FERC on Tuesday rejected a pair of requests for exemptions from a resource availability cutoff under MISO’s new availability-based accreditation method.
The commission used near-identical language to deny Southern Minnesota Municipal Power Agency’s (SMMPA) and Cleco’s asks for exemptions from the new 24-hour lead time threshold for thermal resources’ capacity accreditation (ER23-837, ER23-1103).
Under the new construct, MISO treats offline resources that historically take more than 24 hours to start up as unavailable during predefined, risky hours that factor heavily in accreditation. In those cases, staff assigns a zero-capacity value and reduces accreditation accordingly.
Cleco (NYSE:CNL) had asked for waivers through 2026 for Units 1 and 3 at its 1,700-MW Big Cajun II Power Station in Louisiana. SMMPA asked for a waiver through 2026 for its 41% stake (359 MW) in Unit 3 of the Sherburne County Generating Station (Sherco) in Minnesota.
In both cases, FERC said the utilities did not prove that their waivers wouldn’t have “undesirable consequences, including harm to third parties.” It said while granting the waivers would increase Cleco’s and SMMPA’s seasonal accreditation values, it would also decrease the fleet-wide unforced capacity to intermediate seasonal capacity ratio. That would reduce other resources’ final seasonal capacity accreditation values, the commission said.
MISO took no position on the filings.
Commissioner Mark Christie penned a separate concurrence to express “surprise and disappointment in MISO’s failure to take a position on these waiver requests and to submit comments in these proceedings.” He emphasized that the grid operator characterized its capacity accreditation changes as too urgent to be delayed until the 2024-25 planning year.
“Yet now, when SMMPA and Cleco seek waiver of MISO’s new accreditation calculations — and, by extension, collaterally challenge the fairness of the implementation timeline expressed in MISO’s proposal — MISO remains strangely silent,” Christie wrote. “I would have expected MISO to defend its new [accreditation] or to explain why the waiver requests do not undermine the delicate balance it sought to achieve.”
The commission did not address other arguments from the utilities.
SMMPA pointed out that Sherco Unit 3 has a 26-hour startup time, and it now faces “significantly lower” accreditation values than it’s had for the “vast majority of its 30-year history.” It said the reduced accreditation values “do not reflect Sherco’s expected availability during times of need,” and that the unit “has the same capacity, availability, reliability and characteristics as it had in the past.”
Cleco said it lengthened startup times at the Big Cajun II plant in recent years to avoid violating MISO’s limits on uninstructed deviations from its dispatch orders. (See MISO Plans for New Uninstructed Deviation Rules.)
The utility said it wanted to maintain its eligibility for make-whole payments. It offered that its other units “with similar characteristics and design as the Big Cajun units” could change ramp rates, adjust offers in MISO’s real-time market or change startup times and make offers in the day-ahead market with an economic commitment status that would still require a startup period.
Cleco argued that without the waiver, it faced a “uniquely burdensome, … dramatic decrease in the Big Cajun units’ capacity accreditation value.” It said MISO’s accreditation will reduce Big Cajun II Unit 1’s average availability by 390 MW and cut Unit 3’s average availability by 202 MW for the 2023-24 planning year.
Entergy has a similar waiver request pending before FERC. The utility has warned that without waivers for three units in Mississippi and Arkansas, it risks a capacity shortfall this year in Mississippi. Entergy has pre-emptively adjusted the units’ startup times to less than 24 hours. (See Entergy Seeks Exemptions from MISO Accreditation Rules.)
