International Chernobyl Disaster Remembrance Day
Forty years after the Chernobyl accident, nuclear technologies remain closely linked to debates about safety, cost and long-term reliability. Fusion energy is often presented as a different kind of nuclear technology, with fewer long-term concerns around safety, waste and fuel supply than conventional nuclear fission. However, a recent study published in Nature Energy suggests that economic expectations around fusion should be treated with caution.
Fusion’s economic prospects depend strongly on how fast costs can decline once the technology is deployed. This is usually described through experience rates, which measure how much costs decrease every time installed capacity doubles. For example, an experience rate of 20 percent means that, each time total installed capacity doubles, the cost falls by 20 percent.
Many previous studies assume experience rates for fusion between 8 and 20 percent. The upper end of this range is similar to the historical cost reduction observed in technologies such as solar photovoltaic modules and lithium-ion batteries, which became cheaper as production and deployment increased. However, fusion power plants are expected to be much larger and more complex. For this reason, the study examines whether fusion plants can really reduce their costs as quickly as often assumed.
The authors focus on three characteristics that influence cost reductions over time. These are the size of each unit, the complexity of the design and the need to adapt each plant to its location. Based on expert interviews and comparisons with other energy technologies, they find that fusion power plants are likely to have large unit sizes, very high engineering complexity and limited potential for standardization.
The main result is that fusion’s future cost reductions may be slower than many projections assume. Instead of the 8 to 20 percent experience rates often used in previous studies, the authors estimate a more plausible range of 2 to 8 percent. This is closer to the historical experience of large and complex energy infrastructure than to modular technologies such as solar panels or batteries. This difference matters because first-of-a-kind fusion plants are also expected to have high upfront costs. If costs start high and fall slowly, fusion may struggle to compete with other low-carbon technologies, even if technically feasible.
The study therefore suggests that energy models use more cautious cost-reduction assumptions, while research explores fusion designs that are smaller, less complex or easier to standardize. This does not dismiss fusion, but frames it as a technology whose economic case still needs to be demonstrated.
Researcher in Energy Systems at ISAAC – SUPSI