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

TL;DR

This study investigates whether flexible nuclear can meaningfully contribute to a fully decarbonized European energy system. It combines a comprehensive review of nuclear construction costs and times with a high-resolution multi-vector energy model (AnyMOD.jl) to bound the cost-efficient share of nuclear in 2040 Europe. The results show that, even under optimistic cost reductions, nuclear's cost-effective share hovers around 10% and that system flexibility through grid expansion, long-duration storage, and demand-side measures generally outcompetes dispatchable nuclear for integrating wind and PV. The findings caution against overreliance on nuclear for decarbonization and highlight the importance of cross-sector flexibility and robust grid infrastructure in achieving high-renewable deployment.

Abstract

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.

Figures (21)

• Figure 1: Boxplots for overnight construction costs and construction times
• Figure 2: Overview of model structure
• Figure 3: Spatial resolution and grid connections for electricity
• Figure 4: Potential-cost curve for expanding the electricity grid between Germany and the Netherlands
• Figure 5: Spatial resolution and grid connections for hydrogen