MINNEAPOLIS — MISO Independent Market Monitor David Patton called NERC’s Long-Term Reliability Assessment inaccurate for labeling the RTO a high-risk area and said he believes it is in a good reliability position.

“We find that it is completely inaccurate. MISO should not be colored in red,” Patton said at a June 10 Markets Committee meeting of the MISO Board of Directors.

Patton faulted NERC for apparently conflating installed capacity with unforced capacity in the assessment’s totals. He said NERC tallied unforced capacity values for MISO when calculating a margin that it ultimately compared to an installed capacity requirement. He said the blunder lowered the footprint’s capacity sums on paper by more than 10 GW.

“I don’t frankly understand how they did this,” Patton said. “They basically presented an apples and oranges assessment.”

NERC’s Long-Term Reliability Assessment predicted MISO could be confronted with capacity shortfalls in 2025. It assumed the RTO would have 132.2 GW in generating capacity, or 124.4 GW after factoring in all retirement announcements. (See NERC Warns Challenges ‘Mounting’ in Coming Decade.)

Ahead of summer, MISO reported it has 143.1 GW in offered capacity available to it to meet a likely 123-GW annual peak. (See MISO Prepping for Likely 123-GW Summer 2025 Peak.) Altogether, the RTO has 203 GW of installed capacity.

Patton said NERC’s lapse is influencing national policy, evidenced by the Department of Energy’s directive to keep Consumers Energy’s 1.4-GW J.H. Campbell coal plant in Michigan operating over the summer. (See Consumers Energy Seeking Compensation for Keeping Campbell Open.) He said NERC’s projection could bleed into other rule changes.

“That sort of initiative can lead to FERC ordering market changes that are unnecessary,” Patton said.

Patton also said MISO overstated load predictions used in NERC’s assessment by submitting non-coincident peak forecasts instead of coincident peaks, raising its load requirements and lowering the calculated capacity margin.

Patton said of the four RTO markets he monitors, “I would say MISO is most reliable of the four.”

“It seems like a combination of errors that seems correctable here, but there isn’t a path for correction,” MISO Director Barbara Krumsiek said.

Patton said he hopes NERC will rectify its methods that inform the long-term assessment by the next December report. He said he has reached out to NERC and committed to working with the regulatory authority on its approach.

Michelle Bloodworth, CEO of coal lobby organization America’s Power, questioned whether it was appropriate for the MISO Market Monitor to question a “credible institution” such as NERC. She said she believed MISO’s “elevated risk” status under the assessment was apt.

Bloodworth praised DOE’s actions to keep J.H. Campbell available for a little while longer. She noted that Cleco’s 568-MW Big Cajun II Unit 1 shuttered March 31 due to a settlement decree; she said having the coal plant online at the time might have helped matters during MISO’s load shedding orders in the New Orleans area on May 25. (See NOLA City Council Puts Entergy, MISO in Hot Seat over Outages.)

At the same meeting, MISO said it likely will manage higher-than-normal temperatures paired with drought over the summer.

“If you’re dry and have a pervasive heatwave going on, it can compound challenges in the operating room,” MISO Executive Director of Market Operations JT Smith said.

Smith said a doubled-in-size solar fleet also likely will test MISO’s ramp and regulation capabilities in its ancillary market. He said MISO operators could be managing unavailable resources and higher-than-expected load throughout summer.

As part of a five-year update, Vice President of Operations Renuka Chatterjee said MISO finds itself in the most “dynamic and demanding” operating environment it ever has. She cited steeper evening ramps and mounting long-duration outages, forecasting challenges and stability risks.

MISO entered summer June 1 with a $666.50/MW-day capacity price, signifying the premium the RTO has put on new capacity. (See MISO Summer Capacity Prices Shoot to $666.50 in 2025/26 Auction.)

Carrie Milton, of the IMM staff, said if generation operators would have held off on powering down about 1.6 GW until September, it would have lowered capacity prices to $472/MW-day in the summer.

But Milton said the Campbell plant is not factored into MISO’s clearing prices and isn’t necessary for reliability during the season. She said MISO’s auction already returned a better than one-day-in-10-years standard without the large coal plant.

“We are more than adequate,” Patton said. He repeated that he has “no material concerns” over MISO’s resource adequacy for the upcoming summer.

Patton said factoring in imports and typical planned and forced outages, MISO has a comfortable, 12.2% reserve margin.