Only water exits the exhaust pipes of AC Transit's three hydrogen fuel cell buses. AC Transit of Oakland, CA is one of the first transit agencies in the world to operate a hydrogen bus that combines oxygen and hydrogen (one of the most common molecules in the universe) to form electricity and water. In addition to using clean energy source, the buses also regenerate electricity when braking. AC Transit is planning to use solar power to create the energy needed to create hydrogen from water. So far, thousands of gallons of diesel gas has been saved, and hundreds of thousands of pounds of green house gases have been prevented. One major question that AC Transit has to repeatedly answer is if hydrogen is safe. Hydrogen is known to be very reactive and explosive (like with hydrogen bombs, and the Hindenburg blimp). AC Transit claims that hydrogen will rapidly dissipate into the air if there is a leak, instead pooling up like gasoline and causing a potential fire risk. Hydrogen is also deemed to be harmless to eyes and lungs. An evaluation published last month states that the cost to run a hydrogen bus is more expensive than to run a diesel bus because of the high price of hydrogen. These fuel cell buses though, get more miles per gallon than diesel buses. If you want to be one of the first people in the world to ride a hydrogen bus, the timetable can be found here. You can also track these buses with a GPS here.
Links:
AC Transit HyRoad (Hydrogen Fuel Cell Program) Official Site
National Renewable Energy Laboratory (NREL) Evaluation of AC Transit's HyRoad buses (.pdf)
See how hydrogen and oxygen create energy by clicking on the diagram to the left.
Photo courtesy of National Renewable Energy Laboratory.
