## 2 Background
### Socio-Economic Impacts of Power-to-Gas  
Several studies have analyzed PtG technology from economic, technical, and/or environmental perspectives [53] because it is considered that PtG may provide renewable substitutes for fossil fuels and to solve the problem of grid balancing via long-term storage capacity [19]. Because synthetic methane is a promising option to replace natural gas, PtG would contribute to decarbonized energy systems, particularly those that cannot be decarbonized only by electricity, such as the heating [54] and transport sectors [55]. Thus, the positive effects of PtG are clear. However, the socio-economic impacts related to these facilities is still under study. From an economic perspective, PtG systems are not currently profitable mainly due to a lack of adequate regulation [13]. Different studies show that PtG is generally feasible from a technical perspective at both large (centralized) and small (decentralized) scales [10; 19]. The economic impact of PtG systems is closely linked to the technological solutions of the projects [30; 56; 57; 58]. Previous analysis of the economics of PtG have included overall costs, the storage demand, PtG capacities, and other climate issues according to the expected RES sharing. [PERSON] et al. (2015) found that PtG capital expenditures (CAPEX) do not significantly affect the optimal system in terms of the installed capacity of PtG [20]. [PERSON] et al. (2017) demonstrate that if the product is only hydrogen, these systems cannot compete with conventional gas in the market [57]. [PERSON] et al. (2019) discuss the economic feasibility of an integrated system in which PtG aids cogeneration for non-residential buildings. Therefore, the economic potential of PtG is not yet obvious [59]. The spatial distribution of PtG plants is also relevant to achieve a positive economic performance [10]. The relevance of the spatial dimension is highlighted when a high share of renewable electricity has to be transported to distant load centers [10]. [PERSON] et al. (2016) define suitable locations in Europe for renewable hydrogen storage systems [60]. Furthermore, policymakers must be taken into account when making decisions about the siting of RES projects because their negative impacts are generally noted by communities adjacent to the plants [61]. For similarities, we can refer to PV development, which has been a disruptive technology during the past decade. The socio-technical analysis of PV development includes actors, institutional structures, technologies, and resources [62]. In general, studies focused on the socio-economic impacts of renewables widely analyzed their impact on employment [63; 64]. The socio-economic research on the energy transition toward decarbonized power systems is mainly based on the impacts resulting from RES deployment [65]. With regard more specifically to the impacts of PtG, [PERSON] et al. (2018) highlight socio-ecological impacts based on the benefits of combining PtG plants and battery storage in existing local infrastructure [53]. [PERSON] et al. (2017) analyze the costs of PtG, its feasibility, and the decrease in the environmental impacts generated by these technologies through a life cycle assessment [57]. The analysis of relevant stakeholders in a territory where PtG technology could be installed is also a research topic [53]. PtG acceptance has been analyzed using factors such as the quality of life, citizen participation, and socio-ecological impacts [53]. From the literature review, we can observe that most of the studies carried out to date have focused mainly on technological, environmental, and economic impacts of this technology. In summary, the main social impacts of PtG technology can be linked to supply security, climate change, or health. Furthermore, these impacts are related to the generation and distribution of RES and the storage of hydrogen. However, to the best of our knowledge, the direct socio-economic impacts of PtG are still underexplored.