Simplified Utilization of PV Power Output Forecast for Reducing Imbalance Risk of Electricity Retailer using Battery Energy Storage System

Abstract

For improving the profitability of electricity retailers, it is important to reduce the penalty cost for the imbalance between a day-ahead planned electricity demand and the actual electricity demand on the day. To reduce the imbalance, a Battery Energy Storage System (BESS) installed in customers of electricity retailer can be used, because BESS may not be used so frequently for primary purposes of installation. In consideration that the available BESS capacity is smaller than the imbalance, simply predicting whether the imbalance is positive or negative instead of the amount of imbalance can be useful for using BESS of such a limited capacity. The forecast error of Photovoltaic (PV) power output can be major reason of the imbalance when a certain amount of PV is included in power supply plan of retailer. Therefore, this study investigates the relation between the actual error of PV power output forecast and the change from a day-ahead forecasted value to the forecasted value of later initial time. Then, this study evaluates the usefulness of BESS operation based on the direction of change in forecasted value for reducing the imbalance.