Does hydro generate emissions?
The question of whether hydro power is “clean energy” and not a significant source of carbon or methane emissions is under review. Hydro generates its power by letting water turn turbines as a means of creating electricity, which in itself is not a source of carbon dioxide or methane, two of the worst culprits in climate change. Scientists, however, have been examining the effects on the environment of having large bodies of sitting water. Several recent studies have found that hydro may be releasing more methane from its sitting bodies of water than previously thought. Depending upon how significant the amount of methane being released is, we may need to revisit whether or not hydro remains categorized as “clean energy” or not.
According to the Guardian article “Hydroelectric dams emit a billion tonnes of greenhouse gases a year, study finds” posted in November 2016, the “impact of dams on climate change has been underestimated, researchers warn, as rotting vegetation creates 25% more methane than previously thought” according to a study published in BioScience.
Although the amount of rotting vegetation in different dams varies, overall the study found that in total dams emit about a billion tonnes of greenhouse gases (ghg) every year, which represents an estimated 1.3% of the total emissions we produce each year.
Previously dams were thought to emit very little in the way of ghg emissions, but this study increases initial estimates by 25%. What makes this finding worse, is that methane is now considered 80 to 100 times more heat-trapping than carbon dioxide within the first twenty years, although its effects fade after that.
EcoWatch, Hydropower Will Undermine COP21 as ‘False Solution’ to Climate Change, by Gary Wockner, November 2, 2015.
“Over the past 15 years, the “methane problem” with hydropower has made minor blips in international news and has just begun to infiltrate the discussion of how it is wrong to use hydropower as a solution to fight climate change.
The non-profit environmental group International Rivers has spearheaded much of the education and advocacy, and scientific journals as well as climate-related news sites like Climate Central are also taking up the case. Hydropower has been called a “methane factory” and “methane bomb” that is just beginning to rear its ugly head as a major source of greenhouse gas emissions that have so-far been unaccounted for in climate change discussions and analyses.”