The ERCOT Batch Zero utility-side eligibility filings land tomorrow. Every transmission and distribution utility with projects in the July 10 developer pool has to file a complete eligibility package with ERCOT by close of business Friday, or the projects that fall out drop from Batch Zero and wait for the next batch. The state-wide picture assembles across the tape as the filings arrive. The analytical anchor sits in one utility footprint and inside three sub-reads that Wednesday’s preview scoped.
Two facts frame the Friday read. First, Oncor carries roughly half of the state-wide large-load application volume by megawatts under ERCOT’s own Q2 2026 inventory, and the Oncor sub-total therefore sets the effective ceiling on what Batch Zero can absorb into the April 9, 2027 Phase 1 study allocation. Second, the three sub-reads that matter inside the Oncor filing are the sub-corridor breakdown, the stability study coverage ratio, and any ride-through overlay ineligibility determination against a named Large Computational Load project. Those three inputs, not the state-wide aggregate ratio, are the analytical spine.
The Friday tape sequence
Utility filings do not have to land simultaneously under the PUCT’s June 18 order. Each TDU has until 5 pm Central Friday to file. The order and timing of the filings matter for how the market prices the state-wide pool across the afternoon.
The smaller TDUs typically file earlier. Texas-New Mexico Power historically files ERCOT-facing packages in the mid-morning window on deadline days. AEP Texas has run mid-afternoon on comparable filings across 2025. CenterPoint has typically filed in the two-to-three hour window before the close. Oncor is the largest and most complex package by count and megawatts, and Oncor filings on ERCOT protocol deadlines have clustered inside the final hour more often than not across the 2024 to 2026 record.
The functional implication is a specific pricing sequence. TNMP and AEP Texas eligibility will land first and set the smaller-utility reference. CenterPoint will land next and give the market a Houston and Gulf Coast petrochemical corridor read. Oncor will land last, in the final hour, and the state-wide picture will not resolve until then. The two municipals inside Travis and Bexar (Austin Energy and CPS Energy) will file inside their own service territories and will not materially reshape the state-wide aggregate given the smaller megawatt share.
That sequence produces a specific analytical hazard. The smaller and earlier filings are unrepresentative of the state-wide constraint. The market that reads the AEP Texas eligibility rate as a leading indicator of the state-wide rate at 2 pm Central is trading on a read that resolves in a different direction three hours later. The Oncor filing is where the state-wide read completes, and the Oncor sub-reads inside that filing are where the substantive constraint discloses.
Sub-read one, the corridor breakdown
The Oncor transmission network divides into a set of load pockets defined by the 345 kV backbone and the 138 kV subtransmission tie points. Wednesday’s preview scoped the four pockets that carry the material large-load pipeline: DFW-north around McKinney, Denton, and Frisco; DFW-south through Ellis and Hill counties; East Texas from Tyler to Longview along the ETT corridor; and West Texas into the Permian.
The Friday filing will disclose eligibility on a per-project basis, and the per-project disclosures aggregate into per-corridor totals. The specific analytical anchor is the ratio of the DFW-south corridor eligibility rate to the Oncor state-wide rate. Ellis County alone carries the largest single-county cluster of announced data center campuses inside the Oncor footprint. The DFW-south load pocket is also the corridor where the Sam Switch to Big Brown to Kaufman 345 kV backbone sits closest to its stability limit under Oncor’s own Q1 2026 planning disclosures.
A DFW-south eligibility rate materially below the Oncor aggregate signals that the stability constraint is binding on the specific pocket, and the Q4 CREZ-successor transmission expansion filing the PUCT is expected to open will be scoped around a specific corridor project rather than a broader planning proceeding. A DFW-south rate at or above the aggregate signals that Oncor has already re-modeled the stability envelope inside its planning function, and the Q4 filing runs on a broader clock with less corridor-specific urgency.
Sub-read two, the stability data coverage ratio
Every project in the Oncor filing has to include a short-circuit contribution set, a dynamic model file, and a voltage response envelope. Projects that appear without a complete stability data set are not disqualified. They are flagged for supplemental filing, which pushes the Phase 1 modeling one round back for that project.
The read on Friday is the coverage ratio. Coverage above 90 percent signals that Oncor’s engineering function has been running ahead of the calendar and the July 10 developer submissions did not surprise the utility. Coverage in the 60 to 80 percent range signals that the developer pool ran meaningfully ahead of the utility’s internal modeling capacity, and the operative August question becomes whether the utility can staff further before the September stability model integration deadline the PUCT flagged in the June 18 order. Coverage below 60 percent is the scenario the market has not priced.
The Q1 2026 CCN docket disclosed a 25 percent transmission planning engineering headcount build-out at Oncor over the prior 12 months, specifically justified as necessary to keep pace with the large-load pipeline. If the Friday tape shows sub-80 percent stability coverage anyway, the inference is that the build-out was insufficient at the July 10 pipeline volume, and the September stability model integration deadline becomes a binding calendar constraint on the April 2027 allocation.
Sub-read three, the ride-through overlay determinations
The ride-through envelope requires the Large Computational Load to remain online through voltage sags to 0.65 per unit for up to 200 milliseconds and to controllably curtail within a defined ramp during ERCOT-declared emergency operating conditions. Both obligations together define the operational hinge of the Large Computational Load classification. A TDU-signed determination that a submitted project cannot meet the envelope is a substantive removal from Batch Zero, not a supplemental filing.
The July 10 developer attestations claim the envelope for every submitted Large Computational Load project. The Friday utility determinations are where those claims first meet a signed engineering opinion. Even three or four ride-through-based ineligibility determinations against a named hyperscaler project reprices the December 2025 Google and Meta co-location filings and the Q1 2026 Amazon Web Services filings inside the Oncor footprint. Zero ride-through determinations is the clean scenario. One or two is a data point. Three or more meaningfully repositions the read on the hyperscaler pipeline.
The Monday read
The Friday tape closes at 5 pm Central. The state-wide picture assembles inside that window. The Monday July 27 open is where the Batch Zero eligibility pool carries a clearing price against the next set of proceedings.
Three proceedings will be tracking Friday’s tape into Monday. The first is the ERCOT Phase 1 study prep calendar, which begins Monday and runs into the September stability model integration deadline. The second is the Q4 CREZ-successor transmission expansion filing at the PUCT, which will scope around whichever corridor Friday’s Oncor breakdown flags as the binding constraint. The third is the August 17 FERC Section 206 large-load tariff response deadline on the federal side, which will price the migration risk of announced Texas projects into MISO, SPP, and PJM footprints against whatever eligibility ceiling Friday sets in ERCOT.
The Friday afternoon sequence is not a state-wide clearance. It is a Oncor-anchored disclosure that lands last and carries the substantive constraint inside three sub-reads. The correct analytical posture through the tape is to hold the AEP Texas and CenterPoint numbers as reference points and reserve the read for the final hour when Oncor files. The April 2027 Phase 1 study allocation will run against the pool that clears at 5 pm Central tomorrow. The Oncor sub-corridor breakdown, the stability data coverage ratio, and the ride-through overlay determinations are the three inputs the pool will disclose.