First French testing site for offshore wind at Le Croisic

France's first experimental site for marine energies is up and running 20 kilometers off the Atlantic coast at Le Croisic, west of Saint-Nazaire. The first prototype destined for the site is likely to the floating demonstration turbine Winflo, scheduled for installation early 2014.

"There are very few operational testing sites, and they don't meet the need," said Bertrand Alessandrini, director of development and industrial relations at the Ecole Centrale Nantes (ECN), the engineering school that developed and manages the site.

The site, known as SEM-REV, extends over one square kilometer, with depths of 35-40 meters and a seabed allowing easy anchorage.

It is connected to the grid by a high-tension cable with a total capacity of 8MW, which can connect four prototypes simultaneously. It was manufactured by France's Silec Cable and will be operational in late January or early February.

The site is fully authorised, with a concession for 20 years. ECN has more than two years' worth of data from wind and oceanographic measuring equipment installed at sea. Wind speeds average just under 10m/s.

SEM-REV represents an investment of around €18 million and is funded by ECN, the Loire-Atlantique department, the Pays-de-la-Loire region, the French state and the EU.

Buying and laying the cable took up about 85% of this investment. The cable is buried to a depth of about 1.5m or protected by mats, and tunneled under the coastal zone.

ECN estimates it will cost around €200-400m/year to maintain the cable and the connection point at the site. The school will defray some of this by selling the electricity generated during the tests.

The floating turbine concept Winflo is being developed by France's independent offshore wind company Nass&Wind in partnership with defence and shipping firm DCNS and turbine manufacturer Vergnet.

Under an initial agreement with ECN, the consortium will install a prototype at SEM-REV. Signing of the contract is expected mid-March, according to site manager Christian Berhault.

The prototype will be equipped with an adapted version of Vergnet's 1MW onshore turbine, sitting on a floater manufactured by DCNS. The prototype will probably be assembled in Brest, before being towed to the test site. Tests are expected to last at least 18 months.

ECN is also in discussions with Denmark's Floating Power Plant regarding its Poseidon project, which combines wind and wave energy, Berhault said.