Rotting reservoirs

 作者:江随岈     |      日期:2019-03-02 12:17:00
Hydroelectricity may not be such an environmentally friendly source of power after all. A new study in Canada has found that some hydroelectric reservoirs give off as much carbon dioxide and methane – the two most important causes of the man-made greenhouse effect – as coal-fired power stations producing a similar amount of electricity. The problem is the forests, soils and peat bogs flooded by the reservoirs, say John Rudd and colleagues from the Canadian government’s Freshwater Institute in Winnipeg in the current issue of Ambio. Once these are flooded, they decompose, releasing the gases. A study of one hydroelectric reservoir, Cedar Lake in Manitoba, revealed a likely release of about one kilogram of carbon dioxide for every kilowatt-hour of electricity produced by the reservoir’s power station. This emission was ‘similar to the greenhouse effect of electricity generated by coal-fired plants’ and would persist for at least 50 years. To date,