The consequences of failure should be considered in siting geologic carbon sequestration projects

Abstract

Geologic carbon sequestration is the injection of anthropogenic CO 2 into deep geologic formations where the CO 2 is intended to remain indefinitely. If successfully implemented, geologic carbon sequestration will have little or no impact on terrestrial ecosystems aside from the mitigation of climate change. However, failure of a geologic carbon sequestration site, such as large-scale leakage of CO 2 into a potable groundwater aquifer, could cause impacts that would require costly remediation measures. Governments are attempting to develop regulations for permitting geologic carbon sequestration sites to ensure their safety and effectiveness. At present, these regulations focus largely on decreasing the probability of failure. In this paper we propose that regulations for the siting of early geologic carbon sequestration projects should emphasize limiting the consequences of failure because consequences are easier to quantify than failure probability.

Analysis of potential acid gas leakage from wellbores in Alberta, Canada

“…R I G H T P A G E . E ] acidification, leaching of heavy metals and eventual aquifer plugging due to precipitation of minerals (Price and Oldenburg, 2009;Thomson, 2009). It is, therefore, important to determine the extent and concentration of dissolved acid gas in the formations.…”

“…As little as one breath of H 2 S at a concentration above 500 ppm could prove fatal (Locey, 2005). Leakage of acid gas into valuable aquifers could have detrimental effects (Price and Oldenburg, 2009;Thomson, 2009). To date no incidence of harmful leakage of H 2 S from injection has been reported in Western Canada (Bachu and Gunter, 2004;Bachu et al, 2008a).…”

A probabilistic assessment of geomechanical reservoir integrity during CO2sequestration in flood basalt formations

“…However, the injection of CO 2 into the subsurface causes a disturbance in the pressure, temperature, and chemical systems within the target reservoir, and this response affects the injectivity, storativity, and confinement potential of the site. While the Wallula Pilot Borehole and CarbFix projects show promising results, transitioning basalt CCS technology from pilot scale to industrial applications is complicated by the highly heterogeneous nature of fracture‐controlled basalt reservoirs …”

Assessing health impacts of CO2 leakage from a geological storage site into buildings: Role of attenuation in the unsaturated zone and building foundation

“…To date, most research has focused on the assessment of the CO 2 flow rate that could migrate away from the reservoir (e.g. Nordbotten et al, 2009;Pruess, 2011a) rather than on the impacts of such a flow (Price and Oldenburg, 2009). However, the effects of CO 2 depend much more on the level of exposure (defined as a quantity of substance put in contact with the body barriers) than on the total quantity of CO 2 released (Hepple, 2005).…”