Northwest Ontario Bulk Planning
Two bulk transmission projects were recommended in Northwest Ontario to reinforce the existing 230 kV transmission system that transfers power across the region:
East-West Tie Expansion
This East-West Tie Expansion consists of a new 230 kV transmission line roughly paralleling the existing East-West Tie Line between Wawa and Thunder Bay to increase the electricity transfer capability into Northwest Ontario from 175 MW to 650 MW and improve the flexibility and efficiency of the Northwest electricity system. The new line came into service in March 2022 and is expected to provide long-term, reliable electricity supply to Northwest Ontario that will enable forecast demand growth and changes to the supply mix in the region. As part of this project, upgrades are being completed for the Lakehead, Marathon, and Wawa transformer stations to accommodate the new line.
The East-West Tie Expansion was identified as a priority transmission project in the 2010 and 2013 Long-Term Energy Plans. At the request of the Ministry of Energy, the IESO confirmed the project as the recommended option to maintain a reliable and cost-effective supply of electricity to the Northwest for the long term.
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.
The Ministry of Energy notified the OEB on 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.
Northwest Bulk Transmission Line
The Northwest Bulk Transmission Line ("NWBL") will augment the capacity and maintain the reliability of electricity supply to the area West of Thunder Bay. The NWBL was identified in the Government’s 2013 and 2017 Long Term Energy Plans (the “LTEPs”) as a priority project and was divided into three phases:
- Phase 1 - a line from Thunder Bay to Atikokan;
- Phase 2 - a line from Atikokan to Dryden; and
- Phase 3 - a line from Dryden to the Manitoba border through Kenora.
Following the 2013 LTEP, the Ontario Government issued an Order in Council that amended Hydro One’s license to develop and seek approval for the NWBL according to the scope and timing specified by the IESO. In 2018, the IESO recommended that Hydro One commence development work for Phase 1 (a new double-circuit 230 kV line between Thunder Bay and Atikokan) and Phase 2 (a new single-circuit 230 kV line from Atikokan to Dryden) to shorten the required project lead time. Hydro One subsequently named Phase 1 and Phase 2 of the NWBL the Waasigan Transmission Line.
In May 2022, the IESO sent a letter to Hydro One to describe the recommended high-level scope and timing for the construction of the Waasigan Transmission Line. The letter recommended that Phase 1 should be placed in-service as close to the end of 2025 as possible to meet near-term system capacity needs. At the time, a more detailed examination of the demand forecast was required to determine the timing of the need for Phase 2. In April 2023, the IESO sent a letter to Hydro One to recommend that Phase 2 also proceed with construction staged to prioritize Phase 1 coming in service as close to the end of 2025 as possible (as previously recommended), with Phase 2 coming in service as soon as practical after Phase 1. A report outlining the IESO’s studies and analysis will be posted in Q3 2023.
The IESO does not anticipate a need for Phase 3 at this time.
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.
Documents referenced on this page, but not posted, can be obtained by contacting customer.relations@ieso.ca with a link to the web page that lists the document and advise whether it needs to be provided in an accessible format. Please allow a minimum of one business day for a response.
Key Resources
East-West Tie Expansion
OEB Transmitter Designation Process
East-West Tie Transmission, a NextEra Energy Canada Company
Northwest Bulk Transmission Line
NW Bulk Transmission Line Scope Letter to Hydro One - October 1, 2014
NW Bulk Transmission Line Scope Letter to Hydro One - October 24, 2018
NW Bulk (Waasigan) Transmission Line Letter to Hydro One - May 3, 2022
NW Bulk (Waasigan) Transmission Line Letter to Hydro One - April 24, 2023