Feasibility of Carbon Dioxide Storage Under the German North Sea Confirmed

The German government has approved the underground storage of carbon dioxide (CO2) as part of its commitment to achieving climate goals. A research consortium is currently exploring the potential of CO2 storage in the North Sea.

In its initial report, the consortium, known as GEOSTOR and coordinated by the GEOMAR Helmholtz Centre for Ocean Research Kiel, concluded that while the injection of greenhouse gases beneath the North Sea is feasible, it is limited in capacity. The report emphasizes that such storage solutions do not eliminate the need for emission reductions.

Researchers analyzed the geological characteristics of the North Sea seabed to assess its suitability for CO2 storage, identifying two potential sites. The first is the Westschleswig Block, located approximately 100 kilometers off the coast, while the second, smaller site is found in the Entenschnabel area, the most northwestern part of Germany's exclusive economic zone.

The Westschleswig Block is deemed the most promising site for CO2 storage due to its geological features. This area consists of a domed sandstone formation capped by barrier rock, with the capacity to potentially store between 900 and 550 million tons of carbon dioxide.

The research indicates that up to 10 million tons of CO2 could be transported to these storage locations annually. Initially, transportation will occur via tankers to the coast, where the CO2 will be transferred to ships and then delivered to the injection sites. In the future, a pipeline is planned to facilitate direct pumping of CO2 to the storage sites.

According to Klaus Wallmann, the coordinator of GEOSTOR, the main challenges lie in implementing measures to prevent leaks from the storage formations. Additionally, minimizing noise during the exploration and monitoring phases is crucial to protect marine wildlife, and it is necessary to address potential conflicts with offshore wind farms in marine spatial planning.

The report also discusses the financial aspects of the project. The initial cost of transporting one ton of CO2 to the Westschleswig Block ranges from EUR26 to EUR55, accounting for investment and operational expenses associated with transport and storage. Once infrastructure is established, costs could decrease to between EUR13 and EUR28 per ton. Transporting CO2 to the Entenschnabel site would incur additional costs due to its greater distance.

It is important to note that these estimates cover only the transport and storage aspects. The costs associated with capturing the CO2 and transporting it to the coastal facilities are not included and could be significant.

Germany has set a target to achieve climate neutrality by 2045. To meet this objective, the government authorized underground CO2 storage in early 2024, highlighting that without carbon capture and storage (CCS) or carbon capture and utilization (CCU), the country's climate targets would be unattainable.

However, the GEOSTOR report cautions that the available storage capacities in the German North Sea are limited. It suggests that only unavoidable residual CO2 emissions, which persist despite rigorous climate policies, should be deposited in these geological formations.