Think hydropower is clean energy? Think again.

Organic materials build up behind dams, consuming oxygen as they decompose. This sedimentation can create oxygen-free dead zones, where no river life of any kind can survive. As water stops flowing, its temperature rises. Even a few degrees can be life-threatening, since most aquatic life is highly temperature-sensitive.

But hydropower’s most devastating effect might be that, contrary to popular belief, it’s not actually emission-free.

As trapped material decays in reservoirs, methane bubbles are released and methane emissions rise. As far back as 2000, research suggested that hydropower was a net producer of greenhouse gas, but the data was contested by powerful hydropower lobbies. Today, the abundance of evidence is hard to deny. In 2016, researchers at Washington State University conducted a comprehensive meta-analysis, looking at 100 studies of emissions from over 250 reservoirs, and found that each square meter of reservoir surface emitted 25 percent more methane than previously recognized.

In some cases, greenhouse gas emissions from hydropower are actually higher than a comparable fossil fuel power plant.

According to the Smithsonian Magazine, Philip Fearnside, an ecologist, found that just 13 years after it was built, the Curuá-Una Dam in Amazonian Brazil emitted 3.6 times more greenhouse gases than generating the same amount of electricity from oil.

Central Maine Power and Hydro Quebec claim environmental benefits from the proposed New England Clean Energy Connect transmission corridor. Be aware that CMP or Hydro Quebec during the permitting process refused to go on official record and swear that it is good for the environment. All the CMP ads say it is good for the environment, so why did they not go on official record?

Ed Buzzell 


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