The tall little station wagon is a General Motors product sold in Europe but that wasn't the draw.

It was the colourful livery announcing that it was powered by a hydrogen fuel cell, and the fact its exhaust was little more than a dribble of water, the fuel cell's only byproduct other than heat.

GM and other automakers have brought their prototypes to Vancouver for a major conference on hydrogen and fuel cells Monday and Tuesday, which is drawing delegates from more than 30 countries.

They staged a weekend rally to the mountain resort town of Whistler to demonstrate how far fuel-cell cars have come.

But weren't Canadians - some of them anyway - supposed to be in their own zero-pollution hydrogen cars by now?

Even the technology's steadfast supporters now admit that promise, made in the 1990s, was a little optimistic.

"I think people were a little bit naive then about how long it takes to get a technology into a car and then into the hands of a consumer," says Noordin Nanji, vice-president and chief customer officer at Ballard Power Systems, the Vancouver-based fuel-cell pioneer.

"You can't just put a new technology into a car and start selling it. It takes time."

Few technologies have suffered more from high hopes than fuel cells.

"There was a lot of expectation about the passenger-car market and that was because Ford and DaimlerChrysler invested in Ballard," says John Tak, chief executive officer of Hydrogen and Fuel Cells Canada, a government-industry technology group.

When DaimlerChrysler cemented its alliance with Ballard (TSX:BLD) in 1997, a top executive from the automaker predicted the first cars would be rolling out around 2005.

"There was a lot of expectation about the passenger-car market and that was because Ford and DaimlerChrysler invested in Ballard," says Tak.

But the obstacles to commercializing hydrogen fuel cells, especially for vehicles, have proven more formidable than their boosters foresaw.

Fuel cells use a chemical reaction between hydrogen and air to make electricity. When pure hydrogen is used, there are no pollutants or greenhouse gases, with pure water and heat the only byproducts.

Ballard is producing units for stationary-power uses, such as home electricity generation in Japan, and backup power for telecom centres.

But the only mobile applications so far are in transit buses deployed in experimental fleets around the world and for electric forklifts, where Tak says cost isn't as big a factor.

Cars and trucks present major challenges in an era where even low-cost models are expected to perform flawlessly.

Volume-produced fuel-cell vehicles will have to equal conventional vehicles in long-term durability, reliability, ease of operation, range and cost, says Todd Goldstein, an engineer at GM's fuel-cell activities centre in Torrence, Calif.

"We need to have a vehicle that'll last 150,000 kilometres or more," he says. "That's the target.

"That'll involve us working very closely with our suppliers to make our components automotive grade and also certainly make them cost-effective to meet our targets for cost down the road."

Goldstein says GM is aiming for fuel-cell vehicles initially to carry a small price premium over conventional models the way hybrids do today.

Nanji attributes the initial optimism to the fact automakers' research and development boffins were doing the talking, not the product-development engineers who would have to turn their technology into marketable cars.

That's changed as fuel cells loom larger in future products.

"So that's a real step forward for the industry in terms of being more realistic about what it's going to take," says Nanji.

A consensus is emerging that fuel-cell vehicles will start trickling into private hands within three to five years, with retail sales by the middle of the next decade.

"General Motors is anticipating that around 2010 you'll see these vehicles start to be deployed for fleet applications," says Goldstein. "It's going to be probably 2015 before these vehicles are available to the average consumer."

Honda has promised to begin limited marketing of a fuel-cell car, based on its FCX family of prototypes, within a couple of years.

The fuel-cell Opel - redubbed HydroGen 3 because it's GM's third-generation development vehicle - gives some hint of how far the technology has come in 10 years, and how far it has to go before it's showroom-ready.

Smoother and quieter than previous models, its systems nonetheless send whining noises into the cabin.

Electric direct-drive systems offer inherently good pickup, but the HydroGen 3's 1,600 kilograms is still a lot for the 80-horsepower motor to haul around.

The car's emergency brake also engages at every stop and disengages when the driver steps on the "gas," creating a little lurch every time.

These are all things Goldstein says will have to be ironed out before volume production begins.

GM's next fuel-cell evolution is due this fall - 100 units of the Chevrolet Equinox crossover SUV that will be leased to average consumers in California, New York and Washington, D.C.

"The vehicles themselves will be built at the Canadian engineering centre outside of Oshawa (Ont.)," Goldstein adds.

The Equinox - HydroGen 4 - will have a range of about 300 kilometres, roughly a third longer than the Zafira.

There's no indication any will see a Canadian winter, although reliable cold-weather starting is important. GM's goal is a drive-away start at minus-10 Celsius, with the vehicle plugged into a heater overnight.

But Ballard's Nanji says his company has already achieved minus-20 without auxiliary heating and its target is minus-30 by 2010.

GM is not a Ballard customer. Like Toyota and Honda, it's chosen to develop its own fuel-cell stack.

"GM recognized early on that was a key piece of the equation," says Goldstein.

The automaker believes designing the fuel cell in-house will allow it to perfect it more for automotive use, where companies like Ballard must design it for wider application.

That's understandable, says Nanji. Large automakers want to understand the technology from the ground up rather than out-source. From there, they can decide how to handle manufacturing.

So Ballard's not burning its bridges with players like GM because it hopes eventually to end up as a component supplier.

"We have to be reasonably flexible on how we look at opportunity," Nanji said.