Environmental and Technical Advantages and Bottlenecks of Carbon Dioxide Capture and Storage from a Thermodynamic Perspective

Carbon dioxide capture and subsurface storage (CCS) is considered a major player in reducing CO₂ emission from industrial point sources in the North Sea region. The process consists of CO₂ capture from the flue gas, cleaning and transport to a storage site, and injection into the porous subsurface. The energy efficiency of different elements of CCS is separately studied; however, due to the multidisciplinary nature of the problem, the technical integration of these elements from an energy and environmental perspective needs further attention. Here, we take the countries in the North Sea region as the main emitters and the targeted reservoirs in the North Sea as storage sites. We develop mathematical models that combine phase and chemical equilibrium, and detailed mass, energy, and momentum balance of the sub-processes including amine absorption, pipeline transport, refrigeration and shipping, and compression and injection. We utilize the models to calculate the operating and capital energy demand for the capture, transport, and storage of CO₂ from several major emitters. We report the exergy penalty (exergy per unit stored CO₂) and the emission penalty (CO₂ emission by the CCS process) for several industrial emitters based on their geographical locations. We also investigate the geochemical interactions between the stored CO₂ and the North Sea chalk and sandstone reservoirs and the chemical behaviour of seawater during the potential leakage of carbon dioxide. The model and data, published as open-source software, can screen the most suitable heavy emitters for CCS with minimum energy demand and environmental footprint.