Seam congestion recurring during high-transfer intervals

Recurring seam events materially affect delivered cost for load sited on the import side of the constraint.

• North / Central seam is the operative counterparty; MISO governs the deliverability question.
• Signal class: Grid Constraints. Severity assessed MED on the internal impact scale.
• Geography: Multi-state. Adjacent positions in the same corridor inherit the same constraint profile.
• Source of record: MISO market reports · public.

• Deliverability assumptions built before this development should be re-run; corridor economics move faster than published study timelines.
• Cost exposure concentrates on positions that remain in the process — withdrawal and restudy activity reallocates rather than removes obligation.
• Contract structure (term, minimum take, collateral) is now a larger determinant of total cost of power than the headline tariff rate.
• Timing optionality has value: the interval between filing and order is where outcomes are actually influenced.

• Re-baseline the affected site or portfolio against current upgrade scope and schedule, not the last study cycle.
• Establish a monitoring position on the governing docket or queue cluster with explicit decision triggers.
• Model total cost of power on the rider and escalation trajectory across the full contract term.
• Confirm the injection point versus point of delivery before relying on any adjacency or matched-supply narrative.

Market

MISO

State / Region

Multi-state

Counterparty

North / Central seam

Signal class

Grid Constraints

Assessed impact

64 / 100

Severity

MED

Record date

Jul 23

Source

MISO market reports · public

Verified public intelligence · impact and severity are Stock & Milster assessments, not market quotations

• Grid ConstraintsWest Texas constraint binding through afternoon peak intervalsOpen
• Grid ConstraintsInterface congestion elevated across the mid-Atlantic transfer pathOpen
• Interconnection Queue ChangesDefinitive Planning Phase 2 results shift upgrade obligations across central Illinois clusterOpen
• Transmission ProjectsMISO long-range plan tranche upgrades enter engineering across the Missouri–Illinois seamOpen