Denmark has pledged to reach a 70% reduction of greenhouse gas emissions by 2030 and net-zero emissions by 2050. CCS is recognized as an indispensable technology for achieving these ambitious goals. A critical knowledge gap in implementing a CO2 storage project is the phase behavior of CO2+X, where X stands for not just the impurities in the CO2 stream but also the in-situ fluids that interact with CO2. The phase behavior of CO2+X is directly related to many injection risks, such as hydrate formation and salt clogging: it can also affect the development and movement of CO2 plume. Therefore, the phase behavior of CO2+X is crucial to the risk analysis of a CO2 storage project. This project is in collaboration with several industrial partners investigating the feasibility of CO2 storage in different sites in Denmark. The project will provide a systematic study of CO2+X, covering experimental measurement, model development, and simulation analysis. We will measure the critically missing data for CO2+X related to the candidate storage sites, develop highly accurate models, and finally integrate the models into simulation analysis. The emphasis is on integrating our knowledge on CO2+X into the final analysis of injection risks and storage issues. If successful, we will significantly improve the risk analysis of CO2 storage in various types of storage sites and with different impurities, thus accelerating the implementation of CO2 storage.