The Rasa is a prototype hydrogen car that, like the drone mentioned yesterday, emits only water vapour. It is produced  by start-up Riversimple in Llandrindod Wells, UK, and instead of using pellets like the drone, it is designed around a fuel cell requiring 10 times less power than an ordinary car. This keeps the vehicle cruising, but to generate the bursts of energy needed for acceleration, the Rasa uses a sort of high-tech electricity trap called a supercapacitor. Because they store energy as electricity, rather than in chemical form, supercapacitors can release large amounts of energy faster than anything else – perfect for giving a car some oomph. The hydrogen fuel cell sends a constant trickle of energy into a supercapicitor, then the whole lot is released when the car needs it.

The Rasa slows down by reversing the motor in each wheel. This turns the motors into generators, recapturing the car’s kinetic energy and pushing it into the supercapacitor. Friction-based brakes only come into play for emergency stops. In a normal braking event about 50 per cent of the kinetic energy of the car is recovered.  For comparison, a similar system in the Toyota Prius only recovers 10 per cent of this energy.  Hydrogen offers an alternative to electric cars that is likely to have a place alongside battery power.

The Rasa has a long way to go, literally.  The infrastructure for it has to be developred and that will be expensive.  But the good news is that non-fossil-fueled locomotion should be with us in the foreseeable future.  (based on an article by Hal Hodson in New Scientist)

For hope for the future we seem repeatedly to turn to clever scientists. And whether it is about health or engineering these people are making truly wonderful breakthroughs.