Geological storage of CO₂

Emission of CO₂ from human activities is a significant cause of the greenhouse effect, impacting the Earth's climate. Capture and storage (CCS) of CO₂ is recommended by the UN's climate panel (IPCC) and the Danish Climate Council as a substantial contribution to achieving the necessary CO₂ reductions to mitigate climate change.

GEUS has been studying the possibilities of geological storage of CO₂ for many years and has participated in international networks to strengthen Europe's scientific and technological position in the field. The work covers the entire value chain from capture through transport to storage, but our focus is on providing knowledge about the geological conditions and how CO₂ is stored underground.

To store CO₂, suitable geological formations in the subsurface are needed. The reservoir for CO2 should be at a depth of at least 800 meters and consist of porous geological layers, such as sandstone or limestone. To ensure that CO₂ does not migrate upward and escape into the atmosphere, the reservoir must be sealed by a tight layer, such as mudstone. Geological storage of CO₂ is a technique that has been used for decades and is already occurring in many places around the world, for example in the North Sea. In the Danish subsurface, there are several suitable formations that can accommodate large amounts of CO₂.

GEUS has a particular focus on the safety aspects of CO₂ storage, including which monitoring methods can be used to map the migration of the CO₂ plume in the subsurface and ensure that potential leaks can be detected and prevented.

New data for CO₂ storage

In recent years, GEUS has conducted extensive work to map the potential for CO₂ storage in the Danish subsurface. Denmark's CCS strategy from 2021 included funding for studies of relevant and potential storage sites in the Danish subsurface, with close involvement of relevant municipalities, citizens, etc. In 2022-2024, GEUS is conducting early investigations of eight areas in Denmark that are potentially suitable for CO₂ storage. In connection with the studies, new seismic data are collected, which are used to map the deeper geological structures in the subsurface. 

See the list of available data here.

This is how CO₂ is stored underground

Nina Skaarup
Head of Department
Geophysics and Sedimentary Basins
Charlotta Jenny Lüthje
Head of Department
Geo-energy and Storage