So what happens if the petrol dries up? Some clever and crazy alternative fuels

Recent months have seen reports in various media about Australia's dwindling fuel reserves. But how would it be if we were told that supplies from the largest oil producers in the world had been completely stopped?

That rationing, car-free days and drastic reductions to speed limits would all be implemented immediately to save fuel? It has happened before, accompanied by dire predictions that oil supplies might be completely exhausted within a few years.

So what to do? What miracle fuel could be invented, produced and distributed with the same ease and at similar cost to petrol?  What alternative power units are available or would need to be designed to keep our cars, trucks and buses running?

Long before there was any suggestion the world could run out of hydrocarbon-based fuels, alternatives did exist. Some have been adopted during the years since the 'Oil Shock' of the 1970s, some are under development and others are just too way out and wacky to offer a serious alternative.

Designers have been using electrical energy to make vehicles move for almost as long as there have been motor vehicles. The first viable electric cars appeared in the 1890s and predictably were used as taxis. Electric vehicles fell from favour during the 1920s and even when oil shortages became severe, car-makers were slow to rethink the technology. During the past 50 years various manufacturers have explored  hybrid or full-electric propulsion and sales in some markets are significant. Australia with its huge distances and relatively cheap access to conventional fuels has been slow to adopt the electric vehicle.

Car-makers have been equally reluctant to make electrically-propelled models that meet our needs, however the first one into the market with an all-electric dual-cab utility could be onto a winner. At this stage it could be emerging American EV-maker Rivian's R1T pick-up.

Anyone who has ridden in a cab or on a city bus will have first-hand experience of gas as an automotive fuel. LPG (Liquid Petroleum Gas) became immensely popular during the 1970s and '80s as petrol and diesel prices increased. Taxis and other commercial vehicles sprouted cumbersome gas tanks which reduced luggage space and were frustrating to fill. Leaks were an ever-present problem and limited range made gas-fueled vehicles impractical for long-distance driving. CNG (Compressed Natural Gas) is used mainly in heavy vehicles such as delivery trucks and urban-area buses that can do a series of short journeys then return to their depots for refuelling. Although cheaper than petroleum, automotive gas is a less efficient fuel. It also requires vehicles originally designed to burn petrol or diesel to be adapted and owners  to cover sufficient distance over several years to recover the conversion cost.

Related: CNG: Answer to energy dependence?

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Newsworthy of late has been a Federal Opposition proposal to make Australia a major source of industrial hydrogen. Hydrogen of course is all around us, a major component of water, but isolating, storing and safely transporting the volatile gas are obstacles that to date have prevented it becoming viable as a vehicle fuel.

BMW more than a decade ago announced an engine that burned hydrogen in a similar manner to hydrocarbon fuels. However, for the power unit to function the fuel needed be pressurised and kept in a liquid state at -432C. Other manufacturers including Honda and General Motors have favoured fuel cells which are less finicky about temperature and use hydrogen gas to generate electricity which then runs an electric power unit.

Related: Hydrogen cars: Future or fiction?

Of all the manufacturers to pioneer jet power for road-going vehicles it was traditional old Rover the pioneer; even running a gas-turbine coupe in the Le Mans 24 Hour race. However it was Chrysler in the USA which brought automotive jet power closest to reality. In 1963, 50 examples of the Chrysler Turbine Car were released to selected individuals for real-world testing. In 1964, after being trialled quite successfully and run on 'fuels' ranging from chip fat to tequila and Chanel No.5 perfume, the cars were all collected and the majority scrapped.

Land speed records have over many years been regularly set and then broken but the record for the highest speed achieved by a steam-powered car stood for more than 100 years. Not until 2009 was the record re-set and even then by only a small margin. Why the delay? Well, apparently because nobody after the 1920s really cared much about running motor vehicles on steam. That attitude has begun to change, with new and highly-efficient steam power units being built and that new steam-powered speed record of 225.055km/h being set. Emissions from steam cars obviously depend on what fuel is being burned to create the steam and designers of the 2009 record-setter erred conservatively in choosing LPG as their source of thermal energy.

No one has as yet produced a working prototype of a nuclear-fuelled vehicle and the chance of one appearing in the near future seems unlikely. The concept however isn't new, dating back to 1957 when Ford against a background bombs being tested and atomic power-plants springing up like weeds displayed a 3/8th scale model of a nuclear car. With wings and fins everywhere the Ford Nucleon looked ready to fly and could certainly have scored itself a spot on the set of Thunderbirds, but the Ford concept didn't come with any kind of reactor. Decades would pass before anyone again considered building a vehicle with nuclear power, then in 2009 Cadillac popped up at the Chicago Auto Show with a full-sized 'concept' intended to run on an element called Thorium. The stuff occurs as a hard-to-melt metal and is less radio-active than uranium. In automotive form the thorium reactor would use a concentrated beam of energy to boil water and run the vehicle on an endless supply of steam. To date, no further progress has been announced.

Have you ever inflated a balloon then let it fly haphazardly around the room as the air escapes? Well in decades to come, travel through crowded cities where hydrocarbon fuels are banned could be accompanied by the sound of slowly-escaping compressed air. French-based Motor Developments International back in 2007 displayed a bubble-like design which MDI claimed would shortly be produced as a taxi and light delivery vehicle by Indian-based Tata Motors. Tata, with a range of other interests including Jaguar and Land-Rover, most likely had enough on its plate without getting too involved in the compressed-air revolution and nothing happened. However, in 2012 a prototype with AirPod signage was videotaped easily keeping up with traffic on an Indian street.

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