HD Market Scorecard · Midwest and South
MISO Large-Load Interconnection Grade
Midcontinent Independent System Operator · As of September 14, 2026
MISO
C–
Sep 8 ZGIA comments; ER26-3650 clock runs to Sep 18. Process, not reserve margin.
Opinion index · not a third-party rating
MISO prints some of the strongest data-center load-growth numbers in the country. That is a demand signal. It is not yet a reserve-margin or time-to-power signal, which is why the grade sits at C.
Capacity is tightening and large-load timelines are lengthening. MISO is a FERC Section 206 recipient: on June 18, 2026 it was ordered, with the other organized markets, to justify or rewrite tariff treatment of large and co-located loads. Until those rules are settled, interconnection for a new ≥20 MW load is a regulatory variable, not a calendar.
What the grade is pricing
Uncommitted capacity (25%) and time-to-power (35%) both drag. Tariff climate is Conditional, not Restrictive — there is no statewide hyperscale pause inside MISO comparable to New York, and no ERCOT-style energization freeze. The grade will not move on announcements of load growth. It will move if reserve margin or the 206 filing changes the path to energization.
Sites that already hold utility-confirmed capacity in friendlier MISO subregions still clear. Queue paper that assumes 2025 timelines does not.
Full board, weights, and citation format: HD Market Scorecard. How the 35/25/20/10/10 weights work: methodology.
Grade History
Published changes to MISO, most recent first. Grades held since July 16, 2026 are unchanged from inception.
No published notch since inception — MISO has held at C.