East Ontario Bulk Planning Initiatives

A bulk planning study was triggered by mid-term end-of-life (“EOL”) needs for 230 kV circuits in the Gatineau Corridor that stretches between the Greater Toronto Area (GTA) East and Ottawa and passes through Peterborough. These circuits provide supply to Ottawa, Peterborough to the Quinte West area, connection of Chat Falls area generation, and also helps facilitate imports from Quebec. The purpose of the study is to assess the scope of refurbishment for the EOL facilities in coordination with forecast reliability concerns in Ottawa and Peterborough to Quinte West. The final study report anticipated to be posted in early Q3 2022.

The reliability concerns identified through the study include:

  • Approximately 800 km of the 230 kV circuits on the Gatineau Corridor (Oshawa to Ottawa) are expected to reach end-of-life over the next 5 to 10 years
  • The Load Meeting Capability (LMC) for the Ottawa area is forecast to be exceeded in the mid 2020’s
  • The LMC for the Peterborough to Quinte West area is insufficient today


The IESO engages with local and regional communities, stakeholders and the general public to seek input to help inform planning activities. Learn more about engagement on this electricity planning initiative.

Area Overview

Transmission system map delineating the Gatineau Bulk Study area

The Gatineau is a 300 km long transmission corridor that stretches between the Greater Toronto Area (GTA) East and Ottawa and passes through Peterborough. The corridor consists of five (5) 230 kV lines that were originally constructed in the late 1920’s and early 1930’s primarily to transfer power from the hydro electric facilities in eastern Ontario and Quebec to the province’s major load center in the GTA. The five lines have a combined length of 1300 line-kms, of which 800 line-kms have been identified by the facility owner as nearing EOL and requires a planning decision to be made. The Gatineau Corridor is highlighted in Figure 1 along with the key areas of interest (Peterborough to Quinte West, Chats Falls, and Ottawa).

The Gatineau corridor serves a number of key functions. This study will identify issues forecasted to arise over the long term for these key areas:

  • Peterborough to Quinte West supply
  • Ottawa Supply
  • Chats Falls Area generation and imports