Key Takeaways
- • FERC issued a Section 206 show cause order on June 18, 2026, requiring CAISO and its transmission owners to justify or revise tariff provisions governing large load interconnections within 60 days (deadline: August 17, 2026), with findings that current tariffs are "unjust and unreasonable" in five core areas.
- • Large load definition proposed at 50 MW+ peak capacity at single sites interconnecting at voltages exceeding 69 kV, though CAISO may propose alternatives; study timelines mandated at 60–90 calendar days, substantially faster than current processes.
- • Cost shifting mitigation required through mandatory cost recovery agreements between CAISO, transmission owners, and large load customers, with pro forma provisions ensuring customers bear full responsibility for network upgrade costs; transparency requirements demand "robust, accurate, systematic, and searchable" public data on network upgrade costs and planned projects.
- • New transmission service options mandated for flexible large loads willing to limit withdrawals under grid stress conditions, alongside generator interconnection processes tailored to electrically proximate and co-located loads that can reduce or eliminate transmission system impacts.
- • Operational oversight requirements include mandatory hourly forecasts, telemetry data, fast-ramp monitoring equipment, and disconnection capability at customer expense; pro forma transmission service agreements must memorialize all terms to ensure enforceability and limit disputes.
Summary
The Federal Energy Regulatory Commission initiated a comprehensive regulatory restructuring of California's wholesale electricity market framework on June 18, 2026, when it issued a show cause order targeting CAISO's treatment of large commercial and industrial load customers. The order, docketed at 195 FERC ¶ 61,214, challenges the sufficiency of CAISO's tariff provisions across interconnection procedures, transparency mechanisms, cost allocation frameworks, and operational risk management—finding that existing arrangements fail to protect other transmission customers from cost-shifting while creating uncertainty that delays large load integration.
FERC acknowledged that CAISO's market structure differs materially from other RTOs and ISOs under its jurisdiction. Unlike peers, CAISO lacks formal network and point-to-point transmission service products, firm long-term capacity reservations, or standardized application processes for transmission service. Instead, CAISO operates a single daily transmission service available on an economic basis through scheduling coordinator bids. Load interconnection processes are not codified in CAISO's tariff; transmission owners independently manage load studies using proprietary requirements, while CAISO integrates projected load additions into annual transmission planning conducted alongside California Energy Commission and California Public Utilities Commission forecasts. Despite these structural distinctions, FERC determined that the absence of clear tariff language governing study procedures, readiness requirements, operational standards, and cost responsibility creates regulatory gaps that must be addressed.
The Commission identified four deficiencies in transmission service design for large loads. First, CAISO's tariff lacks a workable definition of "large load" as a distinct customer category; FERC proposed a benchmark of 50 megawatts peak capacity at single sites with interconnection points exceeding 69 kilovoltage, though CAISO may propose alternatives reflecting the unique characteristics of its transmission system. Second, absent from existing tariffs are application procedures accepting rolling submissions, tiered readiness requirements with escalating financial commitments to deter speculative requests, or mandatory evaluation of alternative transmission technologies (grid-enhancing devices, dynamic line rating systems, and other innovations) as substitutes for traditional network upgrades. Studies must complete within 60–90 calendar days and must clearly document why alternative technologies were rejected when traditional upgrades are assigned. Third, CAISO's tariffs contain insufficient operational requirements to mitigate risks posed by large loads' rapid ramp rates and variable withdrawal patterns; the Commission directed CAISO to mandate hourly forecasts, high-resolution telemetry, fast-ramp monitoring equipment, and direct-disconnect capabilities at customer expense. Fourth, pro forma transmission service agreements must be amended to memorialize these operational terms, rendering them legally enforceable rather than subject to dispute.
Cost allocation emerged as a central regulatory concern. FERC found that CAISO's framework creates material risk of cost-shifting, whereby network upgrade expenses constructed for large load projects that fail to materialize or underperform financially are absorbed by other transmission customers. To mitigate this risk, the Commission ordered CAISO to establish pro forma cost recovery agreements binding large load customers, CAISO, and relevant transmission owners, requiring customers to bear all costs—including network upgrades—necessary to provide requested transmission service. Minimum contribution levels should reflect megawatts of jurisdictional transmission service requested, though FERC acknowledged that timing-adjusted methods accounting for phased energization may be equally reasonable. Credit support or financial security commensurate with cost recovery obligations must be required, though retail-level collateral may be credited to avoid duplication. To enhance stakeholder awareness, FERC mandated that CAISO publish centralized, searchable data on the aggregate scale of proposed large load additions, specific network upgrades planned (categorized by equipment type), and cost estimates for each transmission service request.
Co-location arrangements and behind-the-meter generation created additional regulatory friction. CAISO's tariff does not clearly articulate rates, terms, and conditions applicable to facilities collocated with generation or flexible loads willing to constrain withdrawals under certain conditions. FERC expressed concern that large load customers receiving co-location benefits—particularly black start and regulation ancillary services—may not be paying commensurate charges if they withdraw zero or minimal energy from the grid, thereby violating cost causation principles. The Commission directed CAISO to establish transparent rules governing how interconnection customers may use generator interconnection processes to facilitate co-location, specify which eligible customer bears transmission and ancillary service charges, and ensure that co-located loads pay for regulation and black start services on a gross demand basis. Additionally, FERC found that CAISO's netting rules allowing behind-the-meter generation to offset gross load for regional access charge calculations create cost-shifting and reliability risks; the Commission ordered revisions establishing a materiality threshold below which netting is prohibited.
Generator interconnection requirements for facilities serving electrically proximate large loads or co-located loads received separate attention. FERC defined "electrically proximate large load" as load located within approximately two substations of a generating facility, such that the combined impact on the transmission system approximates co-location. CAISO's tariff lacks interconnection study processes or service options reflecting this operational reality. The Commission highlighted Southwest Power Pool's High Impact Large Load Generator Assessment (HILLGA) as an exemplar but did not mandate identical adoption. FERC instead required CAISO to either demonstrate that its existing framework addresses these concerns or propose alternatives, such as processes allowing generators to limit output to match hourly large load forecasts, or arrangements in which new generators and new co-located loads interconnect behind the same point with control technologies ensuring net zero injection to the transmission system. These modifications could materially reduce network upgrade requirements and accelerate commercial operation of generating facilities.
The order imposed strict procedural timelines. CAISO and transmission owners must file responsive tariff revisions or justifications by August 17, 2026—60 days from issuance. CAISO must separately file an informational report on resource adequacy proposals by July 20, 2026—30 days from issuance. Interested parties may submit comments on tariff responses within 30 days of those filings. FERC authorized limited abeyance of up to 90 days to permit stakeholder process development and Section 205 FPA filings, but made clear that extended delays are not contemplated.
Five commissioners issued concurrences underscoring enforcement vigor and strategic intent. Chairman Swett emphasized that individualized show cause orders tailored to each market's characteristics enable faster regulatory adaptation than uniform rulemaking. Commissioner Rosner identified four pillars: consumer protection through affordability measures, reliability safeguards via operational standards, transparency through cost data disclosure, and innovation via flexible transmission services and unified large load–generation studies. Commissioner See stressed that FERC's actions support rather than override state jurisdictions and called for continued state feedback on
FERC acknowledged that CAISO's market structure differs materially from other RTOs and ISOs under its jurisdiction. Unlike peers, CAISO lacks formal network and point-to-point transmission service products, firm long-term capacity reservations, or standardized application processes for transmission service. Instead, CAISO operates a single daily transmission service available on an economic basis through scheduling coordinator bids. Load interconnection processes are not codified in CAISO's tariff; transmission owners independently manage load studies using proprietary requirements, while CAISO integrates projected load additions into annual transmission planning conducted alongside California Energy Commission and California Public Utilities Commission forecasts. Despite these structural distinctions, FERC determined that the absence of clear tariff language governing study procedures, readiness requirements, operational standards, and cost responsibility creates regulatory gaps that must be addressed.
The Commission identified four deficiencies in transmission service design for large loads. First, CAISO's tariff lacks a workable definition of "large load" as a distinct customer category; FERC proposed a benchmark of 50 megawatts peak capacity at single sites with interconnection points exceeding 69 kilovoltage, though CAISO may propose alternatives reflecting the unique characteristics of its transmission system. Second, absent from existing tariffs are application procedures accepting rolling submissions, tiered readiness requirements with escalating financial commitments to deter speculative requests, or mandatory evaluation of alternative transmission technologies (grid-enhancing devices, dynamic line rating systems, and other innovations) as substitutes for traditional network upgrades. Studies must complete within 60–90 calendar days and must clearly document why alternative technologies were rejected when traditional upgrades are assigned. Third, CAISO's tariffs contain insufficient operational requirements to mitigate risks posed by large loads' rapid ramp rates and variable withdrawal patterns; the Commission directed CAISO to mandate hourly forecasts, high-resolution telemetry, fast-ramp monitoring equipment, and direct-disconnect capabilities at customer expense. Fourth, pro forma transmission service agreements must be amended to memorialize these operational terms, rendering them legally enforceable rather than subject to dispute.
Cost allocation emerged as a central regulatory concern. FERC found that CAISO's framework creates material risk of cost-shifting, whereby network upgrade expenses constructed for large load projects that fail to materialize or underperform financially are absorbed by other transmission customers. To mitigate this risk, the Commission ordered CAISO to establish pro forma cost recovery agreements binding large load customers, CAISO, and relevant transmission owners, requiring customers to bear all costs—including network upgrades—necessary to provide requested transmission service. Minimum contribution levels should reflect megawatts of jurisdictional transmission service requested, though FERC acknowledged that timing-adjusted methods accounting for phased energization may be equally reasonable. Credit support or financial security commensurate with cost recovery obligations must be required, though retail-level collateral may be credited to avoid duplication. To enhance stakeholder awareness, FERC mandated that CAISO publish centralized, searchable data on the aggregate scale of proposed large load additions, specific network upgrades planned (categorized by equipment type), and cost estimates for each transmission service request.
Co-location arrangements and behind-the-meter generation created additional regulatory friction. CAISO's tariff does not clearly articulate rates, terms, and conditions applicable to facilities collocated with generation or flexible loads willing to constrain withdrawals under certain conditions. FERC expressed concern that large load customers receiving co-location benefits—particularly black start and regulation ancillary services—may not be paying commensurate charges if they withdraw zero or minimal energy from the grid, thereby violating cost causation principles. The Commission directed CAISO to establish transparent rules governing how interconnection customers may use generator interconnection processes to facilitate co-location, specify which eligible customer bears transmission and ancillary service charges, and ensure that co-located loads pay for regulation and black start services on a gross demand basis. Additionally, FERC found that CAISO's netting rules allowing behind-the-meter generation to offset gross load for regional access charge calculations create cost-shifting and reliability risks; the Commission ordered revisions establishing a materiality threshold below which netting is prohibited.
Generator interconnection requirements for facilities serving electrically proximate large loads or co-located loads received separate attention. FERC defined "electrically proximate large load" as load located within approximately two substations of a generating facility, such that the combined impact on the transmission system approximates co-location. CAISO's tariff lacks interconnection study processes or service options reflecting this operational reality. The Commission highlighted Southwest Power Pool's High Impact Large Load Generator Assessment (HILLGA) as an exemplar but did not mandate identical adoption. FERC instead required CAISO to either demonstrate that its existing framework addresses these concerns or propose alternatives, such as processes allowing generators to limit output to match hourly large load forecasts, or arrangements in which new generators and new co-located loads interconnect behind the same point with control technologies ensuring net zero injection to the transmission system. These modifications could materially reduce network upgrade requirements and accelerate commercial operation of generating facilities.
The order imposed strict procedural timelines. CAISO and transmission owners must file responsive tariff revisions or justifications by August 17, 2026—60 days from issuance. CAISO must separately file an informational report on resource adequacy proposals by July 20, 2026—30 days from issuance. Interested parties may submit comments on tariff responses within 30 days of those filings. FERC authorized limited abeyance of up to 90 days to permit stakeholder process development and Section 205 FPA filings, but made clear that extended delays are not contemplated.
Five commissioners issued concurrences underscoring enforcement vigor and strategic intent. Chairman Swett emphasized that individualized show cause orders tailored to each market's characteristics enable faster regulatory adaptation than uniform rulemaking. Commissioner Rosner identified four pillars: consumer protection through affordability measures, reliability safeguards via operational standards, transparency through cost data disclosure, and innovation via flexible transmission services and unified large load–generation studies. Commissioner See stressed that FERC's actions support rather than override state jurisdictions and called for continued state feedback on
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