Audi makes renewable diesel fuel with CO2 and water

27 Apr 2015

Audi has announced the creation of ‘e-diesel’, a sustainably-sourced and clean diesel fuel that uses water and carbon dioxide as its two biggest ingredients, in a development that could significantly cut carbon emissions.

Rather than just being a concept for development, however, the fuel is already being used in a current Audi car owned by Germany’s Federal Minister of Education and Research, Johanna Wanka, with no apparent difference between the e-diesel and diesel sourced from fossil fuels.

According to Science Alert, the process used to create the e-diesel is a three-step method that first harvests energy from renewable sources, including solar and hydropower, which then powers the process of reverse electrolysis that splits water into pure hydrogen and oxygen.

The harvested hydrogen is then mixed with carbon monoxide, which is sourced from carbon dioxide from the planet’s atmosphere where it has been building up due to emissions from industry, to form what Audi calls its ‘blue crude’ e-diesel.

A graphic detailing the Audi clean diesel production

Audi e-diesel graphic via Audi

For even greater mileage, the e-diesel can be mixed in with traditional diesel, which the company says would make cars even more efficient.

A subsequent report from renewable energy firm Sunfire, also based in Germany, has analysed samples of the e-diesel and has found that, when compared with the efficiency of standard diesel, it achieved efficiency of 70pc.

So far, Audi has begun creating limited amounts of the fuel – equal to about 160 litres per day – at its new processing plant in Dresden, but both Audi and Sunfire have plans to expand the plant, with eventual plans to sell the fuel to customers at a cost of between €1-€1.50 per litre which, they say, depends on the cost of renewable energies at the time of market release.

Colm Gorey was a senior journalist with Silicon Republic