On the suitability of a battery energy storage use in a wind farm

This study analyses the coupling between a wind farm and a Battery Energy Storage (BES) from an economic point of view. The focus is set on the use of the storage to mitigate the so-called “merit order effect”, which essentially is the lowering of the energy market clearing price due to the substantial share of Renewable Energy Sources (RES) dispatched on it. The lowering of the prices translates in a lowering of the profits, such that a further RES development becomes un-economical. The Electric Energy Storage (EES) technologies are seen as a key factor to allow the RES integration into the electric systems, since they are suitable to solve the many technical issues which this process arose. Therefore, it is interesting to investigate if the EES could fulfil the same role for the economic issues posed by the RES development. As a matter of fact, the EES can be used to maximise the economic profit of a RES plant shifting its production towards more profitable moments. In this paper, the economic viability of such practice is analysed, referring to the case of three Italian wind farms. The storage operation is simulated and two different BES technology (NaS and Li-ion) are compared. Both technologies show a good profit increment potential. Despite this, the actual economic benefits brought by the storage are lower than those needed to repay the battery itself. This means that this application cannot be used to counterbalance the profit loss dictated by “merit order effect” in the Italian scenario. Therefore, the study highlights the necessity to resort to alternative solutions to make a further RES development possible also from the economic point of view.