The bus made by Ballard Power Systems can do all the things you'd expect: carry lots of passengers, lumber around turns, and even block the view of smaller vehicles behind it.
What's different about this bus is how it runs - not by a traditional engine but by stacks of cardboard-thin fuel cells that don't cause smog.
The Vancouver company hopes its patented technology will play a central role in creating cleaner buses and automobiles.
So far, clean-car development efforts have focused on electric-battery vehicles. Fuel cells also generate electricity, but use fuel tanks that can be refilled. Unlike batteries, they don't need hours of recharging like a battery.
The fuel cell ''may have a higher level of potential'' than electric-battery vehicles, says David Cole, director of the University of Michigan's Office for the Study of Automotive Transportation. But, he says, the fuel cell is a late-comer to the race. ''There's a lot of development work to do.''
Fuel cells have been around for over 150 years. But only recently has the technology begun to see wide use, mostly in stationary applications, not mobile buses.
In simple terms, a fuel cell converts hydrogen and oxygen into water, with electricity produced during the electrochemical reaction. The hydrogen and oxygen are delivered to opposite sides of the fuel cell. Hydrogen protons migrate through a membrane to link with oxygen. The hydrogen electrons, meanwhile, travel through an external circuit, producing usable electricity.
Ballard Power Systems' fuel cells are roughly eight inches square. Each produces just a little power, but by packing almost 1,000 of them into the back of the bus, Ballard's machine hums along smartly. The company does not plan to make its own cars or buses, but to supply fuel cells to manufacturers.
Officials at Ballard acknowledge they have a long road ahead to commercialize fuel-cell vehicles. But they say they are making steady progress, and have two prototype buses as proof.
The first bus, developed in league with British Columbia Transit, came out in June 1993 to demonstrate the technology's feasibility. The second, almost completed, will set the stage for commercial production. Ballard has an agreement with New Flyer Industries, a Winnipeg busmaker, to jointly market the product in North America.
Mossadiq Umedaly, Ballard's chief financial officer, says the company expects to focus on buses and other fleet vehicles first, and move toward cars as the technology is fine-tuned, costs come down, and the fuel becomes readily available at gas stations.
The fuel can be either pure hydrogen, in various forms, or a hydrogen-rich fuel such as methanol. In the latter case, an on-board reformer is needed to extract hydrogen. Meanwhile, the needed oxygen comes to the fuel cell from air.
Ballard's buses run on hydrogen in compressed-gas form. (This is much easier to use than liquid hydrogen, which must be stored at ultracold temperatures.) Someday researchers predict that the fuel could be economically extracted from water using solar energy.
In the near term, says Ballard chief executive Firoz Rasul, methanol from natural gas appears to be a plentiful fuel, making it the likely candidate for fuel-cell powered cars.
Whatever method is used to get hydrogen, fuel cells produce much less pollution (both ground-level smog and the ''greenhouse'' gas carbon dioxide) than traditional cars do. Fuel cells even beat electric-battery vehicles, some studies suggest. This promises to be important as environmental regulations toughen. Some states, starting with California, have moved to require carmakers to sell ''zero-emission vehicles'' by 1998. Although these rules may be repealed or postponed, the environment is likely to remain a big issue.
Carmakers are already getting involved with Ballard, which has 36 patents and is thought to have a lead of perhaps three to five years over rivals in its class of fuel cells, known as proton-exchange membrane fuel cells. Germany's Daimler-Benz is working with Ballard on manufacturing processes. Ballard is helping General Motors Corporation develop a hybrid battery/fuel cell car for the United States Department of Energy.
''By no means do we see them as the only'' automotive customers for Ballard fuel cells, Mr. Rasul says. He says the firm will sell its fuel cells to any and all interested carmakers.
If Ballard can get its costs down to $100 per kilowatt of power, a passenger-car power system might cost about $1,000 more than systems based around the internal combustion engine. One researcher has even predicted the fuel-cell system could be produced at roughly equal the cost of today's power systems (typically $4,000.)