Old Second Line - New Municipal Transformer Station

A municipal transformer station (MTS) “steps down” the voltage of the electricity being delivered by a high-voltage transmission line to a lower voltage that is suitable for distribution to local customers. Distribution lines are generally on wood poles along the road allowance, and may also be underground in some areas.

In March 2020, the need for a new station was identified in a twenty-year Integrated Regional Resource Plan.

The Old Second Line Municipal Transformer Station (MTS) project is part of Hydro Ottawa’s future planning to modernize our grid, ensure sustainable and reliable electricity supply and meet the projected growth in electricity demand in the north west region in the coming years. The new substation will benefit and serve existing and new communities in West-Carleton March and Kanata-North wards by providing redundancy against outages, effectively decreasing the size and frequency of outages for both urban and rural customers. The existing Hydro Ottawa stations in the area do not have the capacity to supply anticipated future demand in the area.

Until recently, Hydro Ottawa built a new substation every five to seven years. Now, we are on track to energize a new station nearly every year until 2030.

In addition to serving existing and new communities in the north west end of Ottawa, the substation will protect against weather-related events, and support new demand from the growing electrification of heating and transportation in our community.

A reliable source of electricity is essential to supporting community growth - powering homes, schools, businesses, and transportation. 

Contingent on the Class Environmental Assessment (EA) and other approvals, the new Old Second Line 27.6kV municipal transformer station (MTS) will be located at 1310 Old Second Line Road, on the east side, approximately 70 metres south of Thomas Fuller Drive, and connect to Hydro One’s existing 230kV transmission line located to the south west of the proposed station.

The Integrated Regional Resource Plan is a twenty-year plan that has been developed by a regional planning working group consisting of the Independent Electricity System Operator, Hydro Ottawa and Hydro One.

Regional system planning ensures a reliable supply of electricity to regions across the province and considers a range of solutions including conservation, generation, transmission and distribution, as well as other resource options to ensure that electricity is available when needed.

A project of this scale can take five to seven years from initial planning until completion. There are many steps involved including development work, the EA process and other approvals, and construction.

While some trees on the property will need to be removed, we will only cut those which are strictly necessary for the needs of the project.

All vegetation removal will be thoughtfully considered, along with mitigation measures, in accordance with the recommendations of the Class Environmental Assessment and input from the local community.

Mitigation measures could include tree planting, vegetation buffers, decorative and community-friendly fencing, and/or an earth berm along the frontage of the site to visually mask the municipal transformer station and dampen operational noise and vibration.

Yes. As a utility, we plan decades ahead and consider Ottawa’s unique electricity needs, including strengthening our own distribution network and infrastructure. We also look at new opportunities and innovative technology like distributed energy resources that can help build redundancy.

From a climate and planning standpoint, Hydro Ottawa considers recent years and events that point towards a new reality requiring contingencies to better protect the electricity grid, our systems and our customers.

Further consideration is also given to meeting greenhouse gas reduction targets set by various levels of governments (plus our own 2030 zero-emission goal), as well as a future of mass electrification.

We are spearheading a lot of future planning to make the electricity system as sustainable and resilient as possible.

In 2024, Hydro Ottawa customers had power an average of 99.98 per cent of the time (99.921 per cent in 2023). Major weather events can shake customers’ trust in the reliability of the system and stoke fears of lengthier power outages in the future. As such, Hydro Ottawa is building and investing in a more resilient and modernized grid with new technology to mitigate these risks.

A Class Environmental Assessment (Class EA) takes a broad and all-encompassing view of the environment. Potential effects of the project will be examined through a number of detailed studies, taking into consideration factors relating to: 
the natural and socio-economic environments; cultural/heritage resources; recreational resources; existing and planned land uses; visual landscapes; technical/cost considerations; and the concerns and interests of local business and residential property owners, Indigenous communities, government agencies and other interested parties.

A number of natural environment field studies will be undertaken in the project area as part of the Class EA process. This will include:  
Species at Risk (SAR) surveys, as required by government agencies; Ecological Land Classification; botanical and tree surveys; aquatic habitat assessments; incidental wildlife observations; and, potential significant wildlife habitat mapping. Where effects on the natural environment cannot be avoided, appropriate mitigation measures will be proposed.

To provide sufficient electrical capacity to support growth in the southeast area of the City, the current plan is to have two transformers at the new station, similar to the size of our Cambrian municipal transformer station in south Nepean. Specific information about the design of the new station is not available at this time as this will be developed during the environmental assessment. 

Many factors are taken into consideration when planning projects of this size, including feasibility, cost, reliability, and seeking to maximize the use of existing electricity infrastructure, where possible. These decisions are not taken lightly, and above all, are always made with our customers in mind.

A more detailed cost estimate will be developed by Hydro Ottawa as it moves through the project approval process and undertakes detailed engineering and designs for the facilities. The allocation of project costs will be determined as part of the Ontario Energy Board approval process.

Yes. As part of our sustainability commitments, Hydro Ottawa intends to develop Old Second Line as a lower carbon substation.

We are currently undertaking a full project review of the station’s construction, including an innovative design, procurement and construction techniques that include using lower Global Warming Potential (GWP) materials, and equipment that will address embodied carbon associated with the construction and operation of the substation.

Yes. This is currently being reviewed. Additional generation can connect either to the new station or directly to the connection line. It is possible for renewable generation and other innovative technologies, such as energy storage and distributed energy resources, to provide additional power in order to address the area’s need. We will share more information on this as it develops in the future.

Ontario’s electricity sector is one of the cleanest in the world, producing nearly 87 per cent of electricity completely free of GHG emissions.

Electric and magnetic fields (EMFs) are invisible forces that surround all electrical appliances and equipment, power cords and wiring found in your home. This is the same for outdoor power lines and equipment operated by utility companies. These fields are at extremely low frequency. The field strength is strongest close to its source and fades rapidly as you move away from the source.

Hydro Ottawa defers to Health Canada on the issue of EMFs. Health Canada does not consider that any precautionary measures are needed regarding daily exposures to EMFs at extremely low frequencies.

There is no conclusive evidence of any harm caused by exposures at levels found in Canadian homes and schools, including those located just outside the boundaries of power line corridors.

Once the design for the new MTS is determined, Hydro Ottawa will be able to project how EMFs might change.

During the construction phase of the project, local residents may see various types and frequencies of construction traffic depending on the stage of the construction. That being said, there will not be a sustained long-term traffic impact associated with the Old Second Line project.

Once operational, traffic generated by the station will generally be limited to a monthly site visit by a technician since the station will be remotely monitored. During major weather events, required maintenance or other related system needs, the station may be visited more frequently depending on Hydro Ottawa’s need as part of our commitment to deliver safe, and reliable electricity to our customers.

Understanding that any construction activities can be very disruptive, we want to assure residents that all construction activities and any possible power interruptions will be scheduled and planned very carefully.

Further, to ensure the safety of the public and our crews as a result of the work required for this project, the majority of the work will be completed weekdays between 7:00 a.m. and 5:00 p.m., and in accordance with City of Ottawa noise by-law.

Over the course of this project, some customers may experience one or two planned power outages.

If there is a need for a planned power outage, we provide our customers with as much notice as possible. This includes notifications by phone, text and/or email depending on the account contact information we have on file, as well as hand-delivered letters where applicable.

The station is supporting local development in the area which may bring associated increases in property values.

Mitigation measures will be implemented in accordance with the recommendations of the Class EA, which will include input from the local community. There could include, for example, tree planting, vegetation buffers, decorative / community friendly fencing and/or an earth berm along the frontage of the site to visually mask the MTS, and to dampen operational noise and vibration.

A reliable and safe supply of electricity can be a positive attribute for the area, and for property values.

We considered a number of other properties in our selection process. The criteria we evaluated included, but was not limited to, alignment with city planning, environmental stewardship, proximity to Hydro One’s existing transmission corridor, and system reliability.