Abstract
In this paper, energy storage sharing among a group of cooperative households with integrated renewable generations and controllable loads in a grid-connected microgrid is studied. In such a microgrid, a group of households, who cooperatively share an energy storage via a central coordinator, aims to minimize their long term time-averaged costs, by jointly taking into account the operational constraints of the shared energy storage, the stochastic solar energy generations, time-varying load requests and energy contribution to the shared energy storage from all households, as well as delay tolerance of their elastic loads. Exploiting delay tolerance of elastic loads, a joint storage management and load shifting system is present and a distributed online battery sharing control algorithm based on the Lyapunov theory is proposed. The proposed online control algorithm, which provides a suboptimal solution for the joint storage and load shifting problem based only on the current system state, coordinates the utilization of the shared battery among the households in a distributed manner, by jointly optimizing energy charging/discharging and load management for individual households while satisfying each household’s timevarying preference on energy use. Numerical simulation results show that, the proposed load shifting algorithm serves the load demands with a lower delay for each household at a similar average cost per kWh to that of a load shedding algorithm while facilitating a fairer utilization of the shared energy among households.