Thursday, 24 December 2009

Power Source for Fossil Fuel-Free Vehicles

An Australian bus powered by Compressed Natural Gas

by L. Berney

Thinking about the world's future energy requirements and how that energy could be supplied without the use of fossil fuels, it has always seemed to me that the first choice is Geothermal Energy to generate main-line electricity. (The second choice would ne Nuclear. Other 'renewables', solar, wind, wave, tidal flow, hydro-electric (dams), could never produce more than a fraction of the energy the world needs.)

One major problem I foresaw was how to power road vehicles. If petrol and diesel are to be replaced, vehicles will have to be powered by batteries or by hydrogen. Hydrogen could be used to replace petrol/diesel either in a normal internal combustion engine, or in a hydrogen cell to produce 'on-board' electricity. I always thought that, for vehicles, the on-board storage and roadside refueling incurred in the hydrogen option would present serious difficulties. What I have seen here in Australia shows that, in fact, there would be no problem.

Australia has plenty of 'natural gas' but little or no oil. Virtually all the buses and taxis, and many private vehicles in Australia are powered by Compressed Natural Gas (CNG). Petrol/diesel tanks have been replaced by gas cylinders. Many filling stations supply CNG. The NG 'pump' has a hose (like a petrol pump) with a lock-on connector which fits the vehicle's filler pipe. Natural gas is 'pumped' into the vehicle's container cylinders -- just like filling up with petrol/diesel, and just as fast.

The engine of the bus or car running on natural gas works just as it would on petrol or diesel; only the carburetor has to be adapted. The power output and acceleration are the same. The gas cylinders hold enough gas for 200-plus miles. The cost per mile is considerably LESS than petrol/diesel!

The widespread use of CNG to power vehicles goes on in countries other than Australia; notably Argentina, Brazil and India. At the end of 2008 there were said to be world-wide over 8 million CNG vehicles on the road.

Natural gas is, of course, a fossil fuel. In a fossil fuel-free world, compressed hydrogen could easily replace compressed natural gas, so the problems I envisaged are in fact already solved!

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