Quantum Cascade Laser-Based Sensing for Carbon Sequestration Leakage Monitoring

Abstract

Carbon capture and sequestration (CCS) may play a key role in our energy future. However, the widespread sequestration of CO_2 into storage reservoirs is inhibited by safety and leakage concerns. Effective leakage monitoring at the surface is recently made possible by the development of quantum cascade (QC) laser-based sensors, which are capable of tracking fluxes in CO_2 isotope concentrations. In this paper, we initially discuss the status of this technology, including recent results from distributed feedback QC lasers for use in sensing CO_2 isotopic ratios. These lasers show single-mode emission at 4.32 μm, overlapping strong absorption resonances of ^(12)CO_2, ^(13)CO_2, and ^(18)OCO. We then consider the value of such devices for quantifying CO_2 leakage using a climate-economy integrated-assessment model that is modified to include CCS. The sensitivity of model outcomes to reservoir leakage is studied, showing that an average reservoir storage half-life on the order of 1000 years or longer can limit atmospheric temperature increases to 2°C or less over the next 150 years for economically optimal emissions scenarios. The present day economic value of CCS is established versus reservoir half-life, showing a significant return on investment ( ~ 2 trillion U.S.$, or ~ 4% of gross world product) when the average reservoir half-life is 250 years, with a sharp drop in the value of CCS technology for half-life values below 250 years. Quantifying CO_2 leakage rates via QC laser-based sensing will contribute greatly toward accurately assessing CCS technology and its efficacy as part of CO_2 limitation strategies.

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