Krakow is focusing on sustainability and investing in electromobility in public transport. The first electric buses have been operating in the city since 2014.
In 2021, 50 more vehicles were added that transport passengers in the Krakow area. The highest exceedances of air pollution limits were recorded in this region (see: https://cleantechnica.com).
However, the expansion of the e-bus fleet presented the city with a challenge: how can around 80 electric buses be charged efficiently?
How can around 80 electric buses be charged efficiently?
Krakow is playing a pioneering role in Poland when it comes to electromobility. The municipality was the first major city to phase out all buses with Euro 4 engines and older and invest in its first electric buses (see: https://cleantechnica.com). At that time, the city relied on fast opportunity charging on the route and had its small test fleet equipped with roof-mounted charging pantographs from Schunk Smart Charging.
These roof-mounted pantographs work according to the bus-up principle. This means that the bus stops under a charging station and extends the pantograph mounted on the roof. This automatically connects to the charging station and charges the battery. In this way, the battery of the e-vehicle can be charged at intervals.
Charging stations of this type were installed at various terminal stops and in the city's depots and are designed for fast battery charging. At that time, overnight charging was still possible with a classic plug-in solution in the depot.
Fast charging during the day, slow charging at night
In the meantime, however, the requirements have changed. Almost 80 electric buses now require an efficient overnight charging solution. In other words, nobody wants to fiddle with plugs any more. Instead, intelligent and efficient smart charging solutions are required.
For this reason, Krakow has not only invested in 50 new electric buses with roof-mounted pantographs, but also in corresponding contact systems for automated depot charging . This solution enables slow and space-efficient charging of the entire fleet overnight.
Challenges for transport companies with a growing electric bus fleet
"We see this as a typical challenge for transport companies with a growing fleet: How do I implement overnight charging in the future - via a plug-in solution or with pantographs?" says Timo Staubach, responsible for the Strategic Business Area Battery Driven Vehicles at Schunk Smart Charging.
In his view, automated depot charging using pantographs offers decisive advantages.
These include
● At the depot, the vehicle automatically contacts the pantograph already installed on the vehicle. There is no need to plug in charging plugs manually.
● Due to the long charging time overnight, only a small amount of electricity needs to flow. Accordingly, charging stations with a low charging capacity can be used, which are cheaper and more compact in terms of installation.
● The charging current collector combines safe and efficient depot charging with high-performance charging during operation at selected stops. This means that all buses that are charged with high charging power on the route during the day can also use overnight charging. In this way, the depot is used efficiently.
What's more,
● that battery control can be used to bring battery cells with different charge levels to the same charge level, keyword "battery balancing".
● that the energy for heating the vehicle in the morning can be drawn directly from the charging station via the current collector without using energy from the battery.
→ In our blog post Three reasons why depot charging reduces costs, you can find out more about the advantages of depot charging for electric buses and learn about another solution for exclusive charging in the depot.
Krakow transport company pleased with all-day operation
The advantages of this charging combination have also convinced the city's transport operator, MPK Kraków: "The electric buses serve the routes in the Aleja Trzech Wieszczow area, where the greatest exceedances of the permissible limit values for air pollution occur," explains Marek Gancarczyk, press spokesman for MPK Kraków.
"Thanks to the option of rapid charging via a pantograph in the area of the bus stop, which takes place between individual journeys, the vehicles can be operated throughout the day without having to travel to the depot. During operation on the route, the electric buses are charged with a high output of up to 250 kW, while at night they are charged with a low output of 55 kW at the depot."
"The electric buses can be operated all day long," say the delighted managers of the Krakow transport company.
And if problems do occur?
"In any case, it should be emphasized that the cooperation with Schunk is based on professional training of the technical staff, who react with appropriate commitment to technical problems in the pantograph area," says the press spokesman.
Positive feedback from passengers
"For us as a manufacturer of charging solutions in the field of smart charging and depot charging, it's great to see how Krakow is investing in electromobility in public transport, how the infrastructure is growing historically and how our system has established itself," says Timo Staubach happily.
And the electric bus fleet is also very well received by passengers: "The feedback from passengers is positive. They appreciate the travel comfort in these vehicles and the very quiet engine operation," says Gancarczyk.
Schunk technology charges electric buses all over the world
But it is not only in Krakow that Schunk technology has proven its worth in providing electric buses with new energy. Electric buses equipped with pantographs from Mittelhessen are in operation in over 100 cities in 25 countries around the world. Smart charging solutions are in use for a wide range of customer requirements.
