Flexible nuclear power and fluctuating renewables? – A techno-economic analysis for decarbonized energy systems

Many governments are considering constructing new nuclear power plants to support the decarbonization of the energy system. On the one hand, dispatchable nuclear plants can complement fluctuating generation from wind and PV. On the other hand, escalating construction costs and times raise economic concerns. In this paper, we extensively review construction costs and times. On this basis, we apply a detailed multi-vector energy model to analyze the cost-efficient share of nuclear power in fully decarbonized energy systems, i.e., energy systems that do not utilize any fossil fuels. Our analysis finds that even if, reversing the historical trend, overnight construction costs of nuclear half to 4,000 US-$2018 per kW and construction times remain below ten years, the cost-efficient share of nuclear power in European electricity generation is only around 10%. The analysis still omits the social costs of nuclear power, such as the risk of accidents or waste management. Nuclear plants must operate inflexibly and at capacity factors close to 90% to recover their investment costs, implying that operational flexibility-even if technically possible-is not economically viable. As a result, grid infrastructure, flexible demand in multi-energy systems, and storage are more efficient options for integrating fluctuating wind and photovoltaic generation.