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• Power-to-gas has a strong potential in the transition to a renewable network. • Advanced CO 2 capture process allows to reduce the energy consumption. • Heat integration improves the competitiveness of the global Power-to-Gas chain. • Attractiveness of Power-to-gas is economically sensitive to electricity cost. The Power-to-Gas strategy has become a mainstream topic for decarbonization and development of renewables and flexibility in energy systems. One of the key arguments for decarbonizing the gas network is to take advantage of existing network infrastructure, gradually transitioning to lower fossil carbon sources of methane from Power-to-Gas. This work proposes the techno-economic investigation of an integrated system considering an advanced CO 2 capture process, in terms of solvent and process configuration, to treat about 10% of a cement plant's flue gas and convert the captured CO 2 into synthetic natural gas using renewable hydrogen generated from a large-scale wind powered electrolyzer. An optimized heat recovery system is proposed, drastically decreasing the external hot utility demand of the CO 2 capture unit. In addition, it leads to the production of complementary electricity (about 1.06 MW), reducing thus also the electrical demand of the integrated process. The synthetic natural gas produced has a composition (CH 4 92.9 mol.%, CO 2 3.7 mol.%, and H 2 3.4 mol.%) and a Wobbe index (46.72 MJ/m3), corresponding to specification for gas grid injection at 50 bar in Germany. With an overall system efficiency of 72.6%, the process produces 0.40 ton synthetic natural gas per ton of captured CO 2. The cost of the synthetic natural gas produced is higher when compared to the present natural gas market price, but cost reductions and possible commercial use of coproducts like oxygen, represent a likely alternative. Costs are mainly driven by high capital investments (the electrolyzer), and the price of renewable electricity, which is expected to decrease in the coming years. [ABSTRACT FROM AUTHOR]

The carbon capture, utilisation and storage (CCUS) process chain is subject to increasing interest, and its overwhelming implementation on the industrial scale appears to be one of the main ways to reduce CO 2 emissions. In this context, the optimisation of a CO 2 purification process for oxy-combustion cement plant flue gases is proposed. This optimisation is based on a multidimensional study on the energy, exergy, economy, and environmental impacts of the process. The results of the optimisations carried out show that it is more favourable to increase the CO 2 recovery above 90%, from an energy, exergy and economic point of view. The analysis of the evolution of the capture cost as a function of the CO 2 recovery shows that for a given carbon tax, there is a minimum for the total cost which includes the sum of the carbon tax contributions for the uncaptured CO 2 and the capture cost. As the unit uses only electrical energy, the cost and the electricity generation will directly impact the capture cost as well as the overall balance in terms of CO 2 avoided. As the electricity price increases from 50 to 250 €/MWh, the CO 2 capture cost increases by almost 250%. An analysis of the parameter uncertainties allows to observe their impacts on the results, and to define a standard deviation from the optimised points and show the robustness of these. Considering the technical parametric uncertainties, the standard deviation on the electrical consumption (3.65 kWh/t CO2), CO 2 recovery (0.09%) and exergy efficiency (0.92%) is limited. • Study of hybrid CO 2 capture system combining cryogenic and membrane technologies. • 4E analyses considering recovery, energy consumption, exergy yield and capture cost. • Maximum exergy efficiency for the cases where the CO 2 recovery is above 90%. • High sensitivity of the electricity price on the CO 2 capture cost. • Uncertainty quantification of modelling assumptions and impact on 4E analyses. [ABSTRACT FROM AUTHOR]