Powered by chip fat: the cars of the future?

Powered by chip fat: the cars of the future?

It's not just the waste from Friday’s takeaway. Chip fat could be the solution to our fossil fuel problems.

Used chip fat with smelly floating bits…any takers? You could pour it down the drain, throw it out, or use it in your car. Yes, use it in your car! Diesel cars can be converted to run on old vegetable oil for about £700. Old vegetable oil, or chip fat, is free to use whereas diesel is well over a pound per litre. Not a bad deal!

Green and free, so what's not to like?

Would you like to drive a car that smelled like a chip shop? Or spend hours filtering out the gunky bits from litres of vegetable oil? Some people do manage to get past these problems - or maybe they just put up with them. In fact, vegetable oil is a biofuel (a fuel that comes from plant materials rather than petrol) and people have been using old chip fat as a greener, and cheaper, substitute for fossil fuels for years.

 

Green car running on biofuel

This car runs on biofuel

Why don't we use it all the time?

Chip fat is made of hydrogen and carbon atoms. If we could get the hydrogen atoms out of these molecules we could use it as a really good clean fuel. This is because hydrogen contains lots of energy. React it with oxygen and that energy is released with a big bang and a little bit of water as a waste product. It is just about the perfect fuel.

The problem is that it would take a lot of energy to split the hydrogen away from the carbon, because it would have to be heated to very high temperatures: over 800 degrees Celsius. This would use more energy to heat it than you can get out of the hydrogen in the first place. Also, you would get a lot of carbon dioxide, a gas thought to be partly responsible for global warming. That wouldn't be very green at all.

Bring on the scientists!

Leeds University researchers have come up with a way of splitting the hydrogen and carbon without using too much energy.

How do they do it?

The trick is to take a nickel catalyst (a substance that speeds up a reaction without itself being affected) and blast it with air. This causes it to react and forms nickel oxide. The process is exothermic, which means it gives out heat - lots of it! This means a huge saving in energy as the exothermic process boosts the temperature, so you don't have to. The less you have to pay to raise the temperature, the more cost effective the process will be. The chip fat can then be split into hydrogen and carbon dioxide.

Chemical reaction

That's not even the most exciting part. The best trick is saved till last. A special 'sorbent' material is used to absorb the carbon dioxide. Sorbents have huge surface areas and a structure like a microscopic sieve to trap and hold unwanted molecules. This also helps sustain the reaction so that it will run indefinitely. Hey presto, cost effective hydrogen from a waste material.

This means that chip fat really could be the fuel of the future. You'll never look at a bag of chips in the same way again!

Did you know…

Choo choo! The Queen's Royal Train runs completely on 100 per cent recycled chip fat. I didn't know Her Majesty liked chips that much!

Sign up for the newsletter
Sign Up For The Newsletter
Want to get the latest science news from Planet Science straight to your inbox? Sign up now!