Carbon dioxide capture from energy systems will likely become a necessity as the European Union regulations are becoming increasingly more stringent. The greatest disadvantage of the existing methods of CO2 separation is the high energy intensity. In the Integrated Gasification Combined Cycle (IGCC) system, the carbon dioxide capture process is conducted before combustion, which facilitates the separation. In this paper, two methods of CO2 capture are compared. The first is the most frequently considered, known as chemical absorption. The second is membrane CO2 separation, which is not as commonly deployed but has the potential to be an even more efficient process. The models of CO2 capture installations were built in Aspen software. The two processes used in the analyses were primarily compared with respect to the energy intensity of each method. The results of the analysis show that the use of membranes allows for a significant decrease in the energy intensity of the capture process compared with the absorption process. However, the purity of the separated CO2 significantly depends on the type and surface of the membrane and on the process parameters. Nevertheless, it is clear that the development of membrane techniques will enable the most competitive CO2 capture solutions, in terms of effectiveness and cost, compared with other methods. (C) 2012 Elsevier Ltd. All rights reserved.