As one of the three major carbon capture technologies associated with carbon capture and storage (CCS), oxy-fuel technology is currently undergoing rapid development with a number of international demonstration projects commencing in the progression towards commercialisation. The CO2 gas quality from oxy-fuel differs from pre-and post-combustion technologies, having higher levels of inert gases, oxygen, sulphur and nitrogen gases and other impurities such as mercury in the flue gas. Operations are available for adjusting gas quality, in the furnace, and by cleaning and treating flue gas with further removal of impurities during compression. Thus, knowledge of the impact of gas quality on power plant and materials, on transport systems and also gas quality regulations for storage is required, as the cost of gas cleaning is likely to be more significant for oxy-fuel than for other carbon capture technologies. The gas cleaning challenges are identified, with examples of two issues, one being the impact of sulphur impurities, and the other being gas quality impacts and control influencing CO2 compression. (C) 2011 Elsevier Ltd. All rights reserved.