Performances and economic analysis of small photovoltaic–electricity energy storage system for residential applications

Currently, the need to address the issues arising from the uncontrolled growth of photovoltaic installations, such as intermittence and unpredictability of the generation that cause loss of balance in the grid, becomes unavoidable. Promising solutions for minimizing grid injection are the combination of photovoltaic generation with electricity energy storage and load management, the latter commonly known as Demand Side Management. These strategies together with incentives for self-consumption or energy independence from the network will allow facilitating the integration of the always-increasing generation of renewable energy. In Europe, the usage of residential energy grid-interactive energy storage systems for buffering of surplus photovoltaic generation is becoming a field of growing interest and market activity, as a consequence of the less attractive photovoltaic feed-in-tariffs in the near future and incentives to promote self-consumption. This study aims to evaluate the energy exchange with the grid and the rate of self-consumption of combined photovoltaic–electricity energy storage systems dedicated to residential and small commercial prosumers. More specifically, several combinations of sizes of photovoltaic plant, annual household consumptions and electricity energy storage capacity were evaluated. This analysis aims to identify which arrangement among photovoltaic power, electricity consumption and battery capacity allows reaching the highest ratio of self-sufficiency and consequently minimizing the energy exchanged with the grid. Moreover, the financial analysis of the photovoltaic–electricity energy storage system has been performed for verifying the economic viability of the photovoltaic–electricity energy storage systems under the Italian current market and economic circumstances.