The total costs of energy transitions with and without nuclear energy

Within energy system analysis, there is discourse regarding the role and economic benefits of nuclear energy in terms of overall system costs. The reported findings range from considerable drawbacks to substantial benefits, depending on the chosen models, scenarios, and underlying assumptions. This article addresses existing gaps by demonstrating how subtle variations in model assumptions significantly impact analysis outcomes. Historically, uncertainties associated with nuclear energy costs have been well documented, whereas renewable energy costs have steadily declined and have been relatively predictable. However, as land availability increasingly constrains future renewable expansion, development is shifting from onshore to offshore locations, where cost uncertainties are greater and anticipated cost reductions are less reliable. This study emphasizes this fundamental shift, highlighting how uncertainties in future renewable energy costs could strengthen the economic case of nuclear energy within fully integrated sector-coupled energy systems, especially when the costs of all technologies and weather conditions are set in the moderate range. Focusing specifically on Denmark, this article presents a thorough sensitivity analysis of renewable energy costs and weather conditions within anticipated future ranges, providing a nuanced perspective on the role of nuclear energy. Ultimately, the findings underscore that, when examining total annual system costs, the differences between scenarios with low and high nuclear energy shares are minimal and are within ± 5 % for the baseline assumptions, while updated adjustments reduce this variation to ± 1 %. • Nuclear becomes more competitive under moderate renewable cost and weather resource assumptions. • In terms of total annual costs, the cost landscape remains relatively flat across the different shares of nuclear energy. • Cost differences between scenarios vary within ± 5 %, with minor adjustments further narrowing this variation to ± 1 %. • The O&M costs can be an important factor that significantly affects the competitiveness of nuclear energy.