The energy sector is a market that is in the state of transformation. In recent years there has been an increasing trend in Europe towards the use of renewable energy sources and thus regarding the decarbonization of the sector. In the future the increasingly noticeable climate change and thus the shift in societal priorities will significantly intensify this process of change in favor of regenerative production. This transformation of the energy system brings challenges due to the fact that generation from wind power and photovoltaics is difficult to predict. A central issue is the storage of renewable energies and thus their use at different times. One promising approach is sector coupling. The basis for the development of strategies and solutions in this area are hybrid simulation tools that consider the energy system as a whole and include the energy sources electricity, heat and gas. In the present scientific work, the hybrid simulation tool HyFlow is developed in the field of electricity load flow calculation and applied to a concrete task. The influence of the sector coupling on the electricity grid relief in areas with high projected PV feed-in is investigated. The aim is to increase PV integration in the investigated grid area starting from an already approved capacity without additional line extension. At the beginning, a comprehensive literature research on the Power to Gas process and the individual process steps is carried out. The state of the art and the future development of the technology as well as the costs will be considered. The HyFlow tool will be further developed. Afterwards, the case study is examined on the basis of four scenarios, which partly also include the biogas plants existing in the region to be analyzed. Furthermore, the results will be technically and economically evaluated and compared. The simulation results for scenarios 1, 3 and 4 show that the sector coupling element Power to Gas has a grid-relieving effect and thus PV integration in the grid area can be significantly increased. There are limitations due to the position of the electrolysis in the grid area. In scenario 2 is therefore no increase in PV integration achieved. The hydrogen and methane production costs were calculated with a time horizon of five years and are in the range of 12 to 14 cents/kWhH2 and 16 to 24 cents/kWhCH4. Furthermore, it can be seen that energy costs account for a large share of the gas production costs.