Hydropower—both conventional and pumped storage hydropower—is crucial to sustaining our transition to a decarbonized grid. Additional hydropower development that meets modern environmental requirements is essential to reduce the United States’ dependence on carbon. Realizing the full potential of hydropower and maintaining the current hydropower fleet will likely depend on overcoming a number of impediments, including lengthy and complex regulatory requirements, failure of electricity markets to adequately compensate hydropower generators for the grid benefits they provide, environmental opposition to new hydropower, and interest in dam removal. This Article, excerpted from Michael B. Gerrard & John C. Dernbach, eds., Legal Pathways to Deep Decarbonization in the United States (forthcoming in 2018 from ELI Press), examines how these challenges can be overcome with targeted legal and policy reforms.