Since January 2008 we have been powering our vehicles with biodiesel made from waste vegetable oil.

First we collected waste vegetable oil from local chippies. We put the oil in the home-made reactor which is a large steel cylinder with a heating element and stirring paddles. The oil is heated to 55oC , and a ‘methoxide’ mixture (1 litre of methanol for every 4 litres of vegetable oil into which has been mixed 5g of caustic soda per litre of oil) is added. Then we turn on the 2 hp motor that spins a shaft (at 94 rpm) with 10 blades attached for 15 minutes.

Mixing everything together causes the oil to be ‘cracked’ with the methoxide. This produces biodiesel (about 80%) and glycerol (about 20%). The glycerol sinks to the bottom where it is removed and the biodiesel (now much thinner / less viscous than the oil used to be) can be cleaned (to remove traces of soaps, methanol or water) and is then ready to be used in our diesel vehicles.

The glycerol, which is a waste product, can be heated to get rid of any remaining methanol, and then mixed with caustic soda and water. Essential oils are added and then the mixture is poured into a plastic container to set. Hey presto - homemade soap! It looks alot like tablet/fudge but it does the job.