Late December last year, France inaugurated its first, and the globe’s first, “solar highway.” The road in question is paved with solar panels delivering enough energy to power the street lights of the small Normandy town of Tourouvre. The 1-km-long “Wattway” is covered with 30,000 square feet of transparent plastic-coated solar panels treated to replicate similar grip to that of a conventional asphalt-coated street.
|Initial testing of the Wattway was carried out at car parks and spaces adjacent to public buildings.|
The Wattway project has received a total French government subsidy of $5.25 million, with initial deployment having come earlier at a smaller scale at four pilot sites in France in parking lots and in front of public building typically involving areas of 500 to 1ooo square feet. The technology has also been tested on a 70-m-long cycleway in the Netherlands.
An average of 2,000 cars use the road in Tourouvre each day, testing the durability of the panels for the test bed project carried out by French civil engineering firm Colas, a subsidiary of construction giant Bouygues. The developer notes that the typical roadway is occupied by cars only around 10–20 percent of the time. “The remainder of the time it is looking up at the sky.” Colas estimates that in theory France could become energy independent by paving only a quarter of its 621,000 miles) of roads with solar panels.
One reported drawback of the system is that solar panels are more effective when angled toward the sun, typically on slanted rooftops, than when they are laid flat. Further, the cost question is far from being resolved. Each kilowatt-peak generated by Wattway currently costs almost $18, compared with around $1.40 for a large rooftop installation. Colas targets cost competitiveness by 2020, noting that the cost of producing solar energy by conventional means decreased by 60% between 2009 and 2015, according to the French Renewable Energy Association (SER).