fuel cell buses

Amidst continuing conflict in the Mideast, rising gasoline prices and increasing global warming, I found one bit of encouragement on the El Camino Real: a hydrogen-powered fuel cell bus.

The Silicon Valley Transit Authority has 3 fuel cell buses running normal routes as part of an $18.5 million test program inaugurated last year. As I was unaware of the pilot project, I was quite surprised to see the VTA bus drive by. It is very cool in operation as its only emission is a plume of water vapor.

The coaches are Gillig low floor models that use Ballard 205kW fuel cell engines. They run on liquid hydrogen produced by Air Products in Sacramento and fueled at a cryogenic station at VTA Cerone (Zanker Rd and 237). In addition to zero emissions, the hydrogen buses have more horsepower, better acceleration and higher efficiency (since there is no thermal cycle) than their 4mpg diesel-powered relatives.

The fuel cells use an electrochemical process to convert liquid hydrogen into electricity. The cells (they are stacked) strip off hydrogen electrons using a proton exchange membrane, thin plastic coated with a catalyst. The migrated hydrogen protons combine with oxygen to produce water vapor and the captured electrons flow through the circuit to provide power for the bus’s engine.

Watch a video about how PEM cells work or read more about fuel cells and hydrogen production at the increasingly useful Wikipedia