Fusion Power Plant Cost Modeling Uncertainties

Being a novel technology, estimating costs for fusion power plants comes with large uncertainties. Cost uncertainties in prototypes arise from various sources and reduce with program maturity (including the selection of a site), technical and design maturity, as well as the maturity of the commercial strategy (e.g., make versus buy decisions and partnering decisions). In the early design phases, where not much detail is fixed, the cost is typically evaluated via analogy/comparator to existing technologies, which are typically associated with high uncertainties due to the innovative nature of fusion technology. Early cost estimates for fusion power plants are broken down using a top-level cost breakdown structure as this allows for cost uncertainty evaluation over the various fusion components. The STEP prototype fusion power plant is nearing the end of conceptual design with significant uncertainties but seeks to follow best practices to effectively manage costs. Best practice in cost estimating involves evaluating the base cost estimate, corresponding uncertainties, and project risks and correcting for optimism bias as defined by the Infrastructure and Project Authority (IPA). The overall objective is to illustrate the importance of uncertainty definition within fusion prototype/demonstration power plants and their impact on program costs.