|DaimlerChrysler Citaro fuel cell bus prototype|
DaimlerChrysler has delivered three fuel-cell-powered Mercedes-Benz Citaro urban buses to the Beijing Public Transport Corporation (BPTC), as part of a larger fuel cell project designed specifically for the Chinese market.
Starting at the end of this year and continuing through October 2007, the buses will operate in regular service on a congested 19-km long route in Beijing that runs past the Summer Palace as well as the site for the next Olympic Games.
Twelve metres long, the fuel-cell Citaro has a range of approximately 200 kilometers, a top speed of 80 km/h and a capacity for up to 70 passengers, depending on individual customer specifications. The 205-kW fuel-cell unit (from Ballard) and the pressure cylinders containing hydrogen compressed to 350 bar (5,000 psi), are located on the roof of the Citaro bus. The electric motor and the automatic transmission are located in the rear of the bus.
The project is under the organization of the Chinese Ministry of Science and Technology (MOST), which is represented by the Project Management Office (PMO) as the organizing body and CICETE (commercial executive organization) as the vehicle purchaser and owner.
Other partners in the project include BP as the hydrogen supplier; Sinohytec as the hydrogen producer; Tsinghua University in Beijing, which is responsible for scientific monitoring of the project and the evaluation of results; and the UNDP (United Nations Development Program), which is shouldering 40% of the vehicle costs.
DaimlerChrysler has had some 33 fuel cell Citaros in trials in Europe and Australia.
According to a March 2005 update on the progress of the EU’s Cleaner Urban Transport project (CUTE), which is also working with the fuel cell Citaros, the platform has proven more reliable than initially expected.
After a total of 650,000 kilometers of service, representing about 48,000 operating hours:
Of the more than 60,000 cells represented in the stacks, only a few have needed to be replaced. Lifetime of the cells this has been much better than originally expected, and the only main problem was the cell voltage monitoring system.
The electric engines and the power electronics need improvement before becoming “standard.” Most of the failures were in the inverter, although there have been some motor break-downs and starter failures.
The compressed hydrogen storage tanks appear to be working well, although there have been numerous problems with small components such as valves.
Of the more than 120,000 kg of hydrogen consumed so far, nearly half has been produced on-site.
That hydrogen infrastructure needs improvement. Both steam reformers and electrolyzers generated considerable problems during practical operations. There have been several issues with compressors of various suppliers and types, and several times fuel stacks have been poisoned due to polluted hydrogen.