We will assess the threshold cost and performance parameters that fusion technology must deliver to become a substantial contributor to decarbonization at the global scale. This project will determine the parameters for fusion viability and identify which of these parameters are most important for the successful deployment of fusion energy at scale. Even if fusion power is available for deployment in all countries, the expectation is that deployment will be heterogenous due to the availability of other low-carbon energy resources, population density, grid infrastructure, etc. Therefore, we will examine the extent of deployment of fusion power plants in all regions represented in the MIT Economic Projection and Policy Analysis (EPPA) model. We will assess how the timing of fusion commercialization will impact its extent of deployment and overall mitigation pathways.