Common Questions

What is CAISO and which grid does it manage?

CAISO (California Independent System Operator) manages high-voltage electricity transmission across approximately 80% of California and a small part of Baja California. It is one of six US Regional Transmission Organisations under FERC jurisdiction.

Why did FERC send CAISO a show-cause order in June 2026?

FERC issued CAISO a Section 206 show-cause order on 18 June 2026 as part of a six-RTO proceeding, directing each to justify or reform its large-load tariffs on data-centre co-location, interconnection studies, and cost allocation. Responses are due 17 August 2026, with any binding rule deferred to 2027.Source: FERC

When does CAISO have to file its generation-adequacy report with FERC?

CAISO must file its generation-adequacy report by 20 July 2026 under FERC's RM26-4-000 docket, the same rulemaking covering all six US RTOs, ahead of its 17 August show-cause response.Source: FERC

Background

FERC issued CAISO a Section 206 show-cause order on 18 June 2026, directing it alongside the other five US Regional Transmission Organisations to justify or reform its large-load tariffs across five categories including co-location terms, study processes, and cost allocation. The same RM26-4-000 docket also requires CAISO to file a generation-adequacy report by 20 July 2026, a nearer deadline than its show-cause response. Resource-adequacy reports are due 20 July, show-cause responses 17 August, and public comments 16 September, with any binding federal standard deferred to 2027 at the earliest.

CAISO (California Independent System Operator) manages the high-voltage transmission grid serving approximately 80% of California's electricity load and a small portion of Baja California, Mexico. It is one of the six US Regional Transmission Organisations under FERC jurisdiction, operating the wholesale electricity market and coordinating interconnection for the western grid. California's state air-quality rules restrict certain forms of behind-the-meter generation, making CAISO's co-location governance structurally distinct from that of other RTOs.

CAISO's show-cause response and generation-adequacy filing will both be closely watched because California's clean-energy mandates create a tension between accommodating large compute loads and meeting state emissions targets. FERC's decision to issue six separate show-cause orders rather than a single national rule means CAISO can tailor reforms to California's regulatory environment, but it also leaves operators without a harmonised federal standard through at least 2027.