E-Mobility now also on Rubber Tyres

Tramnews issue 97/2021


In the light of the EU’s Clean Vehicle Directive (CVD) and the resolutions passed by the Bundestag (the Lower House of the German Parliament) on national implementation, it is clear – the electric bus is set to gain ground on a large scale. One major point of criticism is that e-buses carry a CO2 backpack because of the energy-intensive battery production which diesel buses do not have. Projects which we are currently working on offer solutions. This article describes how VAB assists Hanover’s public transport operator ÜSTRA Hannoversche Verkehrsbetriebe AG with the introduction of electric buses and how ÜSTRA improves sustainability.


A quick look back at history clearly shows that e-mobility has always been a part of public transport. Since Germany’s first electric tram line took to the streets of Berlin in 1881, this type of propulsion has been at the heart and core of high-capacity passenger transportation in tram, underground and commuter rail services all over the world. The first electric buses with batteries as energy storage units were in operation in Berlin from 1899 onwards. Occasional applications followed in Germany from the 1950s on, including a MAN 750 HO which entered series production in Düsseldorf and Mönchengladbach in the 1970s.


From Exotic to Standard 


The idea of using electric buses in public transport has gained considerable momentum since the mid-2010s. With the signing of the Paris Climate Agreement in 2015 and the resulting commitment to reduction in CO2 emissions, objectives were also defined for the transport sector calling for a change in drive systems. Local emission-free public transport powered by electricity from renewable energy sources makes a significant contribution to climate neutrality. The implementation of the EU Clean Vehicle Directive (CVD) adopted by the German Bundestag in May 2021 sets the framework for vehicle procurement. The arrival of electric buses brings depots new tasks and processes in connection with energy provision and charging. 


The most important aspects to be considered are:


  • the power supply made available by the energy provider at the depot for charging electric buses,
  • this is not the same as the overall power supply, as energy is already required for operation of the buildings, workshop, IT, vehicle maintenance and more.
  • the vehicle idle time required for charging,
  • this idle time does not necessarily have to be non-stop overnight.
  • the length and the expected energy requirement of the runrounds to be served with the electric bus,
  • the capacity of the bus battery installed and the capacity to be charged and
  • the characteristics of the charging infrastructure installed (or to be installed).


In addition to the long established functionalities, our depot management system called VABdepot can help with all of the above and support transport providers with:


  • vehicle allocation in line with their properties
  • monitoring and subsequent regulating of the charging procedures to ensure availability for service,
  • provision of a dashboard for intuitive visualisation of the charging processes and
  • logging of the charging procedures.


ÜSTRA has a clear corporate strategy for providing CO2-free public transport in Hanover, the capital of Lower Saxony. This is also possible with electric buses as ÜSTRA has been purchasing electricity from renewable energy sources since 2015. 


As a long-standing partner for depot management systems (DMS), VAB was commissioned to expand the DMS to include electric bus-specific features in 2020. After ÜSTRA placed an order with EvoBus GmbH to supply 50 electric eCitaro buses, and the set-up of a corresponding charging infrastructure, VAB is now implementing the connection between the two. Extending this charging-monitoring system into a fully-fledged charging-management system (CMS) is the next step.


However, the sustainability of e-mobility does not stop with energy acquisition from renew­able sources; it requires and must be given further thought. The issue of the CO2 backpack from battery production is a frequently voiced criticism.


This is where the GUW+ energy supply project comes in: the idea is for used traction batteries from eCitaro buses to be given a second life at a DC substation where they function as energy storage units. This buffer stores the recuperation energy generated during light-rail operation for efficient use. This enables compensation of peak loads, continued operation in the event of power cuts and supply of the public charging infrastructure. The pilot storage unit has a capacity of around 500 kWh and consists of 20 battery systems which were previously deployed in the eCitaro covering thousands of kilometres as part of operational testing. 


E-mobility can help achieve the goals of the Paris Climate Agreement and make transport operators more economically viable. For many municipal transport operators with public utilities in their company group, sector coup­ling offers the opportunity to make an above-average contribution to Germany’s transportation and energy shift to sustainable sources.


The build-up of stationary battery storage units provided by transport operators for second-life applications allows the energy sector to balance fluctuations in electricity production from renewable sources and to guarantee grid stability and supply.


This offers transport companies new opportunities to decouple the purchase of electricity from the demand for electricity and to purchase larger quantities of energy at off-peak and low-price times, thus reducing costs and increasing flexibility when charging the vehicles as it elim­inates the risk of unexpected purchase peaks which drive up costs. If we now lift our gaze and take electric and autonomous vehicles on board, tomorrow’s public transport can be organised in a climate-neutral, economically-efficient and customer/requirement-oriented manner.