In a forest of tubes eight metres high in eastern Spain scientists hope they have found the fuel of tomorrow: bio-oil produced with algae mixed with carbon dioxide from a factory.

Almost 400 of the green tubes, filled with millions of microscopic algae, cover a plain near the city of Alicante, next to a cement works from which the C02 is captured and transported via a pipeline to the “blue petroleum” factory.

“We are trying to simulate the conditions which existed millions of years ago, when the phytoplankton was transformed into oil,” said engineer Eloy Chapuli. “In this way, we obtain oil that is the same as oil today.”

Every day some of this highly concentrated liquid is extracted and filtered to produce a biomass that is turned into bio-oil. The other great advantage of the system is that it is a depollutant — it absorbs the C02 which would otherwise be released into the atmosphere.

“In a unit that covers 50 square kilometres, which is not something enormous, in barren regions of southern Spain, we could produce about 1.25 million barrels per day,” or almost as much as the daily export of oil from Iraq.