Study shows solar motorways a viable solution for Germany

Solar motorways could provide Germany with renewable energy without the problems associated with wind turbines and solar farms, often opposed by local residents. A feasibility study conducted by Drees & Sommer shows that the innovative solution is legally, technically and economically viable.

Solar panels along a motorway in The Netherlands

“Our research demonstrates the great potential of solar motorways for the development of sustainable infrastructure,” said Alexander Vorkoeper, senior consultant, Drees & Sommer.

The study, conducted on a 24-megawatt project on a 30-kilometre motorway section in North Rhine-Westphalia, analysed issues including choice of technology, ease of implementation, and economic viability, as well as possible operator models and the time frames involved. The combination of transport infrastructure with electricity generation could improve public acceptance in densely populated regions.

The location is significant because that section of the Autobahn is close to the Garzweiler opencast lignite mining pit. Coal is now being replaced by wind and sun and wind turbines and solar panels are replacing environmentally harmful lignite, the mining of which in the past decades has left big scars on the landscape.

“We want to remain an energy region, but without the lignite,” said Volker Mielchen, managing director of the local association Landfolge Garzweiler. “Routes and infrastructure can facilitate the production of renewable energy from solar panels on previously unutilised areas, and this could create synergies between energy production and wind and noise protection. This is exactly what Germany needs.”

Solar power systems are planned for embankments along the motorway A44 and on noise barriers on the motorway A46. Photovoltaic modules can also be mounted, vertically, on wind barriers.

Germany’s motorway network is the fourth-longest in the world at 13,200 kilometres, so the potential for solar installations is huge.  

The Fraunhofer Institute for Solar Energy Systems (ISE) has calculated that 5% of Germany’s land area is covered by transport routes, including not only motorways but also parking spaces and noise barriers. This holds the potential for 300 gigawatts of additional PV output. To put this in perspective, as of April 2024, photovoltaic systems with a total generating capacity of 81.5 gigawatts were installed on German roofs and land.

It is not only the Rhenish mining district that is preparing to exploit this potential. In Ludwigsfelde, south of Berlin, the city government is planning to erect a solar roof over the A10 motorway. Besides being an efficient use of land, this initiative will also have valuable synergistic effects, such as reducing noise and protecting the roadway from heat and rain.

The federal agency Autobahn GmbH is responsible for operating the German motorways, and it plans to expand the use of photovoltaics in order to achieve climate neutrality in the maintenance and operation of the motorway network by 2040. This, as Vorkoeper points out, means that everything is in place for the solar motorways to become a reality.

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