Riding the bus in Perth, Australia became a lot more interesting after the city began running three fuel cell powered buses. A Perth bus driver reported that "the quietness inside the bus has allowed the overhearing of some very lively discussion by passengers …"

But better eavesdropping is just a bonus of using fuel cell buses. Fuel cell buses improve local air quality since they have no tailpipe emissions. Because the fuel cell system is so much quieter than a diesel engine, fuel cell buses significantly reduce noise pollution. Fuel cells are highly efficient, so even if the hydrogen is produced from fossil fuels, fuel cell buses can reduce transit agencies' CO2 emissions. And emissions are truly zero if the hydrogen is produced from renewable electricity.

Over the last four years, more than 50 fuel cell buses have been demonstrated in North and South America, Europe, Asia and Australia. These projects have led to improvements in fuel cell technology and hydrogen infrastructure. They have also helped cities prepare for greater fuel cell vehicle deployments. Finally, they have moved fuel cell buses forward on the pathway to commercialization. The next round of development, demonstration and deployment activities is already underway, building on the progress of these recent demonstrations.

Results of Recent Fuel Cell Bus Demonstrations

The biggest fuel cell bus fleet belongs to DaimlerChrysler, which built 36 EvoBuses equipped with 200kW Ballard fuel cells for widespread demonstrations (including the one in Perth). Since 2003, these buses have accumulated nearly one million miles on three continents and in many environments: hot and dry, cold and humid, flat and hilly. Reliability has been impressive, with DaimlerChrysler reporting 90% average bus availability in the European demonstrations.

Fuel cell buses are showing great fuel efficiency when coupled with a hybrid drive. Two California transit agencies, AC Transit and SunLine Transit, are operating four Van Hool buses with a hybrid fuel cell drive system. The buses use a 120 kW fuel cell system by UTC Power in a hybrid electric drive with three sodium/nickel chloride batteries. Early test results indicate a 56% fuel economy improvement over the diesel fleet, and 149% improvement over the CNG fleet.

In Tokyo, Toyota developed eight Hino buses with a 180kW fuel cell / nickel metal hydride battery hybrid system for a six-month trial in 2005. These hybrid fuel cell buses were reported to be 63% more fuel efficient than their diesel counterparts.

As a result of these demonstrations, fuel cell manufacturers are developing only hybrid fuel cell systems for buses. They are exploring new hybrid configurations and energy storage options to continue to improve efficiency.

Fuel cell buses have also established an excellent safety record, with no major incidents reported during the demonstrations. These results have shown that hydrogen can be safely handled in daily bus operations. They have also provided a blueprint for safe fuel cell vehicle operation which future adopters can follow.

More than 20 hydrogen stations have been built or adapted to fuel hydrogen buses, providing valuable experience in siting, building and operating hydrogen facilities. Now, local safety officials -- such as fire marshals, building inspectors, and first responders - have a better understanding of hydrogen as a transportation fuel, easing the way for future installations.

The next stage for fuel cell buses

Although the future is bright for fuel cell buses, more research is required to make them fully commercial. One key area for future development is durability. For example, most fuel cell buses have run for only two to three years, with the fuel cells typically accumulating no more than 3,000 hours of operation. Another major focus is cost reduction. Currently, fuel cell buses are custom-built, and their price reflects this.

Further progress on these issues will come with more R&D, extended real world testing, and larger production volumes. New government initiatives are helping industry address these challenges. The US Federal Transit Administration has launched a four-year, $49 million program to design and demonstrate fuel cell hybrid buses with new energy storage devices like ultracapacitors or lithium batteries, as well as plug-in fuel cell hybrid bus systems and fuel cell auxiliary power units. The buses will be tested in varied climates and conditions across the US.

The European Union (EU) has launched a four-year, $62 million program to further develop and demonstrate fuel cell and hydrogen vehicle technologies. Through this program, 30 of the DaimlerChrysler fuel cell EvoBuses are continuing operations in Europe, to extend the fuel cell systems' operating hours and learn more about fuel cell stack durability issues. The program will also fund development of next generation fuel cell bus technology.

Other government agencies are forging ahead with procurement plans. Cities in Europe, Canada and Australia have formed an alliance to demonstrate wider demand for hydrogen buses. Consortium members will make their procurement plans public and share information on the procurement process with each other. Their goal is to spur private investment and drive down bus prices while allowing members to benefit from each others' experiences.

One consortium member, Canada's BC Transit, has already committed to purchasing 20 hybrid fuel cell buses, the biggest single procurement to date, for delivery by the 2010 Winter Olympics in Whistler. Another, the city of London, began the procurement process for ten fuel cell buses earlier this year.

Finally, while current research focuses on fuel cell buses for transportation, their role need not be confined to providing mobility alone. With a large fuel cell and an on-board supply of hydrogen, fuel cell buses can become a mobile source of emergency power. When a future hurricane Katrina or other major disaster strikes, fuel cell buses can provide 200Kw or more of power for shelters, communications, and other needs.

Fuel cell buses appear destined to be a major part of transit fleets, reducing petroleum dependence and providing a truly zero emission mobility option.

Lisa Callaghan is the Technology Director at Breakthrough Technologies Institute (BTI). BTI's programs include Fuel Cells 2000 (www.fuelcells.org) and the Bus Rapid Transit Policy Center (http://www.gobrt.org/).