A giant water battery in the Alps could be a key turning point for renewable energy in Europe

Switzerland has unveiled its latest innovation in renewable energy: a giant water cell.

Commissioned in July, Nant de Drance is a pumped-storage hydroelectric power station that offers the same energy storage capacity as 400,000 electric car batteries.

Located high in the Swiss Alps, in the canton of Valais, the plant is equipped with agile and reversible turbines that offer new levels of flexibility, said Robert Gleitz, delegate to the board of directors of Nant de Drance: at the touch of a button, the power plant can switch from energy storage to electricity supply.

The huge project lasted 14 years: about 17 kilometers of underground tunnels were dug in the Alps and the 6 turbines are installed 600 meters underground, in a giant cave the length of two football fields.

The project reused two existing reservoirs – it holds more water than 6,500 Olympic swimming pools. As one of the largest facilities of its kind, the project

Nant de Drance repurposed two existing reservoirs, raising the upper reservoir by 21.5 meters (71 ft) to double its capacity – it now holds more water than 6,500 Olympic swimming pools.
As one of the largest facilities of its kind, the €1.96 billion project could play a vital role in stabilizing Europe’s power grid as the Old Continent transitions to renewables, Gleitz said.

Pumped-storage hydropower plants, which have been around for more than a century, are particularly important for renewable energy, because wind and solar energy are highly dependent on the climate and do not provide a constant energy supply. “We can take power (from the grid) when there is plenty of it and generate it again when we need it,” Gleitz said.

“Open flow” pumped storage hydropower plants are built on river systems and require the construction of dams, with natural consequences for wildlife and damaged ecosystems. That’s why modern designs favor closed-loop systems, like Nant de Drance, that don’t affect river systems, says Andrew Blakers, professor of engineering at the Australian National University.

“The era of building dams is almost over,” says Blakers, adding that these closed-loop power plants take up a relatively small amount of space, given the energy security they provide – he estimated that to power a city of one million people per 24 hours would require approximately two square kilometers of flooded land, adding that pumped storage offers one of the most efficient energy storage solutions currently available. Drance’s Nant sends about 80% of the electricity it takes back to the grid and stores about 20 hours of reserve power, Gleitz says.

Hoping to become the “first climate-neutral continent”, Europe has big ambitions for renewable energy: in 2020, just over a fifth of the continent’s total energy came from renewable sources, but in May this year , the European Commission has raised renewable energies. energy targets for 2030 at 45%.

To that end, new high-capacity storage facilities are essential, says Blakers. The European Energy Storage Association has estimated that the continent will need 200 gigawatts of storage by 2030, more than four times its current storage capacity. Between 2010 and 2020, only 8 gigawatts of storage were added to the network.

This is why Nant de Drance is such an important project: located at the geographical heart of Europe, Switzerland can offer grid stability across the continent, says Rebecca Ellis, head of energy policy at the International Association of hydroelectricity – Nant de Drance has increased Switzerland’s installed electricity capacity by 33%, says Ellis, adding that it “shows the country’s leadership” in the transition to renewable energy.

Reversible hydropower can also provide energy security outside Europe: Blakers and his team have identified around 600,000 potential sites for closed-loop systems – although only 1% of these are needed to meet the needs global total energy storage, he added. .

As the climate crisis intensifies, Gleitz hopes Europe will embrace the “clean energy storage” potential provided by pumped-storage hydropower. “If we want to move in the direction of clean energies, Nant de Drance is one of the stages on this path”, he concluded.

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