GEOMAR led the first coordinated EU program assessing the environmental risks of CO₂ storage in the North Sea (2011- 2015, https://www.eco2-project.eu/) and participated in the Horizon 2020 project STEMM-CCS (2016 -2020, https://www.stemm-ccs.eu/) where technical readiness levels for the monitoring of CO₂ storage sites in the North Sea were raised to industrial applicability (TRL 7). GEOMAR showed that fluid bypass systems are ubiquitous in the North Sea (Karstens and Berndt, 2015) and that they may constitute efficient pathways for advecting gas to the seafloor (Böttner et al., 2019). Moreover, studies conducted by GEOMAR revealed that natural gas is leaking along abandoned wells and that stored CO₂ may escape through these structures (Vielstädte et al., 2017; Vielstädte et al., 2015; Vielstädte et al., 2019). Observations at the seafloor indicate that the gas does not ascend through the wells but through the adjacent sediments and rocks that were mechanically disturbed and weakened during the drilling operation (Vielstädte et al., 2015). Whether or not these observations suggest that drilling through barrier formations of storage sites could create high-permeability pathway for CO₂ leakage is still an open question. GEOMAR has also a long track record in marine studies using OBS for passive seismology, including studying local micro-seismicity, volcanic tremors, and ambient noise studies revealing Green’s function and hence constraints on the velocity structure of the sub-surface.

CAU has participated in a number of CCS studies, focusing on storage capacities, estimation of spatial requirements and induced effects (Bauer et al., 2012). Relevant work also included the development of coupled numerical simulators (Benisch and Bauer, 2013; Pfeiffer et al., 2016), the influence of three-dimensional pressure propagation to estimate pressure effects in the overburden (Benisch and Bauer, 2013) and optimum space usage considering geometrical and stratigraphic effects (Mitiku and Bauer, 2013; Pfeiffer and Bauer, 2019). Furthermore, suitable geophysical monitoring strategies, geochemical reactions, brine leakage pathways and the spatial impact and thus space requirements of geological storage operations as a basis for subsurface spatial planning (Kabuth et al., 2017) were investigated. Kiel University is furthermore involved in experimental and numerical research for geomechanical soil-structure interaction and vibration emission (Wuttke et al., 2011), simulation of seismic wave fields (Basnet et al., 2018; Dineva et al., 2019), constitutive modeling of material behavior on- and offshore (Stutz et al., 2016) and ground behavior by heaving or settlements.

KUM: K.U.M. is an independent developer of 4-component OBS instruments supplied to customers inside and outside the EU. The company is a flexible small enterprise that is well connected with research and industry sectors for 25 years and is capable to link both demands in new developments. The main focus of the company is the development and production of prototypes, tailored to the respective research

North.io is a technology startup that offers a digital platform for hosting, visualizing, and analyzing large marine sensor datasets. The overarching goal is to enable players in the blue economy to unlock the full potential of their hydrographic and seismological datasets using a scalable cloud computing infrastructure combined with innovative AI tools for analysis. TrueOcean offers Software-as-a-Service for highly specialized data analysis and visualization to address the exponential growth of ocean data and the increasing demand for data availability and efficient processing. TrueOcean develops its algorithms and software architecture in-house with a team of dedicated computer scientists, software engineers, and geophysical analysts.

BGR has been involved in 60 research projects investigating various aspects of geological storage of CO₂ such as storage capacity, monitoring in terrestrial and aquatic environments, case studies and environmental impacts. BGR initiated and led several projects (e.g. GPDN, https://www.gpdn.de/, TUNB) to map and characterize the deep subsurface in the German North Sea, to evaluate the characteristics of reservoir and barrier rock formations and to assess the storage capacities for fluids in geological formations (Arfai et al., 2014; Bense and Jähne-Klingberg, 2017; Jähne-Klingberg et al., 2014; Wolf et al., 2015). Further, BGR investigates possible leakage pathways and associated structures in the German North Sea (e.g. polygonal fault systems, crestal faults, chimney structures), which also could be formed or reactivated during CO₂ storage (May et al., 2019; Stück et al., 2018). BGR has successfully applied for ship time at the German Science Foundation for a 3D high resolution multichannel seismic survey (Project GeoBaSIS 3D), to investigate an active seal bypass system and its structures in the Entenschnabel region (area B). This survey will be integrated into the proposed project. BGR has extensive experience in the operation and networking of spatial data infrastructures and operates its own interlinked infrastructure (GDI-BGR) with sustainable storage of data and descriptive metadata. Furthermore, BGR has experience with the use and development of advanced visualization methods, for example in the framework of the GeoERA 3DGEO-EU project and with generation of volumetric input models which allow for a more flexible visualization  (Zehner, 2019).BGR is one of the competent authorities according to the KSpG in Germany with roles in the characterization of storage potential, and in the permitting processes, from exploration to site closure. It developed an outline of a regulatory framework for site exploration, safety concepts, monitoring and assessment of abandoned wells in depleted gas fields (von Goerne et al., 2010).

DMM studies the impact of noise on marine mammals. It contributes to the drafting of regulations for marine protected areas that aim to minimize harmful noise effects on marine mammals induced by seismic surveys and wind mill constructions. Especially the harbor porpoise as well as the grey and harbor seals are potentially affected by future CCS survey work. Recent work on the offshore wind farms alpha ventus and DanTysk (Dähne et al., 2013a; Dähne et al., 2017) showed that establishing wind farms using percussive pile-driving can lead to large avoidance radii in porpoises, but can be mitigated using bubble screens for noise attenuation. Similar work in relation to seismic surveys has only been conducted in the UK and Denmark so far. Any mitigation for those noise effects must, however, be carefully designed to elicit the desired reduction in the effect on marine mammals (Tougaard and Dähne, 2017). Scientific work at DMM encompasses establishing of methods for acoustic biological surveys (Dähne et al., 2013b; Nuuttila et al., 2018; Verfuß et al., 2013) and large scale acoustic impact assessments. Moreover, DMM operates one of the largest natural history museums in Germany that attracts roughly 800.000 visitors per year and directs the attention of the general public to the issues that the marine environment is facing today.

UHH: The international law of the sea and international environmental law, with special focus on the compatibility of activities with the regime for the protection of the marine environment, have been at the forefront of research activities conducted by the legal team of UHH for years. This includes legal studies on the topics of marine spatial planning (Proelss, 2009), the protection of cetaceans in the North Sea and the regime of the Habitats Directive (Proelss et al., 2011), marine scientific research and new marine technologies (Hofmann and Proelss, 2015), domestic mining law in relation to marine areas (Proelss, 2019), conditions for the application of German law in the EEZ (Proelss, 2018) and, specifically, sub-seabed storage of CO₂ (Güssow and Proelss, 2011). The team of UHH was involved in the EU research project “ECO2 – Sub-seabed CO2 Storage: Impact on Marine Ecosystems” (2011-2014), in the context of which it delivered a report on the regulatory framework of sub-seabed storage of CO₂. Furthermore, Alexander Proelss is a member of the Scientific Advisory Group on Maritime Spatial Planning established at the Federal Agency for Navigation and Hydrography (BSH).

FIS: Fichtner is involved in projects dedicated to CCS since many years. FIS prepared a study on the status and the framework conditions of CCS projects in Europe for the Japanese government organization NEDO and acted as Owner’s Engineer for a CO₂ capture plant at the 420 MW CCGT power plant at Kårstø gas terminal in Norway. FIS also conducted a study for the carbon capture demonstration project at Porto Tolle, Italy. Enel contracted Fichtner to develop the procurement strategy for project implementation of the post-combustion project at its newly developed coal power plant. Recently, Fichtner prepared a study for a German utility company on state-of-the-art technology for carbon capture and possibilities for CO_2­-utilization. The study focused on the CO₂-sequestration potential at waste incineration plants, the involved costs and highlighted current international projects. The combination of Fichtner’s know-how with the expertise of the scientists in the project will yield a comprehensive overview on the technical constraints and costs for CO₂ storage in the German North Sea.

TG: TenzorGEO (subcontractor of K.U.M. and TrueOcean) is a long-time partner with access to oil and gas, CCS, and off-shore industries. It is a leader in passive micro-seismic technology and aims to leverage its imaging technique to optimize CCS site selection and long-term site monitoring. Backed by numerous successful deployments of reservoir characterisation and fluid injection monitoring, notably in onshore locations, TenzorGEO is now pushing the envelope to extend its scope of application to offshore CCS in its mission to help reduce global CO₂ levels in the battle against climate change.