The Prague Public Transit Company (DPP) continues to develop ecological electric bus transport. Based on the assessment of the trial operation, DPP has approved the intention of full electrification of bus line no. 140 on the route Palmovka – Letňany – Čakovice – Miškovice. The electric buses with in-motion charging should be deployed on the entire route of line no. 140 no later than in 2021.
Within the first phase of the trial operation, the viability of the in-motion charging concept was verified. However, the examinations revealed comments as well as requirements regarding further phases and vehicles (e.g. increase in the charging currents, improvement of the parameters for driving uphill outside trolley, the possibility of night charging and battery balancing on the garage, etc.). In addition to technical examinations and measurements, trolleybus driver courses were ensured. The trial operation included also repeated presentation drives for passengers. What is important is that the system passed even strong frosts at the end of this winter.
The Board of Directors of DPP has approved the intention of full electrification of bus line no. 140 and the Supervisory Board of DPP has been informed subsequently. The project envisages completely emission-free operation of articulated electric buses on line no. 140, which will be charged in particular through so-called in-motion charging system. This means that the electric bus is charged in certain sections while driving from the overhead contact line.
DPP chooses the way of gradual electrification of the bus transport, since the synergy effects of already built power infrastructure for trams can be used. In future, a large part of the backbone bus lines can be electrified this way, which will significantly reduce the negative impacts of bus transport on the city’s environment and residents. The thing is that transport has the largest share on the air pollution in Prague.
At the moment, one kilometer of the overhead contact line is being installed in Prosecká Street, where the trial verification operation of the electric buses with in-motion charging has been under way since October 2017. The approved intention envisages extension of the overhead contact line also to several other sections of line no. 140. The project includes also the construction of charging tracks and convertor in the Klíčov garages. Additional two convertors will be used for the necessary power supply. The existing one, which powers the mentioned section in Prosecká Street, will be adjusted for continuous operation, and the other one will be the original trolleybus convertor in Letňany, which will be newly reactivated by DPP.
“First preparatory steps are already in progress, the key step will be especially elaboration and discussion of the project documentation for the territorial and construction management. Concurrently, the preparation of the tender for approximately fifteen articulated electric buses, which will replace the current diesel buses, will take place” said Martin Gillar, Chief Executive Officer and Chairman of the Board of Directors, specifying that the intention of DPP is to link the project to the Operational Programme Prague – Growth Pole of the Czech Republic, by which DPP could get a subsidy of up to 85% of the eligible costs.
The principle of in-motion charging
The principle of in-motion charging has great potential precisely because it is particularly suitable for backbone bus lines with high daily mileage and with great transport demand which are operated predominately by articulated vehicles (moreover, often in difficult slope ratios). The in-motion charging while driving under the overhead contact line enables to significantly shorten the charging stops and thus to minimise negative impact on the productivity and economic efficiency of the operation. At the same time it creates prerequisites for a more favourable operating economy, where it is possible, depending on the range of the charging infrastructure, to reduce the need for batteries in vehicles and to simultaneously prolong their lifetime, which decreases weight, purchase price and the vehicle operating cost.
Moreover, the Prague Public Transit Company prepares electrification of line no. 207 between Ohrada and Staroměstská, where the electric buses with opportunity charging should drive.