This study developed climate-informed data and analytical tools to support long-term electricity system planning in California and the broader Western Electricity Coordinating Council (WECC). It produced climate-informed electricity demand and peak load forecasts through mid-century and optimized resource portfolios that meet California’s electric sector decarbonization goals under two different electrification scenarios with different policy assumptions. Results indicated rising temperatures associated with climate change will increase air conditioning demand and decrease electric space heating demand, generally leading to higher electricity demand in the summer and lower electricity demand in the winter across the WECC, relative to a future without climate change impacts. This study found that the impact of climate change on resource capacity needs could be relatively modest, suggesting that diverse resource portfolios that are optimized to meet clean energy policies, greenhouse gas reduction goals, and reliability requirements contribute to resilience to future climate change. The study suggests that in a future with high levels of building electrification, warmer winters, and lower winter-time peak demand, there is a lower total capacity build in California, relative to portfolios optimized for historical climate conditions. Lessons learned from the study highlight both the value and challenges of integrating advanced climate data into grid planning, emphasizing the need for standardized methods, careful interpretation of uncertainty, and close collaboration between planners and climate scientists to support climate-resilient investment decisions.
Research described by this agreement was administered by CEC with ratepayer funds from the Electric Program Investment Charge (EPIC) under the auspices of the California Public Utilities Commission (CPUC). This agreement’s Interim Report describes original, energy-related research that contributes to California’s Fifth Climate Change Assessment (Fifth Assessment). The Fifth Assessment comprises a broad portfolio of research and synthesis reports that address California-specific research needs and knowledge gaps related to climate change. To ensure scientific rigor, Fifth Assessment research was peer reviewed. This research effort was peer reviewed through an editorial board established for the Fifth Assessment, which also served (where applicable) to support appropriate representation of the practitioners and stakeholders to whom each report applies.
Report Information
CCCA5-CEC-Energy-EPC-21-041
Lead Authors: Jennifer Cardona, Ph.D., Adrian Au, Dyami Andres, Eleanor Adachi, Ritvik Jain, Joshua Spooner and Amber Mahone
Coordinating Commission Agreement Manager: Aryana Sherzai