German car manufacturer Audi has reportedly invented a carbon-neutral diesel fuel, made solely from water, carbon dioxide and renewable energy sources. And the crystal clear 'e-diesel' is already being used to power the Audi A8 owned by the country’s Federal Minister of Education and Research, Johanna Wanka.

The creation of the fuel is a huge step forward for sustainable transport, but the fact that it’s being backed by an automotive giant is even more exciting. Audi has now set up a pilot plant in Dresden, Germany, operated by clean tech company Sunfire, which will pump out 160 litres of the synthetic diesel every day in the coming months.

Their base product, which they’re calling 'blue crude' is created using a three-step process. The first step involves harvesting renewable energy from sources such as wind, solar and hydropower. They then use this energy to split water into oxygen and pure hydrogen, using a process known as reversible electrolysis.

This hydrogen is then mixed with carbon monoxide (CO), which is created from carbon dioxide (CO2) that’s been harvested from the atmosphere. The two react at high temperatures and under pressure, resulting in the production of the long-chain hydrocarbon compounds that make up the blue crude.

Once it's been refined, the resulting e-diesel can be mixed in with our current diesel fuel, or used on its own to power cars in a more sustainable way.

Sunfire analyses have shown that the synthetic fuel is not only more environmentally friendly, but also has superior combustion when compared to fossil fuels. The overall energy efficiency of the e-diesel is 70 percent, they report.

"The engine runs quieter and fewer pollutants are being created," said Sunfire Chief Technology Officer Christian von Olshausen in a press release.

Of course, with the initial factory only pumping out around 160 litres each day, the fuel isn’t going to have a huge impact on the market just yet. But Audi and Sunfire now want to build a bigger factory, and anticipate that once production is scaled up, the e-diesel will sell to the public for between 1 and 1.50 Euros per litre, dependent on the cost of renewable electricity.

With traditional diesel currently on the market for upwards of 1.50 Euros per litre in Germany, this would make the fuel extremely competitive, and perfectly positioned to made sustainable travel accessible to everyone. "If we get the first sales order, we will be ready to commercialise our technology", said von Olshausen.

Just imagine being able to tear around the countryside in an Audi sportscar, and not having to feel guilty for all the CO2 emissions you're producing. We can't wait.

How much water?

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.

The house of Saud will do anything to stop it. Not to mention Shell BP Exon.

I haven't seen it on Australian news sites, but it was only announced last week.

Ingolstadt/Berlin, 2015-04-21
Fuel of the future: Research facility in Dresden produces first batch of Audi e-diesel

The verdict: Pilot plant produces high-quality diesel fuel

No need for mineral oil: e-diesel made from water, CO2 and green power

Minister Wanka: “Synthetic diesel using CO2 is a huge success”

Minister of Research, Prof. Dr. Johanna Wanka, and Reiner Mangold, Head of Sustainable Product Development at AUDI AG, refueled the Minister’s official car - a Audi A8 3.0 TDI clean diesel quattro - with the first five liters of Audi e-diesel.

Audi has taken another big step in the development of new, CO2 neutral fuels: A pilot plant in Dresden has started production of the synthetic fuel Audi e diesel.

After a commissioning phase of just 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, 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*, this Tuesday. “This synthetic diesel, made using CO2, is a huge success for our sustainability research. If we can make widespread use of CO2 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,” declared Wanka.

The Dresden energy technology corporation sunfire is Audi’s project partner and the plant operator. It operates according to the power‑to‑liquid (PtL) principle and uses green power to produce a liquid fuel. The only raw materials needed are water and carbon dioxide. The CO2 used is currently supplied by a biogas facility. In addition, initially a portion of the CO2 needed is extracted from the ambient air by means of direct air capturing, a technology of Audi’s Zurich‑based partner Climeworks.

Reiner Mangold, Head of Sustainable Product Development at Audi, sees Audi e‑diesel and Audi e‑fuels in general as an important component that complements electric mobility: “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.”

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.

The Federal Ministry of Education and Research is supporting the sunfire project, which started in May 2012. Construction work on the facility in Dresden‑Reick kicked off in July 2013 and the plant was commissioned on November 14, 2014. The plant is set to produce over 3,000 liters (792.5 US gal) of Audi e‑diesel over the coming months. Audi is sunfire’s exclusive partner in the automotive sector.

Over and above the partnership with sunfire, Audi has been active in the development of CO2‑neutral fuels – Audi e‑fuels – since 2009. The Audi e‑gas plant in Werlte, Lower Saxony, already produces Audi e‑gas (synthetic methane) in a comparable manner; drivers of the Audi A3 Sportback g‑tron* can fill up on it using a special fuel card. Audi is also conducting joint research into the synthetic manufacture of Audi e‑gasoline with Global Bioenergies, of France. In a further project, Audi has joined forces with the U.S. company Joule, which uses microorganisms to produce the synthetic fuels Audi e‑diesel and Audi e‑ethanol.