German car manufacturer Audi has been working on a cutting-edge way to produce synthetic diesel for its autos, and just last week the company announced that its "Audi e-diesel" project is bearing fruit. The first 5 liters of the new clean diesel to roll out of the pilot plant were pumped into the tank of the aptly-named Audi A8 3.0 TDI clean diesel quattro, the official car of Germany's Minister of Education and Research.
The new clean diesel project is notable from a sustainability point of view, and it also demonstrates how manufacturers can use advanced energy technology to promote their green branding.
The main burden has fallen on biofuels. However, first-generation biofuel strategies have given rise to significant food, land and water resource issues. One such example is the unfortunate detour into corn ethanol undertaken by the U.S. during the Bush administration.
Part of the solution has been to turn away from food crops and focus on second-generation biofuel from non-food sources, including forestry waste and algae. However, some of these solutions can also run into stumbling blocks when it comes to land and water use.
The emerging third-generation solution is to leverage the carbon dioxide waste from industrial operations for fuel production, and that's where the Audi clean diesel project comes in.
To be clear up front, the process does require water. However, since it can be uncoupled from agriculture operations, there is the potential to use non-competing water resources.
Using renewable energy, the process involves splitting water into hydrogen and oxygen. The hydrogen can be used directly in fuel cells. The oxygen can be reacted with carbon dioxide to produce synthetic methane, dubbed "Audi e-gas."
The concept is that the synthetic methane and the hydrogen both work as portable energy storage platforms for renewable electricity from wind and solar farms.
Audi e-gas effectively leaps over several obstacles related to the existing fuel infrastructure in Germany. It is virtually identical to fossil methane, so it can be used in any existing compressed natural gas vehicle or fueling station, and it can be distributed through the existing natural gas network.
To gild the sustainability lily, the e-gas facility was built next to an existing biogas plant. The biogas plant provides concentrated CO2 for the e-gas process, and waste heat from the e-gas process goes to boost efficiency at the biogas plant.
As for branding, the idea is fairly straightforward. Audi customers have the option to order Audi e-gas with their purchase of an Audi A3 Sportback g‑tron. They can fuel up at any natural gas station using an Audi branded e-gas card, and the amount is credited to their account as an offset.
Here's how Audi uses the e-gas concept to build brand loyalty along with national identity:
"The Audi e-gas project transcends the automobile industry. It shows how large amounts of green electricity can be stored efficiently and independently of location by transforming it into methane gas and storing it in the natural gas network, the largest public energy storage system in Germany. With the e-gas project, Audi is a part of and a driver of the energy revolution."
Last week's fueling-up of the Audi A8 3.0 TDI clean diesel quattro is the result of a partnership with the company sunfire, which deployed its power‑to‑liquid technology to make the liquid fuel from water and carbon dioxide.
Most of the carbon dioxide is provided by a nearby biogas plant. At the initial startup phase, carbon dioxide was also pulled from the ambient air using a technology provided by the company Climeworks.
The process starts with electrolysis, which refers to a chemical reaction touched off by introducing an electrical current into a liquid. In this step, water is converted into steam. When exposed to an electrical current, the steam breaks down into hydrogen and oxygen.
In the next step, the hydrogen is placed into a chamber with carbon dioxide at high temperature, which creates a liquid hydrocarbon called "blue crude."
According to Audi, blue crude has a chemical composition similar to crude oil, and it can be refined into a sulfur-free, diesel-grade fuel.
You have to read down to the fine print to find out that for now Audi e-diesel is meant to be blended with fossil diesel. However, the company is confident that further development will yield a standalone fuel that can be used without blending.
It looks like Audi is anticipating that environmental awareness, national pride and hometown pride will combine to push the market for locally-sourced, carbon-neutral liquid fuels under the Audi brand.
That's quite a jump from relying on the global petroleum market, and it's one more demonstration of the creative ways in which auto manufacturers are using new energy technologies to attract customers.
Photo credit (cropped): Audi TDI clean diesel, courtesy of Audi.
Tina writes frequently for TriplePundit and other websites, with a focus on military, government and corporate sustainability, clean tech research and emerging energy technologies. She is a former Deputy Director of Public Affairs of the New York City Department of Environmental Protection, and author of books and articles on recycling and other conservation themes. She is currently Deputy Director of Public Information for the County of Union, New Jersey. Views expressed here are her own and do not necessarily reflect agency policy.