If you watched the Olympics in Beijing last year, you may have noticed a fleet of Volkswagen Passats being used as pace cars for some running and cycling competitions. More than just product placement, these Passats were built by Volkswagen's Chinese research laboratory to demonstrate and evaluate the company's hydrogen fuel cell powertrain.

Design

Now that they've done their Olympic tour of duty, Volkswagen brought a number of these fuel cell Passats to the California Fuel Cell Partnership (CFCP), a unique organisation that works with major auto makers, such as Honda, Ford, Toyota, Nissan, Hyundai and Volkswagen on fuel cell research. CFCP also promotes research into hydrogen generation and filling stations.

So, on a hot Sacramento day, we took the wheel of a car that just might be the future of automotive transportation. As the car is built on the previous generation Passat platform, it — decals aside — certainly doesn't exactly look like the car of the future. The controls and ergonomics are all very familiar, but the kilowatt gauge that takes the place of a tachometer in the instrument cluster hints at something more than your bog standard Vee Dub.

As the Passat's wheels are driven by an almost silent electric motor, the car's most prominent aural tone was a steady whining sound; it's not unpleasant, but it's certainly noticeable. The noise originates in the compressor as it pushes hydrogen from the storage tanks into the fuel cell. Packaging-wise, the fuel cell Passat is similar to that of its petrol or diesel brethren, with the fuel cell stack, compressor and control software under the bonnet, with the hydrogen tanks located around the rear axle. The car also has a Lithium-ion battery in the middle of the chassis, which provides electricity storage for the regenerative brakes and supplements the flow to the motor.

Performance

Putting the car in Drive, we quickly found that we had to mash the accelerator all the way to the floor to get going. There was also some shuddering when starting off, which the Volkswagen engineer in the car with us explained away as a software glitch. Initial acceleration was slower than we expected because the electric motor should give it strong initial torque, and the fuel cell doesn't need any significant time to wind up its electricity output, but we suspect that this is how the car has been programmed.

The electric gauge climbed to 40 kilowatts when starting off and stayed up there as we kept our foot down on the accelerator. Acceleration reached its plateau at about 70km/h, so we backed off the accelerator and were able to maintain speed while only drawing about 10 kilowatts. As we continued driving the electricity gauge became much more interesting to watch than the speedometer, and was invaluable in helping us modulate power consumption. Excessive acceleration caused the car to beep, warning us that the fuel cell was being overtaxed.

The car also included a power flow animation (similar to what you would find in a hybrid) in the entertainment system's LCD, plus a few screens of diagnostic information. We didn't spend much time monitoring the large screen while driving, as the power flow animation mostly showed electricity going from the fuel cell to the battery and motor.

Upside

Pure electric cars, such as the evMe, have attracted a lot of attention lately, but there is still a strong argument for hydrogen fuel cell vehicles. With current technology, a fuel cell vehicle has much better range than an electric car, as hydrogen tanks take up much less space, and are much lighter, than a large battery pack. Likewise, electric cars tend to be based on small cars, as less weight helps optimise range, while auto makers have used much larger cars for fuel cell powertrains. On another practicality note, hydrogen tanks, even at pressures up to 69,000 kilopascals, can be filled in a matter of minutes, while battery recharge times are much longer — typically upwards of four hours.

Downside

However, electric cars have the advantage of an already-existing infrastructure in place to recharge them. Electric lines run everywhere, so you generally just need to find a friendly power point or charging station. Hydrogen vehicles would require a whole new infrastructure of filling stations, and either piped or hauled hydrogen, not to mention additional hydrogen generation facilities.