Northern and central Ontario

Sudbury Barrie Transmission Line

Building a stronger grid today to provide safe, reliable power for Ontario's growing communities.

Current project phase: Class Environmental Assessment

Expected completion date: 2032

Community open houses Contact
Arial view of Sudbury's Bell Park

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Project map Project notices

Visit an open house near you

Current open houses

Join us this summer to learn more and tell us what’s important to you within the focused study area. We will be hosting in-person sessions at the following locations, as well as offering virtual options.

French River

Tuesday, July 28

3 – 7p.m.

Alban Community Centre 796 ON-64, French River, ON

Get directions

Georgian Bay

Thursday, July 30

3 – 7p.m.

Baxter Ward Community Centre 25 Community Centre Dr, Port Severn, ON

Get directions

Muskoka Lakes

Saturday, August 1

11 a.m. – 3 p.m.

Bala Community Centre 1008 Maple Ave, Bala, ON

Get directions

Midhurst

Tuesday, August 4

3 – 7p.m.

Midhurst United Church, 91 Doran Rd, Midhurst, ON

Get directions

Parry Sound

Thursday, August 6

3 - 7 p.m.

Waubamik Community Hall, 6 Hurdville Rd, McDougall, ON

Get directions

Severn

Saturday, August 8

11 a.m. – 3 p.m

Coldwater United Church, 14 Harriet St, Coldwater, ON

Get directions

Sudbury

Tuesday, August 11

3 - 7 p.m.

Falconbridge Community Centre, 63 Edison Rd, Falconbridge, ON

Get directions

Seguin

Thursday, August 13

3 - 7 p.m.

Foley Community Hall, 60 Rankin Lake Rd, Foley, ON

Get directions

Can't visit us in person? Register for our virtual community open house

Monday July 27, 2026 - 6 - 7 p.m.

Register now

Monday August 10, 2026 - 6 - 7 p.m.

Register now
TX lines in Sudbury

Building a stronger grid for Ontario's future

Project overview

Ontario's demand for electricity is increasing. To help meet this need, Hydro One will plan and build the proposed Sudbury Barrie Transmission Line. The proposed priority project is a new single-circuit, 500-kilovolt (kV) transmission line that will span approximately 300 kilometres from the Hanmer Transformer Station (TS) in Sudbury to Essa TS near Barrie, including station facility expansions. The line is expected to be in service by 2032.

The designation of this project includes the direction to complete development work for a second, new single-circuit 500-kV transmission line. A recommended in-service date for the second line will be determined by the Independent Electricity System Operator.

Once built, this critical infrastructure will support new generation opportunities in the north, strengthen reliability, foster economic growth and investments and ensure a dependable power supply for the increased need anticipated in northern Ontario.

Partnership with purpose

Building as partners

Hydro One and nearby First Nations will collaborate on the planning, development and construction of the transmission line. Through Hydro One's industry-leading First Nation Equity Partnership Model, nearby First Nations will have the opportunity to invest in a 50 per cent equity stake in the transmission line component of the project.

Learn more
Native Friendship Centre in Sudbury

See the project study area

Project study area

The map shows how the project study area has been refined into a focused study area. This update is based on feedback received and ongoing technical studies and shows where the routes are most likely to be developed and further studied as the Class EA proceeds.

Share your comments on the interactive map below.

View interactive map Download map (PDF)
Project map

See what's coming

Anticipated project schedule

2026
Project announcement and community open houses - round 1, to introduce the project
2026
Notice of Commencement (NOC) of Class EA
2026
Community open houses - round 2, to share the focused study area
2026
Announcement of routes
2026 - 2027
Community open houses - round 3, to present routes
2027
Announcement of the preferred route
2027
Community open houses - round 4, to present the preferred route
2027
Release of draft Environmental Study Report (ESR)
2028
Submit final ESR
2028 - 2029
Completion of detailed design, Section 92 approval
2029
Start of construction
2032
Line energized
*Dates are subject to change.

Guided by standards

Planning process

The project will follow the Class Environmental Assessment for Transmission Facilities, 2024 in accordance with the Ontario Environmental Assessment Act. Work on the Class EA will begin with the publication of the Notice of Commencement. This is an important part of the planning process to assess potential natural, economic, social and cultural effects, determine measures to avoid or minimize impacts and evaluate routes.

In addition to the Class EA, the project will require Ontario Energy Board approval under Section 92 (Leave to Construct) of the Ontario Energy Board Act.

People sitting and conversing

What we shared

Public consultation documents

Community engagement resources

June 2026

March 2026

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What these documents mean

These documents summarize the studies, project notices and resources shared during the consultation process. They explain how routes were evaluated, decisions were made and how we engaged with communities.

Answers at a glance

Frequently asked questions

Why do we need these new transmission lines?

The Sudbury Barrie Transmission Line is designed to support growing electricity demand in both northern and southern Ontario. Electricity demand in the north alone is expected to grow significantly by 2050, with dozens of potential new mines projected in the next decade. The new transmission line helps relieve an existing bottleneck between northern and southern Ontario, improving reliability and enabling future economic and industrial growth in both regions.

Will the project follow the existing transmission line corridor?

We look to follow existing transmission corridors where possible, however, this may not be feasible in all areas due to new development, environmental features or technical requirements.

Why can’t you use the existing towers for the new line?

In this case, the existing towers were designed to carry only a single circuit and cannot safely support an additional one. Accommodating two circuits would require entirely new structures and would involve extended outages on the existing line during construction. Those outages would pose a significant risk to Ontario’s critical north–south power flow and could potentially lead to widespread electricity interruptions across the province.

How is feedback used as part of the Class EA process?

Your feedback is important. The local knowledge we receive helps us select a route that minimizes impacts on the environment and community. Please provide feedback by contacting Hydro One at: Community.Relations@HydroOne.com or 1-877-345-6799

Contact us

We're here to help

To provide comments or to be added to the project contact list, please call or email:

1-877-345-6799

Land acknowledgement

Hydro One acknowledges that the Sudbury Barrie Transmission Line is proposed on the ancestral lands of the Anishinaabe and is now home to many diverse First Nations, Inuit and Métis people. Hydro One understands that Indigenous Nations have been here since time immemorial and are stewards of what many refer to as Turtle Island. We are all Treaty People and with a commitment to friendship and our pursuit of reconciliation, we are thankful to be welcomed on these lands as partners so we can improve on our past and energize our combined futures.

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