As part of the latest project meeting in Germany, Audi invited the other BioCat partners for an inspirational visit to Audi’s 6 MW power-to-gas plant in Werlte – the world’s largest power-to-gas plant currently in operation.
The visit provided interesting and valuable knowledge about the workings of the plant – knowledge which may prove useful for the project’s upcoming establishment of power-to-gas facilities at the wastewater plant in Avedøre, Denmark.
About the e-gas plant
Audi was the first automobile manufacturer to develop a chain of sustainable energy carriers. The proces begins with green electricity, water and carbon dioxide – the end products are hydrogen and the synthetic methane: Audi e-gas.
The e-gas plant works in two process steps: electrolysis and methanation. In the first step, the plant uses surplus green electricity to break water down into oxygen and hydrogen in three electrolyzers. The hydrogen could one day power fuel-cell vehicles. For the time being, however, in the absence of an area-wide infrastructure, a second process step is carried out directly: methanation. The hydrogen is reacted with CO2 to produce synthetic methane, or Audi e-gas. It is virtually identical to fossil natural gas and will be distributed via an existing infrastructure, the German natural gas network, to the CNG filling stations. The plant began feeding Audi e-gas to the grid in the fall of 2013.
The Audi e-gas plant produces about 1,000 metric tons of e-gas per year, chemically binding some 2,800 metric tons of CO2. This roughly corresponds to the amount that a forest of over 220,000 beech trees absorbs in one year. Water and oxygen are the only by-products.
e-gas from the plant in Werlte powers approximately 1,500 new Audi A3 Sportback g-tron vehicles for 15,000 kilometers of CO2-neutral driving every year.