Wattway, the new photovoltaic road

20 February 2016

For the first time ever, roads can produce electricity, while preserving their full capacity to bear vehicle traffic.

Colas, a world leader in transport infrastructure, in a partnership with the French National Solar Energy Institute, has developed Wattway, a new concept of photovoltaic road surfacing that is now market-ready. This innovation is a major technological breakthrough, a building block for cutting-edge projects involving intelligent roads and Smart Cities. Extra thin and extremely sturdy, Wattway photovoltaic panels provide excellent grip and durable performance. They are directly applied to existing roads, highways, bike paths, parking areas, etc., without any civil engineering work and can safely bear vehicle traffic of all types, while producing electricity. To supply an average single home (not including heating), only 20 m² of Wattway are needed. Protected by two patents, the cutting-edge technique is a major breakthrough, as it provides the road with a new function: producing clean, renewable energy locally, in addition to a road’s conventional use.
Thanks to the services it provides, the Wattway solar road is a cornerstone of the 5th generation of roads and Smart Cities.

This new generation of solar collectors will first surprise you by how thin the panels are (just several millimeters thick), by the fact that there is no glass panel, and by the overall impression of sturdiness. Their size can be adapted to fit any kind of road around the world.
Each panel contains 15-cm wide cells making up a very thin film of polycrystalline silicon that transforms solar energy into electricity. These extremely fragile photovoltaic cells are coated in a multilayer substrate composed of resins and polymers, translucent enough to allow sunlight to pass through, and resistant enough to withstand truck traffic. The composite “sandwich” is also designed to adapt to the pavement’s natural thermal expansion. The surface that is in contact with vehicle tires is treated to ensure skid-resistance equivalent to conventional asphalt mixes.
In this perfectly watertight layer cake, the electrical system is designed to ensure that the entire system does not short circuit if one cell is down. Electrical connections can be hooked up on the side of traffic lanes, in gutters or in ducts integrated in the panels themselves.