Environmental and Economic Assessment of Carbon Dioxide Recovery and Mitigation in the Industrial and Energy Sectors.

Abstract

Anthropogenic carbon dioxide (CO₂) is a global pollutant that needs urgent control to prevent large-scale vitiation of ecosystems. Generally speaking, anthropogenic CO2 emissions can be reduced through (1) CO2 capture for long-term sequestration or use in other applications, (2) renewable and low-carbon energy sources and technologies, and (3) demand reduction of carbon-intensive services and products through reduced consumption and efficiency improvements. The first two approaches constitute the “supply-side” of carbon abatement measures, and are the focus of this dissertation in which I examine the environmental and economic attributes of CO2 recovery and mitigation technologies in the U.S. industrial and energy sectors.

Starting by developing a comprehensive picture of the recovered CO2 supply chain, this dissertation provides process-based emissions inventories for recovering and purifying CO2 from combustion flue gases and higher purity point sources for sequestration and use in industrial applications. The strong influence of CO2 quality on the emissions, energy consumption, and costs of carbon capture found through this analysis warrants deeper scientific and economic analyses of carbon capture and sequestration as a carbon abatement option. To estimate the marginal emissions from use of recovered CO2 in industrial applications, a market-based allocation methodology is developed in a consequential life cycle assessment framework, along with new greenhouse gas accounting procedures that incorporate reuse and sequestration as fates for CO2. This methodology is presented with results from experimental studies on recovered CO2-based metalworking fluids, and motivates further exploration of applications employing the thermal and chemical properties of CO2 for pollution prevention and carbon abatement.

The dissertation concludes with an examination of carbon mitigation strategies from the standpoint of CO2 prevention in the U.S. electric and automotive sectors. By creating a stock-and-flow model of the U.S. automotive and power generation fleets, and considering the evolution of all major technologies in both sectors in an optimization framework, cost-minimizing technology trajectories are identified, which collectively cut about 55 gigatons of CO2 emissions by 2050. The analysis reveals that despite anticipated advancements and cost reductions in carbon abatement technologies with time, the technological costs of carbon abatement are likely to increase markedly with delay in climate-action.