Economic Assessment of Grid-Connected Residential Rooftop Photovoltaics with Battery Energy Storage System under Various Electricity Tariffs: A Case Study in Romania

Solar energy has the highest potential among renewable energy sources to gradually replace fossil fuels in electricity generation, paving the road for a cleaner and sustainable energy future. Over the last few years, it has been noticed an increased deployment of grid-connected residential rooftop photovoltaic systems, especially due to their significant cost reduction. A valuable solution for solving the problem of temporal mismatch between the electricity generated by the photovoltaic system and electricity demand is the energy storage system. This paper aims to investigate the feasibility of gridconnected residential rooftop photovoltaics combined with battery energy storage system for a household in Romania taking into account different electricity tariffs. The results pointed out how the system’s profitability is affected by the time of use electricity tariffs and the flat tariffs applied on Romanian residential customers that do not take into consideration the time of use.