Tent Mountain Renewable Energy Complex

Tent Mountain

The Tent Mountain Mine is a reclaimed legacy coal mine, located approximately 16 km west of the township of Coleman, Alberta. Operations ceased at the mine in 1983.

In April 2023, TransAlta purchased 50% of the Tent Mountain Renewable Energy Complex from Evolve Power (Evolve) (formerly Montem Resources). Together, TransAlta and Evolve have formed the Tent Mountain Pumped Hydro Limited Partnership (the Partnership) to jointly develop the Tent Mountain Pumped Hydro Energy Storage (TM PHES) Project (the Project), with TransAlta acting as the Project Developer.

Pumped Hydro Energy Storage Explained

Pumped Hydro Explained Diagram

Pumped Hydro acts as a large battery and provides stability to the power grid. The installation of new inlet/outlet pipes will connect an existing reservoir at the top of Tent Mountain with a reservoir to be constructed at the base of the mountain via a 300m drop (or “head”) between the two reservoirs. The 300 m drop facilitates power generation via four 80 MW reversible Francis turbines to be situated in a power house at the base of the mountain. The power generated by the Project will be connected to Alberta’s electrical grid via a new 240 kV transmission line.

The TM PHES Project will act like a large battery; when there is an abundance of wind and solar power available the TM PHES Project will use grid electricity to pump water from the lower reservoir to the upper reservoir. When there is a shortage of wind and solar power the TM PHES Project can dispatch power to Alberta’s electricity grid for up to 15 continuous hours.

Additional facts & figures at a glance:

Storage CapacityUp to 4,800 MWh
Project Life80+ years
Continuous Generation DurationUp to 15 hours
Turbine Configuration4 x 80 MW fixed speed reversible Francis turbines
Maximum Gross Head320m
Minimum Gross Head288m

While renewable energy generation is rapidly increasing in Alberta, wind and solar power are inherently intermittent, only producing power when the wind blows or sun shines. The Project will provide dispatchable renewable energy to the Alberta power grid. The Project will firm intermittent renewable generation and provide grid stabilizing ancillary services to Alberta’s electric system, which is a critical element of the energy transition in the Alberta.

The TM-PHES will provide approximately 200 construction jobs and approximately 30 long-term jobs. As many as 400,000 Alberta homes could be powered simultaneously by the Project. The TM PHES Project will help to lower power prices for all Albertans, and powered by renewable energy the Project will abate CO2 emissions by up to 400,000 tonnes per year.