Is Fusion Too Late? How Investors Value its Role in a Decarbonized Europe

Sophia A. E. Spitzer, Katja Pelzer, Anton Bauer, and Maximilian J. Blaschke

October 2025

Fusion energy promises clean, firm, and geographically flexible power, making it a potentially breakthrough technology for global decarbonization. However, uncertainty
regarding its commercialization timeline and the rapid expansion of renewable energy question its role in future energy systems. Using a high-resolution energy system model (PyPSA-Eur) and a probabilistic valuation framework, we find market expectations on fusion’s successful commercialization to be low in light of recent fusion investments. With estimated probabilities below 20% in most cases, fusion’s commercialization prospects are seen as limited, despite its high long-term system value, reducing energy system costs and reliance on complementary renewable integration technologies. Our results indicate that the later fusion becomes available, the greater will be the demands on its economic competitiveness and the need for early integration into energy system planning. The misalignment between system benefits and current investments may reflect a rational response to deep uncertainty, yet it may perpetuate a high-risk, high-reward paradox typical of breakthrough technologies. Recognizing this ambiguity calls for a more deliberate evaluation of fusion’s role in future energy systems.

Keywords— Fusion energy, fusion power plants, energy system optimization, binomial decision, PyPSA-Eur, anticipated commercialization probability