The thefts are believed to be carried out by the same gang of criminals, who break into the turbines and climb up to the nacelles before shutting down the power from the turbine, police sources told Le Figaro newspaper.
"Using shears and makeshift tools they then cut and rip out the metal wiring, which is mostly copper," an unnamed policeman said.
Up to a tonne of the metal can be stolen in the raids, which have generally been taking place in sparsely populated areas.
In response to this upsurge in criminal activity in and around the Picardy region, the police have increased patrols, including using night vision binoculars and helicopters to monitor more remote developments. Operators are also said to have increased security at a number of projects seen as at risk.
A tonne of copper is currently worth about EUR 5,000 on the wholesale market.