Introduction

This Technical Review gives an interim overview of research and development aimed at improving and reducing the cost of commercial scale carbon dioxide capture in the power and process industries. It considers technologies principally applicable in post-combustion capture, pre-combustion capture, oxy-combustion capture and finally systems with circulating solids; in that order, which is more or less in line with the current maturity of each approach. It then goes on to consider applications in iron and steel and cement production and oil refining. IEAGHG’s normal practice is for its reports to be sent to external reviewers and for the reviewers’ comments to be taken into account prior to publication. This Technical Review is an interim report which has not yet gone through this process. An IEAGHG Report which has been subject to external review will be published in due course.

The report describes the general status of research and development and the main organisations carrying it out. It also examines the potential impact which each approach could have on the energy consumption and cost of electricity when capture is applied. It does this where possible on the basis of the thermodynamic fundamentals of the process and comparison with benchmark estimates for the established capture processes. Many cost reduction claims are found in the literature but these have been assessed critically as they sometimes give a misleading view of the magnitude of potential improvements. For purposes of comparison the percentage increase in Levelised Cost of Electricity (LCOE) is used as the principal cost comparator. This relates closely to the cost of CO2 abatement which can be calculated directly if also the efficiencies of baseline and capture plants and the fraction of CO2 captured are known. Where precise figures are not available a descriptive statement of the potential for cost reduction is given. Working on a percentage basis eliminates most of the variations in estimates which can arise from different assumptions regarding discount rate, project lifetime, region and currency.

Overall Conclusions

A wide range of alternative CO2 capture technologies has been reported. There may be significant differences between claims of the developers and the practicality, which this study has attempted to highlight. Amongst the many R&D initiatives there are several which stand out usually because of their favourable thermodynamics allowing reduction of the energy efficiency penalty. Of particular note are proposals which have been made for system configurations where recycles are created to concentrate CO2. This allows simpler, lower cost separation processes which do not work well on low concentrations of CO2 to be included in overall schemes.

Figure 6 below shows, in light green, the potential for LCOE reduction of some of the more promising technologies for post-, pre- and oxy-combustion capture which have emerged from the analysis. The reductions shown must be interpreted as rough assessments of the potential. Note that the baseline oxy-combustion process starts with approximately 20% advantage over the baseline post- and pre-combustion processes in this analysis, indicated in hashed dark green, based on the particular references used in this study.

There are also very promising technologies in which CO2 capture is a more integral part of the power generation process, such as solids looping combustion, alternative thermodynamic cycles and certain types of fuel cells. Solid looping technologies, and chemical looping combustion applied to coal has great potential to reduce both the parasitic energy consumption and the LCOE increase for CO2 capture. However, these technologies are at too early a stage to quote numbers for potential reductions and also have to overcome some significant technological hurdles. Only technologies for which percentage reductions have been estimated are shown in Figure 6 of the report.

Direct reduction of the capital cost of the equipment used in the processes does not appear to be a significant target for innovation. This may be because the individual pieces of equipment used in most capture processes are mature products with little potential for further cost reduction. However, the capital cost of capture equipment is a major contributor to LCOE and research directed at reducing this cost may still yield some incremental benefits.

The more developed technologies appear, as perhaps expected, to be taken up and championed by large industrial concerns, which is understandable on the basis of their potential and also the high costs of demonstration and commercialisation. Committed and experienced industrial support on this scale is probably a prerequisite for moving any of the technologies beyond TRL-6.