We minimise our use of car and never fly in our business. All trips in and around London and many other journeys are carried out by public transport.
We do sometimes use our car for businesses. This is when we have significant records to carry or the car journey as a whole will take less than twice as long as public transport journeys.
We record our car use and calculate the business fuel used. We purchase more waste vegetable oil for use in our car then the total business fuel used. The excess of waste veg oil is then used for non business journeys. We use no fossil fuel for our car for business journeys.
Waste vegetable oil is collected from take away food shops and restaurants. This is cleaned and cracked, resulting in a fuel suitable for use in most diesel vehicles of intermediate age. The environmental benefit of using waste vegetable oil is that the oil has been used and will end up in the atmosphere somehow. By using it as fuel a benefit is derived little no additional carbon being emitted to the atmosphere. There are also no wars involved in protecting the supply of waste vegetable oil.
Ultimately the amount of carbon dioxide in the atmosphere is inversely proportional to the amount of fossil fuel that remains under ground. By using waste vegetable oil there is less fossil fuel being used and therefore less carbon dioxide in the atmosphere.