France builds stealth wind turbines to avoid radar interference

France is building the world’s first wind farm with turbine blades designed to minimise interference with radar systems, using technology partially inspired by stealth warplanes.

EDF Energies Nouvelles, the renewables unit of state-controlled utility EDF, aims to install the new Vestas-built turbines next spring in the “Ensemble Eolien Catalan” wind farm near Perpignan and start operating them over the course of 2015.

“It is a world premiere for this new technology,” an EDF EN spokeswoman said.

The turbines will account for the entire 96 megawatts of capacity, which she said would make it the biggest wind farm in France.

Around the world, dozens of wind farm projects have been blocked or delayed because of potential radar interference, which can mask the signals of other objects. Turbine makers have put years of research into radar signature reduction, most of which is still in the experimental stage.

Denmark’s Vestas, the world’s largest maker of land-based wind turbines, said the new blades would have a smaller radar signature.

“We have used surface treatment technologies, including those derived from military applications,” said Nicolas Wolff, head of the Danish firm’s French unit.

Radar-evading jets such as the Lockheed Martin F-117 Nighthawk use a combination of shapes, angled surfaces and radar-absorbing coatings to mask their “radar cross section“, a measure of the extent to which they are detectable by radar. - Reuters