USHANT — Drizzle joined wind gusts to welcome us in the Iroise Sea this cold morning. Having left from Le Conquet, on the western tip of the French region of Brittany, our blue-and-white boat greedily eats up the waves, heavy with foam. The lighthouse of Kéréon, one of the five that keep watch over Ushant, towers in a gloomy sky once we pass the Molène archipelago.

We're two kilometers away from the coast, in the Fromveur Passage, where there's a very strong current of up to nine knots. It's here that a hydraulic turbine that could change the lives of Ushant residents was installed 55 meters below sea level last year. It has since been providing a modest portion of their electricity needs, a part that will hopefully continue to grow. It represents a first for France, and a first in the world for such an island.

Using a turbine that's activated by the flowing water in the same way that a wind turbine is activated by the wind, the project is creating electricity. France is well placed to exploit this blue resource, and promises of energy from the abyss are beginning to materialize.

This is a huge challenge for Ushant and its 900 permanent residents — four times fewer than a century ago. "Up until the 1960s, men were working in the merchant navy while women maintained a subsistence agriculture," says Mayor Denis Palluel. "This system collapsed, and tourism is now our main activity. It's as if we were nothing but a natural reserve. But with the marine power project, we're once again looking towards the future by reviving our maritime past."

Seizing the opportunity

The town council approved without hesitation the energy proposal offered by the Sabella start-up from mainland Brittany. Its 15 technicians designed a machine of "technological rusticity," says CEO Jean-François Daviau, who worked for 25 years in the offshore petroleum sector.

The D10 is a colossal machine that operates in a hostile, corrosive environment. It weighs 450 tons, including 100 tons for its tripod alone. It rests on the sea floor, but at 17 meters (56 feet) tall it's as high as a five-story building. The rotor is 10 meters (33 feet) in diameter, and its blades can rotate one way when the tide rises and the other when it recedes.

"It's a demonstrator," Daviau says. "We're still in a learning phase." For this testing period, scheduled to last one year, the turbine's 1.1-megawatt capacity is restrained, currently providing energy to just 50 houses for now. But if the experiment succeeds, a hydraulic power farm comprised of three machines could be installed in the Fromveur Passage two or three years from now, producing enough electricity for half the island.

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One of the surrounding lighthouses off of Ushant — Photo: Falken

That would represent a dramatic environmental change for Ushant. Located about 20 kilometers from the mainland, this land of rocks and moors isn't connected to the electrical grid. Instead, it draws its power from a plant that burns fuel brought by boat, about 2.2 million liters every year, which releases 6,000 tons of carbon dioxide into the atmosphere.

On a roll

"We're proud of being able to use the island's maritime resources," says the mayor. On top of hydraulic power, the municipality aims to take the energy transition one step further by helping with thermal renovations of houses, distributing low-energy light bulbs, covering the local sports hall with solar panels, and purchasing electric cars that will run on energy drawn from the ocean.

Nature in Ushant is precious. Grey seals and dolphins are plentiful around the island, and its cliffs shelter herring gulls, cormorants and fulmars. That's why before green-lighting the hydraulic turbine project, the Iroise Natural Marine Park proposed a few conditions.

"We recommended that the noise made by the machine under water be monitored, as well as its impact on the wildlife," explains director Philippe Le Niliot. "We also recommended that the sediments be monitored, because the strong currents in the Fromveur Passage bring with them sediments that eventually form dunes in which the fish live."

The machine has therefore been equipped with sensors and cameras to observe its impact on the surroundings and on the ecosystem. But at least one danger seems to have been ruled out: Because the blades make only 13 to 15 rotations per minute, there's no risk of making mincemeat of marine mammals.

Ushant is a pioneer, but bigger projects are being planned elsewhere in Brittany for the next few years. "We're switching from prototypes to an industrial scale," says Pierre-Guy Therond, director of new technology at renewable energy group EDF-Energies Nouvelles. He believes France has the hydraulic potential equivalent to two nuclear reactors. But to extract all that power would take hundreds of turbines, a whole different scale, both technically and environmentally.

For the time being, Ushant dreams only of gaining its energy independence. Now famous thanks to its hydraulic turbine, the island is welcoming delegations from Indonesia and northern Canada, both interested in the technology. Inuits asked about the potential threat that the blades might represent for the seals, explaining that they would never endanger the creature that represents the basis of their diet.