GREENHOUSE-GAS EMISSIONS FROM HYDROPOWER - THE STATE OF RESEARCH IN 1996

This paper reports on the findings of a recent IAEA expert meeting on the assessment of greenhouse gas (GHG) emissions from the full 'lifecy cle' of hydropower. It discusses the different categories of hydropowe r plants in view of the two main sources of GHG emissions: first, dire ct and indirect emissions associated with the construction of the plan ts; second, emissions from decaying biomass from land flooded by hydro reservoirs. In terms of GHG emissions, this paper shows that, in most cases, hydropower is a good alternative to fossil fuelled power gener ation. For hydropower plants in cold climate, a typical GHG emission f actor is 15 g CO2 equivalent/kWh, which is 30-60 times less than the f actors of usual fossil fuel generation. For some hydropower plants in tropical climates, theoretical calculations have shown that reservoir emissions could be very high. However, no measurements of emissions we re taken from tropical reservoirs and the current level of research do es not allow for a reliable evaluation. Research is urgently needed in humid tropical climates. Copyright (C) 1997 Elsevier Science Ltd.