>Zero Emission Buses
>Art Douwes is a Senior Mechanical Engineer with the Valley Transportation
>Authority (VTA). Several months ago VTA officials unveiled plans to start
>trial runs of three buses powered by hydrogen fueled zero-emission engines
>in August of 2004. VTA adopted a Clean Fuels Strategy in December 2000
>with the goal of transitioning from clean diesel technology to fuel cell
>technology as soon as effectively possible.
>Art will describe the fuel cell technology to be employed in the buses,
>how the hydrogen fuel will be managed, and VTA's plan to meet the
>California Air Resources Board (ARB) mandate that 15 percent of new
>bus purchases be ZEBs by the end of the decade.
Art Douwes began his talk by explaining that the fuel cell program bus program is driven by the need to get ahead of the curve on such busses. For the ARB mandate to be real, they need to have the technology ready, and that requires proactive behavior now. Fuel cells are a good choice because the only outputs from the engine are electricity, heat, and water, making it a true zero emissions technology.
Douwes then gave us a brief history of fuel cells. The first ones were developed in the 1880s, but it was not until the space program of the 1960s that practical ones which would provide significant amounts of power were developed. The first fuel cell busses were made in the 1980s. He showed a slide of one, and the fuel cell was about a fifth the size of the whole bus. There was a technology breakthrough in the early 1990s, and since then companies like Ballard have developed practical engines that make sense in busses. He showed us a picture of one, and it is about the size of a four seat restaurant table, but not quite as high.
He then explained something about how a fuel cell engine works. Hydrogen from the tank on the roof of the bus is added from one side of a membrane, and oxygen from the atmosphere is add to the other. A membrane and some catalyst including platinum separates them, as well as an anode and cathode. The membrane allows protons from the Hydrogen to pass, forcing the electrons to go around via the electric circuit that powers the bus. The engine sized above gives out about 200 Horsepower, and the tanks on the bus can be expected to power it for about 200 miles.
The prototypes will be fairly expensive. Gillig is charging VTA about $10 Million for three busses, which will spend about $1 per mile for fuel. For contrast, normal busses cost about a tenth that, and get about four miles out of every fuel dollar. However, some of the price is being offset by grants from other oversight entities like the EPA who are interested in seeing new technologies move forward. It is expected that once production volumes rise, costs will get much more competitive. VTA is currently planning to take delivery of its first fuel cell technology ZEB in the spring of next year.
During the Q&A section of the meeting there was some discussion of where Hydrogen to fuel the buses comes from. At this point, most of it comes from cracking fossil fuels. There are some experimental projects in Palm Desert to get Hydrogen using solar power, but at this point those take a lot of acreage and produce very little fuel.
Measured by themselves, fuel cell engines have about a third better fuel efficiency than internal combustion engines. However, Art was not sure about the relative efficiencies of the fuel making procedures.
Another point discussed was vehicle safety. The Hydrogen tanks have been drop tested from 100 feet, and survived. Art expects them to be crashworthy in use on our streets.
Art Douwes finished his talk by putting a collection of URLs on the board where people could go to find out more about the topic. If you are interested, please visit: