What Ontario's connection assessments actually establish: the assessed station quantities behind the province's largest new industrial loads, the capacities the planning record publishes, and the reconciliations the process itself performs
The engineering layer of Ontario's connection process: final System Impact Assessment reports for the province's flagship new loads (the Windsor battery plant connection, the St. Thomas plant's new station, the Algoma Steel electric-arc-furnace staging, a Toronto data centre, the existing Dofasco station), the planning record's published local capacities (a shared station capacity with two named claimants; a circuit pair assessed across two vintages), and the issuer's own published reconciliations of firm and potential load against total capability. Every quantity is the issuer's own stated figure, quoted from the archived document; nothing is summed, allocated, or inferred. September 30 review adds JBL conditional load and network requirements; Darlington station-scope disagreement; Whitedog equipment phasing; K1/K2 line work; and the withdrawn Pointe Aux Roches proposal, without inferring delivered power.
A Resolution record follows one institution's figures for a defined quantity. It may contain projections, estimates or measured observations. Each version held here keeps its publication date and source, so a newer figure does not erase the earlier one. What is a Resolution record? →
Maintained record. This page preserves successive versions of an official record. It makes no projection and awaits no forecast verdict. Revisions remain visible, and provisional figures retain that status.
The lineage
| Vintage | Issuer | Published | Position | Source |
|---|---|---|---|---|
| Final Report of 2023-07-10, captured 2026-08-03 | Independent Electricity System Operator | 2023-07-10 | current | Source → · accessed 2026-08-03 |
| Final Report of 2023-04-21, captured 2026-08-03 | Independent Electricity System Operator | 2023-04-21 | current | Source → · accessed 2026-08-03 |
| Final Report of 2024-06-12, captured 2026-08-03 | Independent Electricity System Operator | 2024-06-12 | current | Source → · accessed 2026-08-03 |
| Final Report of 2025-06-12, captured 2026-08-03 | Independent Electricity System Operator | 2025-06-12 | current | Source → · accessed 2026-08-03 |
| Final Report of 2024-10-16, captured 2026-08-03 | Independent Electricity System Operator | 2024-10-16 | current | Source → · accessed 2026-08-03 |
| Final Report of 2021-06-10, captured 2026-08-03 | Independent Electricity System Operator | 2021-06-10 | current | Source → · accessed 2026-08-03 |
| Final Report of 2019-09-12, captured 2026-08-03 — superseded on the aggregate-load finding by the 2020 addendum | Independent Electricity System Operator | 2019-09-12 | superseded | Source → · accessed 2026-08-03 |
| Addendum of 2020-11-17, captured 2026-08-03 — the governing vintage for the aggregate-load finding | Independent Electricity System Operator | 2020-11-17 | current | Source → · accessed 2026-08-03 |
| Report of 2024-04-18, captured 2026-08-03 | Independent Electricity System Operator | 2024-04-18 | current | Source → · accessed 2026-08-03 |
| Report of 2020-07-17, captured 2026-08-03 | Hydro One Networks Inc. | 2020-07-17 | current | Source → · accessed 2026-08-03 |
| Report of 2024-12-18, captured 2026-08-03 | Independent Electricity System Operator | 2024-12-18 | current | Source → · accessed 2026-08-03 |
| Final Addendum Report of 2025-06-30, captured 2026-08-04 | Independent Electricity System Operator | 2025-06-30 | superseded | Source → · accessed 2026-08-04 |
| Final Addendum 2 Report of 2026-02-04, captured 2026-08-04 — the governing vintage for the three-station requirement | Independent Electricity System Operator | 2026-02-04 | current | Source → · accessed 2026-08-04 |
| 2026-08-25; public report reviewed September 30, 2026 | Independent Electricity System Operator | 2026-08-25 | current | Source → · accessed 2026-09-30 |
| 2026-08-26; public report reviewed September 30, 2026 | Independent Electricity System Operator | 2026-08-26 | current | Source → · accessed 2026-09-30 |
| 2026-08-26; public report reviewed September 30, 2026 | Independent Electricity System Operator | 2026-08-26 | current | Source → · accessed 2026-09-30 |
| 2026-08-27; public report reviewed September 30, 2026 | Independent Electricity System Operator | 2026-08-27 | current | Source → · accessed 2026-09-30 |
| 2026-02-04; public report reviewed September 30, 2026 | Independent Electricity System Operator | 2026-02-04 | current | Source → · accessed 2026-09-30 |
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| Vintage | Period | Value | Role | Assurance | Basis |
|---|---|---|---|---|---|
| Final Report of 2023-07-10, captured 2026-08-03 | 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 | — | — |
| Final Report of 2023-04-21, captured 2026-08-03 | Final connection assessment of 2023-04-21 — Algoma Steel EAF Stage 1 (CAA 2021-694/695) | 140.0 MW | institutional estimate | — | — |
| Final Report of 2024-06-12, captured 2026-08-03 | Final connection assessment of 2024-06-12 — Algoma Steel EAF Stage 2B (CAA 2023-768) | 250.0 MW | institutional estimate | — | — |
| Final Report of 2024-06-12, captured 2026-08-03 | Final connection assessment of 2024-06-12 — the regional interface transfer limit stated in the Stage 2B assessment | 700.0 MW | institutional estimate | — | — |
| Final Report of 2025-06-12, captured 2026-08-03 | 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 | — | — |
| Final Report of 2024-10-16, captured 2026-08-03 | Final connection assessment of 2024-10-16 — the Toronto data centre's ultimate load (CAA 2024-795) | 80.0 MW | institutional estimate | — | — |
| Final Report of 2021-06-10, captured 2026-08-03 | Final connection assessment of 2021-06-10 — the existing Dofasco station's assessed one-time increase (CAA 2021-693) | 214.0 MW | institutional estimate | — | — |
| Final Report of 2019-09-12, captured 2026-08-03 — superseded on the aggregate-load finding by the 2020 addendum | 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 | — | — |
| Final Report of 2019-09-12, captured 2026-08-03 — superseded on the aggregate-load finding by the 2020 addendum | 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 | — | — |
| Addendum of 2020-11-17, captured 2026-08-03 — the governing vintage for the aggregate-load finding | Addendum of 2020-11-17 — the restated interruptible-load aggregate at the 2020 vintage (CAA 2018-633 Addendum 1) | 608.0 MW | institutional estimate | — | — |
| Report of 2024-04-18, captured 2026-08-03 | Central-West Bulk Plan of 2024-04-18 — firm load in the London area, as the issuer states it | 620.0 MW | institutional estimate | — | — |
| Report of 2024-04-18, captured 2026-08-03 | Central-West Bulk Plan of 2024-04-18 — potential load beyond the firm load, as the issuer states it | 300.0 MW | institutional estimate | — | — |
| Report of 2024-04-18, captured 2026-08-03 | 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 | — | — |
| Report of 2020-07-17, captured 2026-08-03 | 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 | — | — |
| Report of 2024-12-18, captured 2026-08-03 | 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 | 700.0–1,700.0 MW | institutional estimate | — | — |
| Final Addendum Report of 2025-06-30, captured 2026-08-04 | 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 | — | — |
| Final Addendum 2 Report of 2026-02-04, captured 2026-08-04 — the governing vintage for the three-station requirement | 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 | — | — |
| Final Addendum 2 Report of 2026-02-04, captured 2026-08-04 — the governing vintage for the three-station requirement | Final Addendum 2 of 2026-02-04 — the data centre's own ultimate load, restated unchanged (CAA 2024-795) | 80.0 MW | institutional estimate | — | — |
| 2026-08-25; public report reviewed September 30, 2026 | 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 |
| 2026-08-25; public report reviewed September 30, 2026 | 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 |
| 2026-08-25; public report reviewed September 30, 2026 | 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 |
| 2026-08-25; public report reviewed September 30, 2026 | 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 |
| 2026-08-25; public report reviewed September 30, 2026 | 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 |
| 2026-08-25; public report reviewed September 30, 2026 | 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 |
| 2026-08-25; public report reviewed September 30, 2026 | 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 |
| 2026-08-26; public report reviewed September 30, 2026 | 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 |
| 2026-08-27; public report reviewed September 30, 2026 | 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 |
| 2026-08-27; public report reviewed September 30, 2026 | 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 |
| 2026-02-04; public report reviewed September 30, 2026 | 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 |
| 2026-02-04; public report reviewed September 30, 2026 | 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 |
Movement between vintages
This record shows what an institution published and how its figures compare across versions or with later outcomes. It does not rank institutions or grade their forecasting ability.
| Comparison | Compared vintages | Movement | Basis |
|---|---|---|---|
| One circuit pair, two assessment vintages: the 2019 interruptible-load finding against the 2020 restatement | Final Report of 2019-09-12, captured 2026-08-03 — superseded on the aggregate-load finding by the 2020 addendum (institutional estimate 567.0 MW) vs. Addendum of 2020-11-17, captured 2026-08-03 — the governing vintage for the aggregate-load finding (institutional estimate 608.0 MW) | +41.0 MW | same issuer |
| One three-station limit, two assessment vintages: a build obligation replaced by a switching instruction | Final Addendum Report of 2025-06-30, captured 2026-08-04 (institutional estimate 400.0 MW) vs. Final Addendum 2 Report of 2026-02-04, captured 2026-08-04 — the governing vintage for the three-station requirement (institutional estimate 400.0 MW) | 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 requires — from building capacity to stay below it, to switching a breaker when it is crossed. | same issuer |
Evidence qualifications (10)
- 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.
Related on this site
- Brief: 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 →
- Receipt: Evidence summary for 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 →
- Domain: Climate →
- More Resolution lineages →
- Sources & Method →
This record shows what an institution published and how its figures compare across versions or with later outcomes. It does not rank institutions or grade their forecasting ability.
This is the current public record for this lineage. See Work with Countability for a commissioned projection-resolution question.
Work with Countability