Hydro One Orléans Area Reinforcement

Project Objective

Growing electricity needs in the Orléans area identified in 2022 by the Greater Ottawa Regional Planning Working Group mean that a new 230 kilovolt (kV) electricity transmission supply is required. To meet the current and future needs of the community, Hydro One Networks Inc. (Hydro One) plans to convert an existing 115 kV circuit to 230 kV and install a new 115 kV circuit within an existing transmission corridor between Hydro One's Hawthorne Transformer Station (TS) and Orléans TS in Ottawa, Ontario. 

 

Federal and Provincial Involvement

The project crosses approximately 12 kilometres in Ottawa, about 6.4 kilometres of which is property owned by the National Capital Commission (NCC) within the National Capital Greenbelt. The portion of the project on NCC property is subject to a Federal Land Use, Design, and Transaction Approval and an Environmental Effects Evaluation under Section 82 of the Impact Assessment Act.

 

The overall project is also subject to the provincial Class Environmental Assessment for Transmission Facilities, under which Hydro One has undertaken engagement with Indigenous communities, government agencies, stakeholders, and the public, including through Community Open Houses.  Additionally, the project must receive Leave to Construct approval from the Ontario Energy Board.

 

Scope of Work

To replace the 115 kV circuit, a new approximately 12-kilometre 115 kV pole transmission line (wood, composite, or steel) is planned to be constructed in the middle of an existing hydro corridor, between two existing transmission lines. Most of the new line will consist of wood or composite poles in an "H-Frame" configuration. Monopole and lattice steel structures will be required at the Highway 417 crossing, and for station egress and entrances.

 

The existing circuit already has the appropriate conductor and insulators to operate at 230 kV along its length

 

Permanent infrastructure on NCC lands will include one steel monopole occupying approximately 11 m², three lattice structures occupying approximately 12 m² each, one three-pole structure occupying approximately 80 m² including guy-wire anchors, and 38 H-frame structures occupying a combined area of approximately 76 m². The project will also require replacement of one culvert and installation of one new watercourse crossing.

 

Environmental Setting 

The project crosses wetlands, including the Mer Bleue Bog, watercourses, grasslands, agricultural fields, and small portions of wooded areas and is within an existing transmission corridor.

 

Locating the project within an existing transmission corridor substantially reduces potential environmental and socio-economic impacts, including vegetation removal, habitat fragmentation, property acquisition requirements, and associated project costs.

 

Hydro One has worked collaboratively with the project's design engineer and the NCC to minimize the footprint of the project in environmentally sensitive areas including Mer Bleue.

 

Construction Timing and Activities

Construction is planned to start in early 2027 and will be complete by the end of 2029.

 

The construction area will be accessed with small bulldozers, tri-axle dump trucks, and excavators to install access routes and work pads.  Specialized machinery designed to augur holes, erect structures, and string conductors will be used to install the transmission line.

 

Existing access routes will be used as much as possible to reach each structure location.  New access routes consisting of gravel overlaying geotextile membrane will be required in some areas. Work pads about 18 m x 18 m square for pole structures and about 30 m x 30 m square for lattice structures will be required, along with about six approximately 30 m x 60 m stringing pads. Work pads and access routes in agricultural areas will be removed following construction. 

 

Temporary trail closures within and near the corridor may be required during construction.

 

Approximately 1.1 ha of trees would need to be removed from NCC property to ensure the project meets line clearance requirements. Areas requiring tree removal will have stumps removed and will be seeded with a pollinator-friendly seed mix. Tree removals will be compensated for as per NCC's advice in accordance with the NCC's Forest Strategy. 

 

More Information

For more information, please consult Hydro One's public website for the project: https://www.hydroone.com/about/corporate-information/major-projects/hawthorne-to-orleans

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Latest update

July 31, 2026 - The National Capital Commission intends to make a determination regarding whether the carrying out of the project is likely to cause significant adverse environmental effects. To help inform this determination, the National Capital Commission is inviting public comments until August 31, 2026 respecting that determination.

Participate

Key documents

Key documents
Document number Document title File Date
1 Notice of Intent - Hydro One Orléans Area Reinforcement, Ottawa - July 31, 2026

Contacts

National Capital Commission
Environmental Assessment
100-12 York Street
Ottawa, Ontario K1N 5S6
Email: IA-EI@ncc-ccn.ca


Disclaimer

This map is for illustrative purposes. The markers represent the approximate locations based on available data. More than one marker may be identified for a given assessment.

  • Location

    • Between Hydro One’s Hawthorne Transformer Station (TS) and Orléans TS in Ottawa (Ontario)

  • Nature of activity

    • Hydroelectric Energy

  • Assessment status

    In progress

  • Start date

    2026-07-31

  • Proponent

    Hydro One Networks Inc. (Hydro One)

  • Authorities

    • National Capital Commission

  • Assessment type

    Project on federal lands

  • Reference number

    90677

Nearby assessments

...within 200 kilometres
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