In order to combat global warming, a detailed knowledge of the greenhouse gas (GHG) emissions associated with different energy conversion technologies is important. For nuclear energy, GHG emissions result from different process stages of the whole fuel cycle. A life-cycle assessment offers the possibility to properly calculate these emissions. In the past, both indirect energy use and GHG emissions were studied by many researchers. Most of the studies result in low indirect emissions comparable to wind turbines. However, some of the studies in the literature obtain high results adding up to a significant fraction of the direct emissions from a CCGT.
In this paper, the GHG emissions resulting from the overall nuclear fuel cycle are analyzed by making a detailed comparison of the results from three different life-cycle assessments. Hereby, the studies are chosen in order to reflect the range of results available in open literature. The studies under consideration result in indirect emissions of around 8 and 58 g CO2/kWhe and more than 110 g CO2/kWhe.
An explanation is given for these strongly varying results by analyzing the input data, assumptions and estimations made for different process steps.