U.S. energy and climate policy has evolved from the bottom‐up, led by state governments, and internationally recognized for the use of unconventional and innovative policy instruments. This study focuses on policy instruments adopted throughout the era of state energy policy innovation that aim to diversify, decentralize, and decarbonize the electricity sector. Specific attention is devoted to the renewable portfolio standard, net metering, interconnection standards, tax incentives, public benefit funds, and energy efficiency resource standards. This analysis synthesizes the findings from the energy policy literature and provides a summary of the current state of understanding about the effects of various state energy policy instruments, and concludes with a discussion of broader trends that have emerged from the use of policy instruments in the state energy policy innovation era.