General Clean Energy

Innovative technologies for binding and storing CO2 (CO2 Trap)

The project partners are developing geotechnical CO2 storage methods to reduce anthropogenic greenhouse gas emissions. The basic idea is to produce compounds that can be stored for long periods underground in geothermic reservoirs and (decommissioned) coal mines. With anhydrite (CaSO4), coal dust and flue ash, they are testing different sorption media that are easily accessible in mining. 



Industry is a significant emitter of CO2 and thus contributes to climate change. As emissions occur at specific points, there is a possibility of separating the gas. As part of this research project, the researchers are investigating the options for mineralogical and physical fixation of CO2.

Reservoirs containing anhydrite and feldspar can be used to store CO2 dissolved in formation water in the form of calcite (CaCO3). Combination with operation of a geothermic heating system is also being studied.

Based on laboratory experiments, a method was also developed that enables mineral binding of CO2 due to the reaction of flue gas with flue ash (FA). FA represents a highly reactive by-product of coal conversion and occurs in large quantities. 

Sorptive binding of CO2 on coal residue and coal dust and subsequent storage were studied based on experimental work and mathematical simulations. Based on this research, the storage potential of various German coal mines was calculated, while the potential for combining CO2 storage with mine gas production was also studied.


  • Precipitation of CO2 into calcite using anhydrite results in a successive improvement in the hydraulic conductivity of the rock and thus in its geothermic potential.
  • The feasibility of combining CO2 storage and operation of a geothermic heating system can be demonstrated in theory and practice. However, industrial implementation is viewed as critical.
  • The calculated binding potential for the FA studied is around 0.23 kg CO2/kg FA (at T = 75°C). This results in a storage potential of around 3.5 Mt CO2 per year. This amount corresponds to around 2% of the CO2 emitted annually by German lignite power stations.
  • Mine gas production stimulated by CO2 injection is also a worthwhile option.

Project Participants

Implementing Institution

E.ON Energy Research Center (E.ON ERC), RWTH Aachen - Institut für Angewandte Geophysik und Geothermalenergie

Cooperation partner

RAG Deutsche Steinkohle AG

Universität Bayreuth, Lehrstuhl für Hydrologie

Universität Stuttgart, Lehrstuhl für Hydromechanik und Hydrosystemmodellierung

RWE Power AG Köln


RWTH Aachen, Fakultät 5 - Georessourcen und Materialtechnik - FG für Geowissenschaften und Geographie - Lehrstuhl für Ingenieurgeologie und Hydrogeologie

RWTH Aachen, Lehrstuhl für Geologie und Geochemie des Erdöls und der Kohle (LEK)

Evonik New Energies GmbH

GFZ German Research Centre for Geosciences

Deutsche Montan Technologie GmbH & Co. KG, DMG

RWTH Aachen, Lehr- und Forschungsgebiet für Ton- und Grenzflächenmineralogie 

More Project Informations

Project title:  CO2Trap - Entwicklung und Bewertung innovativer Strategien zur mineralischen und physikalischen Bindung von CO2 in geologischen Formationen und der Langzeitdichtigkeit von Deckschichten

Project number:  03G0614A

Project period:  2005 - 2008

Project region:  Germany (North Rhine-Westphalia)

Project contact:

Herr Prof. Dr. rer. nat. Clauser

View Publication

Source: German National Library of Science and Technology Hannover (TIB)