Louisiana-based power generator Pelican Power is the first to register a complaint over MISO’s yearslong miscalculation in its capacity auctions in an effort to stop the RTO’s retroactive pricing corrections.

Pelican Power filed the complaint with FERC in mid-November regarding MISO’s settlement adjustments to the 2025/26 Planning Resource Auction (PRA) (EL26-26).

The utility said MISO’s retroactive pricing corrections run “directly counter to the commission’s longstanding policy of not disturbing auction outcomes.” It called the “after-the-fact tinkering with auction outcomes” unlawful and in violation of the filed rate doctrine. It asked FERC to order MISO to cease resettlements.

Comments and interventions are due in the complaint Dec. 15. MISO leadership during its Dec. 9 Markets Committee meeting acknowledged they may have to undo the pricing adjustments if the complaint is successful.

Pelican argued that nothing in MISO’s tariff allows it to make wide-ranging changes to capacity prices in the 2025/26 auction. It said MISO “has taken a series of ad hoc actions not authorized by, or consistent with, the terms of the MISO tariff and applied rules never reviewed or approved by the commission.” Pelican said MISO appeared to be attempting to expand its remedial authority beyond “straightforward corrective measures” and its duty to enforce a filed rate.

“MISO’s desire to right its wrong does not excuse its further violations of the filed rate, any more than a bank robber’s heartfelt remorse excuses his breaking back into the bank to replace the money he stole,” Pelican wrote.

Pelican added that MISO began taking steps to remedy the error in mid-August, with most of summer 2025 — and therefore the planning year’s highest capacity prices — behind it.

“While it may have been difficult, if not impossible, for MISO to actually re-run the 2025/26 PRA, particularly with the 2025/2026 planning year already underway, the fact remains that the MISO tariff does not authorize any, much less all, of the foregoing steps, and that MISO has simply invented and applied a whole new set of settlement rules to be found nowhere in the MISO tariff,” Pelican said.

For eight years, MISO used a technically incorrect “all hours” approach to calculate its loss of load expectation (LOLE), which according to MISO’s tariff, theoretically should occur only on a day’s peak hour. The error caused the auction to function as if a loss of load event could strike at any non-peak hour, raising the supply MISO secured for nearly a decade. The grid operator discovered in summer that an unnamed vendor since 2017 miscalculated the RTO’s LOLE. The coding error caused a $280 million impact on market participants in the 2025/26 auction, with some owing more money and some getting refunds. (See MISO IMM: Capacity Prices Efficient Despite Yearslong Error and MISO Discloses $280M Error, Over-procurement in 2025/26 Capacity Auction.)

As previously defined, a day with a loss-of-load event is counted in MISO’s LOLE calculations only if the event happens during the hour with daily peak load. MISO received FERC permission to officially use an “all-hours” loss of load approach in its capacity auctions beginning with the 2026/27 planning year.

The Independent Market Monitor has said the error was a good thing and made MISO more reliable as it traded thermal baseload generation for renewable generation.

Independent Market Monitor David Patton said it’s “disturbing” that MISO essentially must resettle the 2025/26 auction to reflect a reliability standard lower than one day in 10 years. “From our perspective, we think these resettlements … are extremely destructive to the integrity of the market,” Patton said during MISO’s September Market Subcommittee meeting.

MISO has been resettling the 2025/26 auction at estimated prices under its continuing error procedure. It’s the only auction where MISO has made pricing corrections. MISO has claimed it’s “not rerunning or resettling the [Planning Resource Auction], taking new bids or establishing a new auction clearing price.”

MISO made the first of three rounds of settlement adjustments Sept. 18. The first set of corrections totaled nearly $77 million. MISO warned market participants that if the adjustment should exceed their credit limit, it would trigger a margin call to cover losses within two business days.

Following discovery of the mistake, MISO Director of Resource Adequacy Neil Shah has said MISO will attempt to make its loss of load expectation calculations more transparent. MISO is working to develop a “masked” model for stakeholders to review, Shah said at the October Resource Adequacy Subcommittee.