Subsurface Computational Modeling and Policy Analysis of Large-Scale Carbon, Capture, Utilization, and Storage

Abstract

Carbon capture, utilization, and storage (CCUS) mitigates climate change by capturing carbon dioxide (CO2) emissions from large point sources, or CO2 from the ambient air, and subsequently reusing the captured CO2 or injecting it into deep geological formations for long-term and secure storage. Almost all current decarbonization pathways include large-scale CCUS, on the order of a billion tonnes (Gt) of CO2 captured and stored each year globally starting in 2030, yet the actual deployment has lagged far behind (around 0.04 Gt CO2 was captured in 2021). In this dissertation, I contribute to several aspects of large- scale deployment of CCUS by (1) developing and applying efficient numerical models to simulate geological CO2 storage and (2) identifying key policies to address the bottlenecks of overall CCUS deployment. This dissertation concerns the United States, China, and the Belt and Road Initiative (BRI) region through research projects that are consistent with each location’s current development stage of CCUS. Chapters 2 and 3 contain computational modeling studies. In Chapter 2, I develop a new series of vertical-equilibrium (VE) models in the dual-continuum modeling framework to simulate CO2 injection and migration in fractured geological formations. Those models are shown to be effective and efficient when properties of the formation allow for the VE assumption. In Chapter 3, I apply a VE model to simulate basin-scale CO2 injection in the Junggar Basin of Northwestern China. The results show that current regional emissions of more than 100 million tonnes of CO2 per year can be stored effectively, thereby confirming the great potential of the Junggar Basin for early CCUS deployment. Chapters 4 and 5 contain policy analyses. In Chapter 4, I propose a dynamic system consisting new CO2 pipelines and novel Allam-cycle power plants in the Central United States, and examine how government policies, such as an extended Section 45Q tax credit, may improve the economic feasibility of this system. Lastly, in Chapter 5, I investigate and quantify CO2 emissions implications of power plant projects associated with the BRI. I also propose a “greenness ratio” to measure the level of environmental sustainability of BRI in the power sector.