Online Control and Near-Optimal Algorithm for Distributed Energy Storage Sharing in Smart Grid

This paper proposes an online control approach for real-time energy management of distributed energy storage (ES) sharing. A new ES sharing scenario is considered, in which the capacities of physical ESs (PESs) are reallocated to users, so that each user manages its own virtual ES (VES) without knowing detailed operations of the PESs. To optimize the ES sharing system in real time, an online algorithm is developed based on Lyapunov optimization framework. The advantage of the online algorithm is that it makes decisions only based on the realization of current system states, without having to predict future uncertain system states such as electricity price, user load, and renewable generation. In performance analysis, it is proven that the online solution is feasible and has a provable performance guarantee. Based on the analysis, an approach for optimal offline parameter selection is proposed to guarantee the online control performance. For practical need of privacy protection, a distributed implementation of the online control is proposed via alternating direction method of multipliers (ADMM). In the distributed implementation, users are allowed to manage their VESs locally without sending their private data to anyone. In simulation, actual real-time data of electricity price, home load, and home renewable generation is used. Results show that the proposed distributed online control approach can provide a near-optimal solution, compared with other benchmarks.