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The World's First and Costly Solar Road in France

Tourouvre au Perche, France is the site of the first solar highway. It’s a short, one kilometer comprised of photovoltaic panels by Colas; named Wattway. There are 2,800 square meters of photovoltaic cells in them, and the hope is that this new solar tech will provide enough electricity to keep the village street lights powered up. But, it was installed at the cost of $5.2 million and because it’s technology has never been tried on a roadway, there are some significant questions concerning whether it will hold up; as thousands of vehicles drive across it daily. It’s also not certain if the experimental project will result in enough electricity to be useful to the town. For these reasons, thinking people are wondering why it was built at all.

Colas, a global leader in road construction, in partnership with the French National Institute for Solar Energy, created Wattway, the first road surface which is photovoltaic. It is a French invention, and is patented. Able to supply clean electric energy regardless of vehicle traffic, the surface is a combination of techniques used in both photovoltaic production and road construction. It took 5 years of joint research to develop Wattway, but both entities hope that it will supply renewable energy harvested from the sun to power streetlights, shops and businesses, and off-grid, isolated locations.

Colas was founded in 1929. Originally known as Société Routière Colas, it’s parent companies were Société Générale d'Entreprises (SGE) and Shell. Its original purpose was to specialize in bitumen emulsion production. Colas realized the patent for cold asphalt bitumen emulsion. During the 1930s, Colas operations expanded to parts of Africa and the French Caribbean. During the period from 1950 to the 1970s, the company continued its global expansion to reach the United States, Canada and spread throughout the African continent. By the 1980s, Colas had expanded into Europe, Oceania and Asia with acquisitions of construction companies, quarries, and gravel pits in its local areas of operation. Though the company business has always involved developing roadways, it also expanded to include civil engineering, railway construction, and joint venture projects such as building the Jakarta airport.

Colas has 57,000 people in its workforce, with the majority working outside of France. The company is responsible for approximately 80,000 projects each year. It maintains a network of 2,000 sites for material production and includes a construction network of 800 units, spread across 5 continents and represented within 50 countries. The consolidated revenue for Colas in 2015 was 12 billion euros. The company’s core business is roads, which account for approximately 80% of its activity.

Colas has a wide variety of road construction and maintenance projects:

  • Roads
  • Highways
  • Runways
  • Ports
  • Industrial platforms
  • Logistics hubs
  • Bus lanes
  • Tramways
  • Bike paths
  • Recreational facilities
  • Motor raceways
  • Environmental projects

The company also operates complementary activities to is core road business including the recycling and production of materials it uses for construction, waterproofing, refined products sales, road signaling and safety products and railways. Creating Wattway was one natural extension of Colas focus on environmentally progressive roadway projects.

Wattway is unique in the rapidly emerging area of solar road technology because it can be applied on existing roads. There is no need to destroy or rebuild the existing roads it lives on. This is one primary advantage, because it costs less overall in regards to the energy it produces. The Wattway panels are sturdy. They have been tested extensively, and proven to bear, without damage, one million passes of truck tires over their surfaces.

Wattway panels are made with encapsulated silicon cells and sealed junction boxes. This makes them not only rainproof but also can withstand snowplow passes, though operators will need to be more careful when removing snow from them. As long as the asphalt pavement is free of asbestos, cracks, deformation or ruts, Wattway panels may be applied over it, regardless of whether it has tight curves and complies with standard commercial and technical specifications. Currently, Colas is taking orders for roadway sections ranging from 10 to 50 meters. The company plans to offer Wattway panels for private driveways and roads within two to three years, but the panels will need an authorized technician to install them. The panels are installed by hand, but the company is designing a mechanical process to improve the time it takes for application. The panels are expected to last for 10 years under heavy traffic and up to 20 years in parking lots and less trafficked sites.

Wattway is able to convert an existing surface into an energy producer. Unlike solar panels, which require either a rooftop or land area for installation, often at high purchase or rental prices, Wattway can use parking lots, walkways, bike paths or unused sites for installation. Wattway panels yield 15% energy in comparison to traditional solar panels which yield 18 to 19% energy. Wattway panels may be recycled when their service life reaches its end. Because the panels use recycled glass and their weight is lower than conventional panels, Colas foresees a future carbon assessment which is favorable.

The little village of Tourouvre hosted Ségolène Royal, the Ecology Minister of France, to officially open the new road. Royal commended the ability of the new road to provide electricity without using large areas of real estate. There are approximately 3, 400 residents in the village, and the trial site will be in testing for two years. But, it is expected that the Wattway will produce an average of 767 daily kilowatt-hours.

Jean-Charles Broizat, Director for the Wattway Tourouvre project site released a statement noting that the site allows Colas to optimize and improve the installation and manufacturing processes associated with Wattway photovoltaic panels. Before the Tourouvre RD5 road was surfaced with Wattway and opened, four car parks in France applied and tested the panels. The village project was financed by grants from the state, and critics have noted that panels installed on flat surfaces are less efficient than those installed on slopes. Some energy experts have stated that the technological advance may not have been the best use of public money because the amount of energy Wattway will produce is yet to be confirmed, and may not prove to be cost-effective.

Though the solar road in Tourouvre au Perche has caused curiosity and much speculation, it is just the beginning for Colas and Wattway in France. Approximately 621 miles of Wattway is scheduled to be installed on French roadways, providing solar energy throughout the country. It is a project which is expected to last five years. The unique multi-layer construction of Wattway provides tire grip and ensured resistance within its 7mm thick system, and this makes it much more roadway friendly than other products. It also has the advantage of being able to provide public lighting for 5,000 city residents with just 1 kilometer of road surface. The world’s first and costly solar road has welcomed the future to today.

Garrett Parker

Written by Garrett Parker

Garrett by trade is a personal finance freelance writer and journalist. With over 10 years experience he's covered businesses, CEOs, and investments. However he does like to take on other topics involving some of his personal interests like automobiles, future technologies, and anything else that could change the world.

Read more posts by Garrett Parker

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