2026-2027 Transmission Planning Process: Preliminary Results to be Posted, Request Window open

The California ISO will be posting the 2026-2027 transmission planning process (TPP) preliminary reliability results by the end of the day on Aug. 14, 2026, and the results will be available on the 2026-2027 transmission planning process stakeholder webpage.

The Transmission Planning Process Request Window is open until Oct. 15, 2026. 

The participating transmission owners (PTOs) with PTO service territories must submit reliability transmission solution proposals within 30 days after the study results have been posted. For this request window, proposals are due by end of day Sep. 14, 2026. 

The request window form has been updated for the 2026-2027 transmission planning process, and the latest version can be found on the Transmission Planning website.

Please contact requestwindow@caiso.com with any questions.