Renewable portfolio standards (RPS) and their accompanying renewable energy credits have been adopted by 38 states and the District of Columbia. This Article argues that they have outlived their usefulness, and proposes a transition to a “carbon reduction standard” (CRS) based on a statewide target for the average carbon emissions per megawatt hour of electricity generation. It describes in detail how a CRS would work, how it aligns with changing policy goals, and how it would take advantage of RPS lessons learned.