420,000 year assessment of fault leakage rates shows geological carbon storage is secure

Miocic, J. M., Gilfillan, S. M.V., Frank, N., Schroeder-Ritzrau, A., Burnside, N. M. and Haszeldine, S. (2019) 420,000 year assessment of fault leakage rates shows geological carbon storage is secure. Scientific Reports, 9, 769. (doi: 10.1038/s41598-018-36974-0) (PMID:30683881) (PMCID:PMC6347600)

Abstract

Carbon capture and storage (CCS) technology is routinely cited as a cost effective tool for climate change mitigation. CCS can directly reduce industrial CO2 emissions and is essential for the retention of CO2 extracted from the atmosphere. To be effective as a climate change mitigation tool, CO2 must be securely retained for 10,000 years (10 ka) with a leakage rate of below 0.01% per year of the total amount of CO2 injected. Migration of CO2 back to the atmosphere via leakage through geological faults is a potential high impact risk to CO2 storage integrity. Here, we calculate for the first time natural leakage rates from a 420 ka paleo-record of CO2 leakage above a naturally occurring, faulted, CO2 reservoir in Arizona, USA. Surface travertine (CaCO3) deposits provide evidence of vertical CO2 leakage linked to known faults. U-Th dating of travertine deposits shows leakage varies along a single fault and that individual seeps have lifespans of up to 200 ka. Whilst the total volumes of CO2 required to form the travertine deposits are high, time-averaged leakage equates to a linear rate of less than 0.01%/yr. Hence, even this natural geological storage site, which would be deemed to be of too high risk to be selected for engineered geologic storage, is adequate to store CO2 for climate mitigation purposes.

• Item Type: Articles
• Additional Information: This work was supported by the Panacea project (European Community’s Seventh Framework Programme FP7/2007-2013, Grant No. 282900) and Scottish Carbon Capture and Storage (SCCS). S.M.V.G was partially supported by a NERC Independent Research Fellowship (NE/G015163/1).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Burnside, Dr Neil
• Authors: Miocic, J. M., Gilfillan, S. M.V., Frank, N., Schroeder-Ritzrau, A., Burnside, N. M., and Haszeldine, S.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy
• Journal Name: Scientific Reports
• Publisher: Nature Research
• ISSN: 2045-2322
• ISSN (Online): 2045-2322
• Copyright Holders: Copyright © 2019 The Authors
• First Published: First published in Scientific Reports 9:769
• Publisher Policy: Reproduced under a Creative Commons License

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