Is switching to solar energy a feasible investment? A techno-economic analysis of domestic consumers in Spain

Grid-connected photovoltaic (PV) facilities are more attractive than ever due to the electricity price surges and the reduction of solar energy generation costs. This paper develops a solving procedure including a simulation model to analyze the techno-economic performance of PV-battery facilities, taking into account the latest Spanish regulatory framework. The procedure finds the best facilities for multiple objectives, maximum profit-ability and maximum self-sufficiency, in different locations, load profiles and economic scenarios. The results indicate that PV modules are profitable without subsidies, with installations between 1 and 6 kWp. Meanwhile, batteries are only convenient when seeking maximum independence from the grid, with capacities up to 9 kWh. The findings suggest that the economic feasibility of facilities is influenced by the location and compensation rate surplus electricity, while the facility is mainly determined by the load profile. A sensitivity analysis shows that a variation in grid tariffs and technology prices has a limited impact on the facility's size but modifies the system's profitability. Finally, an analysis of the latest unprecedented grid price surges indicates that self-consumption facilities help become a more resilient society against unexpected events. Therefore, policymakers should keep promoting the adoption of these technologies and keep the current advantageous regulations.