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Audi expanding e-gas capacity through partnership with Viessmann; power-to-gas with biological methanation of CO2 and H2

Audi is expanding capacities for the production of sustainably produced e-gas. (Earlier post.) The Viessmann Group is Audi’s first partner company to produce additional quantities of the synthetic fuel using a new biological methanation process. The pilot plant in Allendorf, Germany officially opened today.

Audi e-gas is currently produced using two process steps: electrolysis and methanation. In the first step, renewably generated electricity is used to split water into hydrogen and oxygen. In the second step, the hydrogen is reacted with CO2 to yield synthetic methane. In the Audi e-gas plant in Werlte in the German state of Lower Saxony, this is done using a chemical-catalytic process under high pressure and high temperature.

Audi’s basic goal for its e-fuel projects is to combine renewable energy (e.g. solar and wind), water and CO2 to produce liquid or gaseous fuels with a very low carbon intensity. (Earlier post.)

In the new Viessmann plant, methanation is now purely biological. Highly specialized microorganisms absorb the hydrogen that is dissolved in liquid and the carbon dioxide through their cell walls. From these molecules they then form the new molecule methane.

The process is run under a moderate pressure of around five bar and at relatively low temperatures.



The Viessmann Group, a leading international manufacturer of heating, industrial and refrigeration systems, and its group company MicrobEnergy GmbH started up its pilot plant in stages beginning in March 2015 under the BioPower2Gas project supported by the German government.

Initial results presented in 2015 showed lifecycle GHG reduction potential, compared to fossil methane, of 43% using photovoltaic electricity; 75% using wind power; and 83% using hydro power.

We are writing the next chapter of the Audi e-gas story here. Audi began to produce the sustainable fuel in Werlte around two years ago. Now we are also working with a partner who immediately contributed this new process.

—Reiner Mangold, Head of Sustainable Product Development at Audi AG

The pilot plant is the first power-to-gas plant to utilize biological methanation across Germany. Its strength lies in the fact that it processes the carbon dioxide contained in the raw biogas directly. Unlike chemical methanation, the CO2 does not need to be present in high concentration or purified form. This opens up new procurement paths. Smaller sewage treatment and biogas plants, in which no biogas purification is performed, can now come into consideration as CO2 sources.

With the new partnership, Audi will be able to supply a growing number of customers with sustainably produced e-gas in the future. Simultaneously, Audi is also extending its line-up of models with natural gas drive.

At the end of 2016, sales of the new Audi A4 Avant g-tron begin in Europe. This is the second CNG model from Audi after the Audi A3 Sportback g-tron, which has been on the market since the beginning of 2014. Customers can run both g-tron models on gasoline as well as on conventional natural gas, biomethane or the sustainably produced Audi e-gas.

Participating at the official opening of the plant in Allendorf along with Reiner Mangold, Head of Sustainable Product Development at Audi, were the Minister-President of Hesse, Volker Bouffier; and Prof. Martin Viessmann, CEO and partner of the Viessmann Group.



With more wind and solar energy, Germany could produce enough e-gas to replace some NG imported from Russia?


It really depends on the price at which they can produce. Since Russian-sourced NG is fairly expensive here in Europe, I would say that it stands a chance but it is impossible to say without seeing their cost structure.

Of course, the Russians can probably lower their prices to an extent so this process better have some serious price advantage if only market forces are considered.

On the other hand, the EU would like to get rid of their energy dependence on the Russians so political factors may also come into play. If someone can demonstrate that e-gas from renewables is an economically viable substitute to Russian NG, that would garner a lot of interest here.


@ Soltesza.

Agree with you that EU cannot remain dependent on Russian NG but could produce it (or some of it) with clean e-energy from NPPs, Solar or Wind. It could be a long term positive move.

Cost wise, the price of Russian NG will certainly go up as supply progressively diminishes. Cost of bio-gas could go down as the price of REs go down?

Lower cost REs for electricity and vehicles and bio-gas for heating and industries could be a good combination. Bio-gas could be used as (solar + wind) energy storage for 27/7 usage.


Pretty big talk about how DZ will use egas to cut down on Russian natural gas -- considering DZ has a big overhang of coal generator development in the East which will take 40 years to wind down and amortize.

Biomethane is an emerging industry there and egas could conceivably be the best way to add value to this capital intensive product. But that virtually assumes every farm and Dorf will have a methane digester, a wind turbine, and a new Audi.


I think that this project could best be described as green wash.


Natural gas is now 17 cents per therm, at those prices they can make gasoline for less than one dollar per gallon.

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The problem with making methane, gasoline or any other hydrocarbon fuel is that when it is combusted it creates NOx and sot that cause people to die prematurely all over the planet at a massive scale of 7 million people per year.

It would not help much if these hydrocarbons where made entirely from renewable sources. They would still pollute massively with NOx and sot when cumbusted. Therefore there is no other alternative than to direct our industries to focus exclusively on non-polluting non-hydrocarbon fuels. For the auto industry that means focus exclusively on BEVs or FCVs. The latter is also a waste of money IMO and a distraction from making BEVs but that is ultimately up to consumers to decide, not me or any government. However, we should have no more development of polluting technology. Stop developing cars with combustion engines. Use what we have already developed with regard to combustion engines and focus on improving their exhaust treatment systems and direct all other R&D money to the development of better and cheaper BEVs (or FCVs). It is the only defensible road ahead for creating a better future.

WHO on 7 million premature air pollution death per year globally.


NOx when burned in an internal combustion engine. There is no NOx when reformed for fuel cells.

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Good point SJC

If it can be made to work economically with synthetic renewable hydrocarbons using a reformer and a fuel cell I am in for one. I believe that is more feasible than using expensive volumes pressure tanks with hydrogen and a fuel cell. By bet is still that autonomous taxi BEVs is the way to solve sustainable future transportation in the most economic way and I hope we are just a few years (before 2020) from seeing the first such service in commercial action.

Selling cars for private ownership will be a niche market for the very wealthy by 2030 IMO.


Unfortunately, ICEVs, NG furnaces + NG hot water heaters and NGPPs may be around for another 4+ decades.

Making bio-gas, bio-fuels and essential chemicals with clean REs could be cleaner than using fossil fuels (specially from coal and tar sands) and could become a way to store massive intermittent energy such as wind and solar for extended periods.


Renewable diesel (NOT biodiesel) is available, reform on the car to hydrogen and run an EV with a fuel cell range extender.


By mid 2016, over 80% of all Canadians will live in Provinces with carbon taxes (CT). CT rate will be progressive and will add about CAN $0.04/L about (0.11 USD/per US gal) to liquid fuels in 2016.

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