Tesla is trying to convert the world to the electric car. The Japanese are pushing hydrogen. But Audi, the German carmaker, has a different idea. It’s trying to synthesize fuel from the simplest of elements – water, carbon dioxide and solar energy.
Audi’s research facility in Dresden has produced what the company calls an e-diesel – a net-zero-carbon-footprint fuel made from carbon dioxide and water. The company announced the project to great fanfare on April 21. In May, it unveiled another advance – e-benzine, a fuel that acts just like gasoline.
The two are the latest of a suite of six fuels developed by Audi that behave just like traditional gasoline or diesel, but burn without releasing any sulfur or aromatic hydrocarbons, the stuff that produce air pollution. The fuels also can be labeled as carbon-neutral, since the carbon dioxide they’re removing from the atmosphere perfectly matches the CO2 they put back in when they burn. E-benzine currently derives its carbon from organic material – biofuels made from rapeseed, sunflower oil or corn. But Audi officials say they soon hope to switch to atmospheric carbon dioxide.
“To me, this is a historic moment,” said Marc Delcourt, CEO of Global Bioenergies, the French company that is partnering with Audi on the e-benzine project. “It is the first time that we have produced real gasoline from plants.”
The e-diesel process works like this: Audi begins by splitting water by electrolysis into hydrogen and oxygen. The electricity is provided by wind or solar energy, which makes it completely fossil-fuel free. The oxygen is released into the atmosphere. Meanwhile, Audi filters carbon dioxide out of the atmosphere. The C02 is stripped down to carbon monoxide, and the CO and hydrogen are then mixed together under high pressure to produce a long-chained hydrocarbon that Audi calls “blue crude.” It has all the properties of crude oil and can be refined down to commercial fuels like e-diesel. “We’re thinking we’re bringing green-ness to a field that desperately needs green-ness,” said Rick Bockrath, vice president for chemical engineering at Global Bioenergies. “It’s basically how we’re moving away from an oil-based economy towards something that has a renewable, sustainable future to it.”
Johanna Wanka, Germany’s Minister of Education and Research, attended the ceremony at which the first batch of Audi e-diesel, five liters’ worth, was put into her official car, an Audi A8 3.0 TDI clean diesel Quattro (that’s her in the photo above). “This synthetic diesel, made using CO2, is a huge success for our sustainability research,” she said. “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.”
The product has a 100 octane rating and can be used either as an additive or as a stand-alone fuel. Audi says cars run much smoother on the product because of the lack of aromatic compounds, sulfur and other impurities. It also converts to energy at 70 percent efficiency, which is much better than regular diesels.
Audi’s pilot project in Dresden is currently producing 160 liters of e-diesel per day. Obviously, that isn’t enough to shake the world. But the long-term plan is to scale up to a level that will make the product available to the public. The estimated price will be 1 to 1.5 euros per liter, which comes to about $3.75 per gallon. This would not offer any price advantage in the United States, where diesel is selling at $2.88 per gallon, but it would be competitive in Europe, where diesel currently sells for about 1.4 euros per liter.
The problem with all such inventions, of course, is whether they can scale up at a price that remains competitive. Robert Rapier, the highly respected energy analyst, is skeptical. In a lengthy piece in GreentechMedia, Rapier did a step-by-step analysis, including all the chemical reactions. He concluded that the price is going to be $3.76 per gallon, which would put it above the current price of diesel in the United States, but perhaps not in Europe. But that doesn’t include any price increases that may come with scaling up the process. In addition, several critics have wondered whether solar and wind electricity will be available on a scale capable of supporting such a commercial operation.
“To sum up, can Audi produce fuel from thin air? Sure. There is no question about technical viability,” Rapier wrote. But “The question boils down to economic viability, which appears to be challenging given what has been released about the process.”
All this doesn’t mean Audi shouldn’t continue experimenting. There’s always room for improvement, and there may be other breakthroughs down the road. A carbon tax would also benefit the process, particularly if Audi could be given credit for the carbon it takes out of the atmosphere. There is also the possibility of combining the procedure with a carbon-capture and storage operation at a fossil-fuel plant, where carbon dioxide is currently regarded as a noxious waste material.
A system that would manufacture automotive fuel out of carbon dioxide in the atmosphere would be like the philosopher’s stone of the transport sector. Audi should keep trying.
(Photo credit: Audi)