A breakthrough in fuel technology has finally arrived: German car manufacturer Audi announced this week that it has developed a fuel that is both carbon neutral and functional for cars already on the road. The new “e-diesel,” or diesel-fuel containing ethanol, is using water and carbon dioxide.
Clean tech company Sunfire, based in Dresden, Germany, was commissioned by Audi to develop and produce the new liquid fuel that comprises long-chain hydrocarbon compounds, similar to fossil fuels, but without the impurities that cause soot when burned.
The production of the fuel first involves harnessing renewable energy in the form of solar, wind or hydropower. This energy heats water to temperatures in excess of 800oC (1472oF), creating steam that is broken down into oxygen and hydrogen through high temperature electrolysis.
The extracted hydrogen is then separated and mixed with carbon monoxide under high pressure, creating a hydrocarbon product that is essentially the “e-diesel” itself. The e-diesel can then be mixed with regular diesel, or used as a fuel in its own right.
This new product, according to its manufacturer, is both more environmentally safe and efficient than fossil fuel.
The process for using biogas facilities to produce carbon neutral biofuels is not actually new. Known as the “Fischer-Tropsch” process, it has been employed by corporations and governments in countries whose fossils fuel reserves, such as gas and coal, far outnumber their oil reserves.
Audi claims that their version of Fischer-Tropsch is in fact different and more commercially feasible: increasing the temperature at which the water is distilled increases the efficiency of the process since wasted heat can be recovered.
So, while the announcement might not be earth-shattering, it represents an achievement for green tech and another mile down the road toward a new fossil fuel-free era.