Could rubbish, air and chocolate be the fuels of the future?

In the final scene of 'Back to the Future', Emmett "Doc" Brown arrives at Marty McFly's house in a flying car.

What's more interesting about this vehicle, however - to those interested in green cars, anyway - is the fact that its powered by a device called the Mr. Fusion Home Energy Reactor. This uses regular household waste to power the flying car. Doc chucks a beer can, a banana peel and other rubbish into the device before setting off for the future.

That future just happens to be 2015 - a time which no doubt seemed far off when 'Back to the Future' was released in the 1980s, but which is now just a few short months away.

While there are no signs of a Mr. Fusion Home Energy Reactor having been used in a real-life vehicle as of yet, there are a number of other alternative (in every sense of the word) fuels that have managed to successfully power cars across the world.

According to the Daily Mail, for example, one power source that could abolish your fuel consumption worries forever is compressed air. Just last month, Peugeot announced its plans to launch a hybrid vehicle that runs on petrol and air, rather than electricity.

The news source reveals that car fuel consumption - and therefore petrol costs - could be reduced by up to 80 per cent in this car.

A number of vehicle owners have also successfully converted their diesel-engine cars to run on vegetable oil. 

In addition to this, a few years ago a team of researchers from the Warwick Innovative Manufacturing Research Center in the UK were reportedly working on a ... wait for it ... chocolate-powered vehicle. According to the New York Times, the Formula 3 car was running on "30 percent bio-diesel derived from chocolate waste".

Until some - or all - of these vehicles are on the market, having fleet software that allows you to monitor your fuel usage is good way to keep your car fuel consumption down!