Considerations for monitoring, verification, and accounting for geologic storage of CO2

Growing concern over the impact of increasing concentrations of greenhouse gases (GHGs), especially carbon dioxide (CO 2 ), in the atmosphere has led to suggested mitigation techniques. One proposal that is attracting widespread attention is carbon capture and storage (CCS). This mitigation approach involves capture of CO 2 and permanent storage in geologic formations, such as oil and gas reservoirs, deep saline formations, and unmineable coal seams. Critical to the successful implementation of this approach is the development of a robust monitoring, verification, and accounting (MVA) program. Defining the site characteristics of a proposed geologic storage project is the first step in developing a monitoring program. Following site characterization, the second step involves developing hypothetical models describing important mechanisms that control the behavior of injected CO 2 . A wide array of advanced monitoring technologies is currently being evaluated by the Weyburn―Midale Project, the Frio Project, and the U.S. Department of Energy's Regional Carbon Sequestration Partnerships Program. These efforts are evaluating and determining which monitoring techniques are most effective and economic for specific geologic situations, information that will be vital in guiding future projects. Although monitoring costs can run into millions of dollars, they are typically only a small part of the overall cost of a CO 2 storage project. Ultimately, a robust MVA program will be critical in establishing CCS as a viable GHG mitigation strategy.