The hydropower paradox: is this energy as clean as it seems?

New research finds that the world’s hydroelectric dams generate a surprising amount of greenhouse gas emissions

In July, UN Secretary Ban Ki-Moon highlighted the role of hydropower in boosting the use of renewable energy globally, when he visited a nonprofit institute in China that helps emerging nations develop and build hydropower plants. Many countries consider hydroelectricity a clean source of power because it doesn’t involve burning dirty fossil fuels. But that’s far from true. Hydropower is a significant source of greenhouse gas emissions: a new study shows that the world’s hydroelectric dams are responsible for as much methane emissions as Canada.

The study from Washington State University finds that methane, which is at least 34 times more potent than another greenhouse gas, carbon dioxide, makes up 80% of the emissions from water storage reservoirs created by dams. What’s more, none of these emissions are currently included in global greenhouse gas inventories. These are already revealing a worrisome future in which rising global temperatures will likely cause environmental changes such as rising sea levels and stronger hurricanes, which could uproot communities and intensify competition for food and other resources.

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