Ontario, Toronto building third transmission line to power the city’s downtown

TORONTO – The Ontario government and City of Toronto have announced they are jointly bringing a third electricity transmission line into the downtown in order to support new homes, economic growth and major infrastructure like transit.

The City of Toronto is currently supplied by two transmission supply paths, one from the west at Manby Transmission Station (TS) near Kipling Road and Dundas Street, and one from the east at Leaside TS near Overlea Boulevard and Millwood Road, explains a release.

These pathways will start to reach their capacity in the early 2030s. With the city’s electricity demand expected to roughly double by 2050, Ontario’s Independent Electricity System Operator (IESO) confirmed a third transmission line will be required.

The IESO has identified three potential options for new transmission supply:

• An overland route from Pickering to Leaside in Toronto. This line would connect Cherrywood TS to Leaside TS using an existing transmission corridor.
• An overland route from Pickering to the Port Lands in Toronto. This line would connect Cherrywood TS to Hearn TS via Warden TS, using an existing corridor to Warden TS, then possibly transitioning to an underground cable from Warden TS to Hearn TS.
• An underwater cable from Darlington or Pickering to the Port Lands in Toronto. This line would connect underwater through Lake Ontario.

The IESO will conduct further engagement this summer with a final recommendation before the government by the end of August.

The Ontario government will then evaluate what actions must be taken to kickstart its development. Depending on the option selected and the necessary approvals, construction and commissioning could take between seven to 10 years to complete, the release adds.

In addition to a third transmission line, the IESO will also continue engagement to identify complementary solutions to meet electricity demand across Toronto. This could include small-scale generation and storage, such as rooftop solar and battery systems, as well as expanded energy efficiency programs.