Streets That Supply Heat


"Power Road" generates thermal energy that can be used in buildings - a functional demonstrator was presented at RWTH.

  Copyright: © RWTH Aachen

A road that works just like a heat sponge - that is the idea behind Power Road. Experts from the Chair and Institute of Highway Engineering at RWTH Aachen University have now presented the principle together with representatives from VINCI Construction.

"It's like underfloor heating, only in reverse," says Dr. Dirk Kemper, deputy director of the institute, explaining the idea and principle behind the project, which has been dubbed "Power Road". The dark road surface absorbs heat and this is transported and stored via pipes in the asphalt. Using a piece of asphalt measuring around 50 square meters, called a "demonstrator", the experts explained how it works to around 100 guests. The stored heat can be used to heat rooms or swimming pools or to de-ice roads.

This has a climate-friendly side effect: "Using this technology, we can help prevent city centers from heating up so much in the summer - we simply remove the heat from the cities," says Kemper. The system could therefore help to mitigate the so-called "heat island" effect, i.e. the fact that city centers heat up significantly more than surrounding rural areas. The system also protects the roads: If the surface is very hot, the bitumen contained in the asphalt becomes slightly viscous and ruts can form. If heat is removed from the road, this effect is significantly reduced.

Fully Functional Demonstrator

A fully functional demonstrator has been installed at the Institute of Highway Engineering at RWTH Aachen University. The heat extracted from the road is fed into a storage tank and the "Performance Center for Asphalt Testing" next door is heated using this system. RWTH has been researching this system for almost 20 years and, together with VINCI Construction, it now has a market-ready product: "There is still no established set of rules for this construction method, which is why local authorities are still finding it difficult to implement," explains Kemper. RWTH has now provided the basis for ensuring that the principle works and that it is ready for use, and Kemper is also confident that it will soon be used in cities and municipalities: "If one municipality leads the way, others will follow suit automatically."

VINCI Construction CEO Tim Lorenz said: "This demonstrator allows us to rethink infrastructure. The construction industry can make its contribution here with innovative solutions so that the transport system of tomorrow can be climate-neutral and resilient." He is very grateful for his partner RWTH, as the University has shown that it is prepared to break new ground and drive innovation forward. "RWTH Aachen University," says Lorenz, "is known as an excellent University not only in Germany, but worldwide."

The system was developed jointly by RWTH and VINCI Construction, formerly Eurovia, and Professor Alvaro Garcia Hernandez, head of the Institute of Highway Engineering, thanked the partner, saying: "The technology not only demonstrates innovation in the field of thermal energy absorption and storage, but it also represents a step towards a more environmentally responsible future. It's great to have this innovation here and to be able to work with it. RWTH is now using the Power Road demonstrator for research purposes and is constantly optimizing the system in this way. The guests were able to see for themselves how well the system works: Using a thermal imaging camera, the scientists demonstrated how heat is extracted from the road and dissipated through the pipes. Just like underfloor heating, only in reverse.


Dr. Dirk Kemper on the Power Road demonstrator at the Institute of Highway Engineering at RWTH Aachen University.