Polygeneration system, typically involving chemicals/fuels and electricity co-production, is a promising technology for the sustainable development of energy and environment. In this study, a new polygeneration system based on coal and coke oven gas (COG) inputs for co-production of dimethyl ether (DME)/methanol and electricity is proposed. In the new system, an appropriate syngas for the synthesis of DME is from coal gasified gas (CGG) reforming of COG coupled with an oxygen-permeable membrane reactor, in which both COG and CGG reforming process and fuel combustion process are incorporated, which reduces exergy destruction in the whole reforming process. In order to obtain the best performance of CO2 reduction, energy saving and economic benefit, the key operation parameters of the proposed process are analyzed and optimized. The new system is compared with the process based on CH4/CO2 dry reforming, in terms of exergy efficiency, exergy cost and CO2 emissions. Through the new system, the exergy efficiency can be increased by 7.8%, the exergy cost can be reduced by 0.88 USD/GJ and the CO2 emission can be reduced by 0.023 kg/MJ. These results suggest that the polygeneration system from CGG and COG partial catalytic oxidation coupling with an oxygen-permeable membrane reactor (PL-PCO-OPMR) would be a more attractive way for highly efficient and clean use of CGG and COG. (C) 2015 Elsevier Ltd. All rights reserved.