The move, part of the prince's green drive to reduce by 12.5% his carbon footprint up to 2012, was announced in a recent report released on the royal's activities. And according to the report, the prince, an keen advocate of the environment, has already reduced his carbon emissions by 18%.
Sir Michael Peat, the prince's chief aide, called the conversion a "symbolic role" saying: "Charles only travelled two or three hundred miles a year in the Aston but he wanted it to be environmentally friendly. It just happened that our bioethanol supplier makes the fuel from surplus English wine."
The classic 1970 Aston Martin Volante convertible is usually only driven in the summer, having an annual mileage of around 300 miles (480 km).
The prince's other cars, including Jaguars, Audis and Range Rovers, are entirely powered by cooking oil.
The annual report on the Prince of Wales said: "When their Royal Highnesses are travelling in the UK the aim is to reduce emissions through greater use of cars, trains, and turbo-prop aircraft. In accepting and arranging engagements more consideration is being given to reducing travel distances."
The prince's carbon emissions do not include the highly criticized Royal Air Force flights taken by his son Prince William at the British taxpayers' expense. According to The Guardian newspaper, William flew a military helicopter to his girlfriend's home, his father's house, as well as to a stag party in southern England.
The Ministry of Defense said all flights were part of the prince's training, while admitting that there may have been an element of "naivety" in their planning.