Economic and Technical Analysis of Power to Gas Factory Taking Karamay as an Example

Power to gas (PTG) refers to the technology of converting power into energy-storage gas, which can absorb excess power when there is excess power and release energy-storage gas when needed. Based on the carbon dioxide (CO2) emission of Karamay City in Northwest China, this study designed a process flow of the CO2 absorption process, and the hydrogen and CO2 methanation process, in PTG technology. The results show that the efficiency of the CO2 absorption process was 91.5%, and the methanation efficiency was 77.5%. The heat recovery module was set during the process, and the total heat recovered was 17.85 MW. The cost of producing synthetic natural gas (SNG) in the PTG factory was 1782 USD/ton. In terms of cost, the cost of hydrogen production from electrolyzed water accounted for the largest proportion. In terms of product profit, the sale of pure oxygen was the largest part of the profit. At present, the carbon emission reduction index profit brought by SNG production accounted for a small proportion. In the future, with technological progress, industrial upgrading and the improvement in the carbon trading market, PTG technology is expected to become one of the ways to achieve carbon-emission-reduction targets.