As a leading supplier in the fully automatic conductive charging market, Schunk Carbon Technology provides reliable smart bus charging facilities.
With nearly 70 million passengers per year, Amsterdam Airport Schiphol is the third largest airport in Europe; and its operator now wants to turn the airport into one of Europe’s most sustainable. An important contribution towards this aim has been the 100 electric buses in operation since April 2018, which are equipped with smart bus charging pantographs provided by Schunk Carbon Technology.
The Netherlands has long played a pioneering role when it comes to ecological awareness. An important factor in reducing emissions in traffic centres, for example, is increased uptake of electric buses. Ten Dutch cities have already converted their bus fleets to electric vehicles; while the province of North Brabant is scheduled to be served completely by zero-emission buses by the year 2025. Other big e-bus projects are either planned or underway in regions where emissions are particularly high. These locations include Amsterdam Airport Schiphol, which operates nearly 500,000 flights per year. Since April 2018 a total of 100 electrical buses, comprising five lines, have been in use, connecting the airport with the surrounding area. The buses cover a total distance of some 30,000km every day and are completely free of emissions.
Fast and reliable: Smart bus charging systems from Schunk Carbon Technology
With such a high volume of traffic, a particularly fast and reliable charging system is needed so that the buses are operable around the clock. The manufacturer of the electric buses which are used at Schiphol relies on the SLS 102 charging pantograph from Schunk Carbon Technology. The infrastructure for the 23 smart bus charging stations, located at four strategic charging points, is provided by the company. Thanks to the optimally matched combination of pantograph and charging station, batteries can be recharged while passengers get on and off the buses.
Even in the event of a completely empty battery, the entire recharge takes less than 20 minutes. This comparatively short recharging time, together with the extensive range of buses available, were decisive factors in the collaboration between VDL Bus & Coach, Heliox and Schunk Carbon Technology. Furthermore, the success story of the SLS 102 on 43 electric buses in the Dutch city of Eindhoven as well as in numerous other projects around the world provided an additional convincing argument.
The rapid contacting of the pantograph head with the charging infrastructure in only five seconds, as well as a current transmission of 800 amps, makes the SLS 102 from Schunk Carbon Technology the current technological leader and most advanced recharging solution for use in local public transportation with battery-powered electric buses. The pantograph is mounted on the bus roof and docks fully automatically with a contact hood, which is fastened to a mounting pole. Bus ‘kneeling’ during parking and recharging is compensated by the rocking design of the pantograph so that no interruption of the recharging occurs.
Sustainability as a competitive advantage
Schunk Carbon Technology is currently the supplier with the most projects and systems within the fully automatic conductive charging market segment. Intelligent technologies make it possible to significantly reduce required battery dimensions and thus to achieve an optimal relationship between battery size, passenger capacity utilisation and driving range. The success story continues, also in the Netherlands: Eindhoven and Amsterdam are planning to deploy more electric buses with pantographs from Schunk Carbon Technology in order to reduce noise and pollutant emissions from buses to a minimum in the future.
More and more cities and communities are following the Dutch example in other countries; with various cities in Poland, Russia and France presently engaged in ongoing projects with Schunk Carbon Technology.
Pending prohibitions on diesel vehicles have compelled cities and municipalities to take action: suppliers of electric buses can hardly meet the enormous market demand at the moment. When it comes to fast, safe and reliable recharging of batteries, the innovative current transmission solutions of Schunk Bahn- und Industrietechnik GmbH, located in Heuchelheim, in the German state of Hesse, is the market leader. Product Manager Timo Staubach explains where electrical mobility stands today and what can be expected in the near future.
Schunk Carbon Technology has been supplying and developing charging technologies for electrical buses since 2014. The industry is currently working with two different charging concepts: opportunity charging along the bus route and depot-based fleet charging. How do these two methods differ?
Opportunity charging, as it is called in the industry, takes place at strategically selected bus stops. To accomplish this the pantograph, which is mounted on the roof of the vehicle, makes contact with a docking station installed at the bus stop. The advantage is that a comparatively smaller vehicle battery can be used because only a relatively small amount of energy need be stored – just enough until the next stop. This method is particularly well suited for cities operating bus lines across extensive ranges. Overnight charging or depot charging, on the other hand, takes place after operating hours in the vehicle depot. The significantly larger batteries with their correspondingly higher charging capacities require more space and can easily add a few tonnes of additional weight to the vehicle, depending on the operating range requirements. This also means less space on the bus for passengers. For smaller municipalities with less extensive operating ranges, this can, however, be a practicable solution.
Schunk offers current collectors for both concepts. What advantages do they have when compared to the conventional plug-in solution?
Our pantographs are well suited for recharging both at the bus stop and for overnight recharging in the depot; here the contact connection is simply located in the vehicle depot hall. Transit companies with large fleets naturally do not want to individually plug in each bus every evening. That’s why were convinced that the manual plug-in solution has no long term future. Whether opportunity charging or depot charging is the more efficient solution, depends on the respective charging strategy, the number of vehicles to be recharged, the characteristics of the bus routes and their particular requirements. The main thing here is to take into account and analyse the individual needs of the customer.
What technical challenges must be overcome to ensure buses are able to adhere to their schedule?
When parking at the smart bus charging charging station, the tolerance range must be as large as possible. In their day-to-day work, we cannot expect bus drivers to be able to park with millimetre precision. The pantographs developed by Schunk provide a very large tolerance range. A visual orientation aid is sufficient for bringing the vehicle into the proper position. In addition, the current collector automatically connects with the charging infrastructure in just five seconds and, with 800 amps, allows an extremely high current transfer. Because of this, our systems are some of the best engineered recharging solutions currently in use in public local transport with battery-powered electrical buses. The so-called kneeling effect, the sideways tilting of the bus at the bus stop, is compensated by the rocking suspension design of the pantograph so that no interruption of current flow occurs. Our products can be found in many cities around the world, such as Amsterdam,where 100 buses are already serially driven in this configuration and deployment of even more buses is being planned in the country.
What do you expect for the year 2019 with respect to electrical mobility?
I expect that we will have approved a common standard for uniform plugs and interfaces by the end of 2019. Schunk is already working on this together with other suppliers on various standardisation committees. I would like to see the cities, municipalities and transit authorities altogether in Germany become a little more daring. German cities could learn quite a bit from our European neighbours. As a supplier, we have years of experience and have long since progressed beyond the stage of experimenting and designing prototypes and moved on to serial operation. It is certain that significantly more electrical buses will also be used in Germany in the year 2019: not only do e-buses contribute to the reduction of CO2 emissions, they also produce less air and noise pollutions than traditional vehicles. The future surely belongs to the electrical vehicle.
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