Comparing utility and residential battery storage for increasing flexibility of power systems

Evolution of the present-day grid from fossil fuel-based to green, sustainable generation is picking up pace due to environmental concerns and dwindling fossil fuel reserves. The era where renewable energy resources (RES) begin to significantly penetrate the power system has begun. In the future, this trend will be substantial, and RES contribution toward energy production will be significant, here this scenario is referred as the future grid (FG). The intermittent and stochastic nature of RES will introduce many new vulnerabilities in future power systems. This paper explores the merits and demerits of introducing photovoltaic (PV) battery system in FG scenario and discuss how utility and household storage can rectify some vulnerabilities. Here, flexibility in power systems is achieved by utilising the storage in contrast to demand response (DR) suggested in many works. Modified unit commitment (UC) model is used to study the effect of utility storage behaviours, and a bi-level optimisation approach is used to model household storage capability. The case study explores the effect of storage on Australian National Electricity Market (NEM) for the year 2020. For comparison and analysis, three scenarios are compared. Results demonstrate that storage can be used to achieve flexibility in FGs. Also, there exist a trade off for programs supporting large scale and distributed household storage. There is also some condition under which the behaviour and effect of both cases become very similar.