The Midcontinent Independent System Operator and the Organization of MISO States recently released the results of the tenth annual OMS-MISO survey, which reflect market actions such as delayed retirements and capacity additions resulting in 1.5 gigawatts of residual capacity for Planning Year 2024/25.
But without continuation of such actions, a capacity deficit of 2.1 GW is projected for the summer of 2025/26 which grows in subsequent years, the survey results show.
OMS is the regional state committee for the MISO region representing regulatory entities in 15 states and Manitoba, Canada.
OMS and MISO conduct the annual, voluntary survey to assess available resource capacity to serve projected load over the next five years (i.e., 2024 through 2028).
The results align with MISO’s resource adequacy process and were measured by a generating unit’s availability, also known as seasonal accredited capacity. MISO uses this survey along with other information to create a holistic picture of the near and long-term outlook of the grid.
This is the first time the survey incorporated MISO’s new seasonal resource adequacy construct. The results reflect the market responses expressed in MISO’s 2023 Planning Resource Auction, including delayed retirements and making additional existing capacity available to the region. These actions may not be repeatable in the future, and resource accreditation will continue to evolve based on performance during high-risk periods.
The latest survey indicates that non-summer seasons indicate sufficient, yet declining capacity over the survey horizon.
The North/Central subregion shows potential capacity deficits starting in the summer of Planning Year 2025/26, while the South subregion shows increasing tightness and a potential deficit starting in winter 2027/28.
Demand growth is projected to continue for five years across all four seasons at 0.8 GW or 0.68% per year on average.
