In this project, we will study the energy storage with liquid methane linked to a CO2 network that provides heat for district heating. The generated methane enters an hybrid cycle composed of a solid oxide fuel cell and turbines to generate electricity. The goal of this project is to determine the global eciency of the system but also to optimize it with the help of softwares like Belsim Vali and Osmose. In addition, we determine its cost. At the end, we compare the global system with an equivalent one without the CO2 network integration.