Global Use of Hydroelectricity
Globally, hydroelectricity is a major electricity resource, accounting for more than 16% of all electricity produced on the planet. More electricity is produced globally using hydro-power than from plants fueled by nuclear fission or petroleum (natural gas and coal do produce more electricity globally than hydro-power does). More than 150 countries produce some hydroelectricity, although around 50% of all hydro-power is produced by just four countries: China, Brazil, Canada, and the United States. China is by far the largest hydro-power producer on the planet, as shown in the figure below. Hydroelectricity production in China has tripled over the past decade, with the completion of some of the world’s largest dam projects, in particular, the Three Gorges Dam (the world’s largest), which could produce nearly enough electricity to power all of New England during a typical summer and left an area roughly the size of San Francisco flooded underwater.
Once hydroelectric dams are built, they run very cheaply and generally provide reliable supplies of electricity except during times of extreme drought. Developed countries that have substantial hydro resources have, by and large, already utilized those resources to produce electricity. In these countries, hydro-power dominates the electricity supply system as shown in the chart below. Norway leads the pack here – the amount of hydro-power that it produces is not large in an absolute sense (it is the world’s seventh-largest producer) but nearly all electricity generated in Norway comes from hydro-power. Brazil and Canada are also highly dependent on hydro-power. Other large hydro producers, such as China and the United States, produce much less hydro electricity relative to the size of their overall power sectors.