background
They should make heavy goods traffic on Germany’s roads environmentally friendly and climate-neutral: trucks with overhead lines. There are test tracks in three federal states. But an interim balance is rather sober.
Autobahn 5 between Frankfurt am Main and Darmstadt is one of the busiest roads in the country. There are 400 masts at the edges of the road, from which overhead lines are stretched over the right-hand lanes. The purpose is to find out whether electric trucks can be powered like trams. Parallel tests are running in Schleswig-Holstein and Baden-Württemberg: on the A1 between Lübeck and Reinfeld and on the B462 in the Murg valley near Rastatt.
Hybrid trucks with pantographs drive on the three streets. The wagons were loaned to forwarding companies for their commercial use. As long as the trucks draw overhead power, they drive purely electrically and charge their on-board battery. Beyond the test track, they switch to battery operation or diesel drive. At the same time, a test was being carried out by the Technical University of Aachen. On the Siemens company test track in Groß Dölln, Brandenburg, other trolley trucks were tried out.
Technology with obstacles
The Hessian radio has requested files from the authorities, evaluated them and made inquiries. It becomes clear that there were foreseeable initial problems, surprising difficulties and permanent technical problems. The insulators on the masts had to be replaced. The transfer of data from the trucks for scientific evaluation did not work reliably for a long time.
The maintenance of overhead lines and trucks is expensive. On the test routes, the cars often run without overhead line current: because the GPS control is imprecise, the pantographs are automatically extended too late and caught up too early. After a delayed expansion of the test track, a lengthy acceptance test and, most recently, cable damage caused by an excavator, the electricity on the Hessian route has been shut off in one direction since the beginning of the year and in the other since April.
Ecological benefits unclear
It is now clear that overhead lines for trucks can technically function in principle. However, the ecological benefit is not clear. When driving a forwarding agency over 50 kilometers one way, the Hessian test route was used daily over the full five kilometers. Researchers at the TU Darmstadt determined 16 to 21 percent fewer greenhouse gases for the entire route. With stable operation and high utilization, a maximum of 22 percent is possible.
This only applies if green electricity is used. Suppliers are contractually obliged to use green electricity, says the Autobahn company. No evidence is presented – not even by the utility company Entega AG, which responds to questions by saying that it is “contractually obliged” not to say anything. Two years ago, the magazine “Ökotest” criticized the fact that Entega did not provide any evidence of green electricity offers to end customers.
Economically doubtful
The economic benefit is also unclear. A study by the Ökoinstitut and other researchers on the tests has shown that the operation of overhead line trucks will be more expensive than diesel trucks for years to come. 4,000 kilometers of motorway were to be electrified. Then the operating costs of hybrid trucks would fall below those of diesel trucks. However, the price of electricity has risen drastically in the meantime. The construction costs for the lines, estimated at 10 to 16 billion euros, are not included, nor are annual maintenance costs of almost 300 million euros.
The interest of truck manufacturers in the tests is at best minimal. Only VW subsidiary Scania, which had already delivered overhead line trucks during a test in Sweden, competed. However, when the three test tracks were gradually completed from December 2018, there were no hybrid Scanias with pantographs: the Federal Ministry for the Environment had ordered too late. The first truck was delivered in a slimmed down version after five months, the last of the 15 cars originally ordered in April last year. Five more trucks are now in operation and two are still under construction. The cars proved to be prone to failure. They have cost the state ten million euros so far.
The electric roads were first financed by the then social-democratic Federal Ministry for the Environment, then by the new green Federal Ministry for Economic Affairs and Climate Protection. Overall, tests with overhead line trucks have cost the state 191 million euros so far. The Federal Ministry of Transport is skeptical about the tests and has refused any financial participation. A feasibility study for the ministry warned that if it were to be used across the board, there would be an enormous need for electricity at times of the day when electricity is scarce anyway.
Official assessments
Six years ago, before results were foreseeable, the Hessian Ministry of Transport declared that overhead line trucks were “twice as efficient” as diesel. Today there is only talk of “one possible building block” that overhead lines could represent for low-emission freight transport.
Other authorities were cautious from the start. Schleswig-Holstein describes the construction and operation of the test track as full of hurdles and prone to errors. The Baden-Württemberg Ministry of Transport writes internally that it is about testing what is technically feasible. In contrast to parallel projects, it is said that “no high-gloss field test” was aimed at. Statements about the results are “very difficult to make” because the trucks were often broken and data was not reliably transmitted.
The Baden-Württemberg test track will be the first to be demolished next year. The State Ministry of Transport wants to make better use of its resources. Different drives are to be compared in an “innovation cluster” for climate-friendly trucks. The Federal Ministry of Transport is responsible, and its program is based on batteries, fuel cells and hydrogen. Catenary trucks are only mentioned in passing.