Fig. 4
From: Scaling: managing a large number of distributed battery energy storage systems
Results of performing the optimization once for one day: The results from performing a single optimization step of one day are the basis for the proposed framework for managing the BESS. The results are illustrated for the global optimization as the baseline, heuristic 1 without any fchar/dischar modeled and heuristic 4 with a concave piece-wise linear model. The optimal solution clearly exploits the VPP SoC more than the heuristic (zero violations, since all BESS can follow the control). Without any function modeled, a substantial part of the charging and discharging control cannot be implemented by the individual BESS. As shown in the figure on the right, up to 90 % of a control can not be met. This hinders using the full range of VPP capabilities. Considering a concave piece-wise linear model reduces the violations and also allows to exploit the VPP better. But note that next only the first control decisions are implemented and therefore, the later violations are not that important