For the past six months, the streets of Basel, Switzerland have been cleaner than usual. Not only has a street-cleaning prototype been sweeping away debris, but the vehicle is quiet and emits no diesel or other exhaust fumes—just water and heat. The street cleaner, which has been under development since 2008, is the first to be powered by a hydrogen-powered fuel cell. Using just about 15 pounds of hydrogen, the fuel cell can recharge the vehicle’s electric motor battery ten times over the course of a seven-hour shift. At the end of the day drivers can refuel it themselves at a user-friendly hydrogen-fueling station.
Why hydrogen? Slow-moving, heavy machines are a good match for hydrogen fuel cells, says Christian Bach, head of the internal combustion engines lab at the Swiss Federal Laboratories for Materials Science and Technology (EMPA). "This type of vehicle is usually driven at very low load, about five to six kilometers an hour. And fuel cell systems have high efficiency at low speeds," he says. By switching to hydrogen and modifying the engine, the engineers were able to decrease the vehicle’s energy consumption by 50 percent.
Additionally, because the streets are often cleaned at night, they were looking for a quieter solution to the diesel or natural-gas powered engines that are typically used. "The fuel cell and the electric drive train are both free of noise," Bach says. And as additional bonus, he says, "We wanted to demonstrate a zero-emission power-train."
The project was a joint effort among EMPA and a number of other groups, including the city of Basel and many interested collaborators (including the vehicle’s manufacturer, Bucher Schörling, and a hydrogen company). The result was so successful that four other Swiss cities, all of which contributed financially, will be testing it out over the coming months, and Bach and his colleagues are talking to Bucher Schörling about producing 10 more.
The street-cleaner is one of a few pilot programs that are showing how hydrogen fuel cells, and their accompanying infrastructure, are safe enough and robust enough for everyday use. Another Swiss city, Aarau, has five hydrogen fuel-cell powered buses on its streets. In California’s Bay Area, the AC Transit bus system has 12 hydrogen-powered buses on the road. And Germany has gone even further—not only does Hamburg has a fleet of hydrogen-powered buses on its streets, but car-maker Daimler hopes to start selling limited numbers of fuel-cell powered vehicles within the next year. To ensure customers will have somewhere to fill up, Daimler and the Linde Group have announced plans to opening 20 new hydrogen fueling stations in Germany by 2015.