Year-over-year prices rose in MISO to serve a typical September peak.
MISO members served an average 76.3 GW daily load over September, with a 106-GW peak occurring Sept. 16. The month’s peak demand wasn’t unusual, less than a gigawatt from the 105.5-GW peak in September 2024 and smaller than September 2023’s 114.6-GW peak. Average daily load was up slightly when compared to the approximate 75-GW average in September 2024.
Real-time prices, however, rose almost 1.5 times from September 2024, at $41/MWh versus $28/MWh. Average natural gas prices climbed from $2/MMBtu in September 2024 to $3/MMBtu September 2025. Coal stayed flat at about $2/MMBtu year over year.
MISO’s solar peak was 14.5 GW while wind registered a 20.7 GW peak. Both occurred in early September.
Over the month, MISO experienced 47 GW in average daily generation outages, 9 GW higher than last September.
MISO declared a capacity advisory for the entire footprint Sept. 29 because of forced generation outages and limited transfer availability. It also called conservative operations on Sept. 28 due to unseasonably warm temperatures, generation outages and lower-than-normal renewable energy forecasts.
