Fusion power unlikely to become competitive

Nature Energy 1 April(2026) https://www.nature.com/articles/s41560-026-02022-9

While nuclear fusion power is often hailed as a future source of abundant, clean energy, current dominant fusion designs, magnetic and laser inertial, are unlikely to become competitive due to their expected low experience rates. Accordingly, policymakers should not rely on, or fund, fusion power as a core pillar of future clean energy systems unless designs with different characteristics are developed.

Messages for policy

Current cost reduction assumptions for nuclear fusion power plant technologies are overly optimistic.
Current designs for fusion power will likely have low experience rates and high capital costs, preventing it from competing with alternative clean energy technologies, even in the long term.
Given the low likelihood of fusion power reaching cost-competitiveness with competing technologies, policymakers should re-evaluate public funding in this area.
Public research and development agencies should assess alternative fusion power concepts and direct funding to those with more promising technological characteristics that can result in high experience rates.
If assessing the relevance of nuclear fusion power in a future energy system, policymakers should ensure that energy system models use empirically and theoretically backed experience rates of 2–8%.

based on Tang, L., Noll, B., Panda, A. & Schmidt, T.S. Nat. Energy https://doi.org/10.1038/s41560-026-02023-8 (2026)

The policy problem

Governments are committing substantial public funding to nuclear fusion power as a potential source of safe, dispatchable low-carbon electricity to support power-sector decarbonization. These investments should be based on the certainty that fusion power plants (FPPs) may affordably serve an important role in future power systems. However, due to the technology’s nascency and lack of empirical cost data, current assumptions about future cost reductions are weakly substantiated. With inaccurate cost projections overestimating FPPs’ role in future power systems, this distorts investment priorities and funding allocations. Providing empirically grounded cost trajectories for fusion power is therefore key to ensuring that scarce public resources are directed towards technologies most likely to deliver affordable, reliable, timely, and clean electricity.

The findings

We find that the two dominant nuclear FPP designs, magnetic and laser inertial, are inherently large in unit size, extremely complex in design, and require moderate to high customization. Existing technologies with similar characteristics have historically had experience rates (ERs) of 2–8%. We also find that cost estimates for first-of-a-kind FPP vary widely from US$1,400 to $43,000 per kW. Using the interquartile range of these cost estimates and projecting the future cost using our empirically grounded ER of 5%, our results indicate that fusion power is likely to remain uncompetitive relative to other low-carbon electricity supply technologies (see Fig. 1). This casts considerable doubt on the future role of fusion power in a net-zero energy system and whether current investment levels from both the public and private sectors are justified.

The study

We conducted semi-structured interviews with 28 nuclear fusion experts from the public and private sectors, covering both magnetic and laser inertial fusion approaches. Interviewees were guided through a structured survey to assess three technology-inherent characteristics of future FPPs: unit size, design complexity, and the need for customization. Drawing on existing academic evidence, these characteristics were matched to experience rates observed historically in technologies with similar characteristics. Since ERs of existing technologies are derived from empirical cost data, this approach is well-suited to estimating future cost reductions for FPPs, an early-stage technology with no historical data. During the interviews, cost estimates for future first-of-a-kind FPPs were also elicited to supplement those from the literature and to estimate the cost reduction trajectories for fusion power technologies.

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