Coping with Risk Factors in Energy System Transformations - Climate Change Impacts on Nuclear Power Plant Availability in Europe

Nuclear power is currently being discussed in many places as it could contribute to a low-carbon energy transformation. However, the projected effects of climate change, including high cooling water temperatures and intensifying droughts, may increasingly lead to future problems at nuclear power plants. This work establishes and quantifies the relationship between the probability of extreme weather situations leading to lower nuclear availability in certain countries and the expected costs of transforming the energy system. We analyse changes in the recourse decisions, including shifted technology investments and alterations in system operation. Given potentially larger nuclear outages, we expose more robust transformation pathways to a climate-neutral system and show how the new modelling and optimisation framework EMPRISE can provide better decision support. We run the analysis for multiple historical meteorological years and combine several of those in a comprehensive scenario tree. A higher probability for reduced nuclear availability, e.g. 50 % instead of 5 % within one meteorological year, could increase the overall costs of the energy system by only up to 0.4 %, whereas the choice of the meteorological year itself, e.g. 2012 instead of 2010, can increase these costs by up to 4 %.