Audi partner company develops fuel from air and water

Published: April 27, 2015

Updated: July 24, 2018

Author: Callum Micucci



A start-up “cleantech” company in Dresden, Germany has just created the first few litres of a new, carbon-neutral fuel created from carbon dioxide and water, called e-diesel.

The Audi project partner company, Sunfire, has successfully produced synthetic diesel from air, water, and renewable electricity.

German federal minister of education Dr. Johanna Wanka put the first five litres into her personal vehicle on April 21.

Currently, it’s estimated that the price of the e-diesel would be between 1 and 1.5 euros per litre, but the price depends on electricity costs at the time of production.

“This synthetic diesel, made using carbon dioxide, is a huge success for our sustainability research,” Wanka said in a release.

“If we can make widespread use of carbon dioxide 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,” Dr. Wanka said.

The process is relatively simple and easy to understand. The “blue crude” is made using three steps: first, water is heated up and separated into hydrogen and oxygen atoms using electrolysis. The carbon dioxide is converted into carbon monoxide, which is then bonded with the hydrogen atoms to create hydrocarbons. As a carbon-neutral process, the energy used to do all of this is captured using renewable sources, such as wind and solar.

The blue crude is then refined into something usable for cars, such as what Dr. Wanka put into her vehicle.

“In developing Audi e-diesel we are promoting another fuel based on carbon dioxide that will allow long distance mobility with virtually no impact on the climate,” said Reiner Mangold, head of sustainable product development at Audi, in a press release.

“Using carbon dioxide 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,” Mangold said.

The e-diesel is sulfur-free, fossil oil-free, and has a high cetane number meaning it is readily ignitable. It’s suitable for either mixing with regular fossil diesel, or as a standalone fuel, as in Dr. Wanka’s case

The lack of sulfur and fossil oil make this particular fuel much more eco-friendly, and as a result, “the engine runs quieter and fewer pollutants are being created,” said Sunfire CTO Christian von Olshausen in a press release.

Currently, the small start-up’s operations limit production to just 160 litres of the blue crude per day, but the company plans to expand production to an industrial scale in the next phase.

“If we get the first sales order, we will be ready to commercialize our technology,” von Olshausen said.