Fast transportation with no emissions and only a pleasant hum: German municipalities are testing electric buses in public transportation. Unlike in the case of electric cars, the question of range is of little importance.
It’s all been done before: 130 years ago, “electric carriages” were connected to overhead lines in Berlin, and later equipped with batteries to be recharged via current collectors while traveling on rails. Werner Siemens was already envisioning an “electromagnetic taxi” in the mid-19th century, even before Carl Benz invented the first bus with a combustion engine. The first German trolleybus began regular operations in Eberswalde in 1940, and the “Wire Express” is still running today in the city to the northeast of Berlin. However, the efficiency of trolleybuses is disputed given the high infrastructure costs. More flexible and efficient solutions for environmentally friendly buses are currently in great demand.
E-mobility blogs, forums, and internet portals are increasingly reporting news of electric bus fleets without overhead lines that have already been put into service or will be soon, such as in Luxembourg or Malmö (scheduled for the end of 2018). Public transportation electric buses are also whirring from stop to stop in German cities like Regensburg, Hannover, Leipzig, Dresden, and Cologne. The city of Hamburg plans to add only zero emission buses to its fleet from 2020 on, while London and Paris also intend to purchase only electric buses in the future. The advantages: Electric buses are locally emission-free and consume up to 60 percent less energy than diesel buses, according to the Berlin Transport Company (BVG) website.
In the German capital, four electric buses have been running in trial mode for bus line 204 between Berlin Zoologischer Garten and Südkreuz since August 2015.
The BVG project is scientifically supported by e-mobility expert, Professor Dietmar Göhlich from TU Berlin. He believes that the project has been a success so far.
The technology in the vehicles has evolved tremendously in comparison to back in the 1880s. However, in the first trials carried out between 2015 and September 2016, there was damage to the high voltage technology in the prototypes, supplied by Polish company Solaris, which are equipped with a charging system from the German-Canadian company Bombardier and an electric drive from Vossloh Kiepe.
“But it’s a research project, and problems are expected,” says Göhlich in an assuaging manner. BVG spokeswoman Petra Reetz asserts that “electric buses are not generally less reliable than other types of buses.” What still needs improvement is the inductive charging technology: “If three leaves get in during the fall season, nothing works anymore,” says Reetz. For this reason, public transportation companies are testing systems by other manufacturers.
The basic principle of inductive charging is explained by BVG spokeswoman Reetz: “It basically works like an electric toothbrush.” The bus drives onto a charging station at a terminal station in Berlin, and the battery starts recharging.
Range is not the problem at all.
“Range is not the issue,” says Prof. Göhlich. The electric buses only need enough power on board for “the route to be completed,” i.e. the drive to the terminal station and around again, in summer and winter, when up to 50 percent of the electricity is needed for air conditioning and heating. Given a range of 50 to 70 kilometers, depending on heat output, there is a sufficient buffer. “The trick is that you can recharge quickly,” Prof. Göhlich explains.
In Berlin, charging at terminal stations takes only four to seven minutes, the battery capacity of 90 kWh being more than double that of current electric cars with comparably high capacity, e.g. the Renault Zoe. What makes recharging the batteries so fast is the high charging capacity of 200 kW, which is ten times greater than fast charging stations for cars. The system is designed to be part of typical bus stops. An alternative approach is to charge higher capacity batteries at bus depots overnight or longer than charging done at bus stops.
Purchase price still high
The most recent trials carried out in Berlin were for a bus from the Finnish manufacturer Linkker and one from the Dutch manufacturer VDL, both of which were plugged into charging stations at the depot.
“The problem we have worldwide: Electric buses are not yet serially produced. No manufacturer is capable of delivering 80 buses at once,” states BVG spokeswoman Reetz. And this is true despite a high demand. “Together with Hamburg, the state of Berlin has written a letter of intent to tell manufacturers: We want electric buses. You will be able to sell them.” Production of the all-electric Mercedes-Benz Citaro E-Cell will begin at the end of 2018, according to the manufacturer. MAN has a product that is almost complete and that was presented at the 2016 IAA Commercial Vehicles. “In 2018, a small number will be tested in everyday conditions,” says Götz von Esebeck, Head of E-Mobility at MAN Truck & Bus. “The electric Lion’s City will be in serial production before 2020.”
According to Prof. Göhlich, one electric bus costing around 600,000 to 800,000 euros, plus the charging infrastructure, currently has a purchase price roughly three times higher than that of a diesel bus. Even the BVG, Germany’s largest municipal transportation company with 1200 buses in daily operation, has said that it cannot afford the electric buses without state subsidization.
Yet Prof. Göhlich expects a decrease in price as soon as more buses are produced. “From 2025 on, electric buses will be a viable alternative to diesel buses,” the expert predicts. Head of Product Engineering at Daimler Buses, Gustav Tuschen, believes that “in 2030, about 70 percent of all newly registered city buses will have a zero-emission drive unit.” That includes buses with a fuel cell drive. BVG spokeswoman Reetz boldly predicts that “we in Berlin will be using only electric buses in perhaps 25 years’ time.”
In addition to zero emissions, electric buses are also very practical due to the high acceleration rate of the electric motor. Petra Reetz says, “Valuable seconds can be gained in bus schedules.”