The most powerful renewable energy – Future Planet – BBC Future

Written by Adrienne Bernhard

The world’s most relied-upon renewable energy source isn’t wind or sunlight, but water. Last year, the world’s hydropower capacity reached a record 1,308 gigawatts (to put this number in perspective, just one gigawatt is equivalent to the power produced by 1.3 million race horses or 2,000 speeding Corvettes). Utilities throughout the globe rely upon hydropower to generate electricity because it is cheap, easily stored and dispatched, and produced with no fuel combustion, meaning it won’t release carbon dioxide or pollutants the way power plants burning fossil fuels such as coal or natural gas do.

As with other energy sources, however, hydropower is not without an environmental cost. Beyond the profound ecosystem impact of damming and diverting huge waterways, hydropower can wreak havoc on native aquatic species and their ecosystems. The majority of watersheds around the world – some of which have operated on hydropower for more than a century – are highly degraded, with polluted waterways and outmoded technology. Traditional reservoirs are often stagnant bodies of water; because of this, they are frequently sites of harmful algal blooms, or HABs, which are toxic to people, fish, shellfish, marine mammals and birds.

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By Jessica Yap-Chung
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