MISO staff and stakeholders clashed last week in front of board members on whether the RTO’s proposed capacity accreditation design should move forward.

The grid operator said February’s load shedding is further justification to introduce a four-season capacity auction and corresponding reserve margin targets paired with an availability-based accreditation, which compares a generator’s recent availability against predefined risky hours. (See MISO Underscores Need for RA Action in Winter Storm Review.)

The RTO hopes to file the changes with FERC in June, although a majority of members voted to oppose the accreditation proposal during an earlier Resource Adequacy Subcommittee meeting.

Several stakeholders said availability-based capacity is unfair because it relies on sheer luck for generation to be available on the right day. Others said using three years of historic data to judge a generator’s performance is inadequate.

Several stakeholders asked for more analysis into why MISO’s suite of solutions is the best route to address the footprint’s worsening resource adequacy.

“These concepts are not necessarily bad … but we want to make sure we know what we’re getting into,” Exelon’s John Orr said during an Advisory Committee meeting on March 25.  “The information has been sparse, I think, and there’s just this rush to a deadline.”

Attorney Jim Dauphinais, representing the Coalition of Midwest Transmission Customers, said a June filing date may be unrealistic.

“I think we’re just barely scratching the surface of the details we need to work through,” he said.

“We don’t think that this proposal is fully baked,” Minnesota Public Utilities Commissioner Matthew Schuerger added.

MISO CEO John Bear said February’s winter storm revealed that the RTO needs a different resource accreditation method.

“MISO’s scale, diversity and extensive planning really paid off during that trying time,” Bear said, adding that it was “amazing” that staff was able to limit load shed to local events and one two-hour MISO South event.

“Will a resource be there when it says it will? Will we be able to rely on a resource when we need it most?” he asked rhetorically.

Bear said MISO’s emergencies most often occur in winter and fall, when forced outages remove anywhere from 25 to 35% of its fleet.

“So that’s pretty high. … We can’t stay where we are. It’s not sustainable,” he said. “We need to find a better method. We need to really look at the four seasons.”

He asked stakeholders to “please, please” work together with staff on a more pragmatic accreditation.

MISO President Clair Moeller called resource availability during severe winter weather “consistently bad” and said the reserve margins necessary to manage polar vortices “are not in the math.”

“We operated the system at its limits essentially for two days,” he said.

Moeller said NERC load-curtailment procedures could be updated because they are predicated on a slower-moving summer peak that’s easier to anticipate. He said public safety issues “are substantially different in the winter versus in the summer.”

“NERC’s version of reliability is an orderly blackout rather than a disorderly blackout,” Moeller said. “They’re important backdrops, but they’re not sufficient for these kinds of emergencies.”

Manitoba Hydro’s Audrey Penner said that if February’s events weren’t a wake-up call for dramatic change, “then I don’t know what is.”

Travis Stewart, representing the Coalition of Midwest Power Producers, said “but for PJM’s about 30% reserve margin,” MISO might have ordered more load shed.

Stewart asked for the grid operator to develop rules to incent resources to be more available and winterize equipment. “We’re now seeing a pattern where load shed is common to the footprint,” he said.

Renuka Chatterjee, MISO’s executive director of system operations, said the recent string of polar vortices make clear that reliability risks are no longer a summertime game.

“We are in continuous risk assessment mode,” she told the Board of Directors.

MISO estimated that the extensive snow and ice dumped across the system was a once-in-30-year event.

After 40% of its generation fleet was unavailable by Feb. 17, MISO will now classify outages by fuel, mechanical or weather-related issues. Chatterjee said the RTO is working with generation owners to understand the reasons behind the unplanned outages and prevent them in the future.

The grid operator uncharacteristically flowed power east-to-west over its system to manage the ubiquitous cold Feb. 15-17.

“We were seeing flows that we had never seen before, and I have been here since the beginning of MISO,” Chatterjee said. “Many shift operators were telling me that they had never seen congestion like this before. … I describe it more casually as our system was a drain hole in the South.”

As the cold took hold Feb. 16, MISO was forced to cut 3,000 MW of exports flowing to SPP during the morning peak. Staff removed them in two tranches of 1,500 MW separated by half an hour, so as not to shock the system.

“We understood we needed to do this. SPP understood we had to do this,” Chatterjee said.

However, operators still saw dangerous congestion that needed to be managed by manual redispatch and, eventually, load shed orders.

“Directing load curtailment is nobody’s favorite tool, especially in cold weather,” Chatterjee said. “And we use it only in the context to avoid uncontrolled, cascading outages.”

Chatterjee said one generation owner deferred an outage as “500 boots were on the ground,” she said, explaining that a 250-member crew was already on-site to begin maintenance work. Another member brought a unit back online that hadn’t run since November or December, she said.

“I want to highlight the work of the members in bringing every megawatt back to the table,” she said.

MISO said the cold snap caused $122 million in uplift payments, compared to the $90 million in congestion costs that Hurricane Laura caused six months before. Settlements staff is working through charges and bills, Chatterjee said.

Independent Market Monitor David Patton said average energy prices in February rose 226% year-over-year, owing just to the winter storm. He said the month’s transmission emergencies led to a record $1.1 billion in real-time congestion costs, more than MISO accrued in all of 2019.

“We’ve never seen this much congestion accumulate over two days,” Patton said. “At one point, we were violating 33 constraints simultaneously.”

Patton said the Monitor’s staff worked to allow offers above MISO’s $2,000/MWh offer cap during the arctic blast. “These costs are devastatingly high if you can’t recover them,” he said.

Director Nancy Lange noted that staff got “a lot of experience” in load-shed orders between 2020 and 2021. She asked whether MISO could improve its procedures to limit outage durations.

Chatterjee said staff holds monthly load-management drills with members, where they pose load-reduction scenarios using members’ real-time availability. She also said MISO and members could prepare the public earlier for conservation appeals.