What if our roads carried more than just people and goods? With Wattway, Colas has devised a unique concept of photovoltaic road surface.
After five years of research, carried out in partnership with the National Institute of Solar Energy, Colas, a subsidiary of the French Bouygues group, unveiled Wattway, the solar road. It is a major innovation which enables roads to create renewable energy and it contributes to solving the issue of energy transition.
Wattway is comprised of photovoltaic tiles that are placed and glued directly on the surface of existing roads, and does not require civil engineering works. The cells on each tile capture solar energy through a sheet of polycrystalline silicon which transforms solar energy into electricity.
The main innovation lies in the resins and polymers used to coat the photovoltaic cells; they are sufficiently translucent to let light through.
The undersides of the panels are connected to a lateral module containing the electrical safety components. The panels can be used on any road and can withstand all types of vehicles, including heavy goods vehicles. The panels are very thin - only a few millimetres thick - but they extremely sturdy, they are slip resistant and are designed to last.
Wattway could be used to power street lighting, illuminated signs, tram lines, houses, offices, and more. 20 m² of Wattway can supply enough electricity to power a single home (not including heating). According to Colas, one kilometre of roads fitted with its panels could power the street lights for a town of 5,000 inhabitants.
Wattway could also be used to power remote areas where the cost of connections to the electricity grid is too expensive.
More generally, this short-circuit energy production technology could be most useful for isolated rural areas of developing countries in which it is difficult to obtain connections to the electricity grid.