The new Mercedes-Benz Citaro hybrid has been operating at transport companies throughout Europe for a year. Three examples show how it proves its worth in practice – and how the Mercedes-Benz hybrid technology pays off for the bus operators.

Further increasing the efficiency of the combustion engine in the Citaro – that is the job of the hybrid drive. It is available as an optional extra for the majority of the model range, even for the Citaro NGT with gas-powered engine. The electric motor supports the combustion engine first and foremost when setting off normally, when idling at bus stops and when high performance is required; in doing so, it further reduces the already favourable fuel consumption of the combustion engine. The technology is straightforward: power is generated from recuperation and stored in dual-layer capacitors, commonly known as supercaps. They are fitted space-savingly on the roof. The components used are tried-and-tested series production parts. The installation space required is small with almost no impact on the interior, and the extra weight amounts to just 156 kilograms. Above all, this hybrid drive pays for itself.

For Markus Wiedemann, Head of Motor Vehicle Division at SSB, the Mercedes-Benz Citaro hybrid is “an important bridging technology for introducing electrification on a mass scale.” What he likes about the new Citaro hybrid is that it differs little from the familiar standard. This “promises a high degree of reliability and also helps us to acquire more experience with high-voltage technology,” says Wiedemann.

Because the difference from the diesel version is only slight, the Citaro hybrid has also been well received by the drivers. “High acceptance of the new technology among the drivers is key, because we can only fully take advantage of the savings potential through careful handling and an adapted driving style.” With the Citaro hybrid the situation is clear: “The new Citaro hybrid is accepted by the drivers because it is identical to operate,” he explains.

SSB has had five Citaro hybrid articulated buses in service since March 2018, and since October, they have been running on the new X1 express route between Bad Cannstatt and the city centre, with the buses driving in their own bus lane at the particularly busy section around the Neckartor. For Wiedemann, performance and comfort of the Citaro hybrid are just as good as the diesel Citaro. “In terms of fuel consumption, we assume that we will achieve savings of 5 per cent with the Citaro hybrid on the X1 express route.” SSB has ordered 14 more Citaro hybrids for 2019, this time as solo buses. “The Citaro hybrid is an immediate air pollution control measure,” explains Wiedemann.

Our client, the district of Minden-Lübbecke in North Rhine-Westphalia, was immediately taken with the idea of the Citaro LE hybrid,” recalls Jens Foppe, Head of Business Development at Mindener Kreisbahnen and its bus subsidiary, MKB-MühlenkreisBus. The company operates the scheduled services on around three dozen routes using more than 50 of its own buses as well as various contract vehicles. The buses cover around 55,000 kilometres a year on average, with the focus on transporting school children.

“A low-floor area is mandatory,” says Jens Foppe, explaining the choice of vehicle. “We also need a space for wheelchairs and prams,” he says. Young passengers, in contrast, appreciate the seats at the elevated rear area. The operator’s own garage also prefers it due to the economic hypoid axle on the Citaro LE and the easily accessible drive unit.

The hybrid drive appealed to the operator: “It is the best you can get out of a diesel bus,” says Foppe. The result is “interesting potential savings in terms of consumption,” says Foppe, as the buses save around 3 per cent fuel. Six Citaro LE hybrids are in service so far. Alongside their procurement, MKB-MühlenkreisBus introduced the client’s new colour design as well as substantial equipment: LED headlights, pivot-and-slide doors, cross-country seating, a passenger information system with large TFT screens and interior surveillance with four cameras. The story continues: the next seven Citaro LE hybrids will follow this summer.

“We have areas with 20 to 2,000 inhabitants per square kilometre,” says Hans-Jürgen Hennig, illustrating his tasks. regiobus Potsdam Mittelmark, based in the district of the same name in the district town of Bad Belzig, covers long cross-country routes but also runs to Berlin and Potsdam. Brandenburg’s state capital is also the destination of Line 631, on which three Citaro G hybrids operate.

“Very good bridging technology,” says Hennig. Hybrid technology is expected to reduce his fleet’s fuel consumption further. Training is planned for the drivers of the hybrid buses as well as fine-tuning of the drivetrain together with the gearbox manufacturer ZF. “We are still in the test phase,” says Hennig. He likes the combination of the compact OM 936 engine and the supporting hybrid technology. That suits articulated buses in the flat region. Henning also points out: “I have no changeover in the garage thanks to 48-volt technology.”

Besides economy, regiobus Potsdam Mittelmark focuses on environment-friendliness. The buses run CO2-free thanks to the support of a climate project. The operator scores points in the region with attractively painted buses with no third-party advertising. “We run advertising for ourselves,” explains Henning. Tight schedules ensure reliable connections (see “PowerBus” on Line 631; “PowerW” stands for the link from Potsdam to the town of Werder (Havel)). USB sockets and Wi-Fi in the buses increase customer satisfaction. Passenger numbers are rising swiftly. The transport service is even more attractive with the Citaro hybrid – for example, when driving past the environmental measuring station in Potsdam. Hennig says: “We are making our contribution to air pollution control.”