News from IGEM FEDS
Technical Visit to Shinki Bus Company and Hydrogen Bus
To be the fuel of the future, a major use of hydrogen is providing mobility on roads. Toyota built the first hydrogen-powered fuel cell bus in Japan, and Shinki Bus Company (Shinkibus) puts it on trial in Hyogo Prefecture in Himeji City.
Hydrogen to Wheel Power
This hydrogen fuel cell bus is unique and is the only one among the Shinkibus 1,087 vehicle fleet. Contrary to the conventional diesel engine bus, which has a single diesel tank located under the floor, the hydrogen fuel cell unit stores its fuel, total 600 litres of gaseous hydrogen at 82 MPa and -40 °C, in 10 cylinders mounted on the roof-top evenly. Two proton exchange membrane-type fuel cell stacks locate at the rear of the roof-top converts hydrogen into water vapour and electricity, with the latter stored in the on-board batteries as buffer. If needed, the on-board batteries can supply electricity to other power-consuming facilities, such as bus terminus, at 220 V.
The rest of the configuration is same as any step-free, battery-powered electric bus, including such equipment as the air-conditioning unit and re-generative brake. Cabin features are in compliance with the latest requirement defined by Ministry of Land, Infrastructure, Transport and Tourism of the Japanese government (e.g. blue, yellow and black colour in passenger seat cover, handrails and cabin floor respectively, as well as a passenger-accessible emergency vehicle stop button inside the cabin).
Hydrogen Bus Ranges
Despite having the on-board compressed hydrogen, the hydrogen bus is subject to no restriction on roads. From the Toyota production line in Kanazawa, the vehicle was driven on its own hydrogen power to Hyogo Prefecture, passing through multiple tunnels.
Although comparing to the 450 km daily mileage for a diesel bus, the hydrogen bus can only do 200 km per day, it is nonetheless deployed to ordinary passenger services same as its diesel cousins.
Each hydrogen refilling lasting 10 minutes can provide a drive range, with air condition running, of 200 km, at the consumption rate of 7 kg of hydrogen every 100 km. In winter months the consumption becomes 9 kg per 100 km, due to the use of cabin heating.
However, operating a hydrogen bus is not cheap to Shinkibus. Despite having subsidies given by the central government, Hyogo Prefecture and Himeji City to offset the 100 million Japanese yen price tag, which is four times higher than a conventional diesel unit, Shinkibus paid 20 % more than an ordinary diesel bus to acquire one in its fleet. Also, the hydrogen fuel cost is double that of diesel at the pump, meaning that the operating cost of hydrogen bus is two times of diesel bus.
Moreover, contrary to the 18-year service life of a diesel bus as determined by the Japanese laws, hydrogen bus can only operate for only six years. According to Shinkibus, the high capital and operating costs have hindered the wider use of hydrogen bus.
Hydrogen Maintenance
Hydrogen-powered vehicles are new to Japan, reflected by the regulations on vehicle maintenance.
Shinkibus has recorded no fault on the hydrogen storage system and fuel cells since commercial service commenced. Daily inspection comprises a walk-down of the fuel tanks and connecting piping on the bus roof for detecting leakage, while the four times per year statutory vehicle examination is the same as any diesel bus.
While Japan has no specific national qualification for hydrogen vehicle maintenance, the hydrogen bus maintenance personnel have received corresponding training from Toyota.
Remarks
Hydrogen bus has been demonstrated as technologically feasible in the Shinkibus fleet. On the day of the visit, delegates were privileged to be offered a close look around the Shinkibus depot and was given a ride on the hydrogen bus to a hydrogen filling station. The ride experience was the same as any pure battery electric bus, which is becoming more common on the roads in Hong Kong.
Shinkibus’s first and only hydrogen bus was designed, built and operated with no difference to a conventional diesel bus in Japan, including unrestricted passage through tunnels. Also, Japan has not enacted any specific law to govern the competence and qualification of hydrogen vehicle repair and maintenance. The management of the skills needed falls on the individual operators.
EI-HKB, IGEM-FEDS and HIKE G&E would like to thank Shinkibus for their hospitality in receiving the delegation.