Over the past decade, state governments have emerged as US energy policy leaders. Across the country, states are adopting policy instruments aimed at carbon mitigation and renewable energy deployment. One of the most prevalent and innovative policy instruments is a renewable portfolio standard (RPS), which seeks to increase the share of renewable energy electrification in the electricity market. This analysis evaluates the effectiveness of state energy programs with an empirical investigation of the linkage between state RPS policy implementation and the percentage of renewable energy electricity generation across states. We use a variant of a standard fixed effects model, referred to as a fixed effects vector decomposition, with state-level data from 1998 to 2006. Results indicate that RPS implementation is not a significant predictor of the percentage of renewable energy generation out of the total generation mix, yet for each additional year that a state has an RPS policy, they are found to increase the total amount of renewable energy generation. These findings reveal a potentially significant shortcoming of RPS policies. Political institutions, natural resource endowments, deregulation, gross state product per capita, electricity use per person, electricity price, and the presence of regional RPS policies are also found to be significantly related to renewable energy deployment. (C) 2009 Elsevier Ltd. All rights reserved.