AirCompressed air has been used to power forklifts, and seems like a perfect technology on the face of it. There are no emissions, no burning of fossil fuels, and there’s quite a bit of the stuff knocking around, as it happens. However, what’s the first thing that comes to mind when you think of forklifts? Even though they’re highly manoeuvrable, they’re pretty slow. Indian manufacturer Tata Motors – who count Jaguar Land Rover as a subsidiary – have been working on a car propelled by compressed air for a number of years, but the distinct lack of power has been a fatal flaw. It’ll never take off as a concept without significant improvements to the minimal horsepower and current top speeds of 30mph or so.
Likelihood rating: 6/10
WaterLike air, we have plenty of water around us – particularly salt water. It’s been more than a decade since scientist John Kanzius discovered that heat from sea water ignited using radio waves could power a small engine, and almost as long since a Japanese company called Genepax claimed to run a car for an hour at 50mph on one litre of water. But the amount of time that’s passed since these events suggests it may not be proving a viable way of powering our cars in the years to come.
Likelihood rating: 3/10
SteamLong before petrol and diesel became the staple fuel source for cars, that honour belonged to steam. In fact, as recently as 1905 steam power models dominated gasoline when it came to sales. The draw of steam powered cars is that they can burn anything from wood to crude oil and rubbish, but the big problem is that they are very heavy, and inefficient too. This was shown in 2009, when a modern steam car set a new speed record by topping 130mph. It took more than two miles of steam tubing to reach the milestone, and weighed over three tons. Are we going to head back to the future? Probably not.
Likelihood rating: 2/10
HeatYou might not look at NASA’s Curiosity rover and think it signifies the future of motoring. For one thing, it bears more than a passing resemblance to Johnny 5 from Short Circuit. And for another, it drives itself around Mars. However, the way it does so is by converting heat from onboard radioactive material into electricity, bringing the vision of the 1957 Ford Nucleon to life. The likelihood of our roads being filled with cars ferrying around nuclear reactors? Almost zero.
Likelihood rating: 1/10
HydrogenExtracting energy from hydrogen isn’t an easy process, which is a major factor in why it’s yet to hit the mass market. However, hydrogen is abundantly available and fuel cell electric vehicles (FCEVs) only produce water and warm air as emissions. FCEVs such as the Toyota Mirai have made it to production, but are yet to enjoy the same popularity in Europe compared to the US and Japan, where demand is still very limited. With improvements to the infrastructure to allow drivers to refuel more readily, this is a technology that could genuinely become reality for a lot of us in the future.
Likelihood rating: 8/10
EthanolAn alternative alcohol-based fuel, ethanol can be produced by distilling crops such as barley, corn and wheat. It’s used in some fuels already – E10 petrol is 10% ethanol and 90% gasoline – but it’s unlikely we’ll ever see 100% ethanol used in mainstream motoring. For a start, it produces less energy, which means it’s not very efficient. It also diverts crops away from food supplies, which drives up prices.
Likelihood rating: 2/10
AlgaeThis may sound a little far-fetched – and for the moment – it is. Still in its early stages, the concept is that oil can be harvested from algae cells, allowing us to create biofuels to power our cars that are much cleaner than existing fossil fuels. Algae can be grown in a tank, so there’s no threat to things like our food supply, which could make this idea a viable one for the future.
Likelihood rating: 4/10