About Rheticus

Artificial photosynthesis - a contribution to the energy transition

From the idea to innovation - CO2-based specialty chemicals

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 generate valuable chemicals from CO2 and water through electrolysis with the help of bacteria.

It was already successfully demonstrated a few years ago that artificial photosynthesis works in the laboratory (Haas et al., 2018). Another milestone on the way to industrial implementation was reached at the end of 2020: the test facility at Evonik's Marl site, funded by the German Federal Ministry of Education and Research (BMBF), was put into operation. It uses electricity from renewable sources, CO2 and H2O to produce chemicals and thus shows for the first time that artificial photosynthesis also works on a larger scale.

The test facility in Marl consists of a CO electrolyser developed by Siemens Energy, a water electrolyser and the bioreactor with expertise from Evonik. In the first step, electricity is used in the electrolysers to convert carbon dioxide and water into carbon monoxide (CO) and hydrogen (H2). This synthesis gas is used by special microorganisms to produce specialty chemicals, initially for research purposes. These are starting materials, for example, for specialty plastics and food supplements.

Following successful completion of Rheticus, Evonik and Siemens will have a unique technology platform allowing production of useful, energy-rich substances such as specialty chemicals and artificial fuels from CO2 in a flexible, modular process.


Evonik and Siemens Energy are researching a green future: They want to convert carbon dioxide into specialty chemicals - with the help of green electricity and bacteria in an artificial photosynthesis. In the Rheticus research project, they are driving the energy transition forward.

Interactive Infographic

Two steps to green chemistry 

Bayerischer Energiepreis 2020

Winner in the category Products and Applications

Commissioning of the Rheticus test plant in Marl