Receipt — Claims on the grid: what Ontario's connection record proves about its largest new loads — and why the register they sit in cannot be added up

A Receipt is a dated evidence summary for one product. It shows the question, the current answer, the sources, the method, the limits, and the next update.

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The question	Who is asking Ontario's electricity system for large new connections, how much of that is engineering fact rather than announcement — and why can none of it honestly be added into a single number?
Current reading	Battery plants, steel furnaces, and data centres are usually discussed through announcements, and announcements carry no obligation to state what a project asks of the grid. The connection process does: before a large load connects, the system operator assesses it and states the quantity. That makes Ontario's public connection register and its posted assessments the only public layer where these claims become checkable numbers -- and it is easy to misread. The register's size column invites totalling into headline gigawatts; its own fields show why that arithmetic is unsound. And the register is overwritten in place: nothing preserves what it said last month unless someone captures it. This Brief states what the engineering record actually proves, what the register can and cannot say, what the process publishes and withholds, and what Countability watches from here, capture by capture.
Evidence reviewed through	2026-09-06
Basis	The IESO's public connection register (its page's own backing feed, one archived vintage, counted by a committed census script under a stated population rule) and the issuer's own posted engineering documents: final connection assessments for the flagship loads, one assessment's superseding addendum, one bulk plan, one transmitter needs assessment, and one integrated regional plan. Every quantity is the issuer's own stated figure or a count of the register's own fields; the only capacity sums on the page are the issuer's, quoted with attribution. Statistics Canada's two monthly Ontario generation tables are treated as one measurement, their identity re-derived from archived responses. On each maintained pass every reference the register publishes is re-fetched and hashed against what is held, so a silently revised or newly reachable assessment is caught rather than assumed away; the newest assessment in the data-centre lineage was reached this way.
Method	Pinned, cited evidence; no scenario is computed — every figure restates a pinned, re-derivable value from the product's member Resolutions.
Confidence	Every published figure re-derives from archived bytes (register counts by the committed census script; assessed quantities by quote against the archived assessment). What the record does not establish is stated as a named gap rather than estimated.
Next trigger	The next monthly register capture; any newly posted assessment for a large active application; any published apportionment of a shared station capacity.
Next evidence	The next register vintage begins the state-change record -- the first evidence this Brief names but cannot yet show. Between vintages, the maintained re-check of every published reference is what surfaces amended assessments.
Expiry	The reading holds for the 2026-07-10 register vintage; each monthly capture either re-affirms it or changes it on the record.

Material definitions

The large-load population is Countability's stated counting rule over the issuer's own fields -- load-class application types, size stated in megawatts, at or above the IESO's own 75 MW threshold -- published with the counts; the issuer publishes no such population itself.
Assessed station quantities are connection maxima for stations, never any plant's own demand; the Brief maintains this distinction wherever a figure appears.
Register 'Size' has no issuer definition and mixes increments with totals; it is quoted per row and never summed.
Applicants of record are frequently transmitters or distributors, not the named projects' proponents; conduct of an application is never attributed to the project's proponent.

Decisive limitations

Single register vintage: statuses are a snapshot; entries, exits, and status changes become observable only from the second monthly capture onward.
47 of the 67 population members -- including all four active applications above 400 MW -- have no posted assessment, so their stated sizes cannot be checked against any public engineering document.
The register is overwritten in place by the issuer; historical states not captured are unrecoverable.
A shared-capacity requirement in one assessment lineage is driven by a load forecast the issuer places in a confidential appendix: the threshold and the remedy are public, the quantity crossing it is not.

Key sources and licences

Needs Assessment Report — Northwest Ontario (2020-07-17) — Hydro One Networks Inc. Licence terms not read
IESO Connection Assessment & Approval — Application Status list (the page's own backing feed, applicationstatusdata.json), list vintage 2026-07-10 — Independent Electricity System Operator Licence terms not read
System Impact Assessment, CAA ID 2022-726 (Windsor Stellantis TS — new DESN station; applicant of record Hydro One Networks Inc.) — Final Report, Public — Independent Electricity System Operator Licence terms not read
Central-West Bulk Plan (2024-04-18) — Independent Electricity System Operator Licence terms not read
Electric power generation, monthly — table 25-10-0015-01, Ontario / total all classes of electricity producer / total all types of generation (vector v44174769) — Statistics Canada Licence text read in full
Electric power generation, monthly, by producer and generation type — table 25-10-0016-01, Ontario totals (vector v44159114) — Statistics Canada Licence text read in full

Every figure this Receipt covers can be reproduced from the named public sources under Countability's published method. If a correction is ever needed, it produces a new dated version rather than editing this one.