What is LPG?

LPG stands for Liquefied petroleum Gas (also called LPG, LP Gas, or autogas). Wikipedia defines it as "a mixture of hydrocarbon gases used as a fuel in heating appliances and vehicles, and increasingly replacing chlorofluorocarbons as an aerosol propellant and a refrigerant to reduce damage to the ozone layer."

LPG is a byproduct of the petroleum industry and is manufactured during the refining of crude oil, or extracted from oil or gas streams as they emerge from the ground. So whilst LPG does produce around 20% less emissions than standard diesel and petrol powered engines, it's still very much a fossil fuel.

I'm not knocking anyone who chooses to use LPG. It's price alone (unusually less than half the price of petrol at the pump) is enough of a bonus, and 20% less emissions is still a good result. Unfortunately LPG can only be used on Petrol engines (not diesel) after a conversion process, so it's no good for my car.