The ERCOT Batch Zero utility-side eligibility filings land Friday July 24. That is two business days from Wednesday. The single most useful number the market will pull off the tape is not the state-wide ratio of utility-eligible megawatts to developer-submitted megawatts. It is the Oncor sub-total, disaggregated by transmission corridor, taken as a share of the state-wide eligible pool.
Oncor’s own Q2 2026 interconnection tracking report, filed with the Public Utility Commission of Texas on July 3, disclosed that the utility currently has 121 large-load projects inside its service territory that meet the 75 MW Batch Zero threshold, aggregating to approximately 96 GW of nameplate peak demand. That is a working majority of the state-wide developer pool by megawatts and by count. What Oncor files on Friday, therefore, effectively sets the ceiling on what Batch Zero can absorb into the April 9, 2027 Phase 1 study allocation. The other five transmission and distribution utility filings will supply the shape of the pool, but not its size.
Why Oncor is the load-bearing filing
Batch Zero is a state-wide process running under a single ERCOT protocol timeline, but the eligibility bottleneck sits at the utility level. Under the PUCT’s June 18 order, each transmission and distribution utility (TDU) must file a complete eligibility package for every project in its service territory that appeared in the July 10 developer submission list. The package has to include a Load Information Form with verified peak and average demand, a signed developer attestation, the TDU’s own stability study data set for the project, and a documented TDU eligibility determination. Any of the four components missing on July 24 removes the project from Batch Zero.
The state-wide TDU footprint is not distributed evenly. Oncor covers the Dallas-Fort Worth metroplex and much of North, West, and East Texas. That footprint captures the highest-density cluster of announced data center campuses (Ellis, Kaufman, Hood, Denton, Collin, and Rockwall counties account for a working majority of the DFW-perimeter site pipeline) and the Permian-adjacent industrial load additions in the Midland-Odessa corridor. CenterPoint covers Houston and the Gulf Coast petrochemical corridor. AEP Texas covers South Texas and the border. Texas-New Mexico Power carries a smaller Panhandle and West Central footprint. Austin Energy and CPS Energy carry the municipal territories inside Travis and Bexar counties.
By ERCOT’s own Q2 2026 large-load application inventory, the megawatt split across TDUs runs approximately: Oncor 51 percent, CenterPoint 21 percent, AEP Texas 12 percent, TNMP 6 percent, and the two municipals plus the smaller cooperatives together 10 percent. Those shares approximate the eligibility exposure on Friday. Oncor is not just first among equals. Oncor is the state-wide constraint.
The three Oncor sub-reads that matter more than the headline
The Oncor filing on July 24 will disclose a single aggregate eligibility count and a single aggregate eligible megawatt total across the Oncor footprint. The market will read that headline number first. The analytical anchor, though, sits underneath the headline in three sub-reads.
The sub-corridor breakdown
Oncor’s transmission network divides into a set of load pockets defined by the 345 kV backbone and the 138 kV subtransmission tie points that feed off it. The DFW-north corridor around McKinney, Denton, and Frisco is one pocket. The DFW-south corridor through Ellis and Hill counties toward Waco is another. The East Texas corridor from Tyler to Longview, tied into the ETT transmission line, is a third. The West Texas corridor into the Permian is a fourth. Each pocket has a different transmission adequacy profile and a different pool of announced data center and industrial projects.
The July 24 Oncor filing will, by protocol requirement, disclose eligibility on a per-project basis, and the per-project disclosures aggregate into per-corridor totals. If the DFW-north pocket clears at 80 percent eligibility while the DFW-south pocket clears at 30 percent, that is a fundamentally different constraint profile than an even 55 percent state-wide, even if the aggregate megawatts sum to the same headline number. The corridor breakdown is where the CREZ-successor transmission expansion filings that the PUCT is expected to open in Q4 will find their operative rationale. A concentrated bottleneck in a specific pocket produces a specific transmission expansion filing. A distributed constraint produces a broader planning proceeding on a slower clock.
Watch for the following on the corridor read. The DFW-south corridor is the load pocket with the largest pipeline of announced data center campuses inside the Oncor footprint (Ellis County alone has roughly 18 announced sites in the Q2 2026 tracking data). It is also the pocket where the 345 kV Sam Switch to Big Brown to Kaufman transmission corridor is closest to its stability limit under Oncor’s own Q1 2026 filings. A DFW-south eligibility rate materially below the Oncor state-wide rate points at that specific transmission constraint. A DFW-south rate at or above the state-wide rate signals that Oncor has already re-modeled the stability envelope inside its own planning function, which would be a material forward read on the Q4 CREZ-successor filing.
The stability study coverage
The second component of the utility eligibility package is the stability study data set for each project. Under the June 18 PUCT order, the TDU must file the short-circuit contribution, dynamic model file, and voltage response envelope for each project. Those inputs are what ERCOT will feed into the Phase 1 study modeling. A project that appears in the Oncor filing without a complete stability data set is not necessarily disqualified, but is flagged for supplemental filing, which pushes the Phase 1 modeling one round back for that project.
The read on July 24 is the coverage ratio. How many of Oncor’s 121 large-load projects have a complete stability data set filed on the tape, and how many are flagged for supplemental. 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, which becomes an August-September constraint on Phase 1 study prep and puts pressure on the April 2027 allocation timeline. Coverage below 60 percent is a scenario the market has not priced.
Oncor’s Q1 2026 stability study staffing disclosure in the CCN docket indicated that the utility had added roughly 25 percent to its transmission planning engineering headcount over the prior 12 months. That build-out was specifically justified in the filing as necessary to keep pace with the large-load pipeline. If the July 24 tape shows sub-80 percent stability data coverage anyway, the specific inference is that the 25 percent headcount build-out was insufficient at that pipeline volume, 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.
The ride-through overlay determinations
The third sub-read is any Oncor determination that a specific Large Computational Load project cannot meet the ride-through overlay the PUCT set for the Large Computational Load designation. The ride-through envelope requires the 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. The two obligations together are the operational hinge of the Large Computational Load classification.
A TDU-signed determination that a submitted project cannot meet the ride-through envelope is a substantive removal from Batch Zero, not a supplemental filing. The developer’s options at that point are to redesign the load-side infrastructure to meet the envelope (which resets the project timeline outside the Batch Zero window), to re-submit as a Non-Large Computational Load without the overlay (which changes the tariff treatment and the ride-through obligation but keeps a portion of the interconnection package intact), or to exit Texas siting.
The market has not seen an operational test of whether the hyperscaler counterparties can commit to the ride-through envelope as specified. The July 10 developer attestations claim the envelope for every submitted Large Computational Load. The July 24 utility determinations are where those claims first meet a signed engineering opinion. If Oncor’s filing carries even three or four ride-through-based ineligibility determinations across the 121-project pool, that is the specific data point the December 2025 Google and Meta co-location filings, and the Q1 2026 Amazon Web Services filings on the same footprint, will be repriced against.
The three inputs, together
Take the three sub-reads in combination. A high Oncor aggregate eligibility ratio driven by strong DFW-north performance, high stability data coverage, and zero ride-through ineligibility determinations is a clean scenario. Batch Zero absorbs the largest slice of the state-wide pipeline at the pace the PUCT designed for, and the April 2027 Phase 1 allocation runs on a mostly full pool.
A high Oncor aggregate eligibility ratio driven by DFW-north but masking a collapsed DFW-south pocket, weak stability data coverage in the West Texas corridor, and two or three ride-through ineligibility determinations in the East Texas industrial cluster is a different scenario. That reads as headline eligibility above the 0.6 threshold, but with a structurally constrained pool. The Phase 1 allocation on that pool clears fewer projects, weights toward specific site geographies inside DFW, and shifts the Q4 CREZ-successor filing toward a specific corridor expansion rather than a broader planning proceeding.
A low Oncor aggregate eligibility ratio, driven by any combination of the three sub-reads, is the scenario the trade press has framed as a hard binding constraint. Under that scenario, Batch Zero has already run into the utility-side ceiling before ERCOT models a single dispatch case, and the July 10 developer volume that fell out on Friday migrates. Migration paths are the same three from Tuesday’s writeup: non-batch retail electric provider co-location structures inside ERCOT, out-of-state re-siting to MISO or SPP, or exit from Texas siting entirely.
The parallel federal read
The Friday Oncor sub-reads land inside the same 28-day window as the FERC Section 206 large-load tariff responses due August 17. On the federal side, the PJM generation adequacy report Monday disclosed a 0.87 ratio of projected large-load additions to total load additions inside PJM’s five-year planning horizon, well above the 0.5 analytical threshold. MISO came in at 0.68. SPP at 0.58. Those three ratios frame the tariff proceedings that will be argued over the summer and into the fall.
The state and federal tracks are running on parallel clocks with adjacent implications. If the Oncor Friday tape carries a substantively constrained eligible pool, and the August 17 MISO tariff response opens a co-location product that admits large-load projects on faster interconnection paths than ERCOT’s Batch One process is likely to offer, the aggregate effect is a specific migration of announced Texas data center campuses to MISO footprints in Ohio, Indiana, and Iowa. That migration has not shown up in the tracking data yet. It will show up in Q3 2026 large-load application filings on the MISO side if it is going to show up at all. The Oncor Friday read is the anchor on the Texas side of that inflection.
What to watch on Friday
Three specific pieces of information will land on the July 24 Oncor filing that carry material weight for the April 2027 Phase 1 allocation and for the trajectory of the Texas large-load process into Batch One.
First, the Oncor aggregate eligibility count as a percent of the 121 developer-submitted projects inside the Oncor footprint, and the eligible megawatt total as a percent of the 96 GW nameplate. The two numbers together frame the Oncor headline.
Second, the eligibility rate inside the DFW-south corridor specifically, expressed as a share of the corridor pipeline. Any material deviation from the Oncor aggregate rate signals whether the transmission constraint the market has flagged is binding on the specific pocket.
Third, any ride-through overlay ineligibility determination against a named Large Computational Load project. Even one is a real data point. Three or more meaningfully repositions the analytical read on the hyperscaler pipeline.
The Oncor filing is due at close of business Friday. The full state-wide picture assembles across the same tape, but the analytical spine is in one utility’s disclosure. The Phase 1 study allocation next spring will run against the pool that clears at 5 pm Central on July 24. The Oncor share of that pool is the first structural test of whether Batch Zero can carry the load addition profile Texas has now committed to absorb.