CARMEL, Ind. — MISO’s Independent Market Monitor said ramping needs north of 10 GW are becoming increasingly common and MISO should expect challenges ahead as its solar fleet expands. 

MISO IMM Carrie Milton said in analyzing winter operations data so far, MISO’s typical wintertime dual-peaking load pattern in the morning and evening is occurring when its growing solar fleet is unavailable. She said the disparity has become more pronounced as the number of solar panels in the footprint has more than doubled.  

MISO set an all-time solar record of 8.272 GW on Jan. 13, where panels accounted for about 10% of total generation. By comparison, January 2024’s solar peak was almost 3.3 GW.    

On that day, Milton said the RTO had a top 17-GW ramping need, with a 9-GW jump occurring in just one hour as not only solar, but wind generation dropped off.  

“The good news is MISO managed it very well. You probably didn’t even notice it,” Milton said at the Jan. 16 Market Subcommittee meeting. She added that routine pricing that day belied the challenges in the operating room.  

Milton said such challenges will become a more common feature for MISO control room operators. RTO leadership has said its solar capacity will grow to 12 GW before March. (See MISO Estimates Solar Fleet will be 12 GW by Winter’s End.)  

“We continue to set new records with solar,” MISO’s John Harmon acknowledged at the Jan. 23 Reliability Subcommittee.  

Load Shed Drills Announced

MISO signaled it expects a more fraught operating environment by announcing it will conduct tabletop load shed exercises over 2025, hoping to bring in not only load-serving entities, but also regulators and other stakeholders.  

Speaking at a Jan. 23 Reliability Subcommittee meeting, MISO South Manager of Reliability Coordination Jeff Sundvick said MISO’s “ever-evolving energy landscape” and “ever-changing weather” is “putting unprecedented stress on our grid.” He said MISO would mimic seasonal load shed and extended system loss scenarios in the exercises.  

During MISO’s Board Week in December, executives confirmed they would pursue large-scale load shedding drills among its membership.  

Sundvick said MISO doesn’t know some of its members’ “specific capabilities for demand reduction.” He said MISO hopes to standardize some communication through the drills and “simulate high-pressure scenarios.” When it issues load shed instructions, it’s up to the RTO’s local balancing authorities and transmission operators to identify specific loads to shed while prioritizing critical infrastructure. 

“We don’t want to learn of bottlenecks in the heat of battle. We want to learn about them beforehand,” Sundvick said.  

MISO Eludes Max Gen Event Thus Far

Recent months have proven little challenge for MISO, which recorded 75-GW average demand and a 95-GW peak in December, a few gigawatts higher than December 2023’s totals. Peak demand wasn’t anywhere near the almost 107 GW peak set in December 2022.  

Prices rose year over year to an average of $31/MWh, up from $25/MWh in December 2023. Natural gas prices inched upward from their stable $2/MMBtu over most of 2024 to $3/MMBtu. 

MISO also weathered a hard freeze stretching into coastal MISO South using just cold weather alerts and conservative operation instructions Jan. 20 through Jan. 22. The storm dumped a record 10 inches of snow in some parts of New Orleans. The RTO also employed a cold weather alert and conservative operations for the South region only to manage a cold front Jan. 6-9. The cold snaps likely produced a winter peak.  

Harmon said despite back-to-back winter storms in January, “everything performed as expected from the MISO perspective.”  

Ahead of the arctic bouts, MISO asked all members to evaluate equipment outage schedules, fuel availability and staffing levels. 

MISO operations went off without a hitch in November, bringing lower prices and a lower peak than last year.  

The footprint averaged a 70-GW average load in November, in line with the previous three years. The month’s 81-GW peak load Nov. 21 was smaller than November 2023’s 89-GW peak.  

Though coal and gas prices were unchanged year-over-year at $2/MMBtu, the month’s average locational marginal price slid to $23/MWh, lower than November 2023’s $28/MWh.  

MISO experienced the lowest generation outages in November in four years, averaging 47 GW daily, a 2-GW reduction over 2023.