bio fuelsSPECIAL REPORT

ONE MAN’S TRASH, IS ANOTHER MAN’S FUEL

Why running your car on clean-burning, used vegetable oil from your local restaurant, might be easier than you think.

McDonald’s supplies many biofuel manufacturers around the world with used vegetable oil.

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It is said that when Rudolf Diesel first designed the internal combustion engine that now bears his name, he intended it to run on vegetable oil.

Unfortunately for us, if you believe the story, he only turned to fossil fuels (first coal dust then oil) after a chance conversation with one of his former professors at the Royal Bavarian Polytechnic of Munich.

Rudolf: I’m thinking of running my new internal combustion engine on vegetable oil. What do you think?Professor von Sparkplug (for argument’s sake?): Sounds like quite a hassle to me picking all those easy-to-grow vegetables and things. Might need a spade and a wheelbarrow. Pricey. Have you considered sinking a well a few thousand feet into the ground and sucking out some decomposed ancient

vegetation juice instead?Rudolf: Uumm…now you’re talking.

The rest, as they say, is history.

Which would be more of a shame than it actually is, if it weren’t for the fact that a growing number of thrifty motorists around the world are re-discovering Diesel’s original intentions and are ‘brewing’ their own fuel. Not from vegetables as such, but from used vegetable oil, which they obtain, cheaply or often freely, from local restaurateurs, who would otherwise have to pay to dispose of it.

A process that is currently allowing these resourceful motorists to run their ‘diesel’ cars at between 2 and 15% of the cost of standard diesel fuel.

The process itself is relatively

simple. Once you’ve got hold of your oil, ponging perhaps of fried haddock, the first thing you have to do is filter out the bits and pieces of thrice cooked food. To many enthusiasts these bits are known as BCBs, or ‘burnt crispy bits’ and can be eliminated from the mix with the use of a simple wire mesh. After that all you have to do is warm the oil up a bit by adding sodium hydroxide and methanol. The sodium hydroxide, often referred to as ‘lye’ by those in the know, breaks down the molecules of oil and turns them into a combination of fatty acids and glycerol. The methanol is then able to react with the fatty acids to produce ‘esters’.

The glycerol is then drained away and the remaining liquid washed with water to remove any impurities and surplus lye. This is followed by a spot of aerating with an ordinary aquarium type device, a

A process that is currently allowing these resourceful motorists to run their ‘diesel’ cars at between 2 and 15% of the cost of standard diesel fuel.

part of the process that has led to many such amateur fuel alchemists being referred to (affectionately) as ‘bubblers’.

What you’re left with after all that, is a batch of finest home-brewed biodiesel, which will work perfectly well in almost all diesel cars (although unfortunately not quite so effectively in modern cross-rail diesel engines).

At a cost, assuming you are able to strike a deal with your local fish and chip shop (10 cents a litre seems to be the going rate with restaurants who have cottoned on to the fact that their waste is valuable) of about 15 euro cents a litre once you’ve factored in the cost of the chemicals and some equipment.

Not that the equipment need be expensive. As one motorist put it, “It depends how quickly you want to do it and the nature of the junk in your garage.” Most amateur brewers, true to the spirit of pioneering adventure, rely on fairly makeshift equipment for producing what is essentially the motoring equivalent of moonshine, but off-the-shelf products are beginning to appear on the internet at very reasonable prices.

For example, a UK company aptly called ‘Oilybits’ have started marketing a slick little contraption that does virtually everything for you, for under 500 pounds. And they are not alone.

And while you will be forgiven for thinking that the process must be inherently dangerous, what with all that sodium hydroxide and methanol kicking around, it’s actually not as crazy as you might think.

Biodiesel esters aren’t particularly volatile and therefore don’t tend to form an explosive vapour (a quality required by petrol engines) and as long as you are cautious with your handling of the sodium and the methanol, you’re really not putting yourself into any more danger than you do every time you drive your car anyway.

However, before you start drawing up plans

Not that the equipment need be expensive. As one motorist put it, “It depends how quickly you want to do it and the nature of the junk in your garage.”

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Clockwise from top leftChip fryers like this use billions of litres of vegetable oil every year, most of which is wasted.

Rudolf Diesel’s first engine was demonstrated at the Paris Trade Fiar in 1900 and ran on peanut oil.

A biodiesel fuelled lorry collects waste oil from local restaurants in North America.

Traditionally most home processing kits have been makeshift affairs.

for an industrial-sized production facility to sell your clean-burning, sustainable fuel to your local community, it might be worth checking what your country’s taxman has to say on the subject. In the UK for example (after an initial attempt to apply tax and duty to all such home-produced fuels) they have implemented a ‘personal allowance’ quota of 2,500 litres per year. Enough to run most average vehicles with a bit left over for bank holiday traffic jams, but not enough to make a business of it.

Not that that has stopped some producers. Such as the Baltimore Bio-diesel co-op in America which is producing vegetable oil fuel on a large,

tax-paying scale, but still managing to sell it at 30% above the cost of regular petroleum-derived diesel to motorists willing to pay a little extra to know they aren’t directly contributing to global emissions.

Which isn’t to say that you can’t produce vegetable oil derived fuel on a large scale and sell it – the taxes mostly only apply to fuels which have been through the esterification process and can be used as a direct substitute for standard diesel fuel – by opting to use unesterified vegetable oil instead. Many diesel engines, with the addition of a fuel heating system, will happily run on this just as happily.

The heating bit is quite important though if you don’t want to spend every other weekend giving your vehicles’s fuel delivery system the motoring equivalent of an enema. Unesterified vegetable oils it seems, being considerably more viscous than standard diesel oil, need to be heated up before they are used, to rid them of their considerable clogging qualities.

The same is true to a lesser extent with standard diesel engines (with the possible exception of very modern ‘common-rail’ ones, but then again if you can afford one of those, why not just go the whole hog and get a Prius instead?), which is why you

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are generally advised not to start them straight from cold, but to wait 30 seconds or so after half turning the ignition key (depending on the outside temperature) before firing up the engine completely.

A hassle perhaps, but then again who doesn’t need a little bit of warming up in the morning before they can work properly?

Even then there are some impatient home-brew motorists who have addressed this problem head-on by equipping their cars with two separate fuel tanks.

A small one carrying

petroleum-based diesel to feed the engine for the first few miles, or until the radiator is nice and toasty (let’s not even think about the heat-loss inefficiency of most internal combustion engines) at which point hot water from the radiator is bypassed into special pipes running through the second tank of vegetable oil. Then, once the vegetable oil has been warmed up out of its natural cloggy state, the driver just hits a button to switch from the first fuel tank to the second.

Again there are plenty of companies to be found on the Internet making these sorts of conversion kits, for just a few hundred pounds.

Some of you, those with an aversion to the smell of used chip fat oil, might now be wondering whether you can’t just buy large containers of vegetable oil straight from your local supermarket and bypass the BCB straining bit altogether.

This is of course entirely possible, but unfortunately supermarkets are less inclined to give their oil away than restaurants.

And besides, the real beauty of home-brewing vehicle fuel from used chip fat oil, is that it stops the stuff being poured down the drain. Not literally perhaps, but certainly figuratively.