Hydropower Said to Cause More Global Warming Than Coal-Fired Plants

Hydroelectric power’s reputation as a clean source of energy continues to take a pounding. The results of a 3-year study of rivers, lakes, and reservoirs in Southeast Asia which was published today in Taiwan found that hydropower is a greater contributor to global warming than power plants run on coal or oil. The researchers explained that the dead organic matter at the bottom of a reservoir behind a dam does not receive enough oxygen to decompose which results in the production of methane, a more powerful greenhouse gas than carbon dioxide by a factor of 21, and nitrous oxide, a more powerful greenhouse gas than carbon dioxide by a factor of 200. A member of the research team predicted that the Three Gorges Dam built on the Yangtze River in China, which is now in operation, will be a serious contributor to global warming. (Photo of Three Gorges reservoir behind the dam credited to Three Gorges Probe.)

Scientists Disagree Over Greenhouse Gas Emissions from Tropical Hydro

The Observer reports that at a meeting this week in Paris scientists will present evidence that when hydroelectric power plants are built in the tropics, the dead organic matter that accumulates in the reservoir behind the dam eventually decays releasing very large amounts of the greenhouse gases carbon dioxide and methane. As I mentioned in a post last month, I first heard about this extraordinary claim while listening to the radio show EcoTalk. It is tough enough to limit global warming without finding out that what is probably the most important clean method of generating electricity isn’t really clean. According to the Observer, not all scientists in this field agree that the emission of vast amounts of greenhouse gases occurs from hydro plants in tropical regions as some say that after a few years only modest amounts of emissions occur. Certainly global warming policy makers will need to know very soon who is right.