MISO territory map. Photo source: FERC.
Midcontinent Independent System Operator (MISO), which spans the central US, should have adequate generating capacity next summer but faces “significant uncertainty” in overall resource adequacy projections, according to a survey by the grid operator and the Organization of MISO States (OMS), a group of state regulators.
The OMS-MISO Survey provides a resource adequacy view over a five-year horizon. 91% of existing MISO generation participated in the 2025 survey, representing 97.4% of the region’s load.
The findings point to some encouraging developments. Recent MISO market reforms, including the Reliability-Based Demand Curve and revised resource accreditation methods, are creating clearer and more accurate signals for capacity investment.
The survey also points to new methodologies that account for surplus and replacement capacity help fine-tune long-range projections. Further, reforms to the generation queue process have begun to reduce speculative projects, easing integration bottlenecks. Delays in planned retirements of conventional power plants, whether strategic or regulatory, are also providing short-term relief.
Survey projections for summer 2026 show a potential planning surplus of between 1.4 and 6.1GW. However, even in the most optimistic scenario, the region will still need at least 3.1GW of additional uncommitted capacity to meet reserve margin targets.
Even as new tools improve how resource adequacy is managed, the MISO-OMS survey highlights intensifying risks, especially in the winter months and in rapidly growing industrial corridors.
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The survey shows a 2.2% compound annual growth rate in demand over the next five years, primarily driven by commercial and industrial loads. Forecasts now approach the high end of MISO’s long-term projections, and load growth through 2035 will exacerbate capacity shortfall and operational risks.
Other challenges noted include clogged up queues, permitting delays, labor constraints and supply chain disruptions. Regulatory pressures, economic headwinds and aging infrastructure are also pushing more generation offline sooner than expected.
The survey emphasised that maintaining reliability through the end of the decade will require both immediate action and long-term alignment between stakeholders. These actions include leveraging replacement projects, smart resource siting to meet emerging demand patterns and coordinated planning among different entities.
“Today we think we’re okay, but there’s work to do within the region to maintain requirements of where we need them to be,” said Todd Ramey, MISO Senior Vice President of Markets and Digital Strategy, during a FERC technical conference last week.
Originally published by Kevin Clarke on Factor This Power Engineering.
