Hydropower makes up a sizable share of the U.S. electricity supply. A significant portion of this is imported from Canada, which is linked to the U.S. electricity grid through dozens of connections along the border. Expansion of this resource is possible in both nations, though greater quantities are expected to be developed in Canada in the near future. As a zero-emission, dispatchable, baseload power source, hydropower has the potential to play an important role as states seek to reduce power sector emissions to comply with the Environmental Protection Agency’s (EPA) proposed Clean Power Plan. This report assesses the benefits and challenges of hydropower generally, explores the potential for increased imports from Canada driven by the Clean Power Plan, looks at ways the proposed rule could be adjusted to take advantage of this resource, and analyzes the impact of additional imports on selected states.