Authors: Siyue Li Quanfa Zhang
Publish Date: 2014/06/19
Volume: 21, Issue: 23, Pages: 13636-13641
Abstract
Substantial greenhouse gas GHG emissions from hydropower reservoirs have been of great concerns recently yet the significant carbon emitters of drawdown area and reservoir downstream including spillways and turbines as well as river reaches below dams have not been included in global carbon budget Here we revisit GHG emission from hydropower reservoirs by considering reservoir surface area drawdown zone and reservoir downstream Our estimates demonstrate around 3013 Tg carbon dioxide CO2/year and 187 Tg methane CH4/year from global hydroelectric reservoirs which are much higher than recent observations The sum of drawdown and downstream emission which is generally overlooked represents 42 CO2 and 67 CH4 of the total emissions from hydropower reservoirs Accordingly the global average emissions from hydropower are estimated to be 92 g CO2/kWh and 57 g CH4/kWh Nonetheless global hydroelectricity could currently reduce approximate 2351 Tg CO2eq/year with respect to fuel fossil plant alternative The new findings show a substantial revision of carbon emission from the global hydropower reservoirs
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