World’s first solar highway has been opened in France

World’s first solar highway has been opened in France.

Wattway is a patented French innovation that is the fruit of 5 years of research undertaken by Colas, world leader in transport infrastructure, and the INES (French National Institute for Solar Energy). By combining road construction and photovoltaic techniques, Wattway pavement provides clean, renewable energy in the form of electricity, while allowing for all types of traffic.

As the energy transition becomes reality, imagine a road able to harvest solar energy and produce energy locally. In five years, France hopes the panels will supply power to 5 million people.

Wattway produces electrical energy without overtaking farmland or natural landscapes, and contributes to increasing the share of photovoltaic electricity in the energy mix, both in France and worldwide.

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.

Wattway has been tested in car parks, but this is the first time it has been used on an active road. There will now be a two-year test period, to see if Wattway can withstand the rigour of being pounded by thousands of cars and trucks per day, and whether it can actually provide a useful amount of electricity.

Each rectangular section is just 7 millimeters thick. Glued directly to the roadway, the pavers are supposed to be strong enough to support the weight of a continuous stream of traffic, including 6-axle trucks.

A 14-foot section of the solar roadway is projected to generate enough electricity for a single French household. A kilometer (0.62 miles) of the road should generate enough for a community of 5,000 people.

France’s minister of ecology and energy, Ségolène Royal, has said the first Wattway panels will be installed this year. The full 600-plus miles of paneled roads are slated for completion by 2021. The cost will be covered by progressive tax increases on fossil fuels, expected to generate roughly $440 million for Royal’s green energy initiatives.

performance énergétique


Pavement is only occupied by vehicles some 10% of the time. Imagine the solar resources of this surface area, facing the sky.
20 m² of Wattway panels provides enough electricity to power a single home. (Source ADEME/CEREN 2014 – average French household for 1,000 sun hours/year – not including heating).

adhérence et résistance


How to reconcile the fragility of photovoltaic cells and the robust structure of a road? Wattway is composed of cells inserted in superposed layers that ensure resistance and tire grip. The composite material is just a few millimeters thick, making it possible to adapt to thermal dilation in the pavement, as well as vehicle loads, a guarantee of durability and safety.

Pose sur chaussée existante


If Wattway is so revolutionary, it’s also because of the way it is installed! No need to rip out the existing structure, Wattway can be applied directly on the current pavement, without any need for civil engineering work.

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