Next: A new register capture or public engineering amendment, resolution of the Whitedog breaker-designation question, or evidence of completed reinforcement and approved operation can change this reading. JBL timing and…
JBL’s reviewed assessment imposes a conditional 40 MW limit until area reinforcement. The register still measures applications, not delivered power.
The answer
October register reading: the current list contains 2,085 records, with 11 additions and no removals from the held September list. JBL now proposes Q1 2030, and Darlington now names Holt SS and has moved from Complete to Active. The issuer labels the list updated October 7. The existing large-load rule was recomputed: membership remains 75, with no entries or exits. These updates close the date and station-name mismatches with the held reports; engineering conditions and delivered-power limits remain.
Previous September list and engineering reading (preserved): Between the IESO’s August 14 and September 10, 2026 list vintages, the whole register grows from 2,062 to 2,074 records: 12 added and none removed. Under the same large-load rule — load-class applications stating at least 75 MW, excluding sizes stated only in MVA — membership rises from 71 to 75, with four entries and no exits. All four are new register IDs; no existing record enters through a size or type edit. Across the whole register, three applications move from Active to Complete, one from Complete to Withdrawn, and eleven from Part 1 SIA Comp to Complete. The eleven Part 1 SIA Comp to Complete changes are reported separately; the register does not state whether they reflect further assessment work or relabelling. Only one of these 15 status transitions is in the current large-load group: an Active-to-Complete move. Among the 75 qualifying applications, 20 have a hyperlink in the register’s ReportLinks field and 55 do not; link presence does not establish a reviewed engineering assessment. The issuer dates the list September 10; Countability captured it on September 29.
Engineering review, September 30: JBL’s public assessment sets a conditional 40 MW limit until area reinforcement, with load split equally across two buses and the tie normally open; further approval is required above that limit. Its described ultimate load is 79 MW and its studied closed-tie case is 80 MW. The Darlington station scope disagrees with the register, Whitedog work has separate proposed phases, and K1/K2 concerns line refurbishment rather than quantified new power. Pointe Aux Roches’ withdrawn proposal remains available as a historical report. The corrected full-register inventory has four added report URLs, not three, and one removed. Complete remains an application status, not a measurement of energized capacity or power delivered.
Whitedog Falls phasing: the August 26 report proposes switch work in Q4 2027 and the remaining equipment work by October 2028, with G3 possibly as early as July 2028. The register’s Q4 2027 date does not describe completion of every phase. Separate uprate and relocation references are not newly qualified capacity. See the public report, printed pages 3–4 (PDF pages 4–5), and the assessment record below.
Previous register reading, July 10 to August 14 (preserved): Between the IESO's July 10 and August 14, 2026 list vintages, the whole register grows from 2,044 to 2,062 records: 18 added and none removed. Under the same large-load rule -- load-class applications stating at least 75 MW, excluding sizes stated only in MVA -- membership rises from 67 to 71, with four entries and no exits. Across the whole register, 24 status strings change: 6 move to Withdrawn (four from Active and two from On-Hold), 4 move from Active to Complete, and 3 move from Complete back to Active. One of the 24 changes merely corrects 'Actice' to 'Active'. These are register states, not proof that six projects were cancelled or four projects now supply power. The issuer dates the newer list August 14; Countability captured it on September 2.
First reading, register dated July 10, 2026 (preserved for comparison): Ontario's public connection register carries 67 large load applications -- each stating 75 megawatts or more -- at its 2026-07-10 vintage, spanning completed, active, on-hold, and withdrawn states. For the flagship projects, the engineering layer beneath the register states exact assessed quantities: 150 MW for the station supplying the Windsor battery plant, 331.2 MW for the new station supplying the St. Thomas plant, a staged rise -- 140, then 250, then 300 MW -- for Algoma Steel's electric-arc furnaces, and 80 MW for a Toronto data centre. But the register itself cannot be added up, for reasons its own fields prove: its size column has no stated definition and mixes increments with totals -- the St. Thomas project reads 420 MW in the register and 331.2 MW in its own final assessment, with no issuer reconciliation; the 67 applications mix 35 completed, 22 active, 5 on hold, and 5 withdrawn, eight of them already in service; applicant names are not normalized, so even counting who is asking requires judgment the register does not supply; and 47 of the 67 carry no posted assessment to check any figure against, including all four active applications above 400 MW. What the process does publish, it reconciles itself: on the Leamington-area circuits it re-measured its own aggregate vintage over vintage -- 608 MW of load interruptible under the studied contingency, instead of 567 -- and published its own conclusion against its own criteria both times. What it withholds is just as specific: no located document states any plant's own operating demand, only its station's assessed maximum, and no located document splits a shared station capacity between the users it names. The register also moves quietly, and one of its moves is now visible. A public web archive preserved the same feed as the issuer served it on 1 June 2026: there, the 431 MW application for the Honda Alliston project -- filed by Hydro One Networks Inc., not by Honda -- is recorded Active, and a second, separate Alliston application of 24 MW is recorded Complete with its assessment posted. In the vintage the issuer dates 10 July 2026 both are recorded Withdrawn, and both still read Committed 'Yes' -- which the issuer's own connection FAQ says is removed when an application is withdrawn. Only four of the register's 2,044 rows carry that combination, and two of them are these. No public document located states why either application was withdrawn.
Copyright © 2004-2022 Independent Electricity System Operator, all rights reserved. This information is subject to the Terms of Use set out in the IESO’s website (www.ieso.ca)
What this means for the decision
Treat any single number offered as the total of Ontario's connection queue as unsound -- the register's own fields cannot support one. For any specific project, read its posted connection assessment rather than its register row; where the two differ, the difference is real and unreconciled. Read station quantities as connection maxima, not as the plant's demand. And date every claim to a register vintage: the register is overwritten in place, states change without notice, and the month-over-month record starts with this Brief's capture cadence.
The key uncertainty
Register sizes cannot be totalled into delivered capacity. The October 7 list closes the JBL initial-service date and Darlington station-name mismatches with the held reports: JBL now proposes Q1 2030 and Darlington names Holt SS; its current entry carries no Clarington or voltage attribute. This does not establish commissioning, actual load, completion of required reinforcement or a new engineering approval. JBL’s conditional limit and bus/tie conditions and Whitedog’s breaker-designation question remain. The September register’s 20 linked and 55 unlinked large-load applications are a historical hyperlink-presence census. Earlier assessment findings retain their own dates; an accessible report for a withdrawn application does not establish current validity.
What would settle it
A new register capture or public engineering amendment, resolution of the Whitedog breaker-designation question, or evidence of completed reinforcement and approved operation can change this reading. JBL timing and Darlington station-name discrepancies are closed by the October 7 list; original report dates remain distinct from later review and capture dates.
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.
October register update
The newly captured IESO register contains 2,085 application records, compared with 2,074 in the held September list: 11 added and 0 removed. 39 shared records have changed fields.
The JBL entry now proposes Q1 2030, matching the initial 27 MW timing in its held assessment. The Darlington entry now names Holt SS, matching the station in the held report, and its status has moved from Complete to Active. These changes close the previously displayed date and station-name mismatches; they do not establish commissioned power, reactor operation, or a new engineering approval.
The existing load-class rule with a stated size of at least 75 MW identifies 75 records, versus 75 previously: 0 enter and 0 leave. This is membership in the application register, not delivered capacity.
The five held engineering reports retain the same contents on recheck. JBL’s conditional 40 MW limit, separate 79 MW description and 80 MW study, bus and tie conditions, and requirement for further approval remain. The Whitedog breaker-designation question remains unresolved. “Complete” is an application status, not proof of energization. The issuer reply to the earlier inquiry was not checked for this reading. Prior list and report readings remain dated below.
IESO public connection register; issuer list updated 2026-10-07; captured 2026-10-10 UTC (October 9 Toronto). Capture is not an inferred issuer publication date.
Evidence reviewed through 2026-10-09 · 7 cited sources · 2 member Resolutions · 8 chapters
Resolution lineages behind this Brief: What Ontario's connection assessments actually establish: the assessed station quantities behind the province's largest… → · Ontario's public connection register: what the IESO's Application Status list states about large proposed loads,… →
Each attended register capture supports a dated status reading. The current issuer list and capture dates appear in the dated October register reading below. Earlier register and engineering readings retain their own dates.
Chapter 1§
What the newly reviewed engineering reports establish
Public assessment findings reviewed after the September register capture. Every quantity below keeps its own project, publication date and operating conditions. Whitedog equipment work has separate proposed phases; it does not establish additional generation capacity.
| Period | Value | Role | Assurance | Basis |
|---|---|---|---|---|
| JBL: described ultimate load | 79.0 MW | institutional estimate | — | Read conditions and sourcePrinted p.4 / PDF p.5: described ultimate load of 79 MW, distinct from the 80 MW studied configuration. Not energized demand and not a basis for subtracting the conditional limit to infer stranded capacity. JBL CTS#2 — Final Report - Public (CAA 2025-843) · 2026-08-25 |
| JBL: proposed minimum initial load | 27.0 MW | institutional estimate | — | Read conditions and sourcePrinted p.4 / PDF p.5: proposed minimum initial load in Q1 2030. The September register instead gives Q1 2028; the records disagree and do not establish a verified two-year delay. JBL CTS#2 — Final Report - Public (CAA 2025-843) · 2026-08-25 |
| JBL: studied closed-bus-tie load | 80.0 MW | institutional estimate | — | Read conditions and sourcePrinted pp.4–5 / PDF pp.5–6: studied load with the low-voltage bus tie closed; ultimate operation requires area reinforcement and an amended SIA. Distinct from the described 79 MW project load. JBL CTS#2 — Final Report - Public (CAA 2025-843) · 2026-08-25 |
| JBL: conditional interim load limit | 40.0 MW | institutional estimate | — | Read conditions and sourcePrinted p.5 / PDF p.6: until area reinforcement, limit load to 40 MW equally distributed between the two 13.8 kV buses, with the bus tie normally open. Further IESO approval is required above 40 MW. Connection also depends on the new Welland–Thorold 230 kV line and new Crowland TS connections to Q24HM/Q29HM; their completion is not established here. This is an operating condition, not measured energized load. JBL CTS#2 — Final Report - Public (CAA 2025-843) · 2026-08-25 |
| JBL: studied Queenston Flow West interface transfer-capability reduction | 15.4 percent | institutional estimate | — | Read conditions and sourcePrinted p.4 / PDF p.5: at 80 MW with the LV bus tie normally closed, high Queenston Flow West (QFW) transfers and all elements initially in service, loss of Q29S and Q25BM or loss of Q24S and Q23BM causes the respective Q24S or Q29S circuit to exceed its short-term emergency rating. Eliminating this requires a 15.4% reduction in QFW interface flow compared with the pre-project interface limit, exceeding the 5% maximum interface transfer-capability reduction in ORTAC Section 4.1. This is not a percentage reduction of plant load or an observed outage. JBL CTS#2 — Final Report - Public (CAA 2025-843) · 2026-08-25 |
| JBL: maximum interface transfer-capability reduction under ORTAC | 5.0 percent | institutional estimate | — | Read conditions and sourcePrinted p.4 / PDF p.5: ORTAC Section 4.1 permits a maximum 5% reduction in interface power-transfer capability. The specified JBL closed-tie study requires 15.4% relative to the pre-project QFW limit. Neither percentage measures plant-load reduction or a forecast probability. JBL CTS#2 — Final Report - Public (CAA 2025-843) · 2026-08-25 |
| JBL: applicant-wide under-frequency load-shedding requirement | 35.0 percent | institutional estimate | — | Read conditions and sourcePrinted p.8 / PDF p.9: select 35% of peak load across all applicant-owned facilities for under-frequency load shedding. The population is applicant-wide, not this project alone. JBL CTS#2 — Final Report - Public (CAA 2025-843) · 2026-08-25 |
| Darlington: assessed Holt switching-station voltage | 500.0 kV | institutional estimate | — | Read conditions and sourcePrinted p.5 / PDF p.6: new Holt SS on X520B/X521B 600 m from Bowmanville SS, proposed November 30, 2027. The register names Clarington TS at 230 kV. Matched only by CAA 2022-738; this unresolved scope disagreement is retained. The SMR generating unit is separately assessed under CAA 2022-727, not reviewed here. No generation MW or reactor commissioning date is established. Connect Darlington SMR GS to Holt SS — Final Report - Public (CAA 2022-738) · 2026-08-26 |
| K2: approximate line length proposed for refurbishment | 13.7 km | institutional estimate | — | Read conditions and sourcePrinted p.3 / PDF p.4: refurbish approximately 13.7 km of 115 kV K2 radial from Kirkland Lake TS; proposed Q4 2027. Newly added application is already Complete in the newer register, not an observed Active-to-Complete transition. No additional transfer capacity or energized MW is quantified. K1 & K2 Refurbishment — Final Report - Public (CAA 2026-EX1325) · 2026-08-27 |
| K1: approximate idle line length proposed for removal | 1.4 km | institutional estimate | — | Read conditions and sourcePrinted p.3 / PDF p.4: decommission approximately 1.4 km of idle K1 as part of the K1/K2 project. Line length is not power capacity. K1 & K2 Refurbishment — Final Report - Public (CAA 2026-EX1325) · 2026-08-27 |
| Pointe Aux Roches: existing wind-facility rating in the historical assessment | 48.6 MW | institutional estimate | — | Read conditions and sourcePrinted p.3 / PDF p.4: existing 48.6 MW facility; the proposal changes reactive-power controls, not capacity. The September register changes the application to Withdrawn and removes the report link. The PDF was still accessible September 30; availability does not establish current validity or that the existing wind farm was cancelled. Pointe Aux Roches: Reactive Power Control — Final Report - Public (CAA 2024-EX1284) · 2026-02-04 |
| Pointe Aux Roches: historical dispatch condition | 4.9 MW | institutional estimate | — | Read conditions and sourcePrinted p.3 / PDF p.4: the assessed proposal requires no dispatch below 4.9 MW. The related application is now Withdrawn; this historical condition is not presented as a currently valid operating instruction. Pointe Aux Roches: Reactive Power Control — Final Report - Public (CAA 2024-EX1284) · 2026-02-04 |
The infrastructure JBL would connect to
JBL’s assessment proposes a connection through the new Welland–Thorold line. The documents below establish permission to build and a tentative schedule for that dependency. They do not establish energization or power delivered to the plant.
· permission
Leave to construct
The OEB granted Hydro One leave to construct the Welland–Thorold project, subject to conditions. The order requires a separate written confirmation when construction is complete.
Ontario Energy Board, Welland–Thorold Decision and Order, EB-2025-0290 · 2026-07-09 (printed p1 / PDF p3; Schedule B / PDF p36; regulatory decision).
· acknowledgment
The land-rights process continues
The OEB acknowledged Hydro One’s August 28 expropriation application and said it was under preliminary review. Acknowledgment does not grant the requested rights.
Ontario Energy Board, Acknowledgment of Welland–Thorold expropriation application, EB-2025-0290 · 2026-09-08 (p1; regulatory acknowledgment).
· draft forecast
A planned Q3 2029 date
The IESO scoping report gives a planned Q3 2029 date for Crowland and its new line. It also identifies separate Queenston Flow West interface constraints for further regional and bulk planning. The engagement page labels this report a draft and lists it under September 15; the PDF is dated September 16.
IESO, Niagara Region Scoping Assessment Outcome Report · 2026-09-16 (printed p6 / PDF p7; printed pp8–9 / PDF pp9–10; draft on engagement page); IESO, Regional Electricity Planning — Niagara engagement · observed 2026-10-05 (2026 Schedule of Activities; current engagement page observed).
The line’s planned service date does not reconcile JBL’s Q1 2028 register date with its proposed Q1 2030 assessment date, or the 79 MW described load with the 80 MW studied case. Nor does the assessment say that commissioning this line alone removes the conditional 40 MW limit: area reinforcement, an amended assessment and further IESO approval are still required. These records do not establish a delay, completed reinforcement or actual plant demand.
IESO, JBL CTS#2, CAA2025-843, final public System Impact Assessment · 2026-08-25 (printed pp4–5 / PDF pp5–6; final assessment); IESO, IESO connection application register, JBL CTS #2 · observed 2026-10-05 (CAA2025-843, CaaId2880; current register body, captured October 5; same as September 10 list vintage).
Evidence checked 2026-10-05. Source dates describe their own documents; forecasts remain forecasts.
The evidence behind this chapter: What Ontario's connection assessments actually establish: the assessed station quantities behind the province's largest… →
Chapter 2§
What changed in the September register
The August-to-September register comparison. Status changes are grouped by their exact strings; the register does not establish whether these reflect further assessment work or relabelling. They do not measure power delivered.
| Period | Value | Role | Assurance | Basis |
|---|---|---|---|---|
| September 10, 2026 register list - records | 2,074.0 records | institutional estimate | — | Census/delta of the preserved September 10 and August 14 list bytes. Large-load membership requires load-class type and stated size at least 75 MW, excluding… |
| September 10, 2026 register list - population | 75.0 applications | institutional estimate | — | Census/delta of the preserved September 10 and August 14 list bytes. Large-load membership requires load-class type and stated size at least 75 MW, excluding… |
| September 10, 2026 register list - withdrawals | 1.0 status transitions | institutional estimate | — | Census/delta of the preserved September 10 and August 14 list bytes. Large-load membership requires load-class type and stated size at least 75 MW, excluding… |
| September 10, 2026 register list - completions | 3.0 status transitions | institutional estimate | — | Census/delta of the preserved September 10 and August 14 list bytes. Large-load membership requires load-class type and stated size at least 75 MW, excluding… |
| September 10, 2026 register list — Part 1 SIA Comp to Complete status changes | 11.0 status transitions | institutional estimate | — | Census/delta of the preserved September 10 and August 14 list bytes. Large-load membership requires load-class type and stated size at least 75 MW, excluding… |
| September 10, 2026 register list - posted | 20.0 applications | institutional estimate | — | Census/delta of the preserved September 10 and August 14 list bytes. Large-load membership requires load-class type and stated size at least 75 MW, excluding… |
| September 10, 2026 register list - unposted | 55.0 applications | institutional estimate | — | Census/delta of the preserved September 10 and August 14 list bytes. Large-load membership requires load-class type and stated size at least 75 MW, excluding… |
| Corrected September comparison: added report URLs across all register rows | 4.0 report URLs | institutional estimate | — | Correction identified September 30: full ReportLinks URL sets across both preserved captures yield four added URLs and one removed. The previous three counted… |
The evidence behind this chapter: Ontario's public connection register: what the IESO's Application Status list states about large proposed loads,… →
Chapter 3§
Previous reading — July to August register changes
Historical July-to-August register comparison, retained separately from the latest September list.
| Period | Value | Role | Assurance | Basis |
|---|---|---|---|---|
| August 14, 2026 list vintage — records | 2,062.0 records | institutional estimate | — | Census of preserved feed; large-load membership, where applicable, requires load-class type and stated size at least 75 MW, excluding MVA-only records. |
| August 14, 2026 list vintage — population | 71.0 applications | institutional estimate | — | Census of preserved feed; large-load membership, where applicable, requires load-class type and stated size at least 75 MW, excluding MVA-only records. |
| Whole-register July 10 to August 14 change — withdrawals | 6.0 status transitions | institutional estimate | — | Count of the stated status transition between two preserved register feeds; whole-register scope, not the large-load subset. |
| Whole-register July 10 to August 14 change — completions | 4.0 status transitions | institutional estimate | — | Count of the stated status transition between two preserved register feeds; whole-register scope, not the large-load subset. |
| Whole-register July 10 to August 14 change — reversals | 3.0 status transitions | institutional estimate | — | Count of the stated status transition between two preserved register feeds; whole-register scope, not the large-load subset. |
The evidence behind this chapter: Ontario's public connection register: what the IESO's Application Status list states about large proposed loads,… →
Chapter 4§
First reading — What the engineering record proves
Historical evidence at the first-reading register and assessment cutoff. The assessed quantities behind Ontario's flagship new loads -- the figures the connection process, not the press release, states -- each quoted from its archived final assessment.
| Period | Value | Role | Assurance | Basis |
|---|---|---|---|---|
| Final connection assessment of 2023-07-10 — the assessed station maximum for the Windsor battery-plant station (CAA 2022-726) | 150.0 MW | institutional estimate | — | The final System Impact Assessment's own figure ('150 MW in Windsor area (the “project”)'). A station maximum assessed for connection, not the plant's own… |
| Final connection assessment of 2025-09-19 — the assessed station maximum load for Centennial TS (CAA 2023-766) | 331.2 MW | institutional estimate | — | The final System Impact Assessment's own figure for the new station ('331.2 MW (the “project”)'), phased in two equal stages. A station maximum assessed for… |
| Final connection assessment of 2023-04-21 — Algoma Steel EAF Stage 1 (CAA 2021-694/695) | 140.0 MW | institutional estimate | — | The assessment's own Stage 1 figure: 140 MW of new load at the EAF customer transformer station. One stage of one facility; never summable with the later… |
| Final connection assessment of 2024-06-12 — Algoma Steel EAF Stage 2B (CAA 2023-768) | 250.0 MW | institutional estimate | — | The assessment's own Stage 2B figure ('250 MW at their 115 kV EAF Customer Transformer Station'): the facility's successive assessed level, containing Stage 1,… |
| Final connection assessment of 2025-06-12 — Algoma Steel EAF Stage 3, the facility's full assessed level (CAA 2024-787) | 300.0 MW | institutional estimate | — | The assessment's own Stage 3 figure ('300 MW at their 115 kV EAF Customer Transformer Station', December 2029). The register's three Size increments — 140,… |
| Final connection assessment of 2024-10-16 — the Toronto data centre's ultimate load (CAA 2024-795) | 80.0 MW | institutional estimate | — | The assessment's own figure ('80 MW with a power factor' as stated), phased 20/20/40 to the ultimate load. |
| Final connection assessment of 2021-06-10 — the existing Dofasco station's assessed one-time increase (CAA 2021-693) | 214.0 MW | institutional estimate | — | The assessment's own figure ('214 MW at its existing Dofasco' station): a 14 MW increase of the existing 200 MW connection. The separate 280 MW decarbonization… |
The evidence behind this chapter: What Ontario's connection assessments actually establish: the assessed station quantities behind the province's largest… →
Chapter 5§
First reading — The register the claims sit in
Historical evidence at the first-reading register and assessment cutoff. The public connection register counted from its own fields, under a stated rule -- who is in the large-load population, in what status, and how the register keeps its books.
| Period | Value | Role | Assurance | Basis |
|---|---|---|---|---|
| Register list vintage 2026-07-10 — every record in the feed | 2,044.0 records | institutional estimate | — | Derived from the archived feed bytes by Countability's committed register census, under the stated population rule; the Brief's release battery re-derives this… |
| Register list vintage 2026-07-10 — load-class applications with a stated Size of at least 75 MW | 67.0 applications | institutional estimate | — | Derived from the archived feed bytes by Countability's committed register census, under the stated population rule; the Brief's release battery re-derives this… |
| Register list vintage 2026-07-10 — population members whose assessment status reads Complete | 35.0 applications | institutional estimate | — | Derived from the archived feed bytes by Countability's committed register census, under the stated population rule; the Brief's release battery re-derives this… |
| Register list vintage 2026-07-10 — population members whose assessment status reads Active | 22.0 applications | institutional estimate | — | Derived from the archived feed bytes by Countability's committed register census, under the stated population rule; the Brief's release battery re-derives this… |
| Register list vintage 2026-07-10 — population members whose assessment status reads On-Hold | 5.0 applications | institutional estimate | — | Derived from the archived feed bytes by Countability's committed register census, under the stated population rule; the Brief's release battery re-derives this… |
| Register list vintage 2026-07-10 — population members whose assessment status reads Withdrawn | 5.0 applications | institutional estimate | — | Derived from the archived feed bytes by Countability's committed register census, under the stated population rule; the Brief's release battery re-derives this… |
| Register list vintage 2026-07-10 — population members whose proposed in-service field already reads In-Service | 8.0 applications | institutional estimate | — | Derived from the archived feed bytes by Countability's committed register census, under the stated population rule; the Brief's release battery re-derives this… |
| Register list vintage 2026-07-10 — load-class records excluded from the population because their Size is stated only in megavolt-amperes (at or above 75 MVA) | 15.0 applications | institutional estimate | — | Derived from the archived feed bytes by Countability's committed register census, under the stated population rule; the Brief's release battery re-derives this… |
| Register list vintage 2026-07-10 — distinct Applicant field spellings across the full register | 432.0 distinct applicant strings | institutional estimate | — | Derived from the archived feed bytes by Countability's committed register census, under the stated population rule; the Brief's release battery re-derives this… |
| Register list vintage 2026-07-10 — groups of applicant spellings that collapse together under a stated normalization | 25.0 spelling groups | institutional estimate | — | Derived from the archived feed bytes by Countability's committed register census, under the stated population rule; the Brief's release battery re-derives this… |
The evidence behind this chapter: Ontario's public connection register: what the IESO's Application Status list states about large proposed loads,… →
Chapter 6§
First reading — Why the register cannot be totalled
Historical evidence at the first-reading register and assessment cutoff. The register's own fields, against the engineering record beneath them: an undefined size column that mixes increments with totals, one project carrying two unreconciled figures, and stages that nest rather than add.
| Period | Value | Role | Assurance | Basis |
|---|---|---|---|---|
| Register list vintage 2026-07-10 — the Centennial TS register row's stated Size (CAA 2023-766) | 420.0 MW | institutional estimate | — | Size field of CAA 2023-766 ('Centennial TS: New Station', applicant Hydro One Networks Inc., status Complete). The same project's final connection assessment… |
| Register list vintage 2026-07-10 — the Dofasco decarbonization application's stated Size (CAA 2021-712), On-Hold, no posted assessment | 280.0 MW | institutional estimate | — | Size field of CAA 2021-712 ('Dofasco Bayfront CTS - Decarb Project', applicant ArcelorMittal Dofasco G.P., status On-Hold, no posted report link).… |
| Comparison | Movement | Convention |
|---|---|---|
| One project, two issuer surfaces: the Centennial TS register row against its own final connection assessment | not comparable — The register's Size basis is unstated: holding 420 against the assessed 331.2 as a numeric difference would assert a shared basis no issuer document establishes. The unreconciled divergence between… | Same issuer, same project, two published figures: the register row states 420 MW with no definition of Size; the final assessment states an assessed station maximum of 331.2 MW, phased 165.6 plus 165.6. The gap is 88.8… |
Chapter 7§
First reading — What the process publishes -- and what it withholds
Historical evidence at the first-reading register and assessment cutoff. The connection process performs and publishes its own reconciliations, vintage over vintage — and the same process withholds the two quantities a reader most wants: any plant's own demand, and any split of a shared capacity between named users. One lineage shows both halves at once, across three dated assessments: a published limit whose obligation changed, and the forecast behind it kept confidential.
| Period | Value | Role | Assurance | Basis |
|---|---|---|---|---|
| Register list vintage 2026-07-10 — population members carrying at least one posted assessment-report link | 20.0 applications | institutional estimate | — | Derived from the archived feed bytes by Countability's committed register census, under the stated population rule; the Brief's release battery re-derives this… |
| Register list vintage 2026-07-10 — population members carrying no posted assessment report | 47.0 applications | institutional estimate | — | Derived from the archived feed bytes by Countability's committed register census, under the stated population rule; the Brief's release battery re-derives this… |
| Register list vintage 2026-07-10 — the largest Active application (CAA 2025-833), no posted assessment | 707.0 MW | institutional estimate | — | Derived from the archived feed bytes by Countability's committed register census, under the stated population rule; the Brief's release battery re-derives this… |
| Register list vintage 2026-07-10 — the second-largest Active application (CAA 2025-848), no posted assessment | 695.0 MW | institutional estimate | — | Derived from the archived feed bytes by Countability's committed register census, under the stated population rule; the Brief's release battery re-derives this… |
| Register list vintage 2026-07-10 — the third-largest Active application (CAA 2025-863), no posted assessment | 550.0 MW | institutional estimate | — | Derived from the archived feed bytes by Countability's committed register census, under the stated population rule; the Brief's release battery re-derives this… |
| Register list vintage 2026-07-10 — the fourth-largest Active application (CAA 2024-810), no posted assessment | 453.0 MW | institutional estimate | — | Derived from the archived feed bytes by Countability's committed register census, under the stated population rule; the Brief's release battery re-derives this… |
| Final connection assessment of 2019-09-12 — the stated load-security criterion for the Leamington-area circuit pair (CAA 2018-633) | 600.0 MW | institutional estimate | — | The 2019 assessment's stated criterion: up to '600 MW of load' is allowed to be interrupted by configuration with two transmission elements out of service,… |
| Final connection assessment of 2019-09-12 — load along the corridor interruptible by configuration at the 2019 vintage (CAA 2018-633) | 567.0 MW | institutional estimate | — | The 2019 assessment's own aggregate ('567 MW of load along' the corridor, interruptible by configuration under the studied contingency). The same report… |
| Addendum of 2020-11-17 — the restated interruptible-load aggregate at the 2020 vintage (CAA 2018-633 Addendum 1) | 608.0 MW | institutional estimate | — | The addendum's own restatement ('608 MW, instead of 567 MW') of the corridor's interruptible-load aggregate — above the stated 600 MW criterion level; the… |
| Final connection assessment of 2024-06-12 — the regional interface transfer limit stated in the Stage 2B assessment | 700.0 MW | institutional estimate | — | The assessment's own statement of the interface limit: '700 MW under all elements in-service' conditions. A published shared bound on the region's flows — the… |
| Central-West Bulk Plan of 2024-04-18 — firm load in the London area, as the issuer states it | 620.0 MW | institutional estimate | — | The bulk plan's own figure ('620 MW (690 MVA) within the London Area'). |
| Central-West Bulk Plan of 2024-04-18 — potential load beyond the firm load, as the issuer states it | 300.0 MW | institutional estimate | — | The bulk plan's own figure ('300 MW of Potential Load' beyond the firm load). |
| Central-West Bulk Plan of 2024-04-18 — the issuer's own stated total of firm plus potential load ('900 MW in total') | 900.0 MW | institutional estimate | — | The issuer's own reconciliation, in one sentence: firm load plus potential load, '(i.e., 900 MW in total)', held against the area's supply capability. The sum… |
| Needs Assessment of 2020-07-17 — Port Arthur TS #1 station capacity after the low-voltage yard refurbishment, two named supplied parties, no published split | 59.0 MW | institutional estimate | — | The transmitter's own figure (the station 'capacity will revert back to 59MW' once the refurbishment completes) for a station supplying two named parties —… |
| Burlington to Nanticoke IRRP of 2024-12-18 — data-centre connection interest in the Caledonia-Norfolk subregion that the IRRP states its own forecast does not capture | — | institutional estimate | — | The IRRP's own stated range ('1,700 MW of data centre connections' at the top; the report states 700 to 1,700 MW of interest in the subregion), with the… |
| Final addendum of 2025-06-30 — the three-station total the applicant was required to stay below (CAA 2024-795) | 400.0 MW | institutional estimate | — | Energy+ MTS#1, Preston TS and Galt TS, combined: the addendum requires the applicant to build a new station 'in a timely manner so that the total load at… |
| Final Addendum 2 of 2026-02-04 — the same three-station total, now a real-time switching threshold (CAA 2024-795) | 400.0 MW | institutional estimate | — | Energy+ MTS#1, Preston TS and Galt TS, combined: the superseding addendum requires that a low-voltage tie breaker 'remains open when the forecasted total peak… |
| Final Addendum 2 of 2026-02-04 — the data centre's own ultimate load, restated unchanged (CAA 2024-795) | 80.0 MW | institutional estimate | — | The data centre's own load, restated by the newest assessment: 'The project will have an ultimate load of 80 MW with a power factor of 0.95'. The three-station… |
| Comparison | Movement | Convention |
|---|---|---|
| One circuit pair, two assessment vintages: the 2019 interruptible-load finding against the 2020 restatement | +41.0 MW | Same issuer, same instrument lineage, same circuit pair, two vintages: 567 MW of load interruptible by configuration (2019 final report — which itself concluded the load-restoration criteria were violated), then 608 MW… |
| One three-station limit, two assessment vintages: a build obligation replaced by a switching instruction | not comparable — The two figures are identical and the obligations attached to them are not. A numeric difference of zero would state that nothing changed between the vintages; what changed is what the number… | Same issuer, same connection application, same three stations, same stated figure of 400 MW — and a changed obligation. In June 2025 the requirement was to build a new station in time so the three-station total would… |
How much electricity does any of Ontario's flagship new plants actually draw?
What is missing: No located public document states any plant's own operating demand. Ontario's connection record states what a station is assessed to supply -- 150 MW at the Windsor battery-plant station, 331.2 MW at the new St. Thomas station -- and no located document states that a plant is its station's only load, or what share of the station's assessed maximum the plant itself uses. The one public document that does state a St. Thomas plant utility quantity is the city's wastewater master plan, and that figure is the municipal planner's own assumption, not the company's statement.
Consequence: Public discussion routinely reads station connection quantities as plant demand. The two are different quantities, and the gap between them is not publicly measurable for any of the register's flagship projects. Any claim of the form 'plant X uses Y megawatts' sourced to a connection document is overstated by construction.
When two users share one published station capacity in Ontario, who holds how much of it?
What is missing: No located Ontario document publishes a per-user split of a shared station capacity. The clearest instance is on the record: Hydro One's Northwest Ontario Needs Assessment states Port Arthur TS #1's capacity (59 MW after refurbishment) and names the two parties it supplies -- Hydro One Distribution and Synergy North -- but its forecast table carries a single combined row, and neither party's share is published anywhere located.
Consequence: Where a shared capacity is approaching its bound, the public record can show that it binds but not whom it binds first. Allocation questions -- whose growth the constraint stops -- are unanswerable from the public record at station grain.
Why can none of Ontario's largest active connection applications be checked against an engineering document?
What is missing: Of the 67 large load applications in the register's population at the 2026-07-10 vintage, 47 carry no posted assessment report -- including all four active applications above 400 MW (707, 695, 550, and 453 MW as the register states them). Posting is a strong tendency, not a rule: some on-hold and withdrawn applications do carry posted reports, so no status explains the boundary. The issuer states unposted final reports are obtainable by email, by application ID.
Consequence: The register's largest live claims are exactly the ones whose stated sizes cannot be checked against any public engineering document. For the northern interface the record bounds at 700 MW, the assessment that would establish a second large claimant's share would be produced by the very process whose posting practice withholds it — and for a live application it may still be in progress. Either way, the join is not public.
What would Ring of Fire mining loads require of Ontario's northern grid?
What is missing: No public document states how much electricity Ring of Fire mining development would draw. A transmission line toward the area is now a designated provincial priority: on 2026-01-28 Hydro One announced that Ontario had designated it to build the Greenstone Transmission Line, a single-circuit 230 kV line from the existing East-West Tie near Nipigon Bay, through Longlac Transformer Station, to a new switching station at or near Aroland First Nation, expected in service in 2032 — in the announcement the province's energy minister described it as 'delivering the energy backbone and infrastructure to unlock the Ring of Fire's vast mineral potential'. That announcement states no megawatt figure for any Ring of Fire load, and neither does the transmitter's own current regional planning cycle: the Northwest Region Needs Assessment of 2025-09-03 and the Scoping Assessment of September 2025 do not name the Ring of Fire at all, while describing the region's demands — 'such as mining operation, data centers, forestry companies and large industrial manufacturers' — as 'distinctive, urgent and ever evolving'.
Consequence: A line is being built toward the deposit and the load it would serve has never been publicly quantified. Public discussion of Ring of Fire development therefore proceeds with a construction commitment and an in-service year but no published engineering statement of the requirement: no load figure, no delivery point for mine demand, no constraint assessment. Any megawatt figure attached to Ring of Fire mining load in commentary has no public engineering source. The gap is now sharper than an absence of interest — the interest is designated, funded and dated, and the quantity is still missing.
How much load is actually forecast at the Ontario stations whose shared limit now governs a connection?
What is missing: The load forecast that drives a published shared-capacity requirement is not published. In the connection assessment for a Cambridge-area data centre, the system operator states that the applicant's updated forecast for three named stations is projected to exceed a stated 400 MW during the study period, and imposes a real-time switching requirement on that basis — while placing the forecast itself in a confidential appendix ("Table 1 of Appendix A (Confidential) shows the updated load forecast"). The assessments behind the finding are in a second confidential appendix. The threshold and the remedy are public; the quantity that crosses the threshold, and the year it crosses, are not.
Consequence: A reader can see that a shared limit is being reached and what the operator will do about it, but cannot see by how much, how soon, or how much of the growth belongs to which load. The same document shows why the distinction matters: the three-station total is a different quantity from the data centre's own ultimate load, which is stated openly and unchanged. Where the forecast is withheld, no one outside the process can test how much headroom remains, or how quickly a build obligation turned into a switching instruction.
Chapter 8§
First reading — What changes -- and what Countability watches
Historical evidence at the first-reading register and assessment cutoff. The register moves quietly: two applications at one station went from live to withdrawn between vintages, both still flagged committed against the issuer's own stated rule, and no public document says why. A public web archive of the issuer's own feed is what makes the change visible at all -- and two statistical tables publish one series twice. The watch points, and the capture cadence that makes them checkable, are named here.
| Period | Value | Role | Assurance | Basis |
|---|---|---|---|---|
| Register list vintage 2026-07-10 — the withdrawn Honda Alliston connection application (CAA 2024-802), applicant of record Hydro One Networks Inc. | 431.0 MW | institutional estimate | — | The register row's own fields, quoted exactly: Applicant 'HYDRO ONE NETWORKS INC.'; Name 'Honda Alliston ‐ E8V E9V 230kV Connection'; Size '431 MW'; SiaStatus… |
| Table 25-10-0015-01, Ontario monthly generation — published reference months at the 2026-08-03 response | 221.0 reference months | institutional estimate | — | Count of vectorDataPoint entries in the archived Web Data Service response for vector v44174769 (2008-01 through 2026-05). |
| Table 25-10-0016-01, Ontario monthly generation — published reference months at the 2026-08-03 response | 221.0 reference months | institutional estimate | — | Count of vectorDataPoint entries in the archived Web Data Service response for vector v44159114 (2008-01 through 2026-05). |
| Register vintage of 2026-06-01 (web archive) — the Honda Alliston application, then recorded Active | 431.0 MW | institutional estimate | — | The same application, one vintage earlier: CAA 2024-802, applicant of record Hydro One Networks Inc., Size '431 MW', SiaStatus 'Active', Committed 'Yes',… |
| Register vintage of 2026-06-01 (web archive) — a second Alliston application, then recorded Complete | 24.0 MW | institutional estimate | — | CAA 2025-839, 'Alliston TS T2 - Load Increase', applicant of record Hydro One Networks Inc., Size '24 MW', SiaStatus 'Complete', Committed 'Yes', proposed in… |
| Register vintage of 2026-07-10 — the second Alliston application, now recorded Withdrawn, its assessment still posted | 24.0 MW | institutional estimate | — | CAA 2025-839 in the current vintage: SiaStatus 'Withdrawn', Committed still 'Yes', Size '24 MW'. Its posted assessment report remains linked on the withdrawn… |
| Comparison | Movement | Convention |
|---|---|---|
| Tables 25-10-0015-01 and 25-10-0016-01 — the two published monthly Ontario generation series, all shared reference months | +0.0 reference months | Pairwise equality across every shared reference month of the two archived responses: 223 of 223 months identical, zero differing values (re-derived by the Brief's test from the archived bytes). The two tables publish… |
| Two Alliston connection applications, one vintage apart: Active and Complete, then both Withdrawn | not comparable — Both sides state the same quantity. What changed is the application's recorded state, which is not a numeric difference; reporting a difference of zero would conceal the only thing that moved. | The same register, two vintages. In the web archive's capture of 2026-06-01 the 431 MW Honda Alliston application (CAA 2024-802) is recorded Active and the separate 24 MW Alliston TS application (CAA 2025-839) is… |
How much new electricity demand is formally waiting to connect to Canadian grids -- and how much of the projected data-centre and industrial load will actually materialize?
What is missing: No public, machine-readable, openly licensed national series exists for connection-queue or requested-load demand -- the megawatts of proposed data-centre and industrial projects that have formally asked to connect. Provincial system operators publish connection-process material at varying grain, but applicant-level queue detail is confidential under the operators' own processes, published site content does not carry terms extending to third-party analytical reuse, and no federal or Statistics Canada series aggregates requested connection capacity at any grain.
Consequence: The Electricity Delivery Brief reads the supply side of the official projections: the pace at which generation and capacity must grow under each scenario, and the pace the measured record shows. The demand side of the same story -- whether the data-centre and industrial load growth the scenarios' own definitions bracket is actually arriving in connection requests -- cannot be tracked from any public national series. The Brief therefore restates what the scenarios assume about demand and measures delivered supply; it does not and cannot publish an independent measure of queued demand.
Directly observed
Estimated, projected, or otherwise not yet an audited outcome
- JBL: described ultimate load
- JBL: proposed minimum initial load
- JBL: studied closed-bus-tie load
- JBL: conditional interim load limit
- JBL: studied Queenston Flow West interface transfer-capability reduction
- JBL: maximum interface transfer-capability reduction under ORTAC
- JBL: applicant-wide under-frequency load-shedding requirement
- Darlington: assessed Holt switching-station voltage
- K2: approximate line length proposed for refurbishment
- K1: approximate idle line length proposed for removal
- Pointe Aux Roches: existing wind-facility rating in the historical assessment
- Pointe Aux Roches: historical dispatch condition
- September 10, 2026 register list - records
- September 10, 2026 register list - population
- September 10, 2026 register list - withdrawals
- September 10, 2026 register list - completions
- September 10, 2026 register list — Part 1 SIA Comp to Complete status changes
- September 10, 2026 register list - posted
- September 10, 2026 register list - unposted
- Corrected September comparison: added report URLs across all register rows
- August 14, 2026 list vintage — records
- August 14, 2026 list vintage — population
- Whole-register July 10 to August 14 change — withdrawals
- Whole-register July 10 to August 14 change — completions
- Whole-register July 10 to August 14 change — reversals
- Final connection assessment of 2023-07-10 — the assessed station maximum for the Windsor battery-plant station (CAA 2022-726)
- Final connection assessment of 2025-09-19 — the assessed station maximum load for Centennial TS (CAA 2023-766)
- Final connection assessment of 2023-04-21 — Algoma Steel EAF Stage 1 (CAA 2021-694/695)
- Final connection assessment of 2024-06-12 — Algoma Steel EAF Stage 2B (CAA 2023-768)
- Final connection assessment of 2025-06-12 — Algoma Steel EAF Stage 3, the facility's full assessed level (CAA 2024-787)
- Final connection assessment of 2024-10-16 — the Toronto data centre's ultimate load (CAA 2024-795)
- Final connection assessment of 2021-06-10 — the existing Dofasco station's assessed one-time increase (CAA 2021-693)
- Register list vintage 2026-07-10 — every record in the feed
- Register list vintage 2026-07-10 — load-class applications with a stated Size of at least 75 MW
- Register list vintage 2026-07-10 — population members whose assessment status reads Complete
- Register list vintage 2026-07-10 — population members whose assessment status reads Active
- Register list vintage 2026-07-10 — population members whose assessment status reads On-Hold
- Register list vintage 2026-07-10 — population members whose assessment status reads Withdrawn
- Register list vintage 2026-07-10 — population members whose proposed in-service field already reads In-Service
- Register list vintage 2026-07-10 — load-class records excluded from the population because their Size is stated only in megavolt-amperes (at or above 75 MVA)
- Register list vintage 2026-07-10 — distinct Applicant field spellings across the full register
- Register list vintage 2026-07-10 — groups of applicant spellings that collapse together under a stated normalization
- Register list vintage 2026-07-10 — the Centennial TS register row's stated Size (CAA 2023-766)
- Register list vintage 2026-07-10 — the Dofasco decarbonization application's stated Size (CAA 2021-712), On-Hold, no posted assessment
- Register list vintage 2026-07-10 — population members carrying at least one posted assessment-report link
- Register list vintage 2026-07-10 — population members carrying no posted assessment report
- Register list vintage 2026-07-10 — the largest Active application (CAA 2025-833), no posted assessment
- Register list vintage 2026-07-10 — the second-largest Active application (CAA 2025-848), no posted assessment
- Register list vintage 2026-07-10 — the third-largest Active application (CAA 2025-863), no posted assessment
- Register list vintage 2026-07-10 — the fourth-largest Active application (CAA 2024-810), no posted assessment
- Final connection assessment of 2019-09-12 — the stated load-security criterion for the Leamington-area circuit pair (CAA 2018-633)
- Final connection assessment of 2019-09-12 — load along the corridor interruptible by configuration at the 2019 vintage (CAA 2018-633)
- Addendum of 2020-11-17 — the restated interruptible-load aggregate at the 2020 vintage (CAA 2018-633 Addendum 1)
- Final connection assessment of 2024-06-12 — the regional interface transfer limit stated in the Stage 2B assessment
- Central-West Bulk Plan of 2024-04-18 — firm load in the London area, as the issuer states it
- Central-West Bulk Plan of 2024-04-18 — potential load beyond the firm load, as the issuer states it
- Central-West Bulk Plan of 2024-04-18 — the issuer's own stated total of firm plus potential load ('900 MW in total')
- Needs Assessment of 2020-07-17 — Port Arthur TS #1 station capacity after the low-voltage yard refurbishment, two named supplied parties, no published split
- Burlington to Nanticoke IRRP of 2024-12-18 — data-centre connection interest in the Caledonia-Norfolk subregion that the IRRP states its own forecast does not capture
- Final addendum of 2025-06-30 — the three-station total the applicant was required to stay below (CAA 2024-795)
- Final Addendum 2 of 2026-02-04 — the same three-station total, now a real-time switching threshold (CAA 2024-795)
- Final Addendum 2 of 2026-02-04 — the data centre's own ultimate load, restated unchanged (CAA 2024-795)
- One circuit pair, two assessment vintages: the 2019 interruptible-load finding against the 2020 restatement
- Register list vintage 2026-07-10 — the withdrawn Honda Alliston connection application (CAA 2024-802), applicant of record Hydro One Networks Inc.
- Table 25-10-0015-01, Ontario monthly generation — published reference months at the 2026-08-03 response
- Table 25-10-0016-01, Ontario monthly generation — published reference months at the 2026-08-03 response
- Register vintage of 2026-06-01 (web archive) — the Honda Alliston application, then recorded Active
- Register vintage of 2026-06-01 (web archive) — a second Alliston application, then recorded Complete
- Register vintage of 2026-07-10 — the second Alliston application, now recorded Withdrawn, its assessment still posted
- Tables 25-10-0015-01 and 25-10-0016-01 — the two published monthly Ontario generation series, all shared reference months
Unresolved
- One project, two issuer surfaces: the Centennial TS register row against its own final connection assessment
- One three-station limit, two assessment vintages: a build obligation replaced by a switching instruction
- No located public document states any plant's own operating demand. Ontario's connection record states what a station is assessed to supply -- 150 MW at the Windsor battery-plant station, 331.2 MW at the new St. Thomas station -- and no located document states that a plant is its station's only load, or what share of the station's assessed maximum the plant itself uses. The one public document that does state a St. Thomas plant utility quantity is the city's wastewater master plan, and that figure is the municipal planner's own assumption, not the company's statement.
- No located Ontario document publishes a per-user split of a shared station capacity. The clearest instance is on the record: Hydro One's Northwest Ontario Needs Assessment states Port Arthur TS #1's capacity (59 MW after refurbishment) and names the two parties it supplies -- Hydro One Distribution and Synergy North -- but its forecast table carries a single combined row, and neither party's share is published anywhere located.
- Of the 67 large load applications in the register's population at the 2026-07-10 vintage, 47 carry no posted assessment report -- including all four active applications above 400 MW (707, 695, 550, and 453 MW as the register states them). Posting is a strong tendency, not a rule: some on-hold and withdrawn applications do carry posted reports, so no status explains the boundary. The issuer states unposted final reports are obtainable by email, by application ID.
- No public document states how much electricity Ring of Fire mining development would draw. A transmission line toward the area is now a designated provincial priority: on 2026-01-28 Hydro One announced that Ontario had designated it to build the Greenstone Transmission Line, a single-circuit 230 kV line from the existing East-West Tie near Nipigon Bay, through Longlac Transformer Station, to a new switching station at or near Aroland First Nation, expected in service in 2032 — in the announcement the province's energy minister described it as 'delivering the energy backbone and infrastructure to unlock the Ring of Fire's vast mineral potential'. That announcement states no megawatt figure for any Ring of Fire load, and neither does the transmitter's own current regional planning cycle: the Northwest Region Needs Assessment of 2025-09-03 and the Scoping Assessment of September 2025 do not name the Ring of Fire at all, while describing the region's demands — 'such as mining operation, data centers, forestry companies and large industrial manufacturers' — as 'distinctive, urgent and ever evolving'.
- The load forecast that drives a published shared-capacity requirement is not published. In the connection assessment for a Cambridge-area data centre, the system operator states that the applicant's updated forecast for three named stations is projected to exceed a stated 400 MW during the study period, and imposes a real-time switching requirement on that basis — while placing the forecast itself in a confidential appendix ("Table 1 of Appendix A (Confidential) shows the updated load forecast"). The assessments behind the finding are in a second confidential appendix. The threshold and the remedy are public; the quantity that crosses the threshold, and the year it crosses, are not.
- Two Alliston connection applications, one vintage apart: Active and Complete, then both Withdrawn
- No public, machine-readable, openly licensed national series exists for connection-queue or requested-load demand -- the megawatts of proposed data-centre and industrial projects that have formally asked to connect. Provincial system operators publish connection-process material at varying grain, but applicant-level queue detail is confidential under the operators' own processes, published site content does not carry terms extending to third-party analytical reuse, and no federal or Statistics Canada series aggregates requested connection capacity at any grain.
Key evidence
| Issuer | Publication | Published | Vintage | Source |
|---|---|---|---|---|
| Independent Electricity System Operator | System Impact Assessment, CAA ID 2022-726 (Windsor Stellantis TS — new DESN station; applicant of record Hydro One Netwo | 2023-07-10 | Final Report of 2023-07-10, captured 2026-08-03 | Source → |
| Independent Electricity System Operator | System Impact Assessment, CAA IDs 2021-694 and 2021-695 (Algoma Steel new load facility and generation reconnection — on | 2023-04-21 | Final Report of 2023-04-21, captured 2026-08-03 | Source → |
| Independent Electricity System Operator | System Impact Assessment, CAA ID 2023-768 (Algoma Steel EAF project, Stage 2B) — Final Report, Public | 2024-06-12 | Final Report of 2024-06-12, captured 2026-08-03 | Source → |
| Independent Electricity System Operator | System Impact Assessment, CAA ID 2024-787 (Algoma Steel EAF project, Stage 3) — Final Report, Public | 2025-06-12 | Final Report of 2025-06-12, captured 2026-08-03 | Source → |
| Independent Electricity System Operator | System Impact Assessment, CAA ID 2024-795 (GrandBridge Energy TOR1 data centre) — Final Report, Public | 2024-10-16 | Final Report of 2024-10-16, captured 2026-08-03 | Source → |
| Independent Electricity System Operator | System Impact Assessment, CAA ID 2021-693 (ArcelorMittal Dofasco Bayfront customer station — load increase) — Final Repo | 2021-06-10 | Final Report of 2021-06-10, captured 2026-08-03 | Source → |
| Independent Electricity System Operator | System Impact Assessment, CAA ID 2018-633 (Leamington TS DESN #2; applicant of record Hydro One Networks Inc.) — Final R | 2019-09-12 | Final Report of 2019-09-12, captured 2026-08-03 — superseded | Source → |
| Independent Electricity System Operator | System Impact Assessment, CAA ID 2018-633 — Addendum 1 (2020) | 2020-11-17 | Addendum of 2020-11-17, captured 2026-08-03 — the governing | Source → |
| Independent Electricity System Operator | Central-West Bulk Plan (2024-04-18) | 2024-04-18 | Report of 2024-04-18, captured 2026-08-03 | Source → |
| Hydro One Networks Inc. | Needs Assessment Report — Northwest Ontario (2020-07-17) | 2020-07-17 | Report of 2020-07-17, captured 2026-08-03 | Source → |
| Independent Electricity System Operator | Burlington to Nanticoke Integrated Regional Resource Plan (2024-12-18) | 2024-12-18 | Report of 2024-12-18, captured 2026-08-03 | Source → |
| Independent Electricity System Operator | System Impact Assessment, CAA ID 2024-795 — Final Addendum Report (No. 1, Public); GBE TOR1 Data Center, applicant Grand | 2025-06-30 | Final Addendum Report of 2025-06-30, captured 2026-08-04 | Source → |
| Independent Electricity System Operator | System Impact Assessment, CAA ID 2024-795 — Final Addendum 2 Report (Public); GBE TOR1 Data Center, applicant GrandBridg | 2026-02-04 | Final Addendum 2 Report of 2026-02-04, captured 2026-08-04 — | Source → |
| Independent Electricity System Operator | JBL CTS#2 — Final Report - Public (CAA 2025-843) | 2026-08-25 | 2026-08-25; public report reviewed September 30, 2026 | Source → |
| Independent Electricity System Operator | Connect Darlington SMR GS to Holt SS — Final Report - Public (CAA 2022-738) | 2026-08-26 | 2026-08-26; public report reviewed September 30, 2026 | Source → |
| Independent Electricity System Operator | Whitedog Falls GS: Electrical Infrastructure Replacement — Final Report - Public (CAA 2026-EX1319) | 2026-08-26 | 2026-08-26; public report reviewed September 30, 2026 | Source → |
| Independent Electricity System Operator | K1 & K2 Refurbishment — Final Report - Public (CAA 2026-EX1325) | 2026-08-27 | 2026-08-27; public report reviewed September 30, 2026 | Source → |
| Independent Electricity System Operator | Pointe Aux Roches: Reactive Power Control — Final Report - Public (CAA 2024-EX1284) | 2026-02-04 | 2026-02-04; public report reviewed September 30, 2026 | Source → |
| Independent Electricity System Operator | IESO Connection Assessment & Approval — Application Status list (the page's own backing feed, applicationstatus | 2026-07-10 | register list vintage 2026-07-10, captured 2026-08-03 | Source → |
| Independent Electricity System Operator | IESO Connection Assessment & Approval — Application Status page (the register's public face; the citation witne | 2026-07-10 | page statement 'Last Updated: July 10, 2026', capt | Source → |
| Statistics Canada | Electric power generation, monthly — table 25-10-0015-01, Ontario / total all classes of electricity producer / total al | 2026-08-03 | WDS response of 2026-08-03; latest reference month 2026-05 | Source → |
| Statistics Canada | Electric power generation, monthly, by producer and generation type — table 25-10-0016-01, Ontario totals (vector v44159 | 2026-08-03 | WDS response of 2026-08-03; latest reference month 2026-05 | Source → |
| Independent Electricity System Operator | System Impact Assessment, CAA ID 2023-766 (Centennial TS: New Station; applicant of record Hydro One Networks Inc.) — Fi | 2025-09-19 | Final Report of 2025-09-19, captured 2026-08-03 | Source → |
| Independent Electricity System Operator (register); Internet Archive (capture) | IESO Connection Assessment & Approval — Application Status backing feed, prior vintage recovered from the Internet A | 2026-06-01 | Internet Archive capture of the issuer's feed, timestam | Source → |
| Independent Electricity System Operator | IESO Connection Process — Frequently Asked Questions | 2026-08-04 | captured 2026-08-04 | Source → |
| Independent Electricity System Operator | IESO Application Status backing feed, list vintage 2026-08-14 | 2026-08-14 | register list vintage 2026-08-14, captured 2026-09-02 | Source → |
| Independent Electricity System Operator | IESO Connection Assessment & Approval — Application Status page (the register's public face; the citation witne | 2026-08-14 | page statement Last Updated August 14, 2026, captured Septem | Source → |
| Independent Electricity System Operator | IESO Application Status backing feed, list vintage 2026-09-10 | 2026-09-10 | Register list vintage September 10, 2026; captured September | Source → |
| Independent Electricity System Operator | IESO Connection Assessment & Approval — Application Status page (the register's public face; the citation witne | 2026-09-10 | Register list vintage September 10, 2026; captured September | Source → |
| Statistics Canada | Electric power generation, monthly — table 25-10-0015-01, Ontario / total all classes of electricity producer / total al | 2026-09-29 | July 2026 endpoint; released and captured September 29, 2026 | Source → |
| Statistics Canada | Electric power generation, monthly, by producer and generation type — table 25-10-0016-01, Ontario totals (vector v44159 | 2026-09-29 | July 2026 endpoint; released and captured September 29, 2026 | Source → |
Method and limitations
- Numerical evidence tables on this Brief resolve to pinned values inside its two member Resolutions. Dates, project descriptions and conditions also use the cited public reports and captured register fields: register counts are re-derived by a committed census script from the archived feed -- the counting rule (load-class application types, size stated in megawatts, at or above the issuer's own large-load threshold) is published with the counts, and records the rule excludes are counted and named, never silently dropped -- and every assessed quantity is the issuer's own stated figure, quoted from the archived assessment. Nothing here sums, allocates, or nets any capacity quantity: the only sums on the page are the issuer's own, quoted with attribution. Station quantities are never restated as plant demand. Where this Brief cites Ontario monthly generation context, it treats Statistics Canada's two monthly generation tables as one measurement, not two: the archived responses show they publish identical Ontario series at every shared reference month. The maintained record compares dated register captures; every engineering finding keeps its own report date. The September review preserves original PDFs in local custody and publishes bounded attributed findings, not source-document downloads.
- Every quantity here is a station, circuit, interface, or area figure from the connection and planning record. No document located states any plant's own operating demand, and no document states that a plant is its station's only load. Station quantities are never restated here as plant demand.
- The Algoma stages are successive assessed levels of one facility: 140, then 250, then 300 MW. They nest; summing the stages would triple-count one claim, and no such sum appears anywhere in this record.
- Applicants of record are frequently transmitters or distributors. The named plants (NextStar, the St. Thomas plant, the Alliston project) are the register rows' project names, not necessarily the applicants; nothing here attributes an application's conduct to the named project's proponent.
- Assessment reports are posted for a minority of large applications (20 of the 67-member register population at the 2026-07-10 vintage). What is assessed but unposted — including every Active application above 400 MW — cannot be checked from the public record; the issuer states unposted reports are obtainable by email by CAA ID.
- The issuer's published reconciliations (the Leamington vintages; the Central-West firm-plus-potential sentence) are quoted as the issuer's own arithmetic. Countability performs no allocation, no headroom subtraction, and no sum on these quantities.
- The 400 MW figure in the TOR1 lineage is a combined total for three named stations and all the load behind them, including but not limited to the data centre. It is not the data centre's own demand, which the same reports state separately and unchanged at 80 MW. The forecast that crosses the threshold is in a confidential appendix and is not published anywhere located.
- September 30 review adds four reports newly linked between the August 14 and September 10 register vintages, and one removed reference still accessible. These captures were obtained September 2 and September 29; this is not a fresh September 30 register census. Complete does not establish energization.
- Whitedog Falls, CAA 2026-EX1319, report August 26, printed pp.3–4 / PDF pp.4–5: replacement switches, breakers, protection and controls. Switch work is proposed for Q4 2027; the remaining work by October 2028, with G3 possibly as early as July 2028. The register gives Q4 2027, not completion of every phase. The separate uprate (2025-852) and equipment relocation (2024-798) are references, not newly qualified capacity. No additional MW is inferred; the repeated 52-G3 breaker designation is retained as a source ambiguity.
- JBL project description, printed p.4 / PDF p.5: one LV feeder from the new 13.8 kV switchgear is proposed to connect to the existing 13.8 kV feeder of JBL 115 kV CTS. The tie is described as normally open and interlocked with supply availability so that it closes only when one transmission supply is out of service. This described design is distinct from the specific interim load-limit requirements. The 79 MW described load and 80 MW study case remain distinct.
- Darlington applicant naming is retained as a source discrepancy: the cover says Hydro One Network Inc., the project description says Hydro One Inc., and the register says Hydro One Networks Inc. The CAA identifier establishes the join; these names and the differing station descriptions are not silently reconciled.
- The register's Size field has no issuer-stated definition; it records an application's own stated quantity, which is sometimes an increment and sometimes not. No sum of Size values is meaningful, and none is published here.
- The population rule (load-class, megawatt-stated, at least 75 MW) is Countability's stated counting rule over the issuer's own fields — the issuer publishes no such population. Changing the rule would change the counts; the rule is therefore stated with the counts, here and on the Brief, and the archived register makes every count checkable.
- One register vintage shows states, not transitions. What entered, left, or changed status becomes observable only when a later vintage is captured; the issuer overwrites the register in place and publishes no history.
- Applicants of record are frequently transmitters or distributors, not the businesses whose projects the register rows name. Nothing here attributes an application's quantity, or its withdrawal, to the named project's proponent.
- The 431 MW Honda Alliston row is reported exactly as the register states it, including the issuer's own unreconciled Withdrawn/Committed contradiction. Why it was withdrawn, and what it implies for the project, is not in the public record.
- A prior register vintage used here comes from the Internet Archive's capture of the issuer's own feed, not from a Countability capture. It is cited as what the issuer served on that date, with the archive named as the source of the copy.
- In the preserved July 10 list, both withdrawn Alliston rows read Committed 'Yes'. The issuer's own Connection Process FAQ states the 'Yes' is removed when a project is placed in service, and that the 'same will be done for projects that have been “withdrawn” by their connection applicants'. Four of the register's 2,044 rows carry Withdrawn together with Committed 'Yes'; two of those four are these Alliston applications.
- The September 10 register removes the Committed Yes flags and proposed dates on both withdrawn Alliston rows. This is a field update, not evidence of why either application was withdrawn. New posted engineering references remain unresolved in this register-only cycle; prior engineering conclusions remain dated to the documents actually assessed.
- September 30 correction and engineering follow-up: the whole-register comparison has four added report URLs, not the previously stated three, plus one removed URL. The earlier register-only qualification limitation remains a dated account of that reading. All four added reports and the removed reference have now been reviewed in the companion assessment Resolution; current validity and energization are not inferred.
This Brief and its cited evidence are free to read. A related commissioned Brief can address a different question, scope or agreed update schedule.
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