The Fat of the Land

(The Economist) Green-minded motorists are making car fuel at home, from used cooking oil

...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.

...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.

...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). READ MORE