Wattway: Solar Road Powers Homes and Cities

France’s Colas Group is working with the National Institute for Solar Energy to outfit 620 miles of road in the country with solar panels that can be tied into the power grid to provide electricity to surrounding homes and cities.

The partners estimate that a 215-sq-ft section of a solar road could power a house and a 1-km (0.62-mile) stretch could generate enough electricity to power public lighting for a city with 5,000 residents.

Dubbed Wattway, the photovoltaic road surface is made of a thin (less than 7 mm thick) layer of crystalline silicon that can be glued directly on top of existing pavement. Other prototype solar roads have required building a new roadway or tearing up and replacing an existing one, which Colas notes is much more expensive and time consuming.

Currently the panels are installed by hand, but the company says it is developing an automated system. The panels can last 10 years of heavy traffic—and all weather conditions—and twice that long in less traveled areas. The panels are textured to provide grip and are said to be durable enough to withstand a snowplow.

Colas, which has been developing the technology since 2009, is conducting final tests with the French government. The partners hope to start installing the new Wattway in coming months and complete the job over the next five years.

In addition to solar energy, the partners envision future Wattways being used as part of a connected vehicle architecture with embedded sensors that could track traffic conditions, self-diagnose maintenance issues or recharge electric vehicles as they drive over the road.