Germany’s biggest transport service is converting its bus operations to electromobility. From the start, 15 Mercedes-Benz eCitaro buses will be included as of this spring.

The target has been set: according to the Berlin Mobility Act, the BVG – Berlin’s transport service – may only use climateneutral buses with non-fossil drives from 2030 onwards. This means diesel power is out, and electromobility is in. “The aim is a more liveable city,” explains Torsten Mareck, Bus Division Manager at the BVG. It’s a Herculean task for Germany’s largest transport service, with around 1,400 buses. Luckily, electromobility is nothing new for Berliners thanks to the underground and tram system.

The initial challenge is the pure size: the cities of Hamburg, Munich and Frankfurt would fit into the capital’s city limits with around 200 bus lines. Added to that are tough operations: the buses are in use seven days a week around the clock. “Berlin is a challenging patch,” stresses Mareck. Traffic jams, building sites, diversions and lanes full of parked cars demand everything of the buses. In the city’s central area, the BVG buses only reach average speeds of 11 to 12 km/h. Nevertheless, they cover over 70,000 kilometres a year. “All that takes it out of the buses. Anything that survives here can make it anywhere,” says Mareck.

Driving by day and charging by night does not work in Berlin, as the electric buses are deployed in a rolling system. As charging takes several hours, the fleet will grow. What three diesel buses manage today will be taken on by four electric buses in the future. And the depots? “With electromobility, every bus needs its own fuelling station,” says Mareck. This takes up extra space. The number of depots will therefore increase.

The BVG is starting with the Indira-Gandhi-Strasse depot in the east of the city. It is close to a substation, which makes the power supply easier. One cable with 10 kV will suffice at first. The next step is more of these cables or a power supply with 110 kV. The buses will run on “green electricity”. The first electric buses will be parked in three lanes and supplied with power via charging poles. A carport solution, whereby the buses are supplied by cable from the roof, is also conceivable. 34 System 35 “We are driving by sight, starting now, gathering experience,” says Mareck. The selection of the routes is based on the capacity of the solo buses, their range of 150 kilometres and the location near the depot. The first five routes go through the particularly polluted ring road around the central area of the city – Mareck talks about NOx hotspots.

The equipment of the eCitaro buses corresponds exactly to the current major contract for up to 950 Mercedes-Benz Citaro buses with low-emission diesel engines. Alongside these, the BVG is pushing electric buses. At least 120 solo and 15 articulated buses are planned for 2021. Besides price and consequential costs, the emphasis is also on reliability and, above all, their range. In this respect, the BVG is relying on an increase provided by future battery technology, as announced by Mercedes-Benz. The Berlin operator, faced with around 1.2 million bus passengers a day, is also equally considering articulated buses with electric drive. A separate lane is being installed in the garage for the electric buses. The BVG will take care of servicing the eCitaro itself according to manufacturer’s specifications, with repairs being done by OMNIplus.

“We must get the electric drive to the stability of the combustion drive, as the transportation must work in a reliable and stable manner at all times,” explains Mareck. He is even aiming for a further increase in the availability of electric buses and “the durability scenario of a tram”. The former divisional manager of BVG trams is bursting with ideas. For certain operations, the trained heavy-current electrician believes a combination of a battery electric drive with trolley wire is possible. Alternatively, fast charging systems on the routes with a capacity of 450 kW plus a mobile cleaning service would mean that the buses no longer have to enter the depot and can also operate round the clock.

There are many ideas, one clear objective and an enormous challenge. Buses and infrastructure together will require investments of around two billion euros by 2030, the BVG has calculated. All for a more liveable city.