Volvo has so far provided municipal transport operators with over 3,600 electrified buses. Some of them are electric-hybrid vehicles manufactured in the Volvo factory in Wrocław. Electric hybrids are a flexible solution that works well in cities where air quality and noise reduction are important - buses can move on up to 70% of their routes without emissions. They are 20-30% cheaper than completely electric vehicles.

Electric Hybrid - what is this?

There are three types of electrified bus drives: fully electric, hybrid and hybrid electric. Electric hybrids differ from conventional hybrids, in that on most routes only electric power is used - the small combustion engine serves only an auxiliary function. Such bus can drive in electric mode for about 70% of its operation (depending on traffic conditions), and the battery is charged at the end stops, which takes only three to six minutes - after a short period of time, the bus can re-start on the route. Electric hybrids can also be loaded with plug-in functionality - for example, at night in the depot.

Electric hybrid buses in public transport

Electric hybrids are less polluting (carbon dioxide emissions are reduced by 75 to 90% compared to an analogue diesel bus), quiet driving (the electric bus emits only 65 dB - the noise level of a normal conversation) and offer energy savings (60% lower consumption than a comparable diesel bus). Electric-hybrid buses also offer great flexibility for cities and public transport operators.

- The electric hybrid offers the possibility of active and automatic management of the drive in the areas where the bus moves. Thanks to this solution the vehicle can drive completely without emission in selected areas of the city, says Małgorzata Durda, Volvo Buses director for Poland and the Baltic States.

How's it working? In the case of electric hybrids, it is possible to program at which point the bus will use the electric drive and at which the combustion engine. The system enables accurate calculation of energy demand on a given route and uploads it to the computer controlling the drive unit based on an algorithm, which automatically, after reading the GPS data, switches the drive from the combustion engine to the electric one in the low or zero emission areas - e.g. in the vicinity of schools, hospitals, housing estates or city centers.

- From a city perspective, this solution seems to be very interesting, allowing a completely different perspective on the design of urban space. It is possible to create zero-emission zones, free of exhaust gases - the electric hybrid has the ability to drive fully electrically in such zones. Moreover - such a bus may have, for example, a stop inside a shopping mall - where it will move only with the use of electricity, quietly and with zero emissions, says Małgorzata Durda.

Of course - the same can be achieved in the case of fully electric buses. They are, however, 20-30% more expensive than electric hybrids and require the same battery charging infrastructure as electric hybrids.

Volvo electric hybrids

Volvo is the only bus manufacturer that has completely embraced electric mobility a few years ago, abandoning the production of buses with only a combustion engine. Today, its electric hybrids are produced exclusively in Poland - in its largest European bus factory in WrocÅ‚aw. The Volvo 7900 Electric Hybrid moves quietly and produces no emissions on 70% of its route. Charging takes only 3-6 minutes and takes place at the final stop. This is possible thanks to the use of the “opportunity charging” charging system - the bus simply enters the charging station and takes in the current through a pantograph extended out of the station. Batteries are also charged when driving - with braking and surplus engine power, and they can also be charged at night in the depot using the plug-in feature. With this solution, energy consumption is 60% lower than that of a comparable diesel bus, and carbon dioxide emissions are reduced by as much as 75 to 90%.

Volvo electric hybrids in European cities

Volvo's electric hybrids are already running in cities such as Gothenburg, Stockholm and Varnamo in Sweden, Hamburg, Luxembourg and Namur. In Luxembourg alone there are four bus lines with a total length of 86 km, operated exclusively by electric hybrids - a total of seventeen vehicles. Volvo electric hybrids are also currently being tested by public transport operators in Marseille in France and Manchester in the UK.