California is aiming to supply 100% of its electric retail sales with renewable and zero-carbon resources by 2045, a target that — along with the electrification of transportation and other sectors — is driving the need for rapid development of renewable resources and energy storage over the next couple of decades.

This build-out will also necessitate significant transmission additions to connect out-of-state energy, as well as other generation pockets, CAISO noted in the draft outlook. The system operator has a 10-year transmission planning process; however, given that transmission requires long lead times thanks to permitting processes and right-of-way acquisitions, it concluded that a longer-term blueprint is essential.