This year, the price of oil has soared, in recent weeks reaching a new high of $135 a barrel. This has sparked protests in many countries, including Britain, where truck drivers recently blocked roads in several cities to protest the price of fuel.
For some, the high cost of fuel has prompted more creativity. A growing number of motorists are making their own bio-diesel with recycled cooking oil. It's only cheaper, but greener too.
Catherine Drew visited a course near
Oxford, England to see how it is done.