It turns out that all-electric and hybrid cars aren’t the only way to reduce CO2 emissions. Audi is focusing on producing synthetic petrol and diesel using CO2 that would otherwise be pumped in to the atmosphere.
The process involves large water filled transparent tubes up to 100m long that also contain genetically-modified cyanobacteria. When exposed to sunlight and CO2 these bacteria are now able to produce what Audi calls e-ethanol (petrol) and e-diesel.
The easiest way to think about it is that all the CO2 produced burning these fuels will be pumped back in to producing new fuel. Audi says that the net effect of all this is that a petrol or diesel powered car running on these synthetic fuels will produce as much CO2 over its lifecycle as a fully electric vehicle.
It’s better all-round than producing fuel from biomass too because it’s at least 20 times more efficient in terms of the space needed and it doesn’t interfere with food production and only requires waste water or salt water, rather than clean water.
Audi has a plant under construction at the moment, which is hoping to show the process works on a large scale and the first commercial plant is scheduled to be up and running by 2014.
If Audi wants to fuel its fleet of 50 million vehicles with synthetic fuels it will need an area the size of Sicily to actually produce the e-ethanol and e-diesel. Thankfully it has plans to build these plants in deserts unsuitable for growing anything.