About H2 Buses
In terms of road transport, buses in the public transport network are the most thoroughly tested area of application for hydrogen and fuel cells. Since the early 1990s, several hundred buses have been and are being operated with hydrogen worldwide – predominantly in North America, Europe and increasingly also in Asia.
Although hydrogen was initially still used in buses with internal combustion engines, bus developers are now concentrating almost entirely on fuel cell electric buses (FCEB). The use of small FCEB fleets is being promoted in urban areas as a way of contributing to technological development and to clean air policy.
Fuel cell buses have now reached a high level of technical maturity, although they are not yet in series production. Owing to the small numbers, until now they have still been much more expensive, at around 1 million EUR, than standard diesel buses, which cost in the region of 250,000 EUR. The maintenance costs have also been significantly reduced and the reliable operating times increased (Hua et al. 2013).
Depending on annual production numbers, production costs for FCEBs should continue to fall, however, in future projects. The production costs for 12-metre buses are projected to fall to around 650,000 EUR by 2020 and to approx. 350,000 EUR by 2030, bringing them within reach of diesel hybrid buses (RB 2015; Klingenberg 2016).
Modern fuel cell buses draw their energy from two fuel cell stacks, each with an output of approx. 100 kW. They also have a relatively small traction battery and are able to recover brake energy. In addition, they carry approximately 30 to 50 kg of compressed hydrogen on board, stored in pressure tanks at 350 bar. On the other hand, some battery electric bus models have large traction batteries and only small fuel cell stacks, which are used as range extenders.
Fuel cell buses now have a range of 300 to 450 km and so offer almost the same flexibility as diesel buses in day-to-day operation. While some older municipal buses still consume well over 20 kg of hydrogen (rather than 40 litres of diesel) per 100 km, newer fuel cell buses now use only 8 to 9 kg per 100 km, giving FCEBs an energy efficiency advantage of around 40% as compared with diesel buses.
In order to develop the market, demonstration projects with large fleets in long-term use are planned. The FCEB fleet in Europe is expected to expand from 90 to between 300 and 400 vehicles by 2020. The first large fleets have also been announced in China (RB 2015).
The use of fuel cells and hydrogen in municipal buses has made a substantial contribution to the technical and economic development of this drive technology in road transport. For that reason, the use of fuel cell technology and hydrogen in buses is also regarded as a model which can be transferred to other commercial vehicles (ARB 2015).
Technology tried and tested in numerous small fleets worldwide (Europe, North America, Asia), larger projects with several hundred buses at the planning stage; currently only in publicly funded transport projects, studies on commercial use (CFCP 2013; RB 2015).
Flexible, reliable use in scheduled services with short downtimes (for refuelling/charging); ideally no space and weight restrictions for passenger transport.
Range 300 to 450 km, no public infrastructure needed for municipal buses, range still too short for coaches; no air pollutants, low noise emissions, little additional weight from hydrogen tanks.
Vehicles still more expensive than the reference technology of diesel buses.
Gas buses, diesel hybrid buses, electric buses.