H20 + Air = Audi e-Diesel?

Audi makes diesel out of air and water

Audi has just announced its “fuel of the future”. It’s made from air and water and, wait for it, is carbon neutral. Dubbed Audi e-diesel (very original), the synthetic fuel is produced by Audi’s project partner, Sunfire in a facility in Dresden which operates on the power‑to‑liquid (PtL) principle and uses green power to produce a liquid fuel. Audi claims that the only raw materials needed are water and carbon dioxide.  The CO2 used is currently supplied by a biogas facility while some of it is extracted from the ambient air by means of direct air capturing.

Production of Audi e‑diesel involves various steps: First, water heated up to form steam is broken down into hydrogen and oxygen by means of high-temperature electrolysis. Then, the hydrogen reacts with the CO2 in synthesis reactors, again under pressure and at high temperature. The reaction product is a liquid made from long‑chain hydrocarbon compounds, known as blue crude. The efficiency of the overall process – from renewable power to liquid hydrocarbon – is very high at around 70 percent. Similarly to a fossil crude oil, blue crude can be refined to yield the end product Audi e‑diesel. This synthetic fuel is free from sulfur and aromatic hydrocarbons, and its high cetane number means it is readily ignitable. As lab tests conducted at Audi have shown, it is suitable for admixing with fossil diesel or, prospectively, for use as a fuel in its own right.

After a commissioning phase of four months, the research facility in Dresden started producing its first batches of high‑quality diesel fuel a few days ago. To demonstrate its suitability for everyday use, German Federal Minister of Education and Research Prof. Dr. Johanna Wanka put the first five liters into her official car, an Audi A8 3.0 TDI clean diesel quattro*.


It may sound like alchemy but they have actually made this happen. Green is the new gold, especially in the premium segment. Up till now Audi hasn’t fared as well as its two German rivals, Mercedes and BMW in the “clean car” sweepstakes propaganda war. This move may bring them back into the party, albeit a little late.

Before you start thumbing your nose at your local petrol station, there are a couple of points to ponder.

1. This is Malaysia and we are generally the last stop on the innovation train. For gods sake, we are still hoping for Euro 4!

2. The barrier-to-entry in the fuel business is ridiculously high. It is an entire chain of industries that must come together and play ball, and this will not happen without severe prodding.

3. The oil companies. These are threats to their existence and they will do everything they can to ensure that any new developments do not get to market before they have their mitigation strategies in place.

Still, this is really cool news. Fuel out of thin air. Tell me that doesn’t capture your imagination a little bit.