Audi has developed what it terms “e-fuels” that are produced by combining salt or waste water with CO2, sunlight and microorganisms and are already used to power prototypes. The e-ethanol and e-diesel have been developed by Audio and Joule, a US-based fuels specialist it has been in partnership with since 2011, in a process described as “simple, cost-effective and resource-sparing”. FOR ENGINES OF THE 'NEAR FUTURE'The fuels have been designed, the automaker said, for Audi’s petrol TFSI and diesel TDI engines of the “very near future”. The process involves a pipe, waste CO2, sunlight and photosynthetic microorganisms suspended in waste water. The refineries use genetically modified organisms that don’t multiply when exposed to sunlight – as they usually would – but rather are stimulated to use photosynthesis to convert the waste CO2 and waste water into liquid fuels which they then excrete. The ethanol and diesel-range paraffinic alkanes are then separated from the water and ready to use. Audi and Joule are already demonstrating the technology at a facility in New Mexico in the US where it produced “sustainable e-ethanol”. It has the same chemical properties, the partners said, as bioethanol, which has the disadvantage of being produced using biomass (or crops). They are also in the process of producing an “e-diesel” fuel that is free of sulphur and aromatics, but is also easier to ignite thanks to its high cetane value. The “e-diesel” will work with existing Audi TDI diesel systems without the need for modification, the automaker said.