Key deadlines already have arrived for MISO’s spring capacity auction, while the RTO has hiked its planning reserve margin for the 2024/25 planning year.  

So far for the upcoming summer, MISO has accounted for nearly 161 GW in installed capacity across the footprint that whittles down to almost 129 GW in total seasonal accredited capacity. The RTO must meet a 135.7-GW summer planning reserve margin requirement.  

MISO will use a 9% summer 2024 planning reserve margin, higher than the 7.4% annual planning reserve margin used in last year’s Planning Resource Auction. MISO said its shifting resource mix and a move to seasonal modeling for its reserve margin contributed to the increase. This year, the RTO said it’s using seasonal values, rather than annual, in its generator verification testing data, reflecting different capabilities of generators in different temperatures. The upcoming spring auction marks the second time MISO has divided its capacity auction by season.  

MISO stressed Jan. 17 that it’s “too early in the process to make quantifiable conclusions” on how much supply it expects beginning June 1.  

The grid operator plans to update its supply information based on the data it receives from market participants every other week through late March. It said it expects information on energy supply to change “significantly.”  

MISO resource owners have until Feb. 1 to confirm their seasonal accredited capacity values with the RTO. Load-modifying resource owners also have until Feb. 1 to register to participate in the auction. As of mid-January, MISO said approximately 12.8 GW of load-modifying resources from prior years had not started the registration process.