When exposed to light and carbon dioxide (CO2), a genetically modified bacteria can produce liquid fuel, namely ethanol. In a not-so-distant future, it will even be able to produce diesel.
All it takes is 3 cm plastic tubes that stretch over 100 metres and are filled with non-potable water, CO2, and the aforementioned bacteria. Then, let the sun do its magic.
In order to supply the global automotive fleet, 200,000 square kilometres of tubing would be necessary – equal to about 2% of Canada's surface area.
The dream is closer to becoming a reality than you may think. A first experimental site and plant already exist in the U.S., and commercial production will likely begin in 2014... at around 32 cents per litre!
Source: Le Journal du Siècle