The main goal of carbon capture and storage (CCS) is to reduce CO2 emissions to mitigate climate change based on a zero-leakage, emission-free, low-risk technology. In recent years TNO has been involved in numerous projects related to subsurface storage of CO2, leading to an internationally recognised position in this field.
A major issue in CCS is the safety and effectiveness of underground storage in relation to public acceptance, safety and environmental regulation and emission allowance trading and certification. This requires a comprehensive transparent, verifiable and practicable method for risk management. TNO has developed a CO2 storage risk assessment framework using components from existing evaluation methods for complex systems with special reference to two complementary methods:
The first method was originally developed to assess the short to (very) long-term risks related to nuclear waste disposal sites and the second was originally developed to assess and rank investment opportunities in the chemicals and oil & gas industries.
The implementation of large scale CCS therefore requires a complete consolidated workflow for risk assessment and management of underground CO2 storage adjusted to best practice in industrial safety and environmental assessment. The workflow, supported by a risk assessment toolbox, provides guidance and advice to clients in all fields of CO2 geological storage and can also support policy decisions. The explicit choice of models and tools to be used in the various stages of risk management will depend on the site-specific geological and geographical characteristics along with the engineering design of the CO2 storage facility. The choice of appropriate models is very much dependent on the scope and the expected results of the study as well as the lifetime of the CO2 storage project.
The use of tools can be optimised for a site-specific application by building a toolbox that enables the results of the different tools to be combined and a risk-based monitoring and mitigation plan to be developed to improve the overall performance of the site during the total lifetime of a CCS project. The toolbox serves as both a practical guide to industry and regulators in the licensing process and a support for environmental policy decisions.