Modeling the benefits of deploying thermal storage coupled to early commercial fusion reactors in a renewables-dominated grid*

Fusion power plants will be deployed for commercial use in the 2030s at the earliest. Electrical grids already have significant intermittent wind and solar generation and their proportion will only increase over the coming decades. These must be balanced on an hour-to-hour and day-to-day basis to meet grid demand. Fusion power plants paired with thermal storage systems could provide an attractive complement to an otherwise solar- and wind-dominated grid. As a high-capital-cost component, it may be best to run the fusion core continuously. Adding a thermal storage solution would allow for continuous power generation while temporally shifting its deployment to maximize revenue based on the instantaneous demand. In addition, it is possible that the first commercial reactors will suffer frequent unplanned outages. We construct a linear programming model of a fusion power plant with an attached thermal storage system using estimated hourly electricity price series for a 2030s-era wind-dominated grid. We study whether adding thermal storage to a fusion reactor can mitigate losses in availability associated with unexpected shutdowns and increase profits. This model can also constrain the maximum cost of a reactor that must be profitable on an individual basis, given the assumed price series.