The first test plant is scheduled to go on stream by 2021 at the Evonik facility in Marl, Germany which produces chemicals such as butanol and hexanol, both feedstocks for special plastics and food supplements, for example. The next stage could see a plant with a production capacity of up to 20,000 tonnes a year. There is also potential to manufacture other specialty chemicals or fuels. Some 20 scientists from the two companies are involved in the project.

The new technology not only enables chemicals to be produced sustainably, it also serves as an energy store, can respond to power fluctuations and help stabilize the grid. Rheticus is linked to the Kopernikus Initiative for the energy transition in Germany which is seeking new solutions to restructure the energy system. The Rheticus project will receive €2.8 million (US$3.4 million) in funding from Germany’s Federal Ministry of Education and Research (BMBF).

With the Rheticus platform, we want to demonstrate that artificial photosynthesis is feasible.

—Dr. Thomas Haas, who is responsible for the project in Evonik’s strategic research department Creavis

Artificial photosynthesis is a process in which CO₂ and water are converted into chemicals using a combination of chemical and biological steps, in a process similar to how leaves use chlorophyll and enzymes to synthesize glucose.

Siemens is providing the electrolysis technology, which is used in the first step to convert carbon dioxide and water into hydrogen and carbon monoxide (CO) using electricity. Evonik is contributing the fermentation process, converting gases containing CO into useful products by metabolic processes with the aid of special micro-organisms. In the Rheticus project, these two steps—electrolysis and fermentation—are scaled up from the laboratory and combined in a technical test facility.

This research project shows how we are applying the Power-to-X idea.

—Dr. Karl Eugen Hutmacher, BMBF

As one of the four pillars of the Kopernikus Initiative, the Power-to-X concept is to help convert and store renewable, electrical energy efficiently. At the same time, the Rheticus platform also contributes to the reduction of carbon dioxide levels in the atmosphere, as it uses CO₂ as a raw material. Three tons of carbon dioxide would be needed to produce one tonne of butanol, for example.

Evonik and Siemens see great future potential in the Rheticus platform. It will make it simple to scale plants to the desired size – the chemical industry will be able to adapt them flexibly to local conditions. In future, they could be installed anywhere where there is a source of CO₂—e.g., power plant waste gas or biogas.