Integrated Gasification Combined Cycle (IGCC) is believed to be one of the most promising technologies to offer electricity and other de-carbon fuels with carbon capture requirement at a relatively low cost. With the process of carbon dioxide capture, it can also actually meet strict regulations for other pollutants emission. However, the performances can vary depending on what kinds of technologies or processes are used. This paper has developed a model and calculated by using Engineering Equation Solver (EES) program to determine and compare different available technologies and processes. There are four main components in the model: Gasification Island; Gas Cleanup Island; Carbon Dioxide Capture Island and Power Island. Among them, the different options of Gasification Island; and Carbon Dioxide Capture Island are expected to be the most effective factors to influence the performance of the plant. Therefore, different gasification processes are examined in this paper, including Shell, GE (Texaco) and Lurgi. The carbon dioxide capture processes are based on SELEXOL, a physical absorption process, because of the high partial pressure of carbon dioxide in the syngas. A process called "double-absorption" is used for capturing sulfur compounds and carbon dioxide. This paper calculated and compared the net outputs, efficiency penalties for CO2 capture part, and net plant efficiencies for different technologies and processes by using EES program. This model tries to treat the IGCC with carbon dioxide capture part as a whole thermal system, instead of just looking at the capture system alone. Different gasification technologies mentioned above will result in various paths and efficiencies of using steam and waste energy in the system. It will make reasonable use of various waste energies and steams for both mechanical and chemical processes to improve the performance of the plant, and incorporate a CO2 capture system into the design concept of the power plant.