Optimisation of Battery Energy Storage Systems Capacity for Purpose to Reduce Energy Cost

High energy prices are a pressing problem for both developed and developing societies. They deepen social inequalities by causing energy poverty. Therefore, in this article, we propose a method for optimizing the capacity of Battery Energy Storage Systems, which operate in residential billed by a time-of-use tariff. It can reduce the cost of electricity and counteract energy poverty. We propose a control algorithm that minimizes energy costs and an optimization algorithm based on an objective function reflecting profitability. Simulations carried out on half a year of data showed the possibility of achieving savings of 23% for a tariff divided into two zones (on-peak and off-peak) and 21% for a three-zone tariff. An appropriately selected energy storage facility would pay off in 4.5 years and 5 years for subsequent scenarios, compared to 4.7 years and 5.1 years for the reference selection.