Algae growing in Bath's Roman Baths could one day be used to make fuel for our cars, scientists have claimed.
The Roman Baths are at the centre of a University of Bath study aimed at producing commercially viable renewable biofuels from algae.
Biodiesel can be produced by extracting the oil from the algae cell, with certain types of algae having a higher oil content.
Studying the unique algae growing in the hot waters of the baths could make wide-scale production of biofuels a real possibility for future transportation energy.
PhD student Holly Smith-Baedorf, who is working on the project, said: "Algae are usually happiest growing at temperatures around 25C (77F) and that can limit the places in which it can be cultivated on a large scale. Areas where these ideal conditions are available also usually make good arable areas and are therefore needed for food production.
"In an ideal world we would like to grow algae in desert areas where there are huge expanses of land that don't have other uses, but the temperatures in these zones are too high for algae to flourish."
Algae cells are very versatile and can change many of their characteristics in response to their environment. The protected environment in the baths gives an ideal environment in which adaptation can take place.
The temperature of the Roman Baths is created by rain falling in the Mendip Hills, and running down through limestone at 10,000 to 14,000 feet below ground, where thermal temperatures can reach nearly 100C (212F).
The research team, which also includes scientists at the University of the West of England, is growing each of the seven types of algae from the Roman Baths over a range of temperatures and comparing them to 'control' algae known for being good for producing biodiesel at normal temperatures.
Project researcher Professor Rod Scott said: "The results of this study will help us identify whether there is a particular algae species among the seven identified in the Roman Baths that is well adapted to growing at higher temperatures and also suitable for producing sufficient amounts of biodiesel to make wide-scale production viable."