Scientists and energy industry visionaries have been talking about hydrogen fuel cells as a potential source of clean energy for years. Around 2008, a team of Swiss engineers decided to stop talking and start doing. The result was a small hydrogen-powered street-cleaning vehicle called the “CityCat H2″ that began trials in on the streets of Basel in 2009.

While the team was thrilled to see the street sweeper in action—it took 18 months to develop—they were ready for the complications that arose. ”It became clear relatively quickly that the fuel cell system, which had been developed as a one-of specially for the project, was not yet ready for use in a real-life setting,” explained project leader Christian Bach, head of Empa’s Internal Combustion Engines Laboratory, in a statement. “On top of that, the various safety systems kept interfering with each other and bringing everything to a halt.”

Swiss Hydrogen Street Sweeper

Image via Empa

On the positive side, the CityCat H2 consumed less than half the fuel of its contemporaries, and although the hydrogen used to power the vehicle was produced with energy from fossil fuels, the vehicle still boasted a 40 percent reduction in CO2 emissions when compared to similar diesel-powered vehicles.

Since revising the design to include another more mature fuel cell product, implementing a single centralized safety module, and overcoming problems with the voltage converter and water pumps, the researchers say the vehicle has proven to be user-friendly and safe. for the past three months the vehicle has been running so reliably that the city cleaning services are able to use it on an everyday basis as they would a “normal” vehicle.

Although the Basel trial will soon draw to a close, and the CityCat H2 will move on to another city for further testing, the researchers say a hydrogen-powered vehicle of this sort is still around three times as expensive as a conventional diesel-powered vehicle. On the other hand, the costs of fuel cell systems alone have, over the past few years, dropped by a factor of 10, so it’s fair to say that the end of this trend is not yet in sight.