Audi invents way to create crude fossil fuels from mixture of air and water
German automaker Audi says it has developed a process for making diesel fuel out of nothing but water and carbon dioxide, laying the groundwork for a green, carbon-neutral fuel.
Audi calls the diesel produced by the new process "e-diesel" and is trumpeting it as a "fuel of the future." Audi developed the process in conjunction with Dresden-based energy technology company Sunfire.
"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, Audi's head of sustainable product development.
"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."
Cleaner and fossil-fuel free
The new process entails using high-temperature electrolysis (above 1,472°F) to break steam into its component hydrogen and oxygen gases. The hydrogen is pumped into a reactor, where it is combined with carbon dioxide collected either directly from the air or as a waste product from a local biogas plant. The ingredients are processed under high temperatures and pressures, Audi says, using electricity from renewable sources.
The process renders a form of crude oil called "blue crude." This can then be refined using conventional oil refinery techniques into conventional diesel, which can either be used as an exclusive fuel or can be mixed with conventional, fossil-fuel derived diesel (or, presumably, biodiesel).
Unlike diesel derived from crude oil, the diesel derived from the new process is free of impurities such as sulfur or hydrocarbon rings, which contribute additional pollution. In addition, the fuel burns more easily.
"The engine runs quieter and fewer pollutants are being created," Sunfire chief technology officer Christian von Olshausen said.
Audi and Sunfire have already built a dedicated processing plant, which is expected to produce 3,000 liters (around 800 gallons) of the "e-diesel" over the next few months.
At the fuel's official launch, German minister of education and research Dr. Johanna Wanka filled up her Audi A8's tank with the new fuel.
"This synthetic diesel, made using carbon dioxide, is a huge success for our sustainability research," Wanka said. "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."
Era of clean fuel in sight?
With rising petroleum prices and growing concern over the climate effects of fossil fuels, companies are working hard to find alternative ways to fuel vehicles. Audi also began producing a form of synthetic and purportedly more environmentally friendly methane in 2009 for use in gas-powered vehicles.
Another recent advance in petroleum-free fuel came from researchers at Yale University and the University of Bath, who announced the discovery of a new catalyst that could allow for the much more efficient and therefore less expensive production of hydrogen fuels.
All current techniques for producing hydrogen fuel are incredibly energy intensive. While the use of catalysts can reduce the energy needed, all known catalysts degrade quickly.
Unfortunately, the newly discovered catalyst is made of the incredibly rare material iridium. Thus, the importance of the discovery is less of a practical development and more of a promising area for future research.
According to researcher Ulrich Hintermair, hydrogen has great potential as a clean vehicle fuel because it provides a way to store energy generated from sources like the sun and wind. Energy from these sources could be used to split water into hydrogen fuel, which could then be burned and used for powering vehicles or other uses.
"Hydrogen is a fantastically versatile and environmentally friendly fuel," Hintermair said, "however, hydrogen-powered applications are only as 'green' as the hydrogen on which they run. Currently, over 90 per cent is derived from fossil fuels."