Clean electricity can be generated using technologies such as solar panels and wind turbines, but a more sustainable alternative to oil – which powers most forms of transport – is proving harder to find. So-called first and second generation biofuels such as soybean and jatropha have been criticised by environmental groups who say they contribute to deforestation and compete with food crops. According to some calculations biofuels such as palm oil emit more CO2 than crude oil.

A better alternative could be algae, which can produce oil intensively, doubling their mass several times a day and using waste products such as sewage or CO2 from factories to grow. Barack Obama, the US president, has suggested that in the future up to 17 per cent of the fuel the country imports for transport could be replaced by algae biofuels.

In Alicante, Spain, a small company called Bio Fuel Systems (BFS) is running an experimental biofuel plant which uses waste CO2 from a neighbouring cement factory to grow algae in hundreds of tubes that are each eight metres high. The company claims they can produce a staggering 400 times more oil per hectare than traditional biofuels such as soybean or palm oil, and the final product has exactly the same characteristics as fossil oil, but with an important difference.

The idea is to locate algae fuel plants next to heavy-emitting factories and power stations, using their CO2 to feed the algae – and making the oil effectively carbon-negative.

Early results have been so successful that the company now plans to open a 600 hectare site next to a coal-fired power plant in arid southern Spain, with the aim of producing algae-based oil on a commercial scale.

earthrise's Russell Beard visits BFS's plant in Alicante to find out if this really could be the fuel of the future.

Learn more at: www.biopetroleo.com

earthrise airs each week at the following times GMT: Friday: 1930; Saturday: 1430; Sunday: 0430; Monday: 0830. Click here for more on earthrise.