SiteChar will facilitate the implementation of CO2 storage in Europe by improving and extending standard site characterisation workflows, and by establishing the feasibility of CO2 storage on representative potential CO2 complexes suitable for development in the near term.Reasonable estimates of the theoretical capacities of storage sites have been undertaken in previous studies. We will develop a workflow to undertake site characterisation, assessment of risks and development of monitoring plans necessary to reach the final stage of licensing. We will perform detailed site-specific techno-economic analyses and evaluate injection strategies, based on credible and realistic sources of CO2. We will undertake in-depth activities to enhance public awareness.The SiteChar workflow will be tested at a range of onshore and offshore, open and structural traps and depleted hydrocarbon reservoirs, located across Europe. Site characterisation will be placed in an economic context. A key innovation will be the development of internal dry-run licence applications for 2 sites, tested by relevant regulatory authorities. This iterative process will refine the storage site characterisation workflow and identify gaps in site-specific characterisation needed to secure storage licenses under the EC Directive, as implemented in ‘host’ member states. In addition, we will address critical points of the workflow, such as screening of multiple options, fault geomechanics, reactive flow simulation, the presence of geological heterogeneity, trapping mechanisms, a Framework for Risk Assessment and Management and sensitivity analysis. These studies will be conducted through a strong collaboration of experienced industrial and academic research partners. SiteChar will produce practical guidelines for site characterisation and advance a portfolio of sites to a (near-) completed feasibility stage, ready for detailed front-end engineering and design.