its generators are installed, producing 22.5 GW of power, 11% of the national electricity consumption.

Nevertheless, Itaipu is currently the largest power plant in the world. In 2005, it provided 93% of the energy used by Paraguay and 20% of that consumed by Brazil. That is enough energy for millions of people. Itaipu also makes evident the deep cooperation and mutual trust between Brazil and Paraguay.

It is quite likely that hydroelectric dams will always claim the title of the world's largest power plant in the world for a while yet, as you can't easily beat a natural source of tremendous energy such as this. However, hydroelectric dams are limited by the size of the river, whereas alternative sources such as nuclear and solar have no such limitations. Nuclear is limited by the quantity of nuclear fuel, solar by the energy output of the sun. Both quantities are absolutely huge, many times the human race's annual electricity consumption.

It is not easy to chain hydroelectric dams next to each other because of the huge flood basins they create. Sometime around the middle of this century, it would be unsurprising if a solar satellite installation took over for the title of the largest power plant. Though according to some, it wouldn't be the "world's largest," as it would be literally out of this world!