CAISO kicked off an extended 20-year transmission planning process (TPP) on Friday to support the state’s clean energy goals.

The long-term planning process, still in its conceptual stages, was launched in a two-hour stakeholder call covering its broad outline and inviting an initial round of comments from interested parties by May 28.

“How it ultimately gets shaped … will evolve as we go through this process,” Neil Millar, vice president of transmission planning and infrastructure, told stakeholders. “We’re starting this with good intentions and high-level plans, but we’re looking for comments.”

Major objectives include supporting the California Energy Commission and Public Utilities Commission in their efforts to reach the targets of Senate Bill 100, which requires utilities to supply retail customers with 100% clean energy by 2045.

“We do see most of this work being triggered by … state direction on resource planning considerations,” Millar said.

In his presentation, Jeff Billinton, director of transmission infrastructure planning, said the CPUC’s integrated resource planning portfolio envisions importing 3,000 MW of wind from Wyoming and New Mexico, potentially requiring both in-state and out-of-state transmission upgrades. (See Wyoming Wind Power Revs up, but is it too much?)

“These portfolios include out-of-state resources, raising questions as to if or how the ISO would examine out-of-state transmission needs,” Billinton said in his presentation.

CAISO’s 10-year process looks at in-state needs, but clean energy goals may require more interregional planning and collaboration, which the longer-term process will address, Billinton said. He cited the TransWest Express Transmission Project, intended to bring Wyoming wind to California, as one example.

The 20-year process is meant to run in parallel with the ISO’s 10-year TPP. It will consider the CEC’s long-term demand forecasts, including the impacts of increased electrification in the transportation and building sectors. Connecting resources still in development — such as offshore wind, energy storage and utility-scale solar — is part of the agenda.

Additional stakeholder calls are being planned in the months ahead, and CAISO is aiming to produce a draft 20-year transmission document by Jan. 31.