As a part of the long-term strategy of the bus transport emissions reduction, the Prague Public Transit Company (DPP) has been testing an electric bus that is charged from the tram power supply network in real operation with passengers for a year and a half. The charging takes place during operational breaks in the Želivského turning loop via a two-pole pantograph collector located on the vehicle roof, from a short section of a trolley built specifically for this purpose.
The electric bus is deployed for regular operation on the routes of Lines No. 163 and 213 and the total mileage since the launch of its operation has already reached almost 100,000 km. Given the electric heating (which is not common at all in case of other electric buses) and air condition, the electric bus operation is completely emission-free from the local perspective. Thanks to leveraging on favourable prices of traction electricity, which DPP purchases for the metro and trams, as well as thanks to already built tram power supply infrastructure, the economic balance of this project is very good. Overall, it can be said that even internationally this is one of most successful electric bus projects in Europe.
Experiences from previous electric buses projects enable DPP to prepare so far the most extensive project of this kind within the Prague public transport and thus to approach its complete electrification. Based on positive results of the long-term testing, DPP prepares full electrification of bus Line No. 207 which connects Žižkov with the central city area. This is the only backbone bus line entering the very centre of Prague. DPP intends to purchase 14 electric buses for this line (with parameters of standard 12-metre buses) which again will be charged from the tram power supply network via the two-pole pantograph collector and trolley. Daily charging will be located to the Ohrada turning loop. The Vršovice depot is selected for night charging and batteries balancing. A tram (or actually former trolley bus) substation can be found directly in this depot. Due to the need to ensure necessary charging infrastructure, as well as due to announcement of a tender for supply of the electric buses, DPP expects the launch of operation of these electric buses in September 2018.
In the meanwhile, DPP assumes to launch another research and testing project – so called “Electric Bus with Dynamic Charging”. Limiting the charging to depots and turning loops areas can be restrictive, both from technical perspective and from the perspective of economic productivity, especially for backbone lines operated by articulated buses with high daily mileage and often also with high elevation. The aim of the new project is to find and practically verify also the possibilities of charging while driving, so that it is possible to utilise positive effects of the local emission-free transport at the most important and busiest bus lines of the Prague public transport.
Picture: DPP - Petr HEJNA