Renewable energy is an increasingly important source of US electricity due to concerns about global climate change, energy security, and fossil fuel price volatility. This study focuses on the extent to which state regulatory policies impact state renewable energy generation. The Capstone team's research estimates the impact of Renewable Portfolio Standards (RPS) on a state's overall renewable ener­gy generation. Unlike previous research on the effects of RPS, this study attempts to operationalize a number of elements that comprise RPS, such as annual required share of renewable energy and the threat of penalty, in order to assess whether or not these variations have a significant effect on individual states' production of renewable energy.