Enlarge image Rickshaw or Velotaxi in Dresden (© picture alliance / Arco Images G)

The bicycle of the future may require visits to a filling station – unless the driver wants to rely solely on muscular thighs. Just how much effort the rider can save with a full tank is currently being demonstrated by scientists perched atop elegant white vehicles riding through the cities of Dresden and Freiburg. The vehicles are rickshaws, carrying the rider and two passengers, and leaving no exhaust plume in their wake.

Rather than gasoline, the futuristic four-wheeler has a tank filled with hydrogen – and since its chemical element is referred to as “Hydrogenium,” the vehicle’s inventor has baptized his creation the “Hydrogenia.” But what distinguishes the Hydrogenia rickshaw from the usual electric bicycle is not visible from the outside: behind the seat cover lies a fuel cell alongside the hydrogen tank. The hydrogen reacts with oxygen in the air, generating an electric current in the fuel cell that can power an electric motor while giving off nothing more than steam.

The 250-watt unit makes it easy to work a lot. However, the air in the slipstream is not polluted, although more than a little damp. Fuel cells could be a good alternative compared to electric-drive bicycles and could be widely used today, says Lars Röntzsch of the Fraunhofer Institute for Manufacturing Technology and Advanced Materials Research in Dresden, the capital city of the eastern state of Saxony. Röntzsch noted that the batteries currently used in e-bikes have a limited range, and charging them takes a long time.

The Hydrogenia, in contrast, can be refueled in just a few minutes, and the approximately 1.2 cubic meters of hydrogen can power the vehicle for up to 200 kilometers. This means that a rickshaw taxi could conceivably be on the road and operational for an entire day before requiring a fill-up, Röntzsch explained.

Still, such technology is still not ready for serial production – but the Hydrogenia is a useful model to show how fuel-cell technology can be applied to small vehicles. A total of five researchers from the Fraunhofer Institute in Dresden and the Fraunhofer Institute for Solar Energy Systems in Freiburg, in southwest Germany, worked for a year on the adjustment of the fuel cell, the development of a special tank and a control system for their interaction. Mass production is still a ways off, however, Röntzsch says.

In addition, there is still a lack of filling stations for hydrogen tanks. While there are a few such stations in urban centers such as Berlin, Munich and Frankfurt, there are only about 15 throughout Germany.