Power generation from above and below German roads

22 January 2026

Pushing ahead with the energy transition is going to require the use of ever greater amounts of renewable electricity. But what if Germany were to use sealed surfaces for energy production – including, for example, its road network, which extends over hundreds of thousands of kilometres? Read on for some interesting approaches to climate-friendly dual road use.

24 November 2025. The scene is a major railway station in the Port of Hamburg: 150 guests from politics, port management and industry have gathered on the grounds of the container service company to celebrate the world premiere of the Road Energy Production System. This road power plant was developed by Austrian start-up REPS. The twelve-metre-long installation is made up of steel plates embedded in the asphalt. When lorries drive over them, they push the plates downwards. This pressure is transferred by a hydraulic system to a magnetic unit, which generates electrical energy – without the need for any other surfaces to be sealed. It takes 16 HGVs to drive over the installation to generate about one kilowatt hour of electricity. This may sound modest – and yet, according to the start-up’s calculations, if road power plants were to be installed at scale throughout the port, up to ten percent of its energy demand could be met and its CO2 emissions reduced by a similar amount.

The purpose of the pilot project is to determine whether the system will also prove itself in practice in continuous operation. The project has already attracted international attention. According to the company, 40 other ports have expressed interest in the road power plant. Away from ports, however, the system could also be installed wherever a lot of HGVs tend to travel at low speeds, such as at toll booths or entrances and exits. REPS plans to start series production in 2026, and further pilot plants are planned, including in the port of Barcelona and at a logistics centre in Bologna.

However, the Road Energy Production System is by no means the first attempt to turn roads into energy sources. In 2011, the French construction company Colas and the French Institute for Solar Energy (INES) set out to develop a road surface with embedded solar panels. The vision was to equip 1,000 kilometres of roads with solar cells to provide the power to operate streetlamps for some five million French people.

However, the results of the practical trial in the municipality of Tourouvre au Perche in Normandy were disappointing. The Wattway, which opened in 2016, delivered less power than expected. Worse still, the surface proved incapable of withstanding traffic and weather impacts and generated so much tyre noise that the local authority had to reduce the maximum speed.

While this failure did not mark the death of the idea, the focus has shifted from roads to car parks and cycle paths. Wattway has continuously improved its solar roadway over the years and, according to its own information, has already implemented 40 solar cycle path projects worldwide, several of which are in the Netherlands. The largest of their kind to date were inaugurated in 2023 in the provinces of North Brabant and North Holland. Their resilience, efficiency and cost-effectiveness are now being assessed by experts, and the results of the long-term study are due for publication in 2028.

How solar energy can also be produced at elevations above road level is currently being tested on a feeder road to Munich Airport, where a PV system on stilts spanning all four lanes was commissioned in August 2025. The 35-metre-long solar roof is expected to generate enough electricity to cover the annual needs of 70 households – with almost no additional land use. A second, highly desirable side-effect is that it protects the road surface from direct sunlight, which should in theory increase its durability.

This 4.2-million-euro solar roof is intended to provide insights into whether it is practical and viable for solar power to be generated in this way. It is already clear, however, that there is no prospect of building such roofs over motorways across Germany. This is because the stilts must of course also be strong enough to withstand impacts from accidents. This would make the substructure expensive and account for a large part of the additional costs that would be generated compared to a conventional solar power system.

According to the experts at the Fraunhofer Institute for Solar Energy Systems (ISE), who are researching solar roofs, the most rewarding approach would be to concentrate on smaller systems, especially in places where the electricity can be used directly, such as toll booths or tunnels – or at motorway service stations such as Hegau-Ost on the A81 in Baden-Württemberg, where a pioneering solar roof demonstrator has been producing green electricity since 2023.

PV roofs for cycle paths represent an interesting alternative. This is because their slimmed-down design reduces costs while also protecting cyclists from the weather. This is an option above all for big cities, where open spaces for electricity production are hard to come by and expensive to boot.

Germany’s first cycle path with a PV roof, which spans a section of approximately 300 metres in length, was installed at the Freiburg exhibition centre in 2023. The electricity produced by the roof supplies the laboratories of the adjacent Fraunhofer ISE, which launched the pilot project in collaboration with the city of Freiburg and energy supplier Banova.

The partners have invested around one million euros in the project. This is just a quarter of the amount invested in the similarly powerful roadway roof at Munich Airport – but still twice as much as a conventional rooftop system of comparable size would cost. The PV cycle path roof is therefore not an economical option, although the experience gained will be used to further reduce costs in future projects.

However, it would work out cheaper to equip the noise protection walls and embankments on German highways with solar cells. In purely mathematical terms, according to an analysis by the Federal Highway and Transport Institute (BASt), enough electricity could be generated for around 1.2 to 1.8 million households in this way. Pilot projects on noise barriers have already been implemented near Aschaffenburg and Neuötting in Bavaria. Fraunhofer ISE is also working on modules that can be integrated into existing walls, which will at the same time perform their main task of reducing road noise even better.

The verges of motorways and federal trunk roads offer even more potential for photovoltaic use. According to the BASt analysis, if this potential were to be fully realised, it would be possible to supply between eight and 16 million households with solar power from the roadside. Photovoltaic systems on motorways are already no longer confined to the solar technology margins, however: since 2023, in a move which has significantly speeded up the approval process, solar parks have been privileged under building law if they are to be installed within a 200-metre-wide strip extending out from the edge of the road.

Last year, for example, the energy supplier RWE commissioned several large solar parks on the A44N in North Rhine-Westphalia. An expansion is already planned. So there are strong indications that the low-hanging PV fruit on Germany’s roads will be harvested first – for as long, that is, as it takes for the hour of photovoltaic cycle paths and solar roofs to finally come.