Hydrogen-powered vehicles promise no local emission motoring, but face significant problems in the refueling and storage of the hydrogen fuel. Students at the Technical University of Eindhoven in The Netherlands have avoided these problems, albeit at the expense of energy density, by developing a self-contained system that helps power an electric bus using hydrogen produced from formic acid.
The formic acid system is designed to act as a range extender for the electric-powered bus. It's towed behind the bus in a compact trailer, and converts a fuel called hydrozine – made up of 99 percent formic acid and 1 percent a performance enhancing agent – into hydrogen and CO2. In turn, that hydrogen is used to generate electricity in a conventional fuel cell.
According to the students, there are a few benefits of using hydrozine to create hydrogen on the fly instead of just fueling the vehicle with hydrogen in the first place. For one, pure hydrogen needs to be pressurised in big tanks, something that adds weight and complexity to the vehicle as well as refueling stations. The University of Eindhoven team says the fuel has four times the energy density of a conventional battery, too, for big range in small packages.
On top of that, formic acid occurs naturally in some plants and ants, but it can also be manufactured easily on an industrial scale. All the CO2 created in the process of turning the formic acid-based hydrozine is used in the energy production process, making it a net zero-emissions fuel source. And because it's a liquid, it could be slotted into existing filling station infrastructure with very little modification required.
The "Team FAST" students that developed the fuel initially built a scale model of the range-extending trailer, known as REX, in early 2016. The subsequent year and a half was spent refining the design, resulting in a system that can output 25 kW. The standalone system was officially released overnight in Eindhoven, alongside the first hydrozine filling station.
Although it's just a prototype at the moment, Team FAST is hoping to have REX running around Eindhoven before the end of 2017. Long term, the goal is to make hydrozine a widely used, industry standard fuel source.
