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Northwest Ontario Bulk Planning Initiatives

Bulk planning initiatives are currently underway in Northwest Ontario.  In addition to these initiatives, several regional plans are also being developed in this area. For more information on regional planning initiatives, see Northwest Ontario Regional Planning 


Development work is currently underway for two bulk transmission projects in Northwest Ontario:

  • East-West Tie Expansion
  • Northwest Bulk Transmission Line

These projects will reinforce the existing 230 kV transmission system that transfers power across Northwest Ontario. The East-West Tie Expansion will add a second line roughly parallel to the existing tie, which extends between Thunder Bay (Lakehead Transformer Station) and Wawa and connects Northwest and Northeast Ontario (shown in orange on the map below). The Northwest Bulk Transmission Line will reinforce the existing West of Thunder Bay Transmission System, shown in green below, with a new line between Thunder Bay (Lakehead Transformer Station) and Dryden.

Map of Northwest Ontario Bulk Planning Initiatives 


East-West Tie Expansion

The East-West Tie Expansion was identified as a priority transmission project in the 2010 and 2013 Long-Term Energy Plans. The purpose of this project is to provide a long-term, reliable electricity supply to Northwest Ontario to enable forecast demand growth and changes to the supply mix in the region.

The East-West Tie Expansion project consists of a new 230 kV transmission line roughly paralleling the existing East-West Tie Line between Wawa and Thunder Bay. The new line will increase the electricity transfer capability into Northwest Ontario from 175 MW to 650 MW, and will improve the flexibility and efficiency of the Northwest electricity system. As part of this project, upgrades are being planned for the Lakehead, Marathon, and Wawa transformer stations to accommodate the new line. This project is planned to be in-service in 2020.

In August 2013, the Ontario Energy Board (OEB) identified Upper Canada Transmission Inc. (operating as NextBridge Infrastructure) as the designated transmitter to complete development work for the East-West Tie Line. Since that time, the IESO and Hydro One have been working together with NextBridge Infrastructure to develop this project.

The Ministry of Energy notified the OEB, by letter dated March 10, 2016, that the Lieutenant Governor in Council made an order declaring that the construction of the East-West Tie Expansion transmission line is needed as a priority project. The construction of the line is still subject to OEB approval for Leave to Construct. For more information, see East-West Tie designation proceeding (EB-2011-0140/EB-2015-0216) on the OEB website.


Northwest Bulk Transmission Line

The Northwest Bulk Transmission Line Project will augment the capacity and maintain the reliability of electricity supply to the area West of Thunder Bay and was identified as a priority in the 2013 Long-Term Energy Plan. While both transmission and generation are viable options for addressing potential supply needs in the area west of Thunder Bay, Hydro One is carrying out early development work to shorten the long lead time required for transmission projects and maintain the viability of this option.

The preliminary scope of the Northwest Bulk Transmission Line Project consists of a new double-circuit 230 kV line between Thunder Bay and Atikokan and a single-circuit 230 kV line from Atikokan to Dryden. However, alternate routes may be considered as part of the development work.