France is now home to the world's first solar road

Wattway solar roadway
© COLAS – Joachim Bertrand

It's only 1 kilometer long, but a two-year test of the solar road will help determine if a full rollout of 1000 km of solar roads in the country is worth pursuing.

Here we go again with solar freakin' roads, but this time, there's an actual deployment of solar panels in a village roadway in Normandy, France. Almost a year ago, we brought you the news that France was exploring the building of 621 miles (1,000 km) of solar roadway in the country using Colas' Wattway solar pavement, which was met with a rather divisive response - either outright skepticism or undying support for the idea. And that's probably appropriate, because although solar technology is rapidly maturing, and innovations in materials are enabling a new approach to 'embedded' solar, the idea of putting solar cells on roads, instead of in optimal locations such as rooftops or vacant land and tilted toward the sun's path, is still rather odd.

The new solar road, also dubbed Wattway, covers 1 kilometer (.6 miles) of roadway in the village of Tourouvre-au-Perche with 2,880 solar panels, with an estimated 2000 motorists using it each day, and the electricity generated by the system will go to power the street lighting in the small village, which has just 3,400 residents. According to the company, the annual electricity production is expected to be 280 megawatt-hours (MWh), with the average daily electricity production estimated to be 767 kilowatt-hours (kWh), and peak periods of up to 1,500 kWh per day during the summer. The electricity will be fed into the network of Enedis, the French electric provider.

"Each panel contains 15-cm wide polycrystalline silicon cells that transform 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 surface that is in contact with vehicle tires is treated to ensure skid-resistance equivalent to conventional asphalt mixes." - Wattway

The solar roadway in Normandy was a rather expensive stretch of road (considering that it's not actually a new roadbed, but is instead installed over the top of the road), with The Guardian reporting a cost of some €5 million for the project, which could probably buy a massive amount of electricity from an existing solar plant.

"We are still on an experimental phase. Building a trial site of this scale is a real opportunity for our innovation. This trial site has enabled us to improve our photovoltaic panels installing process as well as their manufacturing, in order to keep on optimizing our innovation." - Jean-Charles Broizat, Wattway Director

France doesn't get all the solar roadway glory, though, as there is a small test section (50 square meters) of Colas' Wattway solar panels installed at the Georgia Visitor Information Center in West Point, Georgia, which is expected to generate some 7,000 kWh of electricity annually.

Interestingly enough, Colas isn't a solar company, but a roadway company, and is the world's leading manufacturer of bitumen emulsion for roads. Its name speaks to that ("Cold Asphalt"), as the company was founded in 1929 to commercialize a patent for making bitumen liquid at ambient temperatures, which made for easier handling, application, and immediate hardening of the substance.

One good thing going for this project, regardless of whether the results are favorable or not after two years, is that this real-world testing of solar roads will help inform (or dissuade) future projects such as this. More info on the projects is available at the website.

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