In 1904, The City of Calgary built its own electric plant when its contract with a private supplier ended.

January 1, 2001, Enmax Energy entered the restructured, deregulated electric marketplace in Alberta.

The competitive retail business provides customers with either fixed or variable-priced electricity and natural gas and offers additional energy services.

Natural gas retail contracts are backed by market transactions to provide supply certainty, margin stability and risk mitigation.

The Calgary District Energy Centre began operations in March 2010, capable of providing heat for up to 10 million square feet of buildings.

[10] Located on a 60-acre site east of Calgary, the Shepard Energy Centre is Alberta's largest natural gas-fueled power generating facility.

The RRO is the default option if households and small businesses in Calgary do not choose an energy plan with a retail supplier.

[12] The Bonnybrook Energy Centre is a planned natural gas-fired cogeneration facility that will be built in Calgary's southeast industrial zone.

Once built, Bonnybrook will generate 165 MW of electricity, which is approximately half of downtown Calgary's energy requirements.

This facility will reduce the amount of fresh water used by reusing industrial wastewater from the nearby Canada malting site and will play an integral role in heating office buildings in downtown Calgary.

Bonnybrook will emit less than half of the carbon dioxide associated with conventional coal-fired facilities and will enhance the reliability of the region's power supply.

In 2011, the CEO of Enmax, Gary Holden, resigned after controversial handling of travel expenses that violated the company's ethical guidelines.