The use of public transport is an environmentally friendly way to travel. If more and more passenger cars will be powered by electrical energy in the future, public transport companies will be forced to convert their diesel busses into electric busses in order not to lose this advantage. The requirements of busses are different to those of passenger cars. A bus covers an average distance of 250 to 300 km each day. The bus itself has a weight of, for example, 14-17.5 t (Solaris Urbino 18), 28 t (MAN NG 313) or 26.6 t (Mercedes O 405 GN). A suitable battery that would enable the bus to run for such a long distance without having to be recharged would be far too big, heavy and expensive. In order to overcome this problem, several approaches are currently being investigated, for example switching the battery and the short inductive charging of supercapacitors at bus stops. With these technical solutions, which combine vehicles and infrastructure, fully electric busses should be enabled for use in public transportation.
Technical solutions to enable fully electric busses should be evaluated so that they reflect the prerequisites and requirements of the participating public transport companies. The ultimate goal of the project is to find the best technical solution for HVB, MVB, PVGS and PKM depending on their real input data (timetable, vehicle operation plan, etc.), which in most cases may mean minimising the investment and operational costs. Of course, the best solution may vary between the participating public transport companies due to the strongly different prerequisites, assignments and aims. The best solution does not only involve a technology, but also its optimal application. To achieve this aim, models of all relevant transportational, technical, economic and ecological values will be elaborated. Methods will be developed with which the question as to the most suitable technical solution (depending on the input values) can be answered and which help to apply the technical solution found in an optimal way. A software tool will be developed with which the different solutions can be easily compared. It should be possible to study the gradual integration of fully electric busses into existing fleets of diesel, natural gas and hybrid busses. The preliminary studies with the participating public transport companies will be lead into recommendations for the actors in the field of technology development, namely the manufactures and researchers of fully electric busses and the corresponding infrastructure.
In the CACTUS project, considerations concerning techniques for fully electric busses will be made to decide which best fits a public transport company’s needs. This requires a series of detailed questions to be answered. Some general questions are:
- Is it possible to keep to the timetable with a given configuration (all technical and strategic elements requiring the operation of fully electric busses), a given vehicle fleet (including those with mixed engines) and a given vehicle operation plan?
- How high are the investment and operational costs?
In this context, several optimisation issues arise, some of which are listed here:
- What should the vehicle operation plan look like so the timetable can be kept to?
- How many vehicles are required?
- Where do the charging or switching facilities have to be located?
Within the CACTUS project, methods that can be used to answer these and further questions should be developed. Models have to be developed with which these methods can work. Detailed information on this outlined concept is provided in the detailed work plan.
Models and methods for the evaluation and the optimal application of battery charging and exchanging technologies for electric busses in public transport have been developed. The models and methods address technical, transport, economic and ecological aspects of electric busses in public transport. The individual best solution for a public transport company from the available battery charging and exchanging technologies is found by using the developed tool in which all models and methods are integrated.