Extrapolating Costs to Commercial Fusion Power Plants

For mega-projects like fusion power plants, modularity is a key enabler to cost and schedule efficiency. One way of achieving more modularity is aiming for higher numbers of smaller fusion reactors. Previous work has demonstrated that the levelized cost of electricity (LCOE) of commercial magnetic confinement fusion power plants falls at a decreasing rate with increasing net electric power. Furthermore, net electric power increases more rapidly than size/cost. This is because as fusion power increases the proportion of energy being exported as net electric power plateaus but the size of the plant required increases linearly. Increases in plant size increase upfront capital costs and project complexity. Therefore, there is an optimal design point beyond which any increases in net electric power continue to increase the project cost and complexity but deliver only marginal gains in LCOE. This helps identify a sweet spot between anticipated, better economy of size (cost per unit being smaller at larger unit sizes), and economy of scale (cost per unit being smaller at a higher scale of production).