Grid Flexibility and the Cost of Integrating Variable Renewable Energy: Toward a Renewable Energy Integration Adder for San Diego Gas and Electric Service Territory and the California Electric Grid

Increased integration of solar and wind, variable renewable energy (VRE) sources, brings both benefits and challenges to the grid. VRE requires greater grid flexibility, which includes energy storage, fast-ramping generators, and forecasting. As a market barrier to wider-scale PV deployment, quantification of grid flexibility can help inform policies that accelerate penetration. This study investigates the cost of integrating VRE below and above 30% and 40% penetration in California toward a roadmap for other states and countries. A methodology is introduced and applied to San Diego Gas and Electric (SDG &E), the third largest investor-owned utility (IOU) in the state by electrical demand served.