Abstract: The rapid deployment of wind and solar technologies is reshaping how electricity systems work and changing system planning, operation and financial values. Together, policymakers, planners, and grid operators are working to integrate variable renewable resources while maintaining system reliability and affordability. These actors are innovating within and across many different organizations to achieve both regional integration and decarbonization. I will present a comparative study on innovations in renewables integration taking place in the Midwest and Western United States. This study focuses on negotiations within two regional transmission organizations and highlights the governance challenges for renewables integration. By comparing the recent California Independent System Operator (CAISO) initiative to create an energy imbalance market (EIM) and the Midcontinent Independent System Operator (MISO) negotiations necessary to develop the dispatchable intermittent resources (DIR) program, we provide a detailed examination of renewable energy policy implementation in practice. As grid operators in both systems work to improve renewable resource integration while maintaining reliability, affordability, and improving system efficiencies, this comparative study highlights the importance of policy drivers and institutional negotiations which are altering the distribution of benefits and burdens among stakeholders involved in the electric power system. In doing so, this work outlines the evolving political and institutional challenges requiring more coordination, policy innovation, and new institutional paradigms shaping electricity system governance.