How does Daimler Buses Solutions meet the requirements for smart and safe charging? We spoke to Karsten Wasiluk, responsible for the charging infrastructure at Daimler Buses Solutions.

Several ISO standards have been established for charging an electric bus with a CCS plug or the four‑pole pantograph, which are constantly being developed and adapted. These standards cover a broad market and also and are also prepared for upcoming topics such as ‘vehicle‑to‑grid’ or billing for the charging of touring coaches.

How does Daimler Buses Solutions implement safe, standard‑compliant charging for electric buses?

For communication with the charging management system, we use the standardised OCPP protocol and value‑added services, which are defined in VDV Guideline 261. All standardised interfaces and connections in charging management are operated via secure connections, as is the case with online banking and online shops, for example. We were also able to precondition the buses with inverted pantograph for the first time in the project's history at RVBW in Baden‑Wettingen (CH) with an interface between OMNIplus ON and the charging management systems installed there. Warning signals from the battery are also transmitted straight to the operator’s backend, which significantly increases operational safety.

The cybersecurity of Internet clouds such as those of our German cooperation partner “Sinos” is now at a high level. Internet clouds are definitely the way forwards, as they are more scalable and more stable to operate. And when it comes to security, they rival locally installed systems. This is true when it comes to both safeguarding against failure and cyber‑attack protection, as these data centres are of course optimally protected. Before the IT systems are implemented at the customer’s premises, IT security experts from Daimler Truck carry out a separate checking process. They are accompanied by external consultants to ensure the highest security standards.

What options are there today for charging buses in parallel and in a smart manner?

Smart charging starts with a single eCitaro, whose charging process can be customised in the vehicle. For larger fleets, however, uniform charging management with parallel charging, in which the charging power can be distributed to several buses, plays an increasingly important role. We are seeing this principle being applied in our projects on a growing basis and it has largely replaced the sequential charging process that we used previously.

In our current project in The Hague, for example, the operator wanted to use 300 kilowatts for fast charging during the day, but also set up gentle slow charging at night. Together with our partner ABB, we have achieved this with a new, dynamic charger that distributes its power to four buses at night. Depending on the customer’s deployment scenario, between 60 and 90 kilowatts are thereby made available for each bus. It's not about the highest charging capacity, but rather about the right capacity for the intended use. In this way, only the charging capacity that is actually needed is installed, which leads to enormous savings potential during installation in particular.

From our point of view, this aspect is essential for an efficient design of charging infrastructure. To be able to realise this potential, you need a great deal of experience in real‑life operation with electric buses, which is a clear added value of our work as Daimler Buses Solutions.

Is bidirectional charging the best solution for highly efficient energy management?

It's an interesting topic, but you have to know exactly when and where the customer really needs it. In the city bus sector, the question also arises as to when electricity should effectively be fed back into the grid when most buses arrive at the depot in the evening mostly empty. In contrast to passenger cars, the potentials for buses are very low. We believe that efficiency can be achieved above all through smart charging management, which reduces charging peaks. This makes it possible for the electricity that has been sustainably generated at night to be used in particular. For example, our customer Rhönenergie Fulda already has an interface with the energy supplier, which can reduce peak loads in a targeted manner. In the future, the current electricity exchange price will also be applied here. Flexible electricity tariffs guarantee energy savings of between 30% and 40%. Of course, we all have a responsibility to use electricity smartly and actively support the energy transition. Last but not least, the most important thing is always that all buses are loaded and ready for use the next day.