Who will foot the bill? The opportunity cost of prioritising nuclear power over renewable energy for the case of Finland

Science Direct, Rasul Satymov ^a, Salvatore Ruggiero ^b, Björn Steigerwald ^cd, Jens Weibezahn ^e, Neven Duić ^f, Jero Ahola ^a, Dmitrii Bogdanov ^a, Christian Breyer 15 November 2025

Highlights

•Tripling nuclear power is more expensive than optimised renewables in Finland.
•Tripling nuclear power costs over 71% more, equal to 2.3% of Finland’s GDP.
•Tripling nuclear power exacerbates local social inequalities.
•Renewables meet energy demand more cost-effectively and avoid nuclear risks.
•Timely insights for policymakers quantifying the costs of nuclear power expansion.

Abstract

In an effort to decarbonise their energy systems, several countries have declared intentions to triple their nuclear power capacity by 2050 at the United Nations Framework Convention on Climate Change Conference of the Parties 28. The expansion of nuclear power includes plans for so-called small modular reactors, intended for electricity generation as well as combined heat and power production. This study aims to demonstrate the cost differences between nuclear-based and renewables-based energy-industry systems using the Finnish energy system as a case study. Four nuclear power expansion scenarios are examined, imposing 13.2 GW of nuclear power capacity into Finland’s energy supply mix, with various capacities of small- and large-scale nuclear power plants alongside combined heat and power production from small-scale nuclear plants. These nuclear tripling scenarios are compared to a reference scenario that simulates a free cost optimisation with zero emissions target. The nuclear scenarios show 71–84% higher annualised system cost of 18.4–19.7 b€ compared to a renewables-based system costing 10.7 b€ in 2050. The reference scenario does not include the installation of new nuclear power capacities, indicating that new nuclear power plants are not part of a cost-optimal system. Additionally, the energy-industry system outlined in the reference scenario possesses fewer risks compared to nuclear tripling scenarios, particularly given that SMR technologies are not yet commercially available. The findings have important implications for energy justice, especially in terms of the significant opportunity cost presented by the nuclear decarbonisation pathway.

1. Introduction

There is a growing discourse on energy transition to low-carbon sources, with proponents advocating for both highly renewable energy (RE) systems [1] and the expansion of nuclear power [2,3]. At the United Nations Framework Convention on Climate Change Conference of the Parties 28 (COP28) 25 countries have declared their intent to triple their nuclear energy capacity by 2050 [4]. This commitment comes in spite of the risks associated with nuclear power in terms of cost, long lead times, waste disposal challenges, safety concerns, proliferation, considerable operational risks in war zones, and uranium supply uncertainties [[5], [6], [7], [8], [9]].

The COP28 declaration commits to triple global nuclear energy capacity from 2020 to 2050 by mobilising investments and supporting the construction of various nuclear power technologies, including small-capacity reactors, known as small modular reactors (SMR), although these technologies are not yet commercially viable [10].

New nuclear power plants may struggle to secure sufficient fuel for their entire operational lifetimes due to rising demand for uranium and limited reserves [11]…………………………………………………………………………

While many studies advocate for 100% RE-based systems [19,20], others see nuclear power as a viable option or a necessary complement to RE [[21], [22], [23], [24]]. However, nuclear power is unlikely to meet the expectations for rapid capacity expansion to align with climate goals [5,25,26]. SMRs have been proposed as a cost-effective alternative to conventional reactors, but their lack of large-scale deployment and limited operational experience presents challenges. SMRs, akin to traditional nuclear power plants, require lengthy regulatory approvals, licensing, and operational testing to ensure safety [25], and their economic viability remains uncertain [27,28]. ………………………………………………………. over-insistence on nuclear power may ultimately delay the energy transition.

Conversely, 100% RE-based systems are increasingly recognised as a more affordable option for decarbonisation [20] than nuclear power-centric systems, relying on improved energy storage and grid management, as documented for increasing periods of 100% RE in California [35]………………………………………………………..

With growing calls to deploy SMRs to address climate change [40] and energy security [41,42], it is essential to evaluate the economic costs and energy justice [43] implications of decarbonisation pathways. This study conducts a techno-economic assessment of scaling up nuclear power versus transitioning to a highly RE system using Finland as a case study………………………………………………………………………………………………………………………………………………………………………

Several studies have shown the feasibility of a highly RE-based system in Finland [[57], [58], [59], [60], [61], [62], [63], [64]]. Child and Breyer [58] and Pilpola et al. [61] show that carbon-neutrality can be achieved without nuclear power, and adding nuclear power increases energy system costs.

COMMENT – Lengthy discussion here, with excellent tables and graphs

6. Conclusion

Tripling nuclear energy capacity by 2050, as proposed by the COP28 declaration, would lead to significantly higher annualised costs and levelised costs of electricity compared to a cost-optimised system that prioritises renewable energy sources. …………………………………………………………………………………………. https://www.sciencedirect.com/science/article/pii/S0360544225042720