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Information on the upcoming ENMAX Transmission Reinforcement Project in Downtown Calgary


The demand for power is increasing as Calgary continues to grow. The Alberta Electric System Operator (AESO) has determined that the existing transmission system in downtown Calgary can become overloaded under certain conditions. Overloaded transmission lines reduce the reliability of your power supply and increase the likelihood of interruptions in power supplied to homes and businesses. The AESO has therefore identified the need for transmission reinforcement into the downtown area.

On November 18, 2015, the AESO led its Needs Identi cation Document (NID) for Transmission System Reinforcement in Downtown Calgary with the Alberta Utilities Commission (AUC). On June 1, 2016, the AUC approved the AESO’s NID.

To meet this need ENMAX Power Corporation (ENMAX) is proposing to build a new 138 kV transmission line between ENMAX No. 2 Substation located at 3120 – 9 Street SE, and ENMAX No. 8 Substation located at 903 – 4 Avenue SW. 


The proposed project consists of the following:

Transmission Line:

• Construct a new 138 kV single circuit transmission line approximately 5.5 km in length, from No. 2 Substation to No. 8 Substation.

• Approximately 2 km would be an overhead line from No.2 Substation to the north side of the Elbow River at 1 ST SE.

• Approximately 3.5 km would be an underground line in a new ductbank and manhole system, from the north side of the Elbow River at 1 ST SE to No. 8 Substation.

• ENMAX is proposing to drill 1 km of the underground construction on 9 ST SW starting at 14 Ave SW to 4 Ave SW, due to heavy rail and LRT crossings. ENMAX is proposing to trench the remaining 2.5 km of underground construction .

• Relocation or recon guration of other utilities will be required for the proposed project.


• No. 2 Substation: Connect the new transmission line to the existing switchgear.

• No. 8 Substation: Modify the existing switchgear to connect the new transmission line.

• All substation work will be conducted inside the existing control buildings at both substations.


The proposed single circuit transmission poles for the overhead portion will be self-supporting steel monopoles. All poles except one will range in height from approximately 18 to 28 metres (59 to 92 feet) and will be 50 to 160 metres (165 to 524 feet) apart. One pole located near No.2 Substation will be approximately 32 metres in height. 


During the process of determining and evaluating possible route options, ENMAX considers impact factors such as residential, commercial, environmental, constructability, cost and visuals. ENMAX conducted a thorough routing and siting program that involved extensive data, information gathering, and evaluation.

After evaluation and assessment of several routes, ENMAX is proposing the route identi ed in the map enclosed in this package.


ENMAX plans to le the Facility Application with the AUC by the end of September 2017. Subject to approvals being granted, construction to begin by mid-2018 with a proposed in-service date of early 2021.


ENMAX representatives will be available at several open houses to share information, gather your input and address any questions or concerns you may have on the proposed transmission project. We hope to see you there.

Monday, June 26, 2017
Respsol Sport Centre, in the lounge, 2225 MacLeod Trail SE 4:00 - 8:00 pm

Tuesday, June 27, 2017
Best Western, in the Calgary Room, 1330 - 8 ST SW 11:00 am - 3:00 pm
4:00 - 8:00 pm

Thursday, June 29, 2017
Sandman Hotel, in Great Room 3, 888 – 7 Avenue SW 11:00 am - 3:00 pm
4:00 - 8:00 pm