After much hype, France’s solar roadways dream appears to be shattered. Literally.
The plan was simple. Embed solar cells under a few millimetres of robust, largely transparent material able to protect the fragile cells from the thundering traffic above. Roads are exposed to the sun more often than not so what could go wrong?
From the start, this was a problem that did not need a solution as existing, standard solar technology was doing the job at a fraction of the cost.
The first 1km of solar roadway was built in Normandy, France in 2016 with then Ecology minister Segolene Royal dropping by to mark the occasion. The pilot, which cost $5 million, was the result of French research and the manufacturer of the final product, Wattway, was a subsidiary of domestic construction and engineering firm Colas.
In 2018 there were reports that the yield of the roadway had fallen way below expectations. A section of road was reportedly replaced entirely. Also, leaves on the surface of the road created imbalances in the performance of the panels, which operate to their best with a uniform amount of light across their surface. This is why rooftop installs look to avoid shading from nearby trees and other obstacles whenever possible.
Now, the latest update from the trial, reported by French newspaper Le Monde, is that Wattway will not be focusing on solar roads anymore with small-scale applications such as CCTV now the focus.
Even at the time, this seemed baffling to many in the solar industry. Rooftops are exposed to the sun all day and very rarely have to contend with the weight of traffic above. Neither do those placed on low-grade land, brownfield sites or mixed-use agricultural sites. Sure the standard panels need to be cleaned from time to time, but so will a road surface just a few inches from the 2000 exhaust pipes passing overhead every day.
A lot was made by its proponents about solar roadways’ ability not to take up additional space. Again, using the space between rows of panels for grazing only makes land-use more efficient. Mounting modules above car parks protects the vehicles below from the sun (and rain). Floating solar is providing new uses for water surfaces, including industrial wastewater ponds, reservoirs and lakes. Landfill sites offer another opportunity. The empty land within the perimeter of airports is being exploited, the list goes on.
Solar power has an exciting future with growth fueled by falling costs, investors’ increasing comfort with the technology and a softer demand created by a spate of clean energy targets. The news that one strand of innovation has run into a dead-end is no cause for alarm.
