|AC Transit / UTC Power / ISE / Van Hool hybrid fuel cell bus.|
AC Transit of Oakland, California has unveiled its new hybrid-electric, hydrogen fuel cell bus at the APTA expo last week.
The AC Transit design, three years in the making, features a UTC Power 120-kW fuel cell power system and an ISE Corporation hybrid-electric drive system installed in a Van Hool (Belgium) bus.
AC Transit, ISE and Van Hool are already working together on a gasoline hybrid-electric fleet of 30-foot neighborhood buses.
The bus is one of four such buses being built for the North American market and is due to enter regular service this fall. As the lead transit agency in this partnership, AC Transit will acquire three of the four buses, with SunLine Transit of Thousand Palms, California acquiring the fourth.
|Configuration of the hydrogen hybrid buses under construction for AC Transit and SunLine.|
The 120-kW UTC Power system combines oxygen from the air with hydrogen gas stored onboard the bus, at low, near-ambient pressure, removing the need for a compressor and increasing the fuel efficiency and reliability of the whole system.
It also makes the bus very quiet.
The PureMotion 120-kW fuel cell power system represents the culmination of two years of research and development substantially funded by the U.S. Department of Defense through the U.S. Army Tank-automotive and Armaments Command (TACOM) and the U.S. Department of Transportation through the North American Vehicle Consortium.
Sodium Nickel Chloride high-temperature (“Zebra”) batteries can store as much as 53 kWhr of electrical energy and release up to 95 kW of power, enabling efficiency improvements through regenerative braking, while augmenting the 120 kW of power available from the fuel cell. The bus uses dual Siemens traction motors.
We’ve taken this bus up to 70 miles per hour on the freeway, and in our testing phase, we have achieved twice the energy efficiency of diesel.—Dave Mazaika, President and CEO of ISE
|Comparing Emissions and Fuel Consumption|
|mpgde = miles per gallon diesel equivalentSource: ISE Corporation|
|Conventional Diesel||30||0.24||2,200||4 mpg|
|Conventional CNG||15||0.02||2,500||3.3 mpgde|
|Hybrid Diesel||13–16||0–0.03||1,700||5–6.5 mpg|
|Hybrid CNG||2 (?)||0.01 (?)||2,000||3.9 mpgde|
|Hybrid Gasoline||0.5||0||2,100||3.4–6 mpgde|
|Hybrid Hydrogen ICE||0.5(?)||0||nil||5 mpgde (?)|
|Hybrid Drive Fuel Cell||0||0||0||7–10 mpgde|
AC Transit engineers worked closely with UTC Power, ISE, and with bus and coach manufacturer Van Hool to design a glider that would accommodate this integrated hybrid system. All parties successfully achieved the fuel cell integration without compromising the features of true low floor transit bus: three wide entrance/egress doors, completely low passenger floor from front to very back of the bus, expansive windows and high ceilings, electric air-conditioning, as well as other features typical to a Bus Rapid Transit operation.
Utilizing the same vehicle design developed by Van Hool, UTC, and ISE for AC Transit, a demonstration bus will be built for the European market to conduct additional testing and evaluation of vehicle performance and to further advance the use of fuel cell hybrid-electric technology.