Summary

  • Adopted 16 TAC §25.194 calls an interconnection a large load at 75 MW of total expected non-coincident peak demand on one site, and gives four routes in. It defines no Base Load, Studied Load or Excluded Load; the Commission's own adoption discussion sends Batch Zero eligibility to ERCOT's PGRR145 and Planning Guide Section 9.
  • The rule carries no general duty to reduce consumption. A reduction can be required by an enacted statute that turns on on-site backup able to serve half the site's demand, by a discretionary condition on a co-location arrangement, or by a demand-management proposal with no adoption notice located.

The instrument is 16 TAC §25.194, Large Load Interconnection Standards, adopted under PUCT Project No. 58481, filed with the Texas Secretary of State on 18 September 2026 and effective 8 October 2026, printed in the Texas Register issue of 2 October 2026. Everything a developer meets at the gate of the Texas queue is downstream of one sentence in it.

That sentence is §25.194(c)(14), and it begins in the driest possible way: “Large load customer--An entity requesting a new or expanded interconnection”. The rest of the definition is the part worth carrying into a boardroom. The quantity is the total expected non-coincident peak demand at a single site, and the threshold is 75 MW, whether the connection is made at transmission or distribution voltage. Non-coincident peak means each site's own maximum, measured without being flattened against everyone else's maximum. It is not annual energy. It is not a coincident system peak.

A site that draws 60 MW for eighteen hours a day does not qualify on that arithmetic, and a site that touches 75 MW for a quarter of an hour can.

Four routes lead into the rule under §25.194(b)(1)(A)–(D): a new single-site interconnection of at least 75 MW; an expansion that reaches 75 MW for the first time; an expansion at a site already above 75 MW where the increment is 75 MW or more; and co-location with a generation resource. For an expansion, §25.194(b)(2) applies the rule to the incremental load, not the whole site. Read as printed, the expansion route is a step rather than a slope — the same number governs a first connection and an addition to an existing one, and no smaller increment appears among the four routes.

That is an observation about this list, not a finding that a smaller addition escapes every other requirement in Texas.

Once inside, the customer owes disclosures, study fees, financial security, an agreement, compliance with phased-energisation milestones and the audit requirements. Two provisions deserve a lawyer's attention more than the rest. §25.194(d)(1)(I) requires the customer to disclose whether it plans to register and operate as a controllable load resource — a term the rule hands to ERCOT's protocols rather than defining. And §25.194(k)(1)(D) permits ERCOT, in a future interconnection study, to reallocate capacity associated with a customer that fails by 24 months to satisfy a milestone in its phased-energisation schedule.

A missed switch-in date is not a correspondence problem.

Now the words that carry the weight in this market. Base Load, Studied Load and Excluded Load appear nowhere in §25.194 as definitions. They are Batch Zero treatment categories, and the Commission's adoption discussion states that PGRR 145 addresses Batch Zero eligibility and that the adopted rule does not address those classification issues. ERCOT's own planning-guide change states the mechanism plainly: “The framework determines whether each Large Load is treated as a Base Load, Studied Load, or Excluded Load” (ERCOT PGRR145, approved by the Commission on 18 June 2026 and effective 11 July 2026 for the relevant Batch Zero sections). In ERCOT's description, Base Load is included with its megawatts effectively locked in, Studied Load is included with its allocation determined by the system-wide study, and Excluded Load receives no Batch Zero allocation. That is operator planning-guide material, and it is not the source of the statutory rule's definition, because the statutory rule does not have one.

So what happens when the grid is short? Not what a reader of the label might assume. Adopted §25.194 contains no general operative requirement that an interconnected large load reduce consumption. Its controllable-load provision is a disclosure duty, not a curtailment command. The plain answer to the question everyone asks about firmness is that this rule declines to answer it.

The answer lives in three other places, and the three are not equivalent. The first is enacted statute. PURA §37.0561(e), carried in enrolled Senate Bill 6 of the 89th Legislature, creates a narrow emergency mechanism for an interconnected large load whose on-site backup generation is capable in aggregate of serving at least 50% of on-site demand. After ERCOT has deployed available market services other than frequency-responsive services, ERCOT may direct the applicable utility or municipally owned utility to require “the large load customer to either deploy the customer's on-site backup generating facilities or curtail load” (SB 6, 89R, enrolled). Conditional on a threshold measured against the site's own demand, discretionary in sequence, and not an always-on duty. A parallel provision, PURA §39.170, requires protocols allowing covered transmission-voltage loads interconnected after 31 December 2025 to be curtailed during firm load shed and requires a reliability service procuring demand reductions from large loads of at least 75 MW; the codified chapter carries it in the same terms — “allow the load to be curtailed during firm load shed” (Texas Utilities Code Chapter 39). Note the number's second job there: 75 MW is the floor size of a demand-reduction procurement, not the interconnection threshold, and the two are not the same quantity.

The second is a discretionary condition on one kind of arrangement. Adopted 16 TAC §25.205, Net Metering Arrangements Involving a Large Load Customer Co-Located with an Existing Generation Resource, took effect on 15 April 2026 under Project No. 58479, and §25.205(k)(2)(A) allows the Commission to impose a condition requiring “the retail customer(s) served behind-the-meter to reduce load during certain events” (Texas Register, 10 April 2026). It reaches an approved net-metering arrangement, if the Commission chooses to attach it. No order applying it to a named arrangement was in the set I read, and nothing I read establishes that the condition has ever been imposed.

The third is not in force. Proposed 16 TAC §25.521, Large Load Demand Management Service, published in the Texas Register of 14 August 2026 under Project No. 58482, would require ERCOT protocols allowing covered transmission-voltage customers interconnected after 31 December 2025 to be curtailed during firm load shed, subject to exclusions for critical-load industrial customers and critical natural-gas facilities. It would create a competitively procured service, and proposed §25.521(c)(1)(A) would oblige a pre-qualified large load customer to “offer at least 1 MW of demand reduction”; a deployed participant would stay curtailed for the EEA event or until ERCOT safely recalls the load. No final adoption notice or effective date was located in the documents read. A proposal is not an obligation, and this briefing treats it as what it is.

Three pieces of arithmetic, all mine, on the printed figures. Seventy-five megawatts is three quarters of 100 MW and one twentieth of 1,500 MW — a restatement of units, not a conversion. The 50% condition in the statute and the 75 MW threshold in the rule use different denominators and are never added, divided or reconciled into one number. And the applicability routes make 75 MW a step rather than a slope.

Provenance matters here, so it sits beside the claims. Every quotation above is a provider-reported excerpt from the retained research output for the cited document, not a phrase I retyped from a page I fetched myself. The Commission's own adopting order for Project No. 58481, Item 218 — indexed at Interchange — returned HTTP 402 when opened, so the rule text rests entirely on the Texas Register publication. One common misdirection is worth closing: PUCT Docket No. 56234 is a Rayburn Country Electric Cooperative certificate-of-convenience-and-necessity application concerning conversion of a private 138-kV transmission line in Grayson County, not the large-load rulemaking. No ERCOT Planning Guide Section 9 text, no protocol text on controllable load resources, no interconnection agreement, study report, security instrument, audit finding or capacity-reallocation decision was read. No megawatt figure for the queue, for any project or for any company's classification is asserted here; 75 MW is a threshold, not a project quantity. No finding is made that any operator, developer or official failed a requirement, and nothing here says whether Texas is or is not short of power for data centres.

What a reader holds, then, is one number doing three jobs. Seventy-five megawatts admits a customer to a rule, labels a project in someone else's planning guide, and sizes a statutory demand-reduction procurement. ERCOT administers the queue, runs the study that fixes a Studied Load's allocation, and may reallocate capacity when a milestone slips — but ERCOT does not decide whether a Base Load is firm, because no instrument in this set says a classification is a promise. The door and the promise were never the same document.