Durable Solar Roads Will Be Tested on Four Continents

In the search for sunlight-harvesting real estate, one French engineering group is turning to roadways. As Bloomberg reports, Colas SA, a subsidiary of Bouygues, has plans to incorporate super-strong solar panels into pavement around the world.

The team has already designed technology capable of collecting solar energy while supporting heavy tractor-trailers overhead. At the apparatus’s core is a regular solar panel. Colas SA’s Wattway unit has reinforced it with several coatings of different plastics to protect the solar cells inside without blocking the Sun's rays. A layer of crushed glass on top keeps cars from sliding. Wiring in the road routes the power directly to the grid.

Construction of a test site in Tourouvre in Normandy, France began last month. The kilometer stretch of road includes more than 30,000 square feet of photovoltaics, which are predicted to generate up to 280 kilowatts of energy. According to Wattway, that’s enough electricity to power a year’s worth of public lighting in a town of 5000. In addition to supplementing the power grid, Wattway’s solar roads can also charge electric cars, light billboards, and run hydrogen power plants.

Wattway isn’t the first group to come up with the bright idea. Last year, the Missouri Department of Transportation announced plans to build America’s first public solar road along a section of Route 66, and in that same year a solar bike path in the Netherlands generated enough energy to power homes for year. But this latest project is especially ambitious—after building their next two sites in Canada and the U.S., Wattway has plans to test the technology in Africa, Europe, and Japan. They’re installing panels in 100 test sites over the next year with hopes to have them ready for commercial use by 2018.

Before that happens, the group needs to ensure their panels can withstand the weight of traffic. At this point, their panels can hold up beneath an 18-wheeler truck, but Wattway’s chief technology officer Philippe Harelle says they may have worse luck under a snowplow. Cost is another roadblock: Panels used in solar roads are more expensive than the ones used in solar farms. But unlike solar farms, panels embedded in highways take advantage of free space. As Harelle told Bloomberg, “We wanted to find a second life for a road.”