Duisburger Verkehrsgesellschaft is to convert its first bus line to the fully electric eCitaro G at the turn of 2021/22. Daimler Buses is the general contractor.
Omnibus Magazine
With the eCitaro G to the future
How Duisburg’s public transport is achieving a successful start with e-mobility.
E-mobility right down the line.
The eMobility Consulting team at Daimler Buses in action.
Duisburg: the biggest inland port in the world and a transportation hub. A German city at the junction between the Rhineland and the Ruhr with half a million inhabitants. And with very high levels of noise and airborne pollution. With its “Duisburg 2027” urban development strategy, the City of Duisburg has set numerous goals, including protecting human health against the harmful effects and burdens of pollution, particularly noise and air pollution. One important aspect of this is the electrification of the bus network. This will get going at the turn of 2021/22 with the launch of seven Mercedes-Benz eCitaro G buses by the local transport company, Duisburger Verkehrsgesellschaft AG (DVG).
“we bring with us the added value of the data and experience gleaned from many projects. Also, the customer’s coordination expenses are reduced, as we supply the entire e-bus system including vehicles, charging infrastructure and charging management systems.”
Concentrated expertise.
The company operates 42 bus lines, three trams and one light railway. With around 100 buses and 60 railway vehicles, DVG transports just under 60 million passengers a year. To implement the coming changes, the Duisburg company has opted for a comprehensive turnkey solution including e-buses, charging infrastructure and charging management systems from EvoBus. Because of its rail routes, e-mobility and high-voltage technology are not new areas for DVG. As Marius Dietmann, Daimler Buses Charging Infrastructure Project Manager, notes: “DVG has excellent competence in infrastructure.” But, as Dr Karsten Wasiluk, Ecosystem eMobility at Daimler Buses, explains, “we bring with us the added value of the data and experience gleaned from many projects. Also, the customer’s coordination expenses are reduced, as we supply the entire e-bus system including vehicles, charging infrastructure and charging management systems.”
Electrifying Line 934.
To get its electrification programme going, DVG selected Line 934. It runs on a daily schedule, starting from the depot – one of its terminals – and passing the inland port, the old town and inner city of Duisburg, continuing on to the main station and MSV Duisburg football stadium. Its connection to the bus depot, inner-city route and the link to the local leisure area of the “Sechs-Seen-Platte” in the south of Duisburg were fundamental to the decision for electrifying this line. It runs through areas that are considered particularly noisy and polluted, and should make a positive contribution to improving air quality there.
“Line 934 offers a particularly attractive opportunity to give great benefit to the environment relative to the cost, as every one of these seven electric buses will replace a large number – over 78,000 – of diesel bus kilometres-per-year.”
The prominence of this route should ensure the electrification project gets excellent visibility. This will allow many citizens of and visitors to Duisburg to experience electromobility at close quarters. Marc Schwarzer, Bus Vehicle Technology Department Head at DVG: “Line 934 offers a particularly attractive opportunity to give great benefit to the environment relative to the cost, as every one of these seven electric buses will replace a large number – over 78,000 – of diesel bus kilometres-per-year.”
The selection of the line also took into account the further electrification of the bus network in the future. The newly created infrastructure at the depot – particularly the rapid charging stations – will build up reserves for future e-lines. In addition, DVG will be able to test the rapid charging technology on its home turf at the depot.
A sophisticated battery strategy.
For the battery configuration, DVG gave the Daimler Buses experts a large amount of data, including the intended distances to be travelled, so that the simulation program could give the right recommendations. Nils Richert, manager in charge of the DVG project as a whole for EvoBus: “because of the extensive preparatory work provided by DVG, we have an excellent starting stock of data.” For Christian Rudigier, head of the eMobility System Design & Consulting team, it is important that “we always consider the worst-case scenarios. The requirements of the eCitaro G were able to be fulfilled by eight NMC2 battery packs, but in contact with DVG we configured it with ten battery packs.” The worst case here includes, for example, considering a wide range of expected outside temperatures. Or five minutes’ delay before every charging process. Depending on the deployment, this means in Duisburg only around 40 to 55 percent of the battery capacity will be used. This ensures reserves are kept in readiness, lowers the load on the batteries because of more careful charging and allows them to achieve a longer service life.
Maintenance and workshop services for the seven eCitaro G's will be taken over by the OMNIplus BusPort Duisburg under the eService Contract ePremium – DGV saving itself in this way, for the initial period, the costs for the special garage equipment and staff training needed to work with high-voltage equipment.
“we always consider the worst-case scenarios. The requirements of the eCitaro G were able to be fulfilled by eight NMC2 battery packs, but in contact with DVG we configured it with ten battery packs.”
Daimler Buses as general contractor.
In Duisburg, Daimler Buses is working as the general contractor, that is, taking responsibility for the buses, the infrastructure and its installation.
One key focus is the depot and garage halls with charging infrastructure. The electricity supply to the eCitaro G is not a problem thanks to the existing medium-voltage grid already in place. Even if all seven articulated buses are charged simultaneously at night, the available power of around a megawatt means there won’t be a problem. Rather, it could even provide for additional future buses too. A new transformer station converts the energy from the medium-voltage grid. For daytime interim charging, there is a T-mast outside the hall with two rapid chargers on its arms. Here, two buses can be charged via pantographs at up to 450 kW power.
In the hall the buses are also supplied via pantograph but only up to 150 kW. Thanks to the bloc arrangement of the vehicles, they remain in the same positions, without the need for floor charging stations and manual connection. Marc Schwarzer on pantograph charging at the depot: “we want to achieve unified means of contact at all charging sites including the stations in the terminus, without the driver having to attach cables and plugs by hand.”
Charging management is run by the experienced partner IVU. The bus constantly sends data via OMNIplus ON and the transport company extracts it to its own system. Any bus arriving is assigned its own position based, among other things, on its remaining charge, turnaround time and power needed for the next deployment. As needed, the charging performance can be adjusted to any level desired.
Exciting service
E-mobility consultation.
The conversion to electromobility is a challenge. That’s why Daimler Buses offers more than just buses: supporting transport companies with advice and action through its “eMobility System Design & Consulting” team under Christian Rudigier. He and his colleagues provide their own simulation program for feasibility studies. Companies deliver their own data regarding the individual lines, then the program turns them into a load profile for the eCitaro. If the situation for electrification is critical, detailed calculations and consideration of intermediate charging points or alternative vehicle configurations follow. During the consultation, local energy suppliers and the city administration are involved. Then, the voltage required at the depot and the locations of charging points along the line are addressed. If necessary, specialists in garage planning, charging infrastructure and from OMNIplus ON are brought in.
Reduced noise and airborne pollution.
If Line 934 switches as planned at the turn of 2021/22 to e-buses, the process will have taken almost exactly a year from when the contract was awarded. “And we’ll need every minute too,” says Nils Richert. So that everything goes off without a hitch, the last two months before the changeover are earmarked for driver training, test runs and fine adjustments to all processes. Tests of the charging infrastructure will already have taken place beforehand.
“the electrification of Line 934 has led to an annual reduction in greenhouse gas emissions of 980 tonnes of CO2. ”
And the result: Marc Schwarzer of DVG has the last word: “the electrification of Line 934 has led to an annual reduction in greenhouse gas emissions of 980 tonnes of CO₂. Assuming the electric buses have a service life of 12 years, the savings will add up to a total of 11,800 tonnes of CO₂. The annual nitrogen oxide emissions along the line are reduced by 99.9 percent, from 5,867 to 6 kilograms, while the fine particulate emissions from combustion from 25 to 1.8 kilograms. And let’s not forget that the electrification of Line 934 has also cut noise emissions.”
*Source: Duisburger Verkehrsgesellschaft
