Vol 2 Chapter 25: Lessons Learned from Industrial and Natural Analogs for Health, Safety and Environmental Risk Assessment for Geologic Storage of Carbon Dioxide
Sally M. Benson
Abstract: This literature survey was conducted to gather and interpret information regarding potential approaches for assessing, managing and mitigating risks associated with the deep geologic storage of CO2. Information was gathered from three principle sources:
- industrial analogs such as natural gas storage, deep injection of hazardous wastes and nuclear waste storage and
- natural analogs, especially those with CO2 leaks at the surface and
- industrial uses of CO2 for a variety of applications.
A set of lessons learned from these analogs was compiled and forms the basis for recommendations in the areas of risk assessment framework and methodology, risk management approaches and risk mitigation and remediation methods.
Lessons learned include:
- There is an abundant base of experience to draw on that is relevant and suggests that CO2 can be stored safely if geologic storage sites are carefully selected and monitored.
- The human health effects of exposure to elevated concentrations of CO2 have been extensively studied and occupational safety regulations are in place for safe use. Ecosystem impacts from elevated soil gas concentrations are less well characterized and may require additional research.
- The hazard created by CO2 releases depends more on the nature of the release rather than the size of the release. In particular, since CO2 is denser than air, hazardous situations arise when large amounts of CO2 accumulate in low-lying, confined or poorly ventilated spaces. Releases, even large ones, do not pose a hazard if they are quickly dissipated in the atmosphere, such as from tall industrial stacks or explosive volcanic events.
- Many of the risks of CO2 storage are well understood based on experience from natural gas storage and
deep injection of hazardous waste. Experience from these analogs suggest that the biggest risks from CO2
storage will be due to:
- leakage through poor quality or aging injection well completions;
- leakage up abandoned wells;
- leakage due to inadequate cap rock characterization;
- and inconsistent or inadequate monitoring of injection wells, groundwater in overlying formations and leakage from abandoned wells.
- Regulatory paradigms and approaches for the industrial analogs vary and none address all the issues that are important for CO2 storage.
This chapter reviews the lessons learned and also provides recommendations for additional research to address gaps in knowledge and risk management approaches.
Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO2 Capture Project Geologic Storage of Carbon Dioxide with Monitoring and Verification - Volume 2
Edited by: Sally M. Benson, Lawrence Berkeley Laboratory, Berkeley, CA, USA
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