In Ontario, the Independent Electricity System Operator (IESO) is responsible for
ensuring that future energy needs are being met. According to the IESO, electricity
demand in the southwest region is expected to quadruple by 2035.
To support this growth, the IESO has identified through their long-term planning the
need for the first transmission line to be in-service by 2030. With such significant
demand expected, the Government of Ontario advised Hydro One to concurrently conduct
early development work on the second transmission line while the IESO further assesses
the future energy needs of the region. Pending project approvals, we are focused on starting construction of Line 1 in 2027 to meet the in-service date set by the Independent Electricity Service Operator (IESO). To keep property owners well-informed of the land rights needed for the entirety of the project, we will be securing land rights concurrently for both Line 1 and Line 2.
Over the course of the Class EA, we studied each route alternative by collecting data from a variety of sources, such as existing reports and plans, conducting environmental field surveys and technical assessments, as well as engagement opportunities to gather input and feedback.
A weighted multi-criteria decision-making analysis was used to evaluate the alternative routes to select a preferred route. The analysis balanced project-specific criteria in four equally weighted categories: natural environment, socio-economic environment, Indigenous culture, values and land use, and technical and cost. The evaluation concluded that Route 3B ranked highest across all categories and was selected as the preferred route.
Highlights of the preferred route and evaluation results
- The preferred route maximizes the re-use of existing transmission corridors, including approximately 25 kilometres of idle transmission corridor.
- Route 3B is the shortest of the alternative routes and requires the least amount of land for the project.
- The preferred route minimizes impacts on residential properties.
- Compared to all route alternatives, Route 3B involves the least potential disruption to species at risk and their habitats and requires the least vegetation removal, including trees.
In Ontario, the Independent Electricity System Operator (IESO) determines future electricity needs. It conducts routine planning to identify where electricity demand is growing across the province and works with transmitters, generators and utilities, including Hydro One, to determine how to address those needs.
In 2021, the IESO’s long-term planning identified the need for Longwood to Lakeshore Line 1 to be in service by 2030. With such significant demand expected, the Ontario government advised Hydro One to begin early development work on Line 2 at the same time as Line 1 to preserve flexibility and support meaningful consultation while the IESO continued to assess the future energy needs of the region.
To keep property owners informed of the land rights needed for the full project, Hydro One planned to acquire land rights for both Line 1 and Line 2 under one option agreement. However, an update from the IESO did not identify an in-service date for Line 2.
Pending project approvals, we are focused on starting construction of Line 1 in 2027 to meet the in-service date set by the IESO and ensure we can bring additional power to the region when it’s needed, and without delay. While Longwood to Lakeshore Line 2 may still be needed in the future, Hydro One will only be seeking Line 1 land rights at this time.
Ontario’s farmers are crucial to our economy and reducing impacts on farmland, during and after construction, remains a priority for Hydro One. We’ve had the opportunity to learn about farming operations from other projects we’ve been working on in the region and have incorporated those learnings into our designs for the Longwood to Lakeshore Transmission Line project.
An important part of the EA process involves identifying potential environmental effects of the project, including effects to the socio-economic environment such as agricultural operations, and identifying high-level mitigation measures that could be applied to avoid or minimize these effects. These effects and recommended mitigations are detailed in our final Environmental Study Report which will be the basis for developing site-specific construction plans.
The draft Environmental Study Report (ESR) was available for a public comment period from September 15, 2025 to October 15, 2025. The report summarizes the Class EA process, which was conducted in accordance with the approved Class EA for Transmission Facilities (2024) under Ontario’s Environmental Assessment Act.
Hydro One values community input and carefully considered all comments. Comments and Hydro One’s responses are documented in the final ESR.
To learn more about the findings from the Class EA process, review the final Environmental Study Report.
