Curated reference and analysis. Last full review: June 17, 2026
Verify all figures against ISO sources before relying on them for project decisions.
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CAISO

California Independent System Operator · Most of California
www.caiso.com/Last updated: 2026-06-17Tier:ChallengedConfidence:Medium
Bottom line

Longest interconnection timelines in the country (~9 yrs), a massive backlogged queue, and comparatively modest data-center demand make CAISO a hard place to site large load despite active reform.

Author analysis. Review against primary sources before relying on this for project decisions.

Verified facts and placeholders

Facts
Total queue MW
140,000 MWas of 2026-06-17
Total queue projects
413as of 2026-06-17
Avg interconnection wait
9.2 yearsas of 2026-06-17
Large-load queue MW
4,500 MWas of 2026-06-17
Queue status
reform-in-progress
Large-load posture
Developing
Generation queue notes
Cluster 15 (~347 GW) on hold while Cluster 14 (~94 GW) clears; ~185 GW in Cluster 14 and prior. New zonal, scored interconnection process (commercial interest 30% / viability 35% / system need 35%) approved by FERC. Merchant zones (<50 MW available capacity) require developers to fund upgrades. Interconnection Process Enhancements (IPE) 5.0 in progress.
Large-load posture rationale
~4.5 GW of data-center demand in the 2025-2026 transmission planning cycle; CEC projects CAISO-area data-center load growth of 1.8 GW by 2030 and 4.9 GW by 2040 — modest versus PJM/ERCOT. Exploring interim/non-firm large-load transmission service, still early-stage.
Primary source
www.caiso.com/generation-transmission/generation/generator-interconnection

Analyst read

Editorial analysis
Tier
Challenged
Rationale
Longest interconnection timelines in the country (~9 yrs), a massive backlogged queue, and comparatively modest data-center demand make CAISO a hard place to site large load despite active reform.
What's working
  • Zonal scored process and heightened readiness gates are starting to improve queue throughput.
  • No flex alerts since 2022, suggesting reliability reforms are holding.
What's working against
  • ~9.2-year average timelines, the longest of any ISO.
  • Merchant-zone cost exposure and high development costs; modest data-center demand vs. PJM/ERCOT.
One thing to watch
Whether IPE 5.0 and Track 3 reforms meaningfully cut timelines for Cluster 16 and beyond.
Analyst note
California is reforming a genuinely clogged queue and making progress, but the timelines remain the worst in the country and data-center demand is comparatively light. For large-load siting it is a low-priority market unless a project has a specific California reason to be there. CAISO took 347 GW of Cluster 15 applications and let 68 GW through. The screen is the story: California filters hard at the door rather than carry a speculative queue.

Major announced projects in this market

Exhibit 2 · supporting

Project signal tracking is intentionally blank in this baseline edition.

Recent reforms

Source-backed
  1. 2024-10
    Zonal interconnection reform approved

    FERC approved CAISO's zonal, scored interconnection process applying to Cluster 15, designating merchant zones where developers fund upgrades.

    Source
  2. 2025-10
    IPE 5.0 draft final proposal

    CAISO released Interconnection Process Enhancements 5.0 draft final proposal, refining scoring, deliverability, and readiness reforms.

    Source

Upcoming milestones

Source-backed
  1. 2026
    Track 3 second FERC filing

    CAISO to file second Track 3 reforms in 2026, with more granular processing timelines for Cluster 16 and future clusters.

    Source

Sources & last updated

Provenance
Last updated
2026-06-17
Primary source
https://www.caiso.com/generation-transmission/generation/generator-interconnection
Source registry