Audi creates diesel fuel from air and water

Signal of change / Audi creates diesel fuel from air and water

By Alex Caldwell / 04 May 2015

A CO2-neutral fuel has been developed by Audi in partnership with Sunfire fuels in Dresden, Germany. The synthetic 'e-diesel' was developed in just 4 months by the pioneers in the field of high-temperature fuel cells and reversible electrolysers. The demonstration power-to-liquid rig uses electricity produced from renewables to separate oxygen from water through a process known as reversible electrolysis.


The resultant hydrogen is then mixed with carbon monoxide, which is created from carbon dioxide (CO2) that’s been harvested from the atmosphere. The two react at high temperatures and under pressure, resulting in the production of the long-chain hydrocarbon compounds that make up a 'blue crude' that is further processed to create the fuel.


The factory currently only produces 160 litres per day. However, German Minister of Education and Research Johanna Wanka attests its potential, using the 'e-diesel' in her own Audi A8. The 'e-diesel' can be used on its own or mixed with conventional diesel to yield a 70% more efficient combustion rate and does not contain any sulphur, making it more environmentally friendly. On behalf of the project partner Audi, an independent laboratory confirmed that these characteristics of the fuel make it superior to the properties of fossil fuel.


“This synthetic diesel, made using CO2, is a huge success for our sustainability research. If we can make widespread use of CO2 as a raw material, we will make a crucial contribution to climate protection and the efficient use of resources, and put the fundamentals of the “green economy” in place,” declared Wanka.


It is intended to be sold at €1-1.50 per litre, competitive with today’s diesel prices. However, this price is dependent on renewable electricity costs. The choice of fuel to run your car on now stretches to hydrogen, compressed natural gas, liquefied petroleum gas, ethanol, electricity, gasoline and diesel.


Image Credit: Sunfire / Flickr

So what?

This development of synthetic fuel from CO2 comes after nearly 100 years of research, beginning in the 1920s with the Fischer-Tropsch process. Reiner Mangold, Head of Sustainable Product Development at Audi, said: "In developing Audi e-diesel we are promoting another fuel based on CO2 that will allow long‑distance mobility with virtually no impact on the climate. Using CO2 as a raw material represents an opportunity not just for the automotive industry in Germany, but also to transfer the principle to other sectors and countries."


There is much speculation about what the primary power unit of the future car will be. Last year Toyota launched the Hydrogen Fuel Cell powered Mirai, which runs on electricity generated by separating hydrogen and water. However, this currently costs $30,000 more than a conventional car and can only be fuelled from 13 stations in the US.


With the price of electric vehicles falling, the question remains: which of the growing range of new technologies (or which combination of them) will prove most efficient and cost-effective in years to come, and in which circumstances?


Currently, the most useful applications for Audi's fuel are likely to be for very long distance travel and agricultural fuel.


Audi (2015, April 21) Fuel of the future: Research facility in Dresden produces first batch of Audi e-diesel

What might the implications of this be? What related signals of change have you seen?

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