Audi has made a big splash by creating synthetic diesel fuel from simply water and carbon dioxide.
German startup Sunfire in Dresden operates Audi’s pilot plant, which successfully produced its first batches of the “e-diesel” this month.
In the featured image above, you can see German Federal Minister of Education and Research Johanna Wanka putting some of the new diesel in her Audi A8 to commemorate the company’s breakthrough.
Here is an excerpt from Audi’s press release explaining the production of the company’s e-diesel:
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. This process, involving a temperature in excess of 800 degrees Celsius, 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 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.
According to Sunfire, their research shows the properties of the synthetic diesel are superior to fossil fuel, citing its lack of sulphur and fossil-based oil, making it more environmentally friendly.
“The engine runs quieter and fewer pollutants are being created,” says Sunfire CTO Christian von Olshausen.
Currently, the Dresden pilot plant plans to produce about 42 gallons (160 l) of synthetic diesel per day in the coming months, a figure that could vary depending on demand.
“If we get the first sales order, we will be ready to commercialize our technology,” von Olshausen says.
Should the technology take off, Sunfire and Audi are prepared to build a bigger plant for increased production.