In June 2013, Audi opened the e-gas plant at Werlte in the Emsland region of Germany. This makes Audi the first automobile manufacturer to develop a chain of sustainable energy carriers. It starts with green electricity, water and carbon dioxide. Its end products are hydrogen and synthetic methane: Audi e-gas.
The e-gas plant operates in two process steps: electrolysis and methanisation. In the first step, the plant uses surplus green electricity to split water into oxygen and hydrogen in three electrolysers. The hydrogen could one day be used to power fuel cell cars. At present however, there not a widespread infrastructure. For this reason, the second process step follows immediately: methanisation. The hydrogen reacts with CO₂ to produce synthetic methane: Audi e-gas. It is practically identical to fossil natural gas and is distributed to CNG filling stations across Germany through an existing infrastructure, the German natural gas network. The plant began feeding Audi e-gas into the grid in autumn 2013.
The Audi e-gas plant produces around 1,000 metric tons of e-gas per year, binding around 2,800 metric tons of CO₂. This roughly corresponds to the amount that a forest with more than 220,000 beech trees absorbs in one year. The only by-products are water and oxygen.
The Audi e-gas project goes far beyond the automotive industry. It shows how large quantities of green electricity can be stored efficiently and independently of location, by transforming it into methane and storing it in the natural gas network, the largest energy storage facility in Germany. With the e-gas project, Audi is a part of and a driver of the energy revolution. Meanwhile major German energy suppliers have picked up the idea of power-to-gas cogeneration and are following Audi with initial projects of their own.