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Executive Summary

The Commission accepted applications from Cimarron Energy Storage, LLC and 11 affiliated entities (ER26-1054 et al.) for market-based rate authority. The applicants' proposed tariffs for the sale of energy, capacity, and ancillary services were accepted for filing, effective March 17, 2026. The applicants were designated as Category 2 sellers in the Southwest Power Pool and Category 1 sellers in all other regions. The Commission also granted standard waivers and blanket authorization for future securities issuances.

Key Holdings & Rationale

• Horizontal & Vertical Market Power: The Commission found the applicants lack both horizontal and vertical market power, based on representations that affiliated transmission is subject to an OATT, under RTO/ISO control, or has received an OATT waiver.
• Waivers and Authorizations: Granted waiver of cost-of-service filing requirements (Part 35), accounting/reporting requirements (Parts 41, 101, 141), and blanket authorization under Part 34 for future issuances of securities.

Compliance & Action Items

Applicants must file Electric Quarterly Reports and report any change in status affecting their market-based rate authority pursuant to 18 C.F.R. § 35.42. They must also comply with Order Nos. 860 and 860-A. No specific compliance filing is required in response to this order.

Executive Summary

The Commission accepted Southwest Power Pool, Inc.'s (SPP) proposed Tariff revisions in Docket No. ER26-821-000. SPP sought to eliminate the $25/MWh safe harbor below which resource offers automatically pass the market power mitigation conduct test. The approved changes will instead apply a conduct test threshold using the greater of existing percentage adders or new fixed minimum dollar-per-MWh adders, with a placeholder effective date of 12/31/9998 pending a future compliance filing.

Key Holdings & Rationale

• Proposal Found Just and Reasonable: Applying mitigation tests to all offers, including those below $25/MWh, addresses the growing number of low-marginal-cost resources like wind and reduces the potential for market power exercise while preserving cost recovery (¶ 13).
• Mitigation Thresholds Updated for Modern Resource Mix: The $25/MWh exemption is outdated given the rise of low-cost generation. New fixed minimum adders (e.g., $5/MWh outside Frequently Constrained Areas) ensure mitigation applies to low-priced offers without unduly restricting cost recovery (¶ 4, 7, 11).

Compliance & Action Items

SPP must submit a compliance filing no less than seven days prior to the implementation date to establish the actual effective date for the approved Tariff revisions.