Colas News

Colas trials its innovative solar road solution, Wattway


truck wheels on a WattWay

Colas is set to start trialling its innovative solar road solution, Wattway, and is in the process of identifying potential UK sites with clients interested in the world’s first ever photovoltaic road surfacing.

The innovative technology provides clean, renewable energy in the form of electricity, while allowing for all types of road traffic. Installed on top of an existing road surface, the solar panels are extremely lightweight and strong. 

Carl Fergusson, Colas Executive Director Strategy & Development, said: “Without doubt this is an extremely exciting time for the industry and we are looking for a number of forward-thinking clients who are interested in running Wattway trials with us. The UK trials will form part of about 100 trials taking place world-wide.” 

Designed and tested to endure vehicles continuously passing over the surface, the panels are only 7mm thick and are applied on the surface by using a high performance resin. A glass bead resin coating is also applied to allow the surface to provide acceptable frictional performance without significantly affecting the solar panels efficiency. 

The power generated by Wattway has the potential to be used for highways and transportation infrastructure, such as Variable Message Signs and street lights, but also could be returned to the grid or used to supply energy to nearby homes and businesses. An innovative source of renewable energy, it is particularly well suited for smart grids and short-circuit electricity production, as the need for new sources of energy and electric mobility continues to rise. 

Carl added: “The first trial has already begun in France and by producing renewable energy, Wattway will certainly play a major role in building smart, sustainable roads of the future.”

Data will be gathered on Wattway’s functionality in parallel with the site requirements, as well as on how efficiently it generates energy. This will be shared with Colas’ Campus for Science and Technology (CST) near Paris, where Wattway was developed over a five-year period in conjunction with other key partners and where the innovation is now being pre-industrialised for a full scale global launch from 2018.

Colas’ CST is a cornerstone of the global technical network, providing a platform of capability to serve the Colas Group as a whole. Colas’ UK project engineering arm plays a key role in collaboration and sharing knowledge to further develop further market driven solutions and innovations.

Each solar panel is comprised of an array of 15-cm wide cells making up a very thin film of polycrystalline silicon that transforms 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 even large vehicle traffic.

The composite perfectly watertight “sandwich” is also designed to adapt to the pavement’s natural thermal expansion. The surface that is in contact with vehicle tyres is treated to ensure skid-resistance equivalent to conventional asphalt mixes. Electrical connections can be installed at the edge of the carriageway or in ducts integrated in the panels themselves. Lastly, electronic circuit breakers ensure safety. 

“The trial sites will allow us to experiment with different ways to use this innovative technology and the feedback will help us validate the most appropriate solutions for our market. By reviewing feedback from our UK trial sites, will allow us to validate the most appropriate solutions for the UK market, which will ultimately help build our offers for full scale launch as of 2018,” said Carl