NEW ORLEANS — MISO emerged from winter 2024/25 without turning to emergency procedures despite wide-ranging winter storms Jan. 6-9 and Jan. 20-22. 

During the March 11 meeting of the Markets Committee of the MISO Board of Directors, RTO leadership credited relatively smooth operations to more open communication with members, market improvements and better data and modeling of risks than in past deep freezes.  

“After a quiet December, weather-wise, we had a very busy January,” Vice President of Operations Renuka Chatterjee told board members. “We always talk about how more days are going to get interesting, and here we are.”  

Chatterjee said the snow that fell over Little Rock and New Orleans in early January was unusual for the footprint.  

But Chatterjee said MISO was able to predict risks appropriately during the first bout of icy weather. She also said collaboration with members and the RTO’s risk assessment and uncertainty model shone to predict the gigawatts of market products needed during late January’s footprint-wide freeze.  

The Jan. 20-22 storm was one for the books in MISO South; the region hit an all-time, 33-GW record for wintertime demand. (See MISO South Hit Record, 33-GW Winter Peak in Jan. Storm.) The larger footprint crested at a seasonal peak of 108 GW on Jan. 22 during an average 6.5 F temperature.  

Chatterjee took a moment to reflect on how far MISO has come since the winter storms of early 2021 and late 2022. She said from Jan. 20-22, 2025, MISO experienced just $1.5 million in uplift payments to resources. That’s compared to the $49 million in uplift payments incurred during a storm lasting Feb. 15-17, 2021, and a $22 million tally from another storm Dec. 23-25, 2022.  

Chatterjee said those results happened because MISO improved its operational awareness.  

“I generally don’t believe in luck. I believe in preparation,” she said.   

Chatterjee said she heard one operator in the control room during the storm remark that he moved from feeling “little confidence in the information and high stress” as he had in past years to being confident in MISO’s information and experiencing less stress during winter storms.  

“This is a huge improvement for MISO, and it speaks to how well their processes have evolved,” Independent Market Monitor Carrie Milton said of MISO’s reduction in uplift payments. She also said MISO achieved a “very impressive” decrease in out-of-market actions in the control room to manage congestion over the winter.  

However, Milton urged MISO to trust its look-ahead commitment software more. She said on Dec. 12, 2024, the look-ahead tool recommended calling up about 20 more units than MISO operators ultimately committed. Milton said if MISO had followed the extra commitment recommendations, it might have avoided having one transmission constraint in violation for more than nine hours, which racked up $36 million in congestion costs. 

Milton also said in one February instance, MISO experienced a 30-minute contingency reserve shortage where prices temporarily shot to $1,900/MWh. She again said MISO should direct operators to be more accepting of look-ahead recommendations.  

IMM David Patton said he understood why operators might not perceive the look-ahead tool as an authority. He said the tool historically has not been as accurate as it is now, and MISO operators have long been under pressure to reduce costs and not overcommit resources. Now the tool is more precise, he said.  

“So, it’s a bit of a change in logic and process,” Patton said, adding he was confident MISO would change course and accept the tool as the default more often.  

Otherwise, the IMM reported that winter’s real-time energy prices of $41.08/MWh were 31% higher than last winter on rising gas prices. Milton said the historically low gas prices of 2024 vanished on sustained cold weather across the country.  

MISO Priming for Steep Ramping Needs

Looking ahead, MISO predicts a 99-GW peak during the spring. Chatterjee said MISO will enter the season with twice as much solar as it had last year. MISO was peaking at about 11 GW of solar in February. She said MISO likely will manage an average 9 GW in ramping needs over March, with requirements set to intensify.  

“This is going to be new for us, so I expect some lessons learned,” Chatterjee added.  

Executive Director of Markets and Grid Research DL Oates said rising operating uncertainty is an inevitability for MISO. He said MISO navigated the winter with about 200 GW of resources, including 41% gas, 24% coal and 16% wind. However, by 2043, MISO anticipates overseeing a 515-GW fleet with 18% gas, 4% coal, 35% wind and 27% solar.  

Oates said while MISO experienced an approximate 11-GW deviation between its initial forecasted needs and what generation ultimately proved necessary during the late January storm, that unknown could widen to more than 40 GW within 20 years.  

Oates said by 2043, MISO could require a net load ramp of 100 GW on a sunny day. He said on those days, new energy storage assets would need to charge during the day to be ready to discharge as the sun goes down. He also said it must ensure that reserves are deliverable on its transmission system. 

Milton said MISO already needed more than 20 GW in ramp demand Jan. 19 as the sun set, which ultimately led to higher prices and PJM furnishing imports.  

“It’s important that MISO continue the good work that they’re doing, that DL talked about,” she said.