Toby Walne road-tests humble biofuel of used chip fat oil

A mouth-watering aroma of fish and chips is expected as I power up a car that runs on used chip fat oil. Yet having been warned it may give me an appetite, it is disappointing to stick my head out of the window and smell nothing. Not even a faint whiff of battered cod. 

It might all seem rather bizarre, but using used cooking oil to fuel cars and lorries is very much part of the future as we wean ourselves off petrol and diesel. 

Biofuels may not prove as popular as electricity when it comes to propelling cars, but they could play a role in turning Britain carbon neutral by 2050 – an ambition laid out last week by Prime Minister Boris Johnson as he declared the country would ‘lead the charge’ against climate change. 

Going green:  Toby fills up with biofuel, but there is no mouth-watering aroma of fish and chips 

Inspired by the Prince of Wales, who proudly says his own car is powered by a mix of ‘cheese and wine,’ I have decided to test drive a four-year-old Mercedes S-Class, fuelled by old cooking oil. The £40,000 vehicle belongs to Andrew Freeman, boss of a haulage company based just outside Peterborough in Cambridgeshire. 

Freeman is also a director of Pure Fuels which, from the same site, manufactures biofuel derived from cooking oil. This is used to fuel Freemans Transport’s 50- strong fleet of lorries that do a combined nine million miles a year. Typically, a 44-ton lorry can manage only 12 miles to the gallon on biofuel. 

Freeman may be foolhardy to trust me to take his pride and joy out for a spin around the country lanes near his company’s Stibbington base. But his face gives nothing away as I fill up the fuel tank.

There is an odd smell of rubber as I pour the oil in – a bit like the smell a wetsuit gives off. It is not as pungent as diesel and looks a bright clear liquid gold. 

Having worked out which shiny buttons need pressing to get the automatic started, the vehicle rumbles into life and I head for the nearby Nene Valley Railway museum. There is nothing different to this ride than if I were driving a normal diesel car. It is a smooth drive with no fume smells. 

The Royal heir’s Aston Martin is run on a blend of 85 per cent ethanol – derived from alcoholic gases emitted during the production of wine and cheese fermentation – mixed with 15 per cent unleaded petrol. 

But critics point out it is not a practical solution for most drivers. Yet chip fat oil used to fry up Britain’s favourite meal of fish and chips can easily be turned into a biofuel to power cars.

You do not even have to adapt the engine on older diesel motors, while for modern ones such as the car I drove, you just need to ensure the cooking oil is refined. Producers such as Pure Fuels use waste chip fat oil that might otherwise be thrown away, then filter and distil it so it is clean enough to run on even the most finicky modern diesel engines. 

The electronics and heating systems on diesel vehicles made after 2000 means they struggle to run on just raw vegetable oil – while the oil does not work as a substitute fuel for petrol-driven cars. 

Freeman says: ‘We have come a long way from the dinosaur biofuel of a few years ago. This is a solution for modern diesel engines – and avoids those nasty carbon dioxide emissions from fossil fuels. 

‘It is also far more practical than going electric, where you use up natural resources to build batteries that always need recharging.’ 

Does the maths stack up? Freeman calculates his refined fuel costs less than £1 a litre. This is a bargain compared with the soaring cost of diesel – which currently stands at about £1.44 a litre and is still rising. The fuel economy is pretty much the same for both. 

The biggest hurdle is to convince petrol stations to stock biofuel at the pumps. Freeman says: ‘Sadly the fuel industry is dragging its feet, of course. Selling biofuel is not in the best financial interests of the major petrol stations and the Government has fallen for its own misguided spin on electric cars being the future.’

Biofuels help the planet by not burning fossil fuels – though they might harm the environment in other ways, for example through deforestation to grow plants for the production of vegetable oil. 

Yet while diesel cars pump out an average of three tons of carbon dioxide a year in waste, it works out closer to ‘net zero’ on chip oil. Plants grown to create vegetable oil absorb carbon dioxide.

But this eco-friendly route will not stop biofuel falling foul of a tough new £12.50 ultra-low emission zone charge in London that will apply to most non-electric vehicles from tomorrow. 

The cost of chip fat oil used to produce biofuel can be as high as £850 a ton – though Freeman refines waste that costs just £65 a ton. But a few adventurous eco-warriors have managed their own experiments to power cars without any fancy equipment. 

Alex Kersten, editor of motoring website Car Throttle, says: ‘I tried out cooking oil on a 20-year-old Skoda Octavia. I paid £10 for two 20-litre tubs of used cooking oil from a local chip shop and got 20 litres free from a Chinese takeaway. It took more than a week of slow filtering through old net curtains – which was messy and took time – but the car ran just the same as before and saved me a fortune in fuel bills.’ 

Life in the fast lane: Prince Charles in his car powered by cheese and wine

Life in the fast lane: Prince Charles in his car powered by cheese and wine

Working on the basis that a car manages 40 miles to the gallon and travels 10,000 miles a year, diesel would cost around £1,620. Using chip fat oil, the equivalent cost would be £284. If you produce your own fuel and use less than 2,500 litres of vegetable oil a year, there is no tax to pay – but anything more and you must pay 57.95p a litre in fuel duty. 

Kersten says: ‘Using cooking oil as fuel will certainly save money, and using a waste product to fuel the engine is environmentally friendly, too. But this was an experiment that I would not turn into a full time habit as it takes such a lot of effort. Yet I will miss being able to blast any aggressive tailgating driver with a puff of chip fat smoke.’ 

Another drawback is that vegetable oil is thicker than diesel, so it puts more of a strain on a fuel pump and can clog up fuel injectors. It might be worth installing a dual tank system instead – allowing diesel to start the engine before switching to biofuel. 

Diesel and biofuels can be mixed in a cocktail of 20 per cent diesel and 80 per cent biofuel, making it less likely that you will struggle when starting a vehicle. Biofuel conversion kits can cost £1,000.

Last month – as the petrol pump crisis gripped the nation – the Government started reducing the proportion of fossil fuels in a standard gallon of petrol with the introduction of new rules requiring more environmentally friendly ethanol in the mix. Standard unleaded petrol changed from a mixture of 5 per cent ethanol and 95 per cent petrol (E5) to 10 per cent ethanol and 90 per cent petrol (E10). 

Drivers of modern vehicles are unlikely to notice any difference, but cars built before 2011 may not run as well on the new blend. This is because ethanol – which can also be produced from crops – can damage rubber and parts of older vehicles over time. These cars might have to switch to the more expensive ‘E5 super unleaded’ that typically costs £7 more to fill up a 60-litre tank.

As the recent fuel shortages at petrol stations have shown, the need to find viable alternative fuels is more important than ever. 

Despite the Government’s push towards more vehicles being powered by electricity – banning the sale of new petrol and diesel cars by 2030 – not everyone is convinced by this strategy. 

A lack of fast charging points, sometimes little more than a hundred miles between recharges, plus the additional expense of electric cars, are all major disincentives. 

The mining of precious minerals such as cobalt, nickel and manganese to make car batteries also does not sit well with environmentalists. 

A hundred and twenty four years ago, Rudolf Diesel, inventor of the diesel engine, believed running a motor car on vegetable oil was a future possibility – testing his invention on peanut oil. It seems he is being proven right. 


The ‘bio-bug’ Volkswagen Beetle developed by Wessex Water subsidiary Geneco, runs on human waste. 

The gases produced from sewage that has been flushed down the toilets of 70 homes offer enough power to keep this vehicle motoring for 10,000 miles a year. 

Tapping into a Bristol sewage treatment works, the car runs on ‘biomethane’ created from micro-organisms that break down excrement in an oxygen-starved tank. 

No unpleasant exhaust fumes: The 'bio-bug' Volkswagen Beetle developed by Wessex Water subsidiary Geneco, runs on human waste

No unpleasant exhaust fumes: The ‘bio-bug’ Volkswagen Beetle developed by Wessex Water subsidiary Geneco, runs on human waste

Motorists at the sewage works plug a line into a gas canister stored in the car boot.

It takes two minutes to fill up sufficient fuel for 230 miles of motoring. Once it runs out, the car automatically switches to petrol. 

The gas is odourless with no unpleasant exhaust fumes. 

The vehicle was adapted to run on sewage a decade ago as an experiment – and inspired Bristol City Council to adopt the technology for a fleet of 100 biomethane gas-propelled ‘bio-buses’ that serve the local area – and are powered by sewage.