The Fraunhofer ISE has for the first time calculated what potentials the electricity generation via photovoltaic installations on traffic areas would offer, and has come to a highly positive assessment. Including shoulder strips, the traffic areas in Germany would offer around 300 gigawatts of capacity, three times the total PV capacity installed in the country to date. This is reported by Süddeutsche Zeitung. The concept will also become more urgent in the future because the areas for further PV expansion are scarce in some regions, according to Martin Heinrich, specialist for traffic-integrated photovoltaics at Fraunhofer ISE.
Recently, in Freising near Munich Airport, a 210-kW installation on stilts with lightly translucent PV panels went into operation for the
first time, spanning a 35-meter-long four-lane on-ramp - and also using the side surfaces. The advantage besides electricity production: the asphalt is shaded, and its service life should be extended accordingly.
According to the Fraunhofer ISE expert, PV systems on roads are all the more affordable the slower traffic is allowed to travel, because the constructions must withstand an impact. Therefore, a strict speed limit also allows a slimmer, cheaper construction, which would then achieve a better CO2 footprint because less steel and concrete would be needed. This would significantly reduce investments, because the substructure is the largest cost item, according to Heinrich.
In particular, over bike paths the construction could therefore be cheaper. Cyclists would also
be protected from shading as well as from rain or snow. In fact, the Freiburg-based Fraunhofer ISE, together with the energy provider Badenova, has already realized a bike path with PV roofing, near the institute's headquarters, spanning 300 meters, nationwide a standalone installation.
Also on expressways, the application could be worthwhile, for example when used before tunnel entrances, as confirmed by the Federal Highway Research Institute (BASt). Here the "bright-dark transition" could be mitigated and the produced electricity could be used directly for tunnel lighting. PV constructions would also be conceivable for entrances and exits to gas stations and rest areas, as well as on their parking lots, where the electricity could be used directly for the
charging infrastructure.
Much cheaper than along the road would be placement beside the road, for example over noise barriers or walls, hardly more expensive than normal solar parks, according to the ISE's assessment. The grid connection would also be easier here, because the barriers are usually close to residential development. Overall, according to BASt, the potential lies at 3.2 to 42 GW for berms as well as 0.5 to 0.6 GW for walls, which would supply 1.2 to 1.8 million households. Edge strips would offer an even larger potential, with a staggering 24 to 48 GW, power for 16 million households. Since early 2023, PV installations beside highways have been granted building-law privileges, which enormously accelerate the
