Efficiency of Wind Farmbalancing in the Southern Banat Region Using Integrated Battery Storage of the Prescribed Capacity

The regulatory framework for renewable energy sources integration into power system of Serbia requires the provision of balancing capacities in accordance with the approved installed power by the transmission system operator. Investors typically meet this requirement when developing wind farms projects by planning and constructing battery storage systems integrated with the power plant. However, forecasting errors in wind farm production often exceed the available power capacity of the battery storage system. Moreover, these errors can persistently exhibit either positive or negative values over an extended period, creating a critical condition in terms of the storage energy capacity. In this context, the key question is to what extent such planned balancing capacities can effectively meet the balancing needs of wind farms. This paper analyzes four existing wind farms in the South Banat region, for which historical data on forecasted and observed day-ahead production are available. The aim of the study is to assess the feasibility of self-balancing (covering the imbalance caused by the given power plant in the power system) for these wind farms through the integration of battery systems, in accordance with the current regulatory framework. Since these wind farms employ different forecasting models, quantitative indicators of imbalance reduction will be determined for each one, compared to the current state without a storage system. Additionally, an economic analysis will be carried out to evaluate the potential cost savings if these wind farms take on balancing responsibility. Finally, a theoretical model will be presented to evaluate the impact of wind farm balancing on battery system degradation rate over one year of operation and to estimate its lifespan. The results obtained from the analysis of real wind farms offer a dual benefit. From the investor’s perspective, the established indicators provide a basis for techno-economic analysis in the development of new wind farm projects that are subjected to balancing responsibility. On the other hand, for the transmission system operator, the results offer insights into the effectiveness of the current regulation framework in terms of reducing total balancing energy, average imbalance percentage error, and the maximum imbalance generated by the wind farms.