Understanding California’s Transmission Development Delays and Paths to Reform

The Union of Concerned Scientists finds that major transmission projects in California are experiencing significant delays, averaging an additional 6.1 years beyond original estimates. These delays, driven by utility reprioritization and permitting hurdles, hinder the integration of clean energy and threaten grid reliability. The brief recommends expanding competitive solicitation, increasing agency permitting capacity, implementing public financing, and deploying grid-enhancing technologies.

• Major transmission projects in California are experiencing severe delays; a subset analysis of 21 significant projects shows they took an average of 6.1 additional years to complete, which is more than double the original estimated time.
• The California Independent System Operator (CAISO) estimates that the state requires between $45.8 billion and $63.2 billion in transmission investment to reach a carbon-free electricity grid by 2045.
• Investor-owned utilities (IOUs) show high rates of project delays: 61% of PG&E's CAISO-approved projects, 62% of SCE's, and 76% of SDG&E's projects are delayed.
• For PG&E, the primary cause of delay is the 'prioritization' of other investments, specifically the 2018 Community Wildfire Safety Program and impacts from inflation and supply chain issues.
• Permitting is a dominant barrier for other utilities, cited as the reason for delay in 63% of SDG&E's delayed projects and 21% of SCE's, often due to CEQA requirements and local community concerns.
• Insufficient transmission capacity has directly impacted grid reliability, as seen during the summer 2020 rolling blackouts where transmission constraints limited the transfer of available imports into the CAISO footprint.
• The brief recommends several reforms to accelerate development: expanding competitive solicitation beyond projects over 200 kV, increasing staff capacity for CEQA reviews, adopting public transmission financing to lower costs, and utilizing grid-enhancing technologies like advanced reconductoring.

APA

Union of Concerned Scientists (2025). Understanding California’s Transmission Development Delays and Paths to Reform. https://www.ucs.org/sites/default/files/2025-07/understanding-ca-transmission-development-delays.pdf

Chicago

Union of Concerned Scientists. Understanding California’s Transmission Development Delays and Paths to Reform. 2025. https://www.ucs.org/sites/default/files/2025-07/understanding-ca-transmission-development-delays.pdf.

Wikipedia

{{cite report |author=Union of Concerned Scientists |title=Understanding California’s Transmission Development Delays and Paths to Reform |date=July 2025 |url=https://www.ucs.org/sites/default/files/2025-07/understanding-ca-transmission-development-delays.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{unionofconcernedscientists2025understanding, author = {{Union of Concerned Scientists}}, title = {{Understanding California’s Transmission Development Delays and Paths to Reform}}, institution = {Union of Concerned Scientists}, year = {2025}, month = jul, url = {https://www.ucs.org/sites/default/files/2025-07/understanding-ca-transmission-development-delays.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }