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The fat of the land
Green-minded motorists are making car fuel at home, from used cooking oil
Dec 3rd 2011 | from the print edition

  DIESEL engines are famously unfussy about what they burn in their  cylinders. Indeed, Rudolf Diesel’s original design ran on powdered coal.  But even he might have been taken aback by the recipe concocted by  Peter Ferlow. Mr Ferlow, who lives in a suburb of Vancouver, British  Columbia, is one of the leaders of a growing band of enthusiasts who  brew their own car fuel. His diesel engine runs on oil collected from  the kitchen of a local pub.
The recipe starts by filtering  the breadcrumbs out with a mesh screen. After that you warm the oil up  and add sodium hydroxide and methanol. The sodium hydroxide (known as  “lye”, in the trade) breaks the oil molecules into fatty acids and  glycerol. The methanol reacts with the fatty acids to form esters. Drain  away the glycerol. Wash the remainder with water to remove impurities  and surplus lye. Drain that water. Then aerate what is left with an  aquarium bubbler to drive off the last traces of moisture. The result is  175 litres of finest home-brewed biodiesel—enough to drive Mr Ferlow’s  pickup truck for 1,200km (750 miles). And the cost, he reckons, is a  mere C$45 (about $44, south of the border) plus two hours of his labour.  The oil itself is free. Restaurants are glad to give it away, to avoid  the cost of disposal.
That may change. According to Miles  Phillips, the head of the Cowichan Energy Alternatives Society, based in  Duncan, British Columbia, local demand for veggie-oil fuel is already  outstripping supply. Moreover, biodiesel made from restaurant oil can be  sold for a tidy profit. On the other side of North America, the  Baltimore Biodiesel Co-op, in Maryland, says green-minded drivers are  prepared to pay a premium of about 30% over the cost of petroleum-based  diesel to fill their cars with biodiesel. The co-operative reports that  its sales are up by 20% this year. Eventually, presumably, restaurant  owners will want a slice of the action, too. At the moment, though, they  seem glad to collaborate for nothing. The co-op can rely on an  industrial producer—a so-called “grease puller”—driving a lorry around  the area’s restaurants to collect its raw material free. And it plans,  starting next year, to buy biodiesel from home producers as well.
  Some of these producers rely, like Mr Ferlow, on Heath Robinson  lash-ups of their own devising to make their motoring equivalent of  hooch. Others use off-the-shelf reactors. Oilybits, a British company,  will, for £395 ($620), sell you a device that produces batches of 120  litres of biodiesel—and the firm’s owner, Adrian Henson, is modest  enough to admit that many other firms do likewise. The process is not  particularly hazardous. Biodiesel esters are not so volatile that they  form an explosive vapour (which is why they can be used only in diesel  engines, not petrol ones), and though the methanol and sodium hydroxide  need careful handling (they are unpleasant by themselves, and truly  noxious if allowed to react together), so far the health-and-safety  authorities in countries where home-brewed biodiesel is taking off have  not stepped in to interfere. Even the taxman generally turns a blind  eye. In Britain, which once tried to fine people for failing to pay duty  on home-brewed fuel, the tax-free manufacture of up to 2,500 litres a  year is now permitted.
Brewing up nicely
If the  authorities did ban home esterification, though, enthusiasts who wished  to declare independence from the oil companies could go down another  route. The advantage of esters is that they substitute directly for  petroleum-based diesel fuel. But, with a bit of modification, many  diesel engines will run on unesterified vegetable oil, too.
  The main reason raw vegetable oils do not normally work in diesel  engines is that they are more viscous than standard diesel oil, and thus  clog the engine’s fuel-delivery system. Heat them, and that problem  goes away—at least in older engines (modern, “common-rail” motors, with  high-tech fuel-injection systems, are less forgiving).
A  common way of converting a vehicle to run on unprocessed vegetable oil  is therefore to fit it with two fuel tanks. A small one filled with  petroleum-based diesel keeps the engine running until the car’s radiator  has heated up. At that point water is diverted from the radiator into  pipes that run through a larger tank filled with vegetable oil. Once  this is nicely warm and runny, the driver flicks a switch and the engine  starts burning the vegetable oil.
Last year John Shepley, a  member of the Baltimore co-operative, converted his 12-year-old  sports-utility vehicle to work this way. That cost him about $1,500. But  prices are falling as such conversions become more popular. An Oilybits  conversion kit costs about $315.
To Greece on grease
  Once the conversion is made, the world is your oyster. In August 2008,  for example, eight teams set out on a car rally from London. Their  intention was to drive across Europe fuelled only by oil scavenged from  restaurants. All made it to Athens, the destination, without buying  fuel.
Even now, three years later, getting waste oil free is  still easy, according to Andy Pag, the rally’s organiser. He has driven  more than 30,000km on vegetable oil, in countries as far afield as  Mauritania, without once paying for the stuff. There are wrinkles, of  course. In place of the screen used by Mr Ferlow, Mr Pag carries a  centrifuge (solar powered, naturally) around with him. Before filling  up, he puts the oil he has scrounged through this. Food particles and  water are spun off as a creamy gunk that he removes with a rag. It takes  him about half an hour to purify a tank’s worth of fuel in this way.  The chief difficulty, he claims, is keeping his clothes clean.
  That, though, is a small price to pay for the warm, virtuous glow which  comes from converting waste into motive power. It is cheap,  environmentally friendly and, according to Mr Ferlow, even the exhaust  gases smell sweeter.