WECC and SPP Lead Grid Headroom Rankings as Constraint Pressures Mount in PJM, MISO

## Grid Intelligence: Western ISOs Pull Ahead

Cheyenne, WY climbed to a **69.5 excess power score** in the DC Hub Power Index (DCPI) this week, signaling strong transmission headroom in the WECC region. Rural SPP markets in Kansas followed at 67.2, while Midlothian, TX (ERCOT) posted 65.6—underscoring a Western and South-Central advantage in grid capacity for hyperscale builds.

Meanwhile, **Northern Virginia recorded a 64.2 constraint score**, the highest among all 300+ tracked US markets, despite maintaining core colocation density. Mount Pleasant, WI (MISO) logged an 80.0 constraint rating, reflecting acute interconnection queue and reserve margin pressures in the upper Midwest. Phoenix (WECC) also entered the constraint watch list at 61.5, driven by summer peak load and transmission bottlenecks.

## What It Means for Developers

ISO-level transmission planning cycles and fuel-mix transitions are reshaping where new data center load can interconnect without multi-year delays. Markets in SPP and WECC continue to offer faster queue timelines and lower curtailment risk, while PJM and MISO face growing opposition from utilities citing inadequate generation reserves. Developers targeting 100+ MW campus builds should layer DCPI constraint scores with ISO interconnection data and state PUC filings before committing capital.

## Methodology

The **DC Hub Data Center Power Index** synthesizes 15 grid variables—including substation headroom, ISO reserve margins, interconnection queue depth, and renewable penetration—across 300+ US markets and 7 ISOs. Updated daily.

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**Source:** DC Hub Data Center Power Index (https://dchub.cloud/dcpi). Updated daily.
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