Hydroelectric power's dirty secret revealed

Hydroelectric damns release dissolved methane from organic plant matter when the water passes through the turbines.

A study has shown that the greenhouse effect of emissions from the Curuá-Una dam in Pará, Brazil, was more than three-and-a-half times what would have been produced by generating the same amount of electricity from oil.

The emissions from hydro-electric plants will now be included in IPCC guidelines, but these guidelines will only take account of the first 10 years of a dam’s operation and only include surface emissions.

Contrary to popular belief, hydroelectric power can seriously damage the climate. Proposed changes to the way countries’ climate budgets are calculated aim to take greenhouse gas emissions from hydropower reservoirs into account, but some experts worry that they will not go far enough.

The green image of hydro power as a benign alternative to fossil fuels is false, says Éric Duchemin, a consultant for the Intergovernmental Panel on Climate Change (IPCC). “Everyone thinks hydro is very clean, but this is not the case,” he says.

Hydroelectric dams produce significant amounts of carbon dioxide and methane, and in some cases produce more of these greenhouse gases than power plants running on fossil fuels. Carbon emissions vary from dam to dam, says Philip Fearnside from Brazil’s National Institute for Research in the Amazon in Manaus. “But we do know that there are enough emissions to worry about.”

In a study to be published in Mitigation and Adaptation Strategies for Global Change, Fearnside estimates that in 1990 the greenhouse effect of emissions from the Curuá-Una dam in Pará, Brazil, was more than three-and-a-half times what would have been produced by generating the same amount of electricity from oil.

This is because large amounts of carbon tied up…

Posted by PerceptualChaos
PerceptualChaos is a physics (photonics) student from the University of Auckland, Aotearoa (NZ). He is working towards eventually getting a PHD and doing R&D on renewable energy sources and technology as we approach the end of the fossil fuel era Learn...