South and Central Bulk Planning

Forecasting and Planning

The engagement activities to support the South and Central Bulk Plan that actively involved communities and stakeholders in shaping the future of Ontario's transmission system have been completed.

The South and Central Bulk Plan was initiated to identify near-term actions and longer-term options to ensure the province’s transmission system can meet forecasted demand growth. The IESO also evaluated the grid’s ability to enable the connection of potential future generation resources — including new nuclear — and to reliably supply emerging demand across the Greater Toronto Area (GTA) and Windsor to Hamilton corridor.

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All comments and enquiries related to this engagement initiative can be directed to engagement@ieso.ca.

Related Information

Report: South and Central Bulk Plan

Backgrounder: South and Central Bulk Plan

Annual Planning Outlook

Southwest Bulk Electricity Planning

Regional Electricity Planning

Related Engagements

Kitchener-Waterloo-Cambridge-Guelph

South Georgian Bay/Muskoka

Central-West Bulk Plan

North-South Transmission Reinforcement Plan (Northern Ontario Bulk Plan)

Schedule of Activities

Anticipated timing for this engagement is presented below.

Date	Engagement Activity	Expected Actions
August 20, 2026	Report: South and Central Bulk Plan Communication	Final documents posted
May 21, 2026	Feedback due for the items discussed during the April 30, 2026 engagement session. Feedback received: 1001490547 Ontario Inc. Town of Bradford West Gwillimbury GrandBridge Energy Inc. London Hydro County of Middlesex Mississaugas of Scugog Island First Nation Ontario Rivers Alliance Power Workers’ Union Township of Wellesley August 20, 2026: IESO Response to Feedback
April 30, 2026	Public Engagement Webinar The IESO will share the draft recommendations for the South and Central Bulk Plan with sector participants and Ontario communities. Presentation Feedback Form	Recorded Presentation
January 23, 2026	Feedback due for the items discussed during the December 12, 2025 engagement session. Feedback received: Hydrostor Mississaugas of Scugog Island First Nation Ontario Power Generation Power Workers’ Union March 6, 2026: IESO Response to Feedback June 12, 2026: IESO Response to Feedback
December 19, 2025	Due date to provide feedback about generation assumptions for each scenario in the energy model, the sub-zonal load forecast used in the energy model, and the revised zonal diagram demarking the sub-zones created for the energy model. Feedback Received: TC Energy January 26, 2026: IESO Response to Feedback
December 12, 2025	Public Webinar The IESO will provide sector participants and Ontario communities with an update about our current Bulk Planning initiatives. Presentation Feedback Form	Recorded Presentation
November 21, 2025	As a follow-up to the September 30th Quarterly Bulk webinar, this IESO is sharing details of the portfolios of transmission investments under consideration, generation assumptions for each scenario in the energy model, the sub-zonal load forecast used in the energy model, and the revised zonal diagram demarking the sub-zones created for the energy model for input. Note that as this is still an active planning process, changes to these scenarios are still possible before a final recommendation is made. South and Central Bulk Data Tables Feedback Form	Materials Posted
October 8, 2025	Indigenous Engagement Webinar The IESO will provide sector participants and Ontario communities with an update about our current Bulk Planning initiatives. Presentation	Recorded Presentation
September 30, 2025	Public Engagement Webinar The IESO will provide sector participants and Ontario communities with an update about our current Bulk Planning initiatives. Presentation	Recorded Presentation
June 19, 2025	Feedback due on the items discussed during the May 29th engagement session. Feedback Received: Grand Bridge Energy Haldimand County London Hydro Ontario Power Generation Ontario Rivers Alliance TC Energy September 8, 2025: IESO Response to Feedback
May 29, 2025	Public Engagement Webinar The IESO will provide sector participants and Ontario communities with an update on the Bulk Planning initiatives underway. Part 1 Presentation Part 2 Presentation Feedback Form The webinar will be broken-up intro two parts: Part 1 May 29 from 1 p.m. to 2 p.m.: During this session the IESO will provide an overview of Bulk Transmission Planning, introduce the North of Sudbury Bulk Plan, share updates on the progress of the Northern Ontario Bulk Plan, the Eastern Ontario Bulk Plan and the Ontario-Manitoba Intertie Joint Study, seek feedback and answer questions. ⁠Part 2 May 29 from 2:30 p.m. to 4 p.m.: During this sessions the IESO will share preliminary portfolios of transmission options as part of the South and Central Bulk Study to support future generation connections and demand growth in key areas throughout southern and central Ontario, including the GTA, and to enable a decarbonized power system in the future, seek feedback and answer questions.	Recorded Presentation - Part 1 Recorded Presentation - Part 2
December 6, 2024	Feedback due on the items discussed during the November 20th engagement session. Energy Storage Canada Ontario Greenhouse Vegetable Growers Pattern Energy April 15, 2025: IESO Response to Feedback
November 20, 2024	Public Engagement Webinar The IESO will provide sector participants and Ontario communities with an update on the active Bulk Planning initiatives underway. Presentation Feedback Form	Recorded Presentation This webinar was presented during the IESO's November stakeholder engagement sessions, see full agenda for more information.
October 15, 2024	Feedback due following the September 24, 2024 engagement session. Feedback Received: ESC TCE November 19, 2024: IESO Response to Feedback
September 24, 2024	Public Engagement Webinar Presentation Feedback Form	Recorded Presentation This webinar was presented during the IESO's September stakeholder engagement sessions, see full agenda for more information.
July 31, 2024	Feedback due following the July 10, 2024 Indigenous Relations Webinar.
July 10, 2024	Indigenous Relations Webinar: Bulk Transmission Planning Session on 1) South and Central and 2) Northern Ontario bulk studies This webinar will provide participants with information about the South and Central and Northern Ontario bulk studies, including its scope, objectives and timeline. Presentation Feedback Form	Recorded Presentation
July 10, 2024	Feedback due following the June 19, 2024 engagement session. Feedback Received: Greater Sudbury Utilities TC Energy April 15, 2025: IESO Response to Feedback
June 19, 2024	Public Engagement Session: Bulk Transmission Planning Session on 1) South and Central and 2) Northern Ontario bulk studies This public webinar will provide participants with information about the South and Central and Northern Ontario bulk studies, including its scope, objectives and timeline. Presentation Feedback Form	Recorded Presentation This webinar was presented during the IESO's June stakeholder engagement sessions, see full agenda for more information.