Defining CCS Ready: An Approach to An International Definition

Chapter 4: Storage Ready Plant Definitiontheir CCR storage assessment.” 92 Regulators in the UK are expected to use the data todetermine whether the proposed storage area has sufficient capacity, taking into accountother applications for the same sites.4.2 Storage Site CharacterizationThe geology and geological attributes of the subsurface are highly variable among countries,regions, basins, and even among sites within any basin. Therefore, the appropriateness of astorage site has to be determined by a process of characterisation and assessment of thepotential site. The appropriateness of a storage site (mostly defined by the safe andpermanent storage of CO 2 ) is determined primarily by three principal requirements:• Capacity: i.e., whether sufficient storage volume is available, and can be accessed (e.g.,see injectivity);,• Integrity: i.e., whether the site is secure with negligible risk of leakage; and• Injectivity: i.e., whether suitable reservoir properties exist for sustained injection atindustrial supply rates into the geological formations, or reservoir properties can beengineered to be suitable. 93Assessing these characteristics of a storage site is a critical first step in the series of activitiesthat are needed for geological storage of CO 2 . For example, reliable assessment of thenumerical capacity of geological formations to sustainably inject and store CO 2 is a crucialrequirement for commercial decisions that allow investors to understand the likelihood thatthere will be viable storage at a site for the life of a CCS project.The entire chain of activities needed for CO 2 storage is shown below in Exhibit 4-1. As onepasses through these different stages, the developer achieves progressively more detailedknowledge about the storage capacity of the site and the characteristics of the storagereservoir, with reduction in uncertainty and better understanding of technical risks.Broadly, the technical components of a geological storage process will comprise thefollowing phases:• Regional Prospectivity Studies• Catalogue of Potential Sites Desktop study to assess the validity of any existing regional prospectivity studies.• Site Screening and Selection Identifying potential reservoir seal pairs, drainage cells, migration pathways, andtrapping mechanisms.• Characterisation of Site AssessmentFinding injectivity and containment.92 Paragraph 39, Page 17 of U.K. Department of Energy and Climate Change (U.K. DECC). (2009a). Carbon capturereadiness (CCR): A guidance note for Section 36 Electricity Act 1989 consent applications (Publication no. URN 09D/810).London, UK: Author.93 For example, by fraccing the reservoir or dropping formation pressure to prevent reservoir build-up.23 February 2010 50