Optimization of a grid connected residential battery storage system in Sweden : Home Energy Management System Approach

Abstract: The market for energy production has experienced relevant changes to reach more sustainable characteristics, during the last two decades. In this context, residential photovoltaic (PV) system has gained popularity as a practical and profitable alternative to complement the electric supply from the grid. In the same line, the seasonal and variable nature of PV supply generates an interest in BESS-battery energy storage systems.The aim with this thesis is to investigate HEMS-home energy management system for a residential electricity production using PV and storage in Sweden. HEMS allows residential customer and producer to sell or buy energy to minimize the final electricity bill. The capacityof BESS and the scheduling are optimized by using a proposed algorithm. Results gained indicate that factors such as household electricity demand and allocation during the day, electricity price, and tariff scheme are the critical variables to consider in the design of the BESS system. Optimal battery capacities obtained are within the range of available battery market stock-sizes. However, several of the standard battery capacities of the leading manufacturers are oversized for this case. For Swedish context, a BESS installation cost below 270 €/kWh generates saving on the annual electricity bill of having BESS in comparison with not using BESS. In addition, the daily charge of EV, electric vehicle, was studied to see if a higher demand for household electricity could generate an optimal capacity and higher savings.