Study of interest for integrating wind energy with a power-to-methane system based on the Molten Carbonate Electrolyzer

摘要

Power-to-methane is an attractive technology to be explored for massively storing electrical energy in the form of chemical energy. This work aimed to investigate the feasibility of integrating wind energy into a power-to-gas system based on a Molten Carbonate Electrolyzer (MCEC) from an economical and technical perspective. Two scenarios were analyzed. In the first scenario, a different number of modules of 1 MW each were operated at nominal power supplied by wind resources with grid support when needed. After that, the techno-economic study for selecting the best modular configuration system for coupling with Variable Renewable Energy Source (VRES) revealed that installing more than two modules is technically infeasible and that 1 module is more economical, with a final methane price of 13.032 euro/kg compared to 14.074 euro/kg for two modules. In the second one, the system of 1 module was fully coupled with the wind resource to investigate the dynamic operation of the power-to-gas system. It was found that the methane gases obtained have a high CO2 content at a power supply below the nominal one, which does not allow their injection into the natural gas grid. Therefore, a purification process would be necessary either after or before methanation to remove excess CO2. This study highlights the importance of exploring a modular system with a control strategy to control the input renewable source with the output target of the system.