Geological Storage of CO2: What's Known, Where are the GAPS and What More Needs to be Done

Abstract

This chapter presents an overview of the research work that is currently underway and provides an analysis of the current state of knowledge on geological storage of CO2. The analysis will be broken down to address the key geological storage options—deep coal seams, depleted hydrocarbon reservoirs, and deep saline aquifers. In each case, areas of uncertainty and areas where it is considered that further work will be needed will be highlighted . If deep reductions in greenhouse gas emissions are required to meet the UNFCC goal of stabilization of anthropogenic greenhouse gas emissions, then one method to use would be CO2 capture and storage. The technology would be used in combination with the other mitigation measures, such as fuel switching, energy efficiency and renewable energy. CO2 can be captured from a variety of anthropogenic sources such as power and large industrial plants and either stored in the oceans or in geological reservoirs. Currently, because of uncertainties about the science and the attendant legal issues ocean storage is unlikely to be promoted as a mitigation option. There are a number of potential geological reservoirs that can be used to store captured CO2. These geological reservoirs include depleted and disused oil and gas fields, deep saline aquifers and deep unminable coal seams. The capacity estimates for these reservoirs show that geological storage of CO2 can make a substantial impact on CO2 emissions reduction. From a capacity perspective, deep saline aquifers offer a significant potential.