Greenhouse gas emissions of hydropower in the Mekong River Basin

Abstract

The Mekong River Basin in Southeast Asia is undergoing extensive hydropower development, but the magnitudes of related greenhouse gas emissions (GHG) are not well known. We provide the first screening of GHG emissions of 141 existing and planned reservoirs in the basin, with a focus on atmospheric gross emissions through the reservoir water surface. The emissions were estimated using statistical models that are based on global emission measurements. The hydropower reservoirs (119) were found to have an emission range of 0.2-1994 kg CO 2 e MWh -1 over a 100 year lifetime with a median of 26 kg CO 2 e MWh -1 . Hydropower reservoirs facilitating irrigation ( The emission fluxes for all reservoirs (141) had a range of 26-1813 000 t CO 2 e yr -1 over a 100 year lifetime with a median of 28 000 t CO 2 e yr -1 . Altogether, 82% of hydropower reservoirs (119) and 45% of reservoirs also facilitating irrigation ( These results are tentative and they suggest that hydropower in the Mekong Region cannot be considered categorically as low-emission energy. Instead, the GHG emissions of hydropower should be carefully considered case-by-case together with the other impacts on the natural and social environment.