This paper describes one approach to find two optimum energy storages (ESs) to build a hybrid system which is part of a virtual power plant. Here it means the combination of the hybrid energy storage system and wind power plant (WPP). The
discussed approach is applied in a case study on the power market in western Denmark. The optimum ESs are selected based on the highest net present value (NPV) out of many different combinations of ESs in terms of power rating and technologies. Due to its many possible combinations a simulation model has been built which uses historical market data and also the latest available price data for ESs.