Abstract Research has been conducted at Argonne National Laboratory to identify and evaluate the advantages and deficiencies of several technologies, both commercially available and alternative technologies, for capturing CO 2 from the flue gas of utility boilers that use air as an oxidant (the current universal practice). The technologies include chemical solvent, cryogenic, membrane, physical absorption, and physical adsorption methods. In general, technologies for capturing CO 2 are expensive and energy‐intensive. Therefore, they result in a substantial overall increase in the cost of power generation. Research to improve the performance and economics of these technologies is discussed.