The effect of electricity price and consumption level on the Power-to-Energy Ratio for the sizing of hybrid PV-BSS: Techno-economic Analysis of Mediterranean prosumers

Due to the remarkable growth of Photovoltaic (PV) systems in recent years, which have already reached Grid Parity in many countries, the focus related to their supporting schemes has been shifted to mechanisms promoting self-consumption (for both residential and non-residential prosumers). In addition, their integration with Battery Storage Systems (BSSs) is seen as a solution to alleviate technical counter-effects and benefit the grid with more self-sufficient and sustainable prosumer sites. Considering the continuous increase in electricity prices in recent years, this work aims to avail as a sizing guideline for residential PV-BSS and as an evaluation of their techno-economic feasibility under relevant supporting schemes, focusing on two of the most effective parameters and by considering current technology prices. The results showed that for the case of the three Mediterranean countries considered as case studies, the supporting scheme under which the hybrid PV-BSS operates impacts significantly its sizing towards maximum economic benefits. In addition, they demonstrated a similarity between the optimal Power-to Energy Ratio (PER) sizing index of each country for both cases addressed (i.e. electricity price and consumption level) for the Pure Self-Consumption scenario, while for the Net-Billing scenario differences between the three countries and higher optimal PER values were noted, due to Net-Billing favoring higher PV system ratings. Finally, the optimal PER generally reduces as the electricity price and/or the consumption level increases, recommending avoiding unnecessary investments in excess system capacities.