Generation and wires



What is a Substation?

Substations are important components of the electrical infrastructure required to keep reliable electricity available for customers.

Substations consist of high voltage electrical equipment like transformers, switchgear, circuit breakers and associated devices.

  • Transformers step down the high voltage electricity coming in on the transmission lines, to a much lower voltage suitable to send out on distribution wires.

  • Circuit switches direct the flow of electricity, like the switches that turn the lights on and off in your home.

  • Breakers interrupt the flow of electricity when unexpected surges or faults occur, in order to protect the system from damage -- like the breakers in the main service panel of your home.

  • Capacitors improve the quality of the electricity supply to customers, in two important ways: they smooth out voltage depressions caused by increased loads, and they “filter out” voltage distortions.


Why do we have Substations?

The purpose of a substation is to ‘step down’ high voltage electricity from the transmission system to lower voltage electricity so it can be easily supplied to homes and businesses through our distribution lines.

ENMAX Power Corporation operates 40 high voltage electrical substations and three lower voltage distribution substations, located in all parts of Calgary and our surrounding service area. Managing the environmental aspects of our substations is an important part of environmental stewardship at ENMAX Power.

As the City of Calgary continues to grow, so does the need for electricity. As a result, ENMAX Power is proposing to build and operate new substations in Calgary.

Learn more

Questions and Answers

What's the difference between transmission and distribution lines?

Besides the voltage, transmission lines  typically are mounted on taller wood poles or steel towers. Distribution lines are most often mounted on wooden poles such as the ones seen on city streets and alleys or they are buried underground.

Why are new substations required?

Calgary has been growing rapidly and more development is planned. The high growth in certain areas means there is need for more electricity. When the electrical infrastructure in an area is at full capacity, a substation is required to continue to provide reliable electricity.

Is the location of the proposed substations final?

No. Substation locations are not final until ENMAX Power Corporation has received approval for a license and permit from the Alberta Utilities Commission (AUC). The AUC is the governing body that regulates the energy industry in Alberta. The exact location of the substation is subject to a number of things.

First, ENMAX Power will review the area from an engineering perspective and review load requirements, location of existing transmission and distribution lines, etc. Wherever possible, substations are located in Provincial Transportation Utility Corridors. Once ENMAX Power has researched the area, we identify a proposed site and at least two alternate sites. Before we apply for a license and permit from the AUC, we want to understand what questions, if any, people who work and live in the area may have regarding each site. We hope to address those questions through different public involvement processes, information packages and meetings. Following the public consultation, ENMAX Power submits an application to the AUC for a permit and license to build, operate and maintain the substation. Building of the substation will not proceed until we receive a permit and license from the AUC.

What does a substation look like?

​A substation consists of a fenced off area containing a building and a yard with electrical equipment. While the technical and safety requirements of a substation cannot be compromised, we are open to suggestions regarding the overall appearance of the substation. We have some flexibility regarding landscaping such as trees, shrubs and fencing providing associated costs are approved by the AUC.

Is a substation noisy?

No. If you are standing beside a substation you may hear a low humming or buzzing sound from the energized equipment within the fenced off area.

Is it safe?

Electricity can be very dangerous if it is not treated with respect. Because substations have high voltage they are not accessible to the public and can only be entered by authorized personnel. For safety reasons all substations are constructed with minimum 2.5-metre-high fencing. If you lose an object in a substation, call 403-514-6100, and we'll get it back for you.

What does each substation cost?

We estimate the overall cost for a new substation will be between $5 million to $6 million.

Who pays for it?

ENMAX Power recovers the cost of substation infrastructure to supply safe, reliable electricity to Calgarians through the Transmission Tariff which is set by the Transmission Administrator (TA) and is approved by the TA's regulator, the Alberta Utilities Commission (AUC). The Transmission Tariff is billed to electricity distribution companies who, in turn, pass these charges on to electricity retailers. Electricity retailers then pass these tariffs onto customers through their electricity bills.