Montem first started looking at an end of mine life PHES for Tent Mountain in 2019, undertaking a site assessment and economic analysis. The results were promising, but at the time Montem decided to continue progressing Tent Mountain primarily as a steelmaking coal mine re-start. With the current uncertainty surrounding the timeline of the mine re-start, Montem has brought forward plans to develop a PHES at Tent Mountain. The Tent Mountain PHES will be one of the primary elements of the TM-REX.

Montem has completed various technical, economic, and social studies for the Tent Mountain PHES that show a technically viable project that will create approximately 200 construction jobs and approximately 30 full time operational jobs over a 50+ year project life.

How Does a PHES Work?

Water is pumped into the upper reservoir using cheaper energy when demand is low or there is an excess of renewable energy.

When there is a spike in demand, or a drop off in wind or solar generation the water is released.

The water flows quickly down the pipes which turns the turbines to generate power.

Alberta needs dispatchable energy to firm intermittent renewables

Last 30 Days
Last 7 Days

Solar Generation

Wind Generation

PHES Grid Stability Benefits

Renewables Firming

The PHES can supply much needed energy when the wind is not blowing, and the sun is not shining


When the grid has too much renewable energy, the PHES can absorb the excess power

Transmission Congestion

The PHES is located near a major cluster of wind generators, and will help reduce congestion on transmission lines leading out of the region

Ancillary Services

The PHES can respond quickly to unexpected disruptions on the grid


The PHES will contribute inertia to the grid, which helps keep the frequency stable