Energy beyond the battery

Stacked cement blocks. Molten salt. A flywheel. Compressed air. Water pumped to higher reservoirs. And… the good old battery. Energy storage technologies are booming. As renewable energies are often intermittent, it is necessary to find bridges between windy and sunny moments.

Mathieu Perreault
The Press

Batteries

Since last year, Hydro-Québec has set out to conquer the planet’s energy storage markets. Its EVLO division, with its 0.5 gigawatt-hour (GWh) batteries, has won contracts near a wind power plant in France and near a solar power plant in the suburbs of Montreal. “We also launched a 1 GWh system and we are working on a system with even more storage capacity, probably 1.65 GWh”, explains Sonia St-Arnaud, CEO of EVLO.

EVLO systems are also installed in Quaqtaq, to ​​test solar potential in Nunavik, and in the Lac-Mégantic microgrid. According to M^me St-Arnaud, the capacity density of EVLO’s batteries is constantly increasing, with an expected improvement of 50% between the 1 GWh system and the 1.65 GWh system.

Batteries are likely to be needed near variable energy sources, such as wind turbines and solar power plants, to guarantee storage for a few hours, said Venkat Srinivasan, energy storage manager at the US government’s Argonne National Laboratory.

“For longer-term storage, such as at night when there’s no sun and the few times in the week when it’s not windy, you’ll need other systems,” says Srinivasan. But it is estimated that costs will have to be reduced by a factor of ten for the other storage systems to become operational. »

Ontario

Ontario has been experimenting with several of these “exotic” storage technologies over the past decade. Network-connected systems include flywheels, inertia-rotating wheels, and compressed air. “We’re also looking at chemical storage, like molten salt, which releases energy when you solidify it,” says Katherine Sparkes, director of innovation at the Independent Electricity System Operator of Ontario (IESO). .

The IESO currently has 48 MWh of energy storage, the vast majority in the form of batteries, and plans to contract additional storage systems under a general tender for 1,200 MWh this year. Companies in Ontario are working on a system of pulleys where cement blocks are stacked. When we need the energy, we bring them down.

Hydrogen

Another avenue is the production of hydrogen by electrolysis – hydrogen which can then be used, if necessary, in a fuel cell. “If you want to store a lot of energy, for example for several months, hydrogen will probably be the best solution,” says Loïc Boulon, from the University of Quebec at Trois-Rivières, who is working on this technology.

“Think of the energy we need in winter in Quebec, or in summer in regions where there is a lot of air conditioning. The problem is that we have an efficiency of 50% with fuel cells, compared to 80% for batteries. According to Mr. Boulon, fuel cells are on the eve of a rapid technological advance, just as batteries were 10 years ago.

Switzerland

Since last year, Switzerland has had a natural battery in the form of a pumping station at the Nant de Drance hydroelectric power station. This infrastructure is the equivalent of a 900 megawatt battery. It is powered by nuclear energy purchased in France at night, when costs are low. “We have had a 175 MW pumping station in Niagara Falls since the 1950s,” says Ms.^me Sparkes.

Hydro-Québec, for its part, does not plan to add a pumping station in its existing power stations because they are too far from the wind farms whose current supply must be regulated, according to Francis Labbé, head of communications for innovation. to the state corporation. In any case, Quebec reservoirs already play the role of giant batteries, underlines Mr. Labbé.

An Australian study last year targeted more than 600,000 places around the world where pumped storage of water could be profitable. Pumped storage is not usually part of energy storage statistics since it is a mature technology for decades, with energy losses below 20%.

The Montreal solution

For the past year, engineers have been testing the pumping of a fluid 2.5 times denser than water, in a laboratory on the edge of the Lachine Canal. The fluid used is called R-19 and was developed by the company. Its recipe is secret but it is an inexpensive powdered solid suspended in water. RheEnergise, founded in London, will test its pumped energy storage solution this summer on Mont Montcalm, near Rawdon. “With a denser fluid, you need less height or less infrastructure to store energy by pumping fluid up,” explains RheEnergise CEO Stephen Crosher in an interview from the United Kingdom. United.

These facilities should be the size of the basin of a water treatment plant, and the necessary height, that of Mount Royal, according to Tamás Bertényi, chief technology officer of RheEnergise. Mr. Bertényi moved to Montreal eight years ago and worked on sustainable energy projects with Aboriginal businesses. “Montreal is very conducive to hiring engineers, we have four of them and we aim to hire about ten more within a year,” says Mr. Bertényi. All the engineering is done in Montreal, and a pilot plant is planned for mid-2024 near Plymouth, England.

An underestimated cost

If you take into account energy storage needs, or the need to build and maintain a natural gas plant to compensate for fluctuations in wind power, the cost of renewable energy is probably twice as much higher than the outright construction of a solar or wind power plant, according to Mr. Srinivasan, of the Argonne laboratory.

“But it’s an average,” he adds. In regions where there is a lot of hydroelectricity, the increase in cost is small, and in the extreme, in regions that are poorly connected to other electricity networks, it is higher. In Hawaii, for example, each island must have its own storage capacity. »