Due to the increasing share of renewable energies in the power sector, the need for energy storage and flexible performance is rising. This study provides an in-depth investigation of the flexibility of a Power-to-Gas plant for the production of synthetic natural gas. Model-based analysis is conducted for the individual technologies PEM electrolysis, MEA absorption and fixed-bed methanation as well as for the continuously operated process. This study reveals that the Power-to-Gas plant offers a capacity flexibility of 87-125 %, corresponding to 4.79-6.88 MW electrical input power.