Sizing, installation and comparison with simulation of a 5kW hybrid photovoltaic system: a case study amid regulatory and economic shifts

In recent years, Romania has witnessed a significant acceleration in the adoption of photovoltaic systems, with the number of prosumers tripling in the past two years. National programs have actively supported the integration of renewable energy sources, promoting on-grid photovoltaic systems with installed capacities ranging from 3 kW to 400 kW. This trend is further amplified by the sharp increase in electricity prices, which have doubled starting July 1st, 2025, reinforcing the economic attractiveness of self-consumption and energy independence. This paper presents a real-world case study of a residential prosumer located in Northern Dobrogea, Romania. The focus is on a 5 kW photovoltaic system paired with a 5 kWh battery storage unit, designed to optimize daytime energy consumption and reduce dependency on the public grid. The analysis includes updated cost-benefit evaluations under current energy pricing conditions, highlighting the return on investment and operational efficiency of small-scale hybrid systems