Natural gas fuel of the future

With the focus firmly on electric cars as the preferred future form of transport, natural gas has dropped off our radar. But natural gas is here now and could be a cheap and clean alternative fuel for the medium term, if not the long term.

Australia is blessed with vast reserves of natural gas and it's already being piped into our homes for use in heating and cooking, so it's a small step to using it to fuel our cars.

The issue with natural gas is, like electric cars, the range you can achieve. In the case of a natural gas the volume of the tank you can realistically fit into a car determines the range.

Typically, the tank you would need to do 400 km between refills is too large to be practically fitted to a passenger car.

That rules natural gas (CNG) out in a single-fuel use, but it doesn't rule out its use in a dual-fuel application, much as a dual-fuel vehicle uses LPG and petrol.

Systems are in place that combine CNG and petrol systems that give vehicles an attractive running cost equation along with the flexibility of use of a regular petrol-fuelled car.

The natural gas is stored under pressure in a tank in the car, and fed to the engine through lines under pressure before entering the engine in much the same was as with an LPG system.

The same electronics that drive the car's petrol system are used to control the CNG system, the two systems work in tandem in the same way the current fuel injection and LPG systems work together.

There is little difference in the way the cars drive on CNG and petrol and there is little difference in performance once the timing is adjusted for the lower energy value of natural gas.

Cars running on CNG now have a range of around 150-160 km between refills, which makes it ideal for day-to-day commuting.

The issue right now is refilling the car with natural gas. There are few commercial outlets where it can be done, but that problem is likely to be solved when home refilling stations become available.

They are in use in other countries and are on trial here. When they become available commuters would be able to refill their cars overnight simply by plugging into the refilling station, which would be installed in their garage at home. Refilling is a rather slow process with CNG, it could take as much as six hours to fill the tank being used in cars today, but it could easily be accomplished overnight while we're tucked up in bed and be ready to go the next morning.

The advantage of CNG in a dual-fuel application, unlike an electric car, is that the same car can be used as cheap commuter during the week and a regular long distance cruiser whenever needed.