2 Carbon Capture, Transport and Storage — A Background

As indicated in Chapter 1, carbon capture and storage (CCS) involves capturing CO2 mainly from fossil fuel power plants (or other large stationary industrial sources), compressing and then transporting it via pipelines or ships and finally storing it underground in a geological site, such as saline aquifers or depleted oil and gas fields or alternately using it for enhanced oil recovery (EOR), enhanced gas recovery (EGR) or enhanced coal bed methane (ECBM). The CCS techniques were pictorially depicted and descriptively summarized in Chapter 1. The chapter also depicted the role of pipelines in the CCS; however, an overview of the entire CCS process is shown schematically in Figure 2-1. This chapter in a consolidated form provides detail descriptions of all aspects of carbon capture technologies and carbon dioxide sinks: storage and sequestration, namely, enhance oil recovery (EOR).

The CCS method provides a potential way of reducing carbon emissions and achieving a stabilized level of CO2 in the atmosphere. It has been predicted that the total emissions avoided would be approximately 1 GT of carbon per year minimum by 2054 [1]. It can be said that CCS will provide a bridge to the fully renewable technologies while meeting the demand for energy worldwide.

The CO2 storage site has to be selected so that it is geologically secured for significant timescales. Storage sites for CO2 are available in depleted oil and gas reservoirs and saline aquifers. The other potential opportunity is to use the captured CO2 for enhanced oil recovery (EOR), where it has been practiced onshore for over the past 4 decades in the United States. The advantage of CO2 injection for EOR is that it mobilizes oil that conventional recovery methods are unable to remove. Therefore, using CO2 for EOR has the dual benefit of increasing oil production, particularly from fields nearing the end of their life, while also reducing finding a permanent storage space (i.e., sink) for CO2 instead of emitting it to the atmosphere.