Exploration of resource and transmission expansion decisions in the Western Renewable Energy Zone initiative

► We describe a new tool to evaluate transmission expansion and renewable resource selection. ► We examine a scenario where 33% of the energy in the Western Interconnection comes from renewables. ► Wind energy provides the majority of new renewable energy. ► For some loads, the decision to procure wind and the required transmission is insensitive to assumptions. ► For other loads, assumptions can shift toward more solar, which also changes the needed transmission.