Evonik and Siemens Energy commissioned a pilot plant—sponsored by the German Federal Ministry of Education and Research (BMBF)—that uses carbon dioxide and water to produce chemicals.

The necessary energy is supplied by electricity from renewable sources. The pilot plant is located in Marl, in the northern Ruhr area. It is an essential part of the Rheticus I and II research projects, which are sponsored by the Federal Ministry of Education and Research (BMBF) with a total of €6.3 million.

For the idea of artificial photosynthesis, which is behind the Rheticus experimental facility, the researchers took nature as a model. Just as plants use solar energy to produce sugar, for example, from carbon dioxide (CO₂) and water in several steps, artificial photosynthesis uses renewable energies to produce valuable chemicals from CO₂ and water through electrolysis with the help of bacteria.

This type of artificial photosynthesis can serve as an energy store and thus help to close the carbon cycle and reduce carbon dioxide pollution in the atmosphere.

The pilot plant has started up in Marl, the largest Evonik site. It consists of a CO electrolyzer, developed by Siemens Energy, a water electrolyzer and the bioreactor with Evonik’s know-how.

In the electrolyzers, carbon dioxide and water are converted into carbon monoxide (CO) and hydrogen (H₂) with electricity in a first step. This synthesis gas is used by special microorganisms to produce specialty chemicals, initially for research purposes. These are starting materials for special plastics or food supplements, for example.

In the coming weeks, the composition of the synthesis gas and the interaction between electrolysis and fermentation will be optimized. In addition, a unit for processing the liquid from the bioreactor will be set up to obtain the pure chemicals.

After successful completion of the current Rheticus project phase (Rheticus II), Evonik and Siemens Energy will have a unique platform technology at their disposal that can produce energy-rich and valuable substances such as specialty chemicals or artificial fuels from CO₂ in a modular and flexible manner.