TransAlta

In 1909, TransAlta began the planning and construction of the Horseshoe Falls Hydro Plant in Seebe, Alberta. Two years later, Calgary Power Company, Ltd. was born.

That first dam was built by a crew of about 200 with primitive tools such as picks and wheelbarrows. It initially had a 10 MW capacity . A second dam was commissioned in 1913 at Kananaskis Falls and was built by close to 500 workers.

At the time, streetcars were responsible for a significant share of Calgary's electrical load. Residential power was just being introduced, and many homes were lit for the first time with electrical lamps because of Calgary Power. Calgary Power's cheap energy is credited with Canadian Pacific Railway's decision to locate its regional engine repair shop in Ogden, Calgary, spurring the city's economic development.Notable leaders from the company's early years included W. Max Aitken and R.B. Bennett, who went on to become Canada's Prime Minister from 1930 to 1935.

The company's monopoly position and behaviour made its status as a private corporation unpopular among rural customers and some Calgary residents, and a move to nationalize it was converted to a province-wide referendum in 1948, which came down very narrowly on the side of maintaining its private ownership.

In 1981, the company changed its name to its current name of TransAlta Corporation.

At the end of 2010, TransAlta became the first company to own and operate more than 1,000 MW of installed wind capacity in Canada—almost 30 per cent of the country's total.

TransAlta has gradually been transitioning its energy-generating facilities away from coal, due to adverse environmental effects, towards natural gas. Its last remaining operational coal mine, in Highvale, AB, will cease mining operations on December 31, 2021, and transition to mine reclamation in the years to follow.