Utilizing local energy storage for congestion management and investment deferral in distribution networks

Small wind and solar units are becoming a common view within the urban, suburban and rural landscapes. Intermittent renewable energy sources (iRES) and electric vehicles (EVs) are integrating into local grids at increasing rates. The number of congestion events is therefore increasing and hence investment in grid infrastructure is required. If congestion issues take place during a limited number of hours per year, it is valid to question whether incremental expansions are efficient investments. It might be reasonable for the DSO to defer these investments by installing its own local energy storage. The objective of our analysis is to determine the optimal investment in local energy storage and incremental expansions from the perspective of the distribution system operator (DSO). This paper delivers a modeling scheme to determine the optimal mix of incremental grid expansions and installed local energy storage. In addition, the optimal placing and sizing of the storage elements within the network topology are calculated. Additionally, the case of using mobile energy storage units is considered, as well as the optimal mobility of these units within the network topology. Finally, a sensitivity analysis is carried out for prominent factors of the model.