What Germany’s limited CO2 storage capacity beneath the North Sea means

The CDRmare research consortium on CO₂ storage deep beneath the German North Sea (GEOSTOR) has today published two new special episodes of its (video) podcast ‘CCS: What is it?’ as well as a new factsheet to provide information on Germany’s limited CO₂ storage capacities beneath the German North Sea.

“The German government intends to present its strategy for decarbonising German industry by the end of the year. The capture and storage of heavy and unavoidable CO₂ emissions – such as those produced during cement production and waste incineration – play a key role in this. The volume of these emissions exceeds our storage capacities beneath the German North Sea. For this reason, careful consideration must be given to determining for which industrial sectors geological CO₂ storage beneath the sea should be permitted and for which it should not,” says Prof. Dr Klaus Wallmann, coordinator of the GEOSTOR research consortium and head of the Marine Geosystems research unit at GEOMAR Helmholtz Centre for Ocean Research Kiel.

Key findings at a glance:

• Germany’s CO₂ storage capacities beneath the North Sea are limited: GEOSTOR preliminary surveys show that the static CO₂ storage capacity in Buntsandstein reservoirs seaward of the coastal zone amounts to approximately 0.9 to 5.5 billion tonnes of CO₂, however, a large proportion of the potential storage sites is currently inaccessible, as the North Sea in these areas is already being used for other purposes (e.g. wind energy, shipping, military activities) or is a protected area. To nevertheless enable CO₂ storage on an industrial scale, concepts for the multiple use of the sea must be developed in the relevant North Sea areas and taken into account in maritime spatial planning.

• Despite the GEOSTOR calculations, the actual usable storage capacities are not yet known. They may amount to approximately 0.5 to 1.5 billion tonnes of CO₂. If this assumed capacity were utilised between 2035 and 2100, this would result in an annual storage rate of 8 to 23 million tonnes of CO₂. By contrast, the estimated annual storage requirement in Germany in 2045 is around 8.5 to 70 million tonnes of CO₂. Furthermore, capacity must be reserved to store CO₂ in the future that has been removed from the atmosphere through the use of BECCS (Bioenergy with Carbon Capture and Storage) and DACCS (Direct Air Capture and Storage) technologies (negative emissions). By way of comparison: if Germany were to inject 8 to 23 million tonnes of CO₂ per year beneath the German North Sea, the amount of CO₂ stored would correspond to 1 to 4 per cent of the country’s current CO₂ emissions.

• CCS should only be used for CO₂ quantities whose generation cannot be avoided. Germany’s limited CO₂ storage capacity underscores the fact that avoiding greenhouse gas emissions is the most effective climate protection measure and must be the top priority in all political decisions. The storage of CO₂ in the seabed of the German North Sea should, due to the limited storage capacity, be restricted to those quantities of CO₂ that cannot in principle be avoided (primarily cement production and waste incineration) or that have been removed from the atmosphere (e.g. BECCS and DACCS, the removal of CO₂ from the air followed by storage in the ground). Until CO₂ storage in the deep subsurface of the German North Sea becomes possible (from 2035 at the earliest), Germany could export captured CO₂ to countries bordering the North Sea.