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.