Grease is the word

'STEP on the grease" may not have quite the required ring to it, but it gets you there just the same. Eight cars rolled triumphantly into Athens this week, having driven across Europe from London in a cloud of dust and cooking smells.

The 2,000-mile "Grease to Greece" challenge ran entirely on non-fossil fuels, its formerly diesel-powered vehicles running either on biodiesel or vegetable oil, all of it recycled from used cooking oil collected from restaurants, service stations, hospitals, even old folks' homes along the way, to demonstrate the viability of "green" fuels.

Just as we're told that, despite widespread efforts to persuade us to use public transport, more Scots than ever before are taking to the roads, raising concerns about increased emissions, the Grease to Greece rally has demonstrated that driving – indeed long-distance driving – can be can be almost emissions-free, even if it does mean raiding the nearest deep-fryer.

The rally's organiser, Andy Pag, likes to call it a "fat-finding mission". No stranger to alternatively-powered peregrinations, he led a team of "chocolate-powered biotrucks" from the UK to Timbuktu, via the Sahara Desert last year, the trucks powered by a biodiesel converted from waste cocoa butter.

The 34-year-old former engineer and journalist who, when not filling his tank with unorthodox fuel mixes, runs a company which webcasts weddings, has driven on some lengthy journeys. He had begun to feel increasingly concerned at what he saw as the hypocrisy of burning fossil fuels while admiring the very natural environment which was being put in jeopardy by carbon emissions.

"My wife and I have done a number of big trips, including driving down to Capetown a few years back," he explains, "and we were conscious of the environmental impact. So we looked at the idea of biodiesel, and the more I learned about it, the more I realised there was a tremendous amount of confusion about biodiesel and vegetable oil and whether it was good or bad for the planet. This is the sort of thing I enjoy doing and it was an opportunity to try and set the record straight."

He was talking to The Scotsman from Athens, where he and his fellow "greasers" were donning their formal attire of black bow tie, dress shirt, shorts and flip-flops to meet the British Ambassador, Simon Gass, who was due to present the rally's Golden Lard Award (an antique brass grease gun) to brothers Adrian and Andy Henson, who scavenged the most waste oil.

Eight out of the rally's original ten cars finished the journey on Tuesday: "One of the others pulled out because he had to attend a wedding and his wife threatened to divorce him if he was late, and another retired because they didn't have the right paperwork to get into Montenegro. "

Asked if he had any bad moments, Pag says that his heart sank in Germany when he and his wife, Esther Obiro-Darko, were pulled over police, who wanted to search his rather battered-looking old red Peugeot 405, piled high with a roof tent and oil containers: "They ordered us into a motorway service station and we showed them some newspaper cuttings and they just had a laugh about it." Their brush with the law turned out to be fortuitous: the service station gave them 40 litres of waste oil from its café.

The Grease to Greece challenge's website had warned participants that all they needed for the journey was "a diesel car – it doesn't have to be converted (but it helps if it is)", plus "the capacity to explain to a Croatian kebab shop owner that you need his grease".

However, there were occasional moments, Pag admits, when they wondered where their next batch of oil would come from. "There were a few dicey moments when you'd think, 'Oh, we're not going to make it,' then all of a sudden you'd come across a stash of 80 litres of really lovely oil. It wasn't so much from chip shops, but from any kind of restaurant, hotel, hospital, old people's home – anywhere, really, that had a kitchen or canteen. Almost certainly they'll have been doing French fries." While Pag's own car has been converted to run on waste vegetable oil, a built-in centrifuge heating and spinning it to separate the grunge from the clean oil, other vehicles in the rally have been running on biodiesel. The expedition's main sponsor, GreenFuels, provided a biodiesel processor, Pag says, enabling those with unconverted engines to convert waste vegetable oil into biodiesel. "It looks like a Dalek, and is the sort of thing that people have in their garages in order to make biodiesel at home. We've got it in the back of a van, making it the world's first mobile grease-guzzling refinery."

He argues that no special expertise is required to run a car on converted cooking oil: "What's really nice is that is that no-one who came was really an expert at this. Their first tank of vegetable oil was the tank they set out with, so we've all learned an awful lot about how this works. We discovered that the real expertise lies in being able to get the oil out of all the different strange containers in restaurants and, ideally, just getting the nice clear stuff off the top and leaving the sluggish stuff at the bottom. That's the key to successful vegetable oil driving."

Their reception along the route has been enthusiastic, if sometimes puzzled. "Some people have been slightly sceptical, initially, but when they understood what we're doing, they've been so helpful. It's been wonderful." And, he adds, they made converts along the way: "Pretty much everywhere we stopped, they wanted to know what it was all about, and when they learned how cheap the conversion system is and how cheap it is to change your engine over, they were interested … especially restaurants, who have plenty of oil on the premises anyway."

An example was a taverna owner in Kalpaki, Mrs Theodora Elftheria, whom they met after arriving in Greece from Albania, and who handed over a container of waste vegetable and olive oil, declaring she would like her cars to run the same way.

While there is unlikely to be enough waste cooking oil about to fuel all of Britain's diesel vehicles, the Governent's Better Regulation Commission has stated that using waste cooking oil "makes economic and environmental sense", and at least one local authority, Great Yarmouth Borough Council, runs its vehicles on biodiesel, having engaged a biofuel company to collect oil from takeaways and restaurants.

For Pag, chocolate-powered desert crossings and grease-powered rallies are only the beginning: he is planning an eco-fuelled round-the-world trip – including flying a motorised paraglider which runs on fuel processed from plastic bags.

• For more, see www.fatfinding.com

FUEL OF THE FUTURE?

THE term biofuel has become associated with fuels made from specifically cultivated energy crops such as sugar cane, rape, maize and palm oil, which have attracted growing criticism over their impact on the environment and role in food shortages. But the biofuels dealt with here are created by recycling such oils after they have been used as cooking oil.

Since April last year, a change in the law permits the individual with the correct equipment to make up to 2,5000 litres of his or her own biodiesel – sufficient to run the average family car – without having to pay tax. This is an attractive prospect, both in lowering emissions and making savings against pump prices.

An increasing number of filling stations sell biodiesel made from recycled oil, which can be added to some unconverted engines. Switching to waste-based biodiesel can cut a vehicle's emissions by some 85 per cent, according to the Department for Transport. A knock-on effect is that the waste oil would otherwise have gone into the sewage system or into landfill.

Converting a conventional diesel engine to run on unprocessed vegetable oil can cost between £500 and £1,000 initially. As explained by Andy Pag, you can also make biodiesel from waste cooking oil, adding alcohol (the Grease rally used bio-ethanol from cheese whey), using a fuel pod processor that costs around £2,500, the subsequent savings paying for this within a year. Many diesel cars built from the mid-1990s can run on biodiesel without conversion.

• See www.bbc.co.uk/bloom/actions/cookingoil.shtml#quickjump