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Audi's Actually Making The Fuel That's Here To Save Internal Combustion

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Audi and the Volkswagen Group in general will make a bunch of electric cars in the future, mostly to keep Californian law makers happy, but the start of their synthetic e-diesel production shows they’re also dedicated to building combustion engines as well.


Audi’s pilot plant in Dresden has started making its first batches of e-diesel. This is a big deal, because the only raw materials needed for the process are water and carbon dioxide.

The facility operates according to the power-to-liquid principle and uses CO2 sourced from a biogas plant and from direct air capturing, a technology developed by Audi’s Zurich-based partner Climeworks.


Reiner Mangold, Head of Sustainable Product Development at Audi had this to say about this step:

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.

Here’s how the magic happens:

First, water heated up to form steam is broken down into hydrogen and oxygen by means of high-temperature electrolysis. This process, involving a temperature in excess of 1,472 degrees Fahrenheit, is more efficient than conventional techniques because of heat recovery, for example. Another special feature of high-temperature electrolysis is that it can be used dynamically, to stabilize the grid when production of green power peaks.

In two further steps, 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 sulphur 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.


That’s quite an achievement, Audi definitely deserves a freakin’ medal or something.


But don’t hold your breath yet because the Dresden plant is only going to produce about 3,000 liters of e-diesel in the coming month. Hey, it’s a start!

Audi also has an e-gas plant in Lower Saxony that produces synthetic methane so one can fill up a A3 Sportback g-tron. The Germans are also looking into the synthetic manufacture of Audi e-gasoline with the French and joined forces with the U.S. company Joule, which uses microorganisms to produce the same synthetic fuels.


So, how about an RS6 g-tron?

Photo credit: Audi