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Chemical looping air separation (CLAS) is as a very promising technology for the production of pure oxygen through the cyclic reduction and oxidation of a solid material at elevated temperatures. This study focused on the environmental potential of electricity and CO2 production through oxyfuel combustion of lignite. First, an attributional LCA assessed the operations which mainly contribute to the total environmental impacts for two different scenarios at the limits of the operating window (100% and 25% active material). Then, this study analysed the potential of electricity and pure CO2 production through CLAS when compared with conventional power production technologies from renewable and fossil alternatives, including electricity from hydro power, electricity from wind power, electricity from nuclear, electricity from photovoltaic, electricity from biogas, electricity from biomass, electricity from waste, electricity from hard coal and electricity from natural gas. Overall the results, analysed per MJ of electricity produced, showed how the chemical looping technology consistently performs better than the other technologies, especially thanks to the recovery of the pure CO2 stream used for industrial purposes, which avoids the production of CO2 from fossil resources. However, the cleaning of the flue gas of the oxyfuel combusted lignite strongly limits the toxicities indicators.

Chemical looping can be used in a variety of forms to enable the separation of carbon dioxide emissions in a pure form suitable for sequestration or re-use, principally from combustion, reforming or the production of hydrogen. Chemical looping processes are generally second generation or novel technologies that are currently at lower levels of technological readiness than other options such as post combustion capture using amine solvents. A number are at the point where the next stage would be a demonstration plant. These processes use either a metal oxide or calcium carbonate as chemical intermediates since they are able to undergo reversible reactions with oxygen or carbon dioxide respectively. All chemical looping processes for carbon capture are high temperature processes, enabling them to be more energy efficient than low temperature processes such as amine scrubbing. With the exception of calcium looping for post-combustion capture, the capture of carbon dioxide emissions is also an inherent part of the process, rather than an additional step, downstream of the main process.