According to the engineer, the widespread use of natural gas for vehicles was someway off, but argued that increasingly aggressive political legislation has been making it more attractive to car manufacturers with time.

"It's also cheaper for the consumer than petrol and easier to store than either electricity or hydrogen. What's more, a wider spread of use of CNG would take some emphasis off oil, and open up more opportunities for worldwide suppliers - there would be no reliance on certain countries for supply," said Hahn to Autocar at the Geneva Motor Show 2012.

“With all the work we do on internal combustion engines to hydrogen powered cars, making big gains in CO₂ reduction is either incredibly difficult or incredible expensive. That's why I see big potential in CNG. It can offer a 20% CO₂ reduction just like that - what other technology can give you that?,” he added.