Techno-economic comparison of DEMO power conversion systems

The transition to low-carbon technologies lies in the support of modern energy sources, which are also represented by fusion power plants. One of the first fusion power plants will be the European Union DEMOnstration fusion power plant. Among the key attributes that influence the entire design of this power plant, belongs the power conversion system. In addition to the classic Rankine steam cycle, it is possible to use different cooling media, such as supercritical CO2 in the Brayton cycle. The advantages of supercritical CO2 are mainly in the compactness of the power conversion system, that is, lower investment costs for the entire power plant while maintaining the high efficiency of the entire power plant. The key question that can influence the choice of the power conversion system is the levelized cost of electricity. The direct cost of the supercritical CO2 cycles is lower compared to the Rankine steam cycles, in general. On the other hand, supercritical CO2 cycles for the DEMOnstration fusion power plant offer slightly lower efficiency (by approximately 1.5 percentage points), which negatively influences supercritical CO2 cycles levelized cost of electricity by 10%–20% against Rankine steam cycles. [Display omitted] •The capital expenditures are lower in the case of sCO2 fusion power plant power conversion system.•Steam Rankine cycle achieves higher efficiency in the case of specific heat sources of the fusion power plant.•The overall analysis determined a lower LCOE for the power conversion system based on steam Rankine cycle.