Auction Timeline
| Milestone | Date | Status |
|---|---|---|
| Offer Window Opens | March 26, 2026 | Complete |
| Offer Window Closes | March 31, 2026 | 2 Days Left |
| Results Posted | April 28, 2026 | Pending |
| Planning Year Begins | June 1, 2026 | Pending |
The 1.9 GW Capacity Gap
MISO’s preliminary data for the 2026/27 PRA shows 135.6 GW of accredited capacity against a 137.5 GW total planning reserve margin requirement. This 1.9 GW gap is the tightest supply-demand balance since MISO’s Zone 4 (MISO South) experienced clearing prices of $236/MW-day in 2022.
The gap is driven by three simultaneous pressures:
- Load growth: MISO added roughly 2 GW to its peak load forecast for 2026/27, driven primarily by data center development in central Illinois and Indiana.
- Thermal retirements: Continued coal plant retirements, particularly in MISO Zone 4 and Zone 6, are removing baseload capacity faster than replacement resources come online.
- Accreditation tightening: MISO’s seasonal accreditation methodology now assigns lower capacity credits to intermittent resources during winter peak hours.
Seasonal Reserve Margins
| Season | PRM | Risk Profile |
|---|---|---|
| Summer | 7.9% | Traditional peak concern |
| Fall | 11.6% | Shoulder transition risk |
| Winter | 18.9% | Emerging risk — gas-electric |
| Spring | 23.4% | Maintenance period buffer |
The 18.9% winter PRM is notable — it reflects MISO’s shifting risk profile from traditional summer peaks toward cold-weather events, a pattern reinforced by Winter Storm Fern in early 2026.
Demand Response Crackdown
MISO is mandating actual performance verification tests for demand response resources (Load Modifying Resources) starting with this auction cycle. Previously, some LMRs qualified using hypothetical mock drills. The new rules require demonstrated real-world curtailment capability.
If even 500–1,000 MW of previously accredited DR resources fail verification, the 1.9 GW gap could widen to 2.4–2.9 GW — significantly tightening supply and pushing clearing prices higher.
Clearing Price Scenarios
- Base case ($15–25/MW-day): Sufficient DR and new fast-tracked gas resources clear. Modest increase over last year.
- Tight case ($30–40/MW-day): DR verification failures widen the gap. MISO South zones clear at premium. Possible bifurcation between North and South.
- Stress case ($50+/MW-day): Multiple zones fail to meet local clearing requirements. Would signal structural supply adequacy problems requiring emergency procurement.
Midwest Commercial Buyer Action Items
- Budget for capacity increases: Even the base case represents a meaningful increase. Build $2–5/MWh capacity cost escalation into Q3/Q4 2026 procurement budgets.
- DR enrollment deadline: If your facility has curtailable load in MISO territory, the 2026/27 LMR enrollment deadline has passed — but start positioning for 2027/28 now while qualification rules are known.
- Watch April 28: Results posting will immediately signal the direction of Midwest commercial rates for the next 12 months.
- Compare across ISOs: MISO capacity costs remain far below PJM ($329/MW-day). Multi-site operators should factor this into portfolio allocation decisions.
Source: MISO Planning Resource Auction documentation; MISO LOLE Study 2026/27; RTO Insider; ESAI Power.