A Discussion of the HSE Aspects of Carbon Dioxide Sequestration

Abstract

Abstract Amidst increasing global warming concerns, carbon dioxide, being a major Greenhouse Gas (GHG), poses a threat to the environment if its amount in the atmosphere increases substantially. In this context, carbon dioxide sequestration has emerged as a key technology pathway to reducing GHG emissions. Sequestration is the long term isolation of carbon dioxide from the atmosphere through physical, chemical, biological, or engineered processes. The very nature of the sequestration process involves dealingwith a gas as hazardous as CO2, capable of polluting air, water and land. Hence, health, safety and environment considerations need to be carefully examined at every stage of the sequestration project; right from design to implementation. Major risks involved with a sequestration project are the chance of leakage of sequestered CO2 as well as the risk of fracturing subsurface formations wherein CO2 might be injected. These risks should therefore be strictly maintained in the As Low As Reasonably Practicable (ALARP) region. Safe gas storage, transport, compression, injection and monitoring facilities need to be designed and reviewed regularly. The aim of this paper is to review all the current Health Safety & Environment (HSE) practices, risk analyses as well as HAZOP/HAZID studies being conducted and followed for the implementationof sequestration projects worldwide. The binding laws and policies aimed at safe implementation of sequestration projects are also presented. New methodologies that are being employed for the monitoringof sequestered CO2 gas are also discussed along with possible reasons for their success. Also, previous actual CO2 leakages are presented, along with the damages they caused to the ecosphere of the concerned region. This, being a review paper, the safe practices needed to be implemented for sequestration projectsare highlighted and the state of the art for the same is presented in a consolidated manner.