## 1 Introduction
As mentioned above, the integration of a storage system gives more flexibility to the EMS and thus can allow the economic optimization of microgrids or hybrid energy systems. In [20], energy cost minimization was carried out with respect to the design of an EMS for a  
Figure 1: DC branch topology of a grid connected to an EVCS associated with a BESS in parallel. The orange arrows indicate in which direction the power can flow in each converter of the system. It can be seen that no power is injected into the grid and that the electric vehicles are used only for charging. hybrid storage system operating in a microgrid with PV installation. The cited study shows how important it is for an EMS to consider a technoeconomic model of the microgrid in order to reduce microgrid costs. In addition, the authors show that charging the BESS with the entire surplus PV power is not economically profitable, as the battery degrades further, increasing the overall cost. In [21], the importance of optimally managing BESSs in order to lengthen their lifetimes and thus decrease their costs is also highlighted. In [22], an EVCS with PV and BESSs is analyzed. The aim was to economically optimize the BESSs by using a new rule-based (RB) strategy. The cited study considers a degradation cost model of the BESSs and the volatile price of the grid in the minimization of the overall EVCS cost. The authors conclude that implementing a proper EMS reduces the cost of the system and that the benefit of BESSs is greater when the electricity price has a large variance. In [23], a BESS and a hydrogen station were integrated into an EVCS, and different possible strategies were compared. The authors concluded that a 31.53% cost reduction could be achieved by optimizing this system. Numerous articles have studied the optimal power flow of BESSs for cost reduction [3; 4; 5; 6; 7; 8; 9; 14; 15; 16; 17; 18; 19; 20; 21; 22], but few studies have been found in which BESSs are not connected to a renewable energy source [6; 7]. Moreover, many studies do not consider the degradation cost of BESSs [3; 4; 5; 6; 7; 12], while other manuscripts highlight the importance of this cost when carrying out a cost optimization of a system containing a BESS [20; 21; 22]. Finally, in this context, the authors of this article have not found any methodology for developing an EMS that can easily adapt to different EV charging scenarios and electricity price fluctuations. In this manuscript, a study on the development of technoeconomically optimized EMSs for EVCSs for a real-life case of an urban bus fleet associated with BESSs (as in Figure 1) is presented. This research focuses on an electric bus fleet charging station but can be adapted to any kind of EV fleet charging station that has a fixed available charging time for each electric vehicle. Regarding the literature, an optimized EMS design for variable loads and grid electricity prices has not been found. Moreover, grid electricity price-sensible adaptive EMSs have not been found either. It is also noticeable that the degradation cost of BESSs is not taken into account in many studies, while in others it is remarked to be an important factor when trying to optimize the utility of a BESS. Considering the existing knowledge gaps identified in the scientific literature analysis, the main contributions of the study are as follows:  
* The comparison between a real charging strategy EMS and optimized ones. * The consideration of the BESS degradation cost in an optimized EMS. * The design and comparison of different RB and FL EMSs optimized with a GA, in realistic varying study cases. * The design of an adaptive EMS depending on the forecasted electricity price. * The use of an optimized FL EMS in a BESS integrated into an EVCS. In the next section, the abovementioned methodology is described. Then, in the following section, this methodology is applied to a specific case study and the obtained results are analyzed and discussed. The last section gives the main conclusions of the research study.