Economics of Acid Gas Reinjection: An Innovative CO2 Storage Opportunity

Publisher Summary The capture of CO 2 from the production and use of fossil fuels and its storage in geological formations may offer the ability to make early and deep reductions in CO 2 emissions without abruptly abandoning our fossil-based energy infrastructure. While the economics of CO 2 mitigation are uncertain, to a rough approximation, it appears that CO 2 capture and storage (CCS) fills the gap between the lowest costs, most immediately available measures of CO 2 mitigation, such as moderate energy efficiency improvements, and the higher costs associated with a transition to a non-fossil primary energy supply. Acid gas streams, consisting primarily of hydrogen sulfide (H 2 S) and carbon dioxide (CO 2 ), are commonly generated as a by-product of the gas sweetening process used to bring produced gases and solution gases up to pipeline specifications for sales and transport. A new technology called acid gas reinjection has emerged over the past ten years in Canada as an effective way of ensuring that acid gases are not emitted into the atmosphere. There are 38 acid gas reinjection projects presently operating in Alberta. This technology involves compressing the acid gas and injecting it into a suitable underground zone, similar to deep well disposal of produced water. Essentially, the sulfur compounds and CO 2 are permanently stored in the deep geological formation preventing their release to the atmosphere. Therefore, most acid gas reinjection projects can be considered existing examples of CO 2 geological storage projects. These projects provide important practical experience with CO 2 storage. In addition, this technology could be extended to capture a significant fraction of the natural gas-associated CO 2 stream at low cost.