Transit service is an ideal application for hydrogen vehicles:

• Clean urban transit is urgently needed, replacing older diesel vehicles in environmentally impacted communities,

• Hydrogen buses carry, typically, 48-58 kg hydrogen, and thus modern buses with hybrid drive have range from 200-400 miles.

• They serve from 8-20 hours per day, and may carry over a thousand passengers during that day. Thus they are great “community ambassadors” for showing the advantages of hydrogen, and although they are expensive the cost is amortized over a large ridership.

Hydrogen buses have a long history, with significant progress in recent years. This paper will review the high points of the history, HICE and fuel cell, and describe the hybrid technology that is now – in prototype and short production run form – in daily revenue service.

Both AC Transit (Oakland/Berkeley CA) and SunLine Transit (Palm Springs region) operate hybrid electric hydrogen fueled buses in their transit service. ACT presently operates three fuel cell buses in daily revenue service, and SunLine operates a fuel cell bus and a HHICE (Hybrid Hydrogen Internal Combustion Engine) bus. All these buses use similar electric drive train and electric accessories, although the detailed design differs notably between the fuel cell and the hybrid ICE buses. The fuel cell buses use a 120kW UTC fuel cell and a Van Hool Chassis, whereas the HHICE bus uses a turbocharged Ford engine which is capable of 140kW generator output in a New Flyer Chassis. The engine is basically a dry gas equipped 6.8L V10. It is operated with ultra lean combustion such that with no after treatment the NOx emissions are typically in the range of 10 ppm. All buses have all electrical accessories and the capability of regeneration during braking.

The HHICE bus was the first in service, and has been subjected to both winter testing in Manitoba, Canada and summer testing in the Palm Springs, CA region.

ISE hydrogen buses have now accumulated over 100,000 miles in revenue service. The paper will describe the buses and the experience of the transit properties in operating the buses. Further, it will discuss early work towards improved hydrogen buses.