MISO Zeros in on Seasonal Capacity Auction, Accreditation
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MISO is confirming final details of its bid for seasonal capacity auctions & availability-based accreditation while some stakeholders continue to criticize it.

MISO is firming up last-minute details for its seasonal capacity auctions and availability-based accreditation that some stakeholders continue to criticize as rushed and rash.

The grid operator says it will file with FERC in September a proposal to create four independent seasonal auctions, seasonal reliability targets and a tougher capacity accreditation. Stakeholders have overwhelmingly asked for more time before MISO makes the filing. (See MISO Stakeholders Demand Breather on Seasonal Auction, Accreditation.)

Staff has held two workshops since Aug. 19 on the auction’s design. MISO will also dedicate its Wednesday Resource Adequacy Subcommittee teleconference and another virtual workshop Sept. 8 to the proposal.  

“This is a lot of work and a pretty significant push, so I appreciate you all’s work on this,” Zakaria Joundi, director of resource adequacy coordination, told stakeholders during the first workshop.

“I don’t think I’ve seen anything that demonstrates that these proposals will improve reliability. It strikes me as kind of a strange patchwork,” Power System Engineering’s Tom Butz said. “We haven’t gotten answers, and the burden of proof is on MISO.”

Joundi said the workshops were meant to detail the near-final proposal, not to justify the changes. Over the past year, MISO has repeatedly explained that more emergency declarations, emerging winter reliability risks and accreditation that isn’t indicative of actual unit performance necessitate the resource adequacy changes.

The new accreditation will be based on generator performance during “resource adequacy hours,” or tight margin hours, and emergency hours over four historical planning years. Units with insufficient performance data will rely on a generator-class average for seasonal accreditation.

However, the new accreditation will only apply to conventional generation, not renewables and storage. MISO is holding off on calculating seasonal effective load carry capability (ELCC) values to accredit wind and solar generation. Staff said they would discuss the accreditation of intermittent resources in the fourth quarter. Until then, the annual ELCC calculations stand.

The RTO is also waiting for more offer data on storage resources before it assigns them an accreditation method. The grid operator has until mid-2022 to fully bring storage into its markets under Order 841. (See MISO: No Choice but to Double Up on 841 Compliance.)

“We’re going to be moving to the same accreditation principles for all generation,” Lynn Hecker, MISO’s senior manager of resource adequacy coordination, said.

The RTO has changed some aspects of the plan this month. Offline capacity resources will now have a 12-hour grace period instead of 24 to start up during the resource adequacy hours. Failure to do so will result in accreditation reductions.

MISO Independent Market Monitor David Patton had criticized the 24-hour grace period as too lenient.

Kevin Vannoy, the grid operator’s director of market design, said rooting accreditation in a resource’s observed performance will provide a better indication of how it will perform when capacity is needed.

Scott Wright, executive director of market strategy and design, said the new accreditation proposal is an improvement over the current “extremely diluted accreditation that we go through event after event with.”

“One case in point that comes screaming to mind is how folks position themselves for a winter event. There’s a lot of practical decisions folks make before the winter,” he said, mentioning weatherization and fuel commitments.

More LMR Accessibility 

Stakeholders questioned MISO’s increase of load-modifying resources’ required availability from a minimum of 10 calls per year to 16, divided by season, to receive a 100% capacity credit. Starting with the 2023/24 planning year, staff is proposing LMRs be available for five emergency calls in the winter, five in the summer, and three calls apiece in the two shoulder seasons. The grid operator reduces LMR capacity accreditations proportionally for anything less than full availability during the required calls.

MISO staff pointed out that LMRs can receive a full seasonal capacity credit by participating on a per-season basis.

“So that’s the benefit of this proposal. An LMR that can’t be available for the 10 days per year but can do five in the summer can receive full credit for a season,” MISO market design adviser Dustin Grethen said.

Hecker said staff decided that the six additional calls are necessary because MISO is “seeing more and more emergency events, and we expect more as the resource mix changes.”

Outage Treatment

MISO is no longer proposing to disqualify capacity resources that plan to be on outages longer than 30 days in a season. Now, the grid operator will require those resources to procure replacement capacity for every day they’re on planned or forced outage beyond the 30-day limit.

Grethen said the 30-day limit is based on MISO’s “reasonable expectation” that capacity resources are available “most of the season, at least two-thirds of it.”

WPPI Energy’s Steve Leovy said MISO was creating “a cliff” between 29-day and 31-day outages. He also said procuring replacement capacity in MISO is a “pain” because few suppliers are offering.

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