Could cars be running on oil produced from algae in a test-tube? One group of Japanese scientists certainly think so, according to The Times.
The Japanese government is supplying a research team with substantial grants to develop the properties of an algae called Botryococcus braunii, which has some amazing qualities.
If given enough light and carbon dioxide, the algae excretes oil. This rises to the surface, where it can be harvested and then refined using the same techniques used in the oil industry to convert crude oil into plastics and fuel.
Another advantage is its potentially huge yield: corn used to make bioethanol produces around 0.2 tonnes of oil per hectare, and rapeseed might manage 1.2 tonnes, but these algae have the potential to produce between 50 and 140 tonnes per hectare.
The team believes there is the potential for the algae to answer many of the criticisms of current biofuel production, principally that humans are growing food their cars, not themselves. The Japanese team says its oil can be harvested easily in a laboratory without impacting on world food production.
There are many problems to overcome before the oil from Botryococcus braunii fills our cars' tanks, though. For a start, for Japan to meet its current oil needs, it would require an algae field the size of Yorkshire.
Also, although it's easy to harvest the oil, any oil-producer would have to invest in expensive algae breeder tanks that cost about three times what the oil would sell for over the lifetime of the tanks.
The alternative is to find an enormous plot of well-irrigated land where labour is cheap, such as Indonesia or Vietnam - but that brings back the 'food versus fuel' argument that the fuel is intended to resolve.
The other issue is whether its production would be carbon-neutral. There's no information on whether the energy needed to harvest the oil, or its ultimate burning in cars, would outweigh how much the algae would consume during their growth.