‘Radiator road’ that never freezes tested in France

A high-tech road that stores renewable thermal energy to heat the surface and can be used to eliminate ice and snow, is being tested in France. 

Égletons (Correze), in southwestern France, installed just 120 metres of the road in 2021, initially to showcase the technology for local public works students. 

“We created this experimental road for educational purposes and to promote the smart image of public transport,” Mayor of Égletons Charles Ferré told The Connexion. 

Power Road, pioneered by Eurovia, a subsidiary of French construction company Vinci, works by capturing solar energy inside the road surface, storing the energy, then transferring it to nearby buildings and other structures through heat pumps. 

As well as heating the road surface, it can be used to heat and cool offices, homes, sports facilities and public buildings, as well as heat swimming pools and cool paved areas in summer. 

It can be used to clear snow and ice from airport runways in winter. 

The Égletons road, however, draws its heat from the town’s heating network, which means it is “energy intensive”, Mayor Ferré explained. 

The bituminous road has a heat exchanger built into the surface layers at a depth of around five to eight centimetres. The heat exchanger is a network of tubes, similar to those used in underfloor heating. 

Heat-transfer fluid flows through these tubes, and under solar radiation can heat to as much as 35C. 

This thermal energy can then be used immediately, for example, to keep the road surface warm and ice-free, or stored and used later. 

This type of road was first installed in France 2017 at a truck stop in Saint-Arnoult-en-Yvelines, Île-de-France, where it has also been used to heat the shop on the site. According to Eurovia, the technology has cut energy bills by 80% and C02 emissions by 96%.

Since then, it has been used for several projects across France, including to help heat local swimming pools in Brittany (Saint-Pol-De-Léon) and Lyon, and to help provide heating and hot water for 61 apartments in Normandy (Fleury-sur-Orne).

A targeted approach

But the technology does not come cheap. And its cost could mean many towns cannot afford to implement it on more than a small section of road. 

This has been the case in Égletons, where Mayor Ferré said that it has been “effective” in preventing snow and ice from settling on the road, but had not “changed the lives of drivers” because it was used on such a short stretch. 

The technology was too expensive to roll out more widely in the town, he added. It cost €230,000 for 130 metres of road. 

He said the technology was perhaps more suited to “highway companies, toll stations and airports” but “for other towns, no” suggesting they could look to other renewable energy sources such as solar panels.

The technology would not be beneficial for stretches that are too long, and is best used in a targeted way, according to Eurovia. 

"For de-icing and snow removal, (it is) more about targeting accident-prone areas. And regarding heat reuse, you need a nearby point of consumption, so I do not know if it would be useful on a highway, for example," Loïc Bernard from Eurovia, told French daily Ouest France.