Hydroelectricity | The promise of pumped energy storage

The megawatts of wind and solar electricity are multiplying like hot cakes. But what to do when the sun or the wind is so strong that production exceeds consumption? Around the world, pumped energy storage projects are emerging. Canada is lagging behind, paradoxically because of its hydroelectric wealth.

Global hydroelectric storage capacity, or pumped energy storage, is expected to increase from 160 GW to 240 GW by 2030, according to the World Hydropower Association (IHA). China alone plans to double its capacity, from 60 GW in 2025 to 120 GW in 2030.

“Hydropower storage is one of the fastest solutions to meet a peak in demand or a need to balance grid frequency,” says Alex Campbell, director of research at the International Hydropower Association (IHA), contacted in England.

In early July, the Ontario Society of Professional Engineers (OSPE) released an analysis supporting pumped energy storage. The analysis concluded that if batteries rather than pumped storage were used to compensate for the intermittency of solar power, electricity rates could triple.

The only existing storage pumping station in Canada, whose emptying would generate 600 MW for eight hours, is located in Niagara Falls. It has been around since the 1950s. Its reservoir was recently renovated at a cost of $60 million.

Seven projects in Canada

Seven other pumped hydro storage projects are planned in Canada: in Ontario, Alberta and the Yukon. They are all planned for the 2030s – some have been in the planning for a decade.

“I have been working on hydroelectric storage for five or six years, explains John Mikkelsen, director at TC Energy. Our project in Ontario, on a military base, is planned [géographiquement] based on the entire Ontario network. »

The base in question is near Meaford, north of Toronto. This 1000 MW project, which could provide this energy for 11 hours, would pump water from Georgian Bay to a reservoir built on this base.

In Alberta, the TC Energy project is located in a former mine near Canyon Creek, 300 km north of Edmonton. With a capacity of 75 MW for a power supply for 37 hours, it is “closed loop”, that is to say that the water would be pumped from one reservoir to another, located at the top of the mine.

Alberta has two other hydroelectric storage projects, at Tent Mountain and at Brazeau in the foothills of the Rocky Mountains. “We are still in the process of planning the financing of the operations,” says Blain van Melle, vice-president at Transalta, which manages the two projects. Interestingly, “Alberta has a funding program to balance the frequency of the power grid,” he says. However, intermittent energy such as solar or wind power introduces frequency fluctuations in the networks”.

Taking advantage of a disused mine located on top of a mountain, Tent Mountain has a capacity of 320 MW for 15 hours. Two configurations, 600 MW for six hours or 900 MW for four hours, are being considered for pumped storage at Brazeau, which is located near the river of the same name. A hydroelectric plant has existed nearby since the 1960s.

Another hydroelectric storage project is planned in Ontario, at La Marmora near Belleville. With a capacity of 400 MW for a supply for 5 hours, this project involves the construction of a reservoir on the surface, fed by a second reservoir at the bottom of an abandoned mine, 200 meters below. It is therefore also a closed-loop project.

The more embryonic Yukon project would have a total capacity of 48 GWh, which is equivalent to 480 MW for 100 hours, thanks to a drop of almost a kilometer between the two lakes.

Relative delay

Paradoxically, Canada’s relative backwardness in pumped energy storage is probably explained by the high proportion of hydroelectricity in its production.

What is the proportion of hydroelectricity in production that ensures trouble-free growth of wind or solar? “That’s the $64 billion question,” says Campbell. An as yet unpublished government report suggested that hydroelectric storage capacity equivalent to half of the intermittent capacity was needed. »

The search for an appropriate financing model is delaying the construction of pumped storage sites. “We’re going to have to pay the operators of these plants even if they don’t produce energy all the time,” says Campbell. When there is a monopoly, it is a little easier. England has also launched a pilot project to fund network frequency balancing services. »

And Quebec?

Hydro-Québec currently has no pumped storage project. “If the option of pumped reserves is indeed part of the range of possibilities evaluated, we have no project in development at the moment,” says Francis Labbé, communications advisor at Hydro-Québec.

Last year, however, the British company RheEnergise did a test of pumped storage at the Montcalm ski mountain, near Rawdon. “It worked very well,” says Christian Porowski, engineer at RheEnergise. This allowed us to win a competition to build a 500 kW demonstration station in England. »

RheEnergise, which has no other project in Quebec, does a large part of its engineering tests in laboratories in Lachine. It has just inaugurated a new laboratory in Montreal, to carry out tests with a more viscous fluid that it uses for energy storage. With a fluid denser than water, comparable to almond milk, it takes less height to store the same amount of energy.

“There is a lot of interest in fluids other than water around the world,” confirms Mr. Campbell of the IHA.