The hybrid engine is environmentally sustainable for overland transport. The first hybrid Postbus was in operation for four months over the summer as part of a pilot test. During this time, its fuel consumption was measured and compared to that of a traditional Postbus. The results are positive – diesel consumption can be reduced by up to 30%.

Hybrid buses are already in use in cities across Europe. Thanks to the stop-and-go nature of city traffic, these buses can save enough energy to rely on an electric engine rather than a diesel one. This results in significant fuel savings. But how do they fare when it comes to overland transport? Until now, there have been no definitive historical data in this area. PostBus Switzerland tested a hybrid bus alongside comparable diesel buses on a daily basis for a period of four months in order to gain a better insight into consumption and cost-related factors in rural areas. The results confirmed expectations that the hybrid bus is also environmentally sustainable in this environment. No conclusive statement can be made with regard to economic sustainability as the test period was too short.

Fuel savings of 20-30%

The first Volvo 7700 hybrid Postbus began operation in the conurbation of Berne in mid-April 2010. For the purpose of the pilot, it was compared to pure diesel buses from Volvo (B7L), MAN (Lion’s City) and Mercedes-Benz (Citaro), which were run under similar conditions. The hybrid consumed 20% less fuel than the Mercedes-Benz and achieved a saving of 28% and 29% respectively compared to the Volvo and MAN models. As such, the pre-pilot expectation of a 20% fuel saving was met.

Economic sustainability yet to be confirmed…

In an overall cost comparison, however, the hybrid bus comes in behind its diesel counterpart. Taking investment, operation and maintenance costs into account for the same period of use and mileage, the overall costs of the hybrid bus are around CHF 11,000-15,000 more. This is attributed to the higher procurement cost (CHF 520,000 for a hybrid bus; CHF 400,000 for a traditional diesel bus), higher write-downs and capital interest rates. Moreover, the hybrid bus comes with the added cost of the essential replacement battery (CHF 50,000). The estimated repair costs for the hybrid bus were thus 10 centimes more per kilometre. This cost factor can only be assessed conclusively after several years of operation, however.

… but conceivable for the medium term

The pilot revealed that from an environmental perspective, the hybrid bus is worth operating in rural as well as urban areas. Under the test conditions, however, economic viability is not yet assured. This said, it would be incorrect to stop operating the hybrid bus purely on this basis. If the price of diesel were to increase by a couple of centimes, for example, the results would quickly turn in favour of the hybrid. Furthermore, larger production series would result in lower investment costs for hybrid buses in future. And thanks to technical advancements, batteries will not only become more powerful but also less expensive.

Comparison with diesel consumption

*incl. repairs, investment, interest and write-downs, operation. Hybrid bus incl. one replacement battery. 12-year period of use, diesel price of CHF 1.00 (current price minus VAT and fuel taxes), rounded to TCHF

PostBus signs UITP Charter for sustainable development

PostBus signed the UITP (International Association of Public Transport) Charter for sustainable development on 18 September 2010. The Charter’s objectives focus on overall environmental protection through measures such as reducing CO₂ emissions. The Charter also targets measures in favour of social justice and promotes economically sustainable transport systems. The companies who sign the Charter confirm that they have integrated economic and environmental sustainability into their strategic objectives.