In December 2016, the then French Environment Minister Ségolène Royal opened an approximately one-kilometer-long road paved with photovoltaic modules near the small town of Tourouvre in Normandy. The aim of the project, which cost around €5 million, was to test whether the electricity thereby generated would be sufficient to operate the town’s street lamps. If successful, France planned to pave up to 1,000 km of highways with the panels. The project is though now considered a flop. In July, the Global Construction Review reported that the coating was proving to be insufficiently stable and was splintering in several places; by summer 2018, part of the road already needed to be redone. Moreover, even at peak times, the amount of electricity generated was reaching only around half the expected value. In addition, the speed limit needed to be reduced to 70 km/h due to the noise generated on the road.
The road surface, known as Wattway , was developed by international civil engineering company Colas near Paris in cooperation with the French National Institute for Solar Energy . The solar cells used consist of polycrystalline silicon and are embedded in a multilayer substrate. The film is supposed to be able to withstand the weight of tractors and trucks, but that obviously wasn’t the case.