Ontario’s transmission network is preparing for another major northern expansion. Hydro One and Hydro One Sault Ste. Marie have filed with the Ontario Energy Board for approval to construct the North Shore Link, a new transmission project intended to strengthen the connection between northeastern and northwestern Ontario and support growing electricity demand.
The proposed project is an approximately 105 km, double-circuit 230 kV transmission line connecting Mississagi Transformer Station near Wharncliffe with Third Line Transformer Station in Sault Ste. Marie. The project also requires upgrades at Mississagi TS and Third Line TS, plus an expansion of Algoma TS, located east of Algoma Mills. Hydro One estimates the investment at $1.3 billion, with construction targeted to begin in 2027 and the line planned to enter service in 2029.
The map powered by Rextag Energy DataLink puts that project into a wider Ontario transmission context. It shows Hydro One-owned operational 230 kV+ powerlines and substations across the province, while the North Shore Link corridor and its key project locations are highlighted separately around Sault Ste. Marie and the North Shore region.
That broader view helps explain the role of the project. North Shore Link is not an isolated line. It is intended to reinforce a much larger transmission network connecting northern Ontario communities and load centers with the rest of the provincial grid. Hydro One says the project will improve northern system resiliency while adding capacity to support future electricity needs of communities, industries, and businesses.
For infrastructure, power, industrial development, and market intelligence teams, the key takeaway is the corridor itself: where new transmission capacity is being added, which existing stations anchor the project, and how the line fits into Ontario’s existing high-voltage system.
Why it matters
● North Shore Link is a proposed double-circuit 230 kV transmission line.
● The preferred project extends approximately 105 km.
● It connects Mississagi TS near Wharncliffe with Third Line TS in Sault Ste. Marie.
● Related work includes upgrades at Mississagi TS and Third Line TS and expansion of Algoma TS.
● Hydro One estimates the project at approximately $1.3 billion.
● Construction is targeted for 2027, with planned service in 2029.
● Nine potential First Nation partners could invest in up to a 50% equity stake in the transmission line component.
What the map shows
An Ontario-wide transmission view with the North Shore Link highlighted as a new northern corridor.
● Hydro One-owned operational 230 kV+ powerlines
● Hydro One operational substations
● proposed North Shore Link corridor
● Mississagi TS
● Third Line TS
● Algoma TS
● Wharncliffe
● Sault Ste. Marie
The project corridor and station callouts are added from Hydro One project information because the North Shore Link is not yet shown as an operational Energy DataLink asset. Surrounding transmission infrastructure is shown for context.
A deeper dive with Energy DataLinkA deeper dive with Energy DataLink
Using Rextag Energy DataLink, users can review high-voltage transmission lines and substations in one mapped view, compare proposed projects with the existing network, and understand how new transmission corridors fit into broader regional infrastructure patterns.
