Three oxy-fuel IGCC power plants using different air separation technologies and carbon compression and compression (CCP) are developed to near-zero CO2 emission power systems. If capturing CO2 is treated as a byproduct, Design 2 by an integration of IGCC and natural gas-fueled integrated intermittent chemical looping air separation (NG-IICLAS) may have a promising economic potential. Through the techno-economic assessment of Design 2, its internal rate of return (IRR) by 17.99% is higher than a chemical looping combustion (CLC)-based IGCC power plant connecting carbon capture and storage (CCS) with IRR = 12.5%, its levelized cost of electricity (LCOE) by 69.92 (sic)/MWh is close to the LCOE of supercritical coal-fired power plant in 2015, and its CO2 production cost by 12.35 (sic)/ton is also close to the market price for CO2 in 2011. It is successfully verified that the investing in Design 2 is superior to other designs.