Carbon dioxide emission accounting for small hydropower plants-A case study in southwest China

Small hydropower plants, which are one of most important means for producing clean energy, have a high prestige in the carbon trade market. In this paper, a method for accounting the carbon dioxide emission of small hydropower plants is proposed. Twenty-six small hydropower plants (SHPs) in southwest China are chosen as a case study. The following results were found: (1) the carbon dioxide emission during the construction period (COEc) per installed capacity ranged between 0.01957 t/kW and 0.1926 t/kW, with its average value 0.04592 t/kw; (2) the carbon dioxide emission during the construction period is classified into two groups; for each group, there is a reciprocal relationship between the installed capacity and the annual COEc per installed capacity, and (3) the annual CEOo (carbon dioxide emission during the operation period) declines with increasing installed capacity, the two related by a straight line. Specifically, when the installed capacity increases by 1 kW carbon emissions are reduced by 16.33 t. COEo is directly determined by hydropower. In addition, (4) the trend of carbon dioxide emission during the system lifecycle of SHPs is determined by COEo. The most important factor in determining the carbon dioxide emission of SHPs is to ensure the precise hydropower of SHPs.