The prince was given the car as a 21st birthday present
Prince Charles has spoken about his decision to convert his Aston Martin sports car to run on waste wine during a visit to a Cornish village.
The prince told a resident in Tintagel that he had the vehicle altered for environmental reasons, and not to save money on fuel.
He was given the Aston Martin Volante DB6 as a 21st birthday present from the Queen and the Duke of Edinburgh.
The car now runs on wine past its sell-by date from a Wiltshire vineyard.
James Hygate, managing director of Gloucester-based Greenfuels, which produces the prince's bioethanol, said: "You heat the wine up, you put the vapours through a still, like making whisky, and you distil the pure alcohol.
"The 100% pure alcohol is then mixed with 15% petrol to create E85."
Mr Hygate claims that locally produced bioethanol, made from waste products, creates energy savings of around 85%. It can be made from any liquid that can be distilled.
Last year the prince became the first member of the royal family to travel on the Royal Train after it was converted to run on bio-diesel, which is produced from waste vegetable oil.
His official cars also run on bio-diesel.