As relicensing and maintenance costs of hydropower generation increase, many operators are considering whether to relicense or to surrender their operating licenses. These economic decisions are made in the context of a power system that is installing historic new capacity to meet rising demand while attempting to meet company, state, and federal emissions goals and targets. This research investigated the CO2 emissions implications of various scenarios for retiring or relicensing existing hydro generators that are eligible for retirement, and the cost implications of retiring/relicensing such generators both under a policy scenario including on-the-books state and federal policies and a potential 100% clean electricity standard by 2035.