Resumen de Monitorización de almacenamiento de dióxido de carbono en formaciones geológicas submarinas: sistemas de alerta precoz y análisis de riesgo ambiental
The overall goal of this Dissertation is to contribute to the safe use of carbon dioxide (CO2) Capture and Sequestration (CCS) as a mechanism to reduce atmospheric concentration of this gas. The dissertation starts by an introduction of the importance of CCS as the main short-term solution to effectively reduce the concentration of atmospheric CO2 and mitigate the effects of climate change. A combination of meta-analysis of bibliographic information and laboratory experiments are used to develop methods and a conceptual framework to provide insights on i) the legal requirements for the use of CCS, especially for the Mediterranean Sea; ii) the dynamics of CO2 dissolution in the injection stream and the behaviour of the stream inside the geological formation; and iii) the required methodology to assess the potential impact of CO2 leakage into marine eco-systems. Chapters 2 and 4 provide the required work for developing a framework for the risk assessment of CCS, with special application to its use in the Mediterranean Sea. The legal requirements to modify existing international conventions to allow for the use of CCS are summarized, the views of Mediterranean countries on the issue were collected and analysed, and the applicability of weight of evidence methods to assess the potential impact of leakage of CO2 from storage sites is discussed. In Chapter 3, two important aspects of the CCS process are analysed from an experimental perspective; i) the solution of CO2 in the injection stream and how to maximize it; and ii) the characterization of the storage formation and the behaviour of CO2 inside the storage site. Both theoretical work and dedicated laboratory experiments are used to conclude that solution of CO2 in the injection stream can be maximized with the use of appropriate mechanic mixers, and that the use of chemical tracers can be an useful monitoring tool to characterize the storage formation and provide information on the fate of the stored CO2, including on the percentage of it that mineralize and becomes a solid component of the geological storage formation. The work included in this PhD has lead to the development of a proposal to the Convention for the Protection of the Mediterranean Sea Against Pollution (Barcelona Convention) for a risk framework for the use of CCS in the Mediterranean, and is the basis of a research document that has been awarded a Spanish national research prize (Premio CEPRECO).
