13 - Battery energy storage in micro-grids

Abstract

This chapter introduces the integration of battery energy storage systems (BESS) into the Micro-grid to improve the grid’s economic efficiency and sustainability. Firstly, basic concepts for Micro-grids and the recent developing trend of key energy storage technologies are introduced in detail. Then, along with two different time frames, this chapter presents two methodologies respectively for long-term BESS expansion planning in micro-grids considering battery degradation effects and short-term operational planning of BESS to cope with high-level renewable power generation. Specifically, (1) For the planning method, the uncertainties in distributed generation resources and load demand are modeled using scenario analysis. A detailed battery degradation model is taken into consideration. A two-layer planning model is formulated to optimally determine the allocation and operation scheduling of BESS. Then, a two-layer differential evolution algorithm is designed to solve the problem. Simulation studies are carried out to prove the efficiency of the proposed method. (2) For the operational planning method, on a day-ahead and intra-day dispatch basis, a two-stage optimal scheduling model is proposed. In the operation stage, the operational cost of batteries is calculated considering BESS degradation effects. The objective function captures the total cost of power exchange with the main grid, the operating cost of distributed generators (DGs), and the degradation cost of BESS, respectively. Moreover, the conditional value at risk criterion is applied to evaluate the risk induced by intermittent renewable power output and load demand variation. Simulation tests have demonstrated the effectiveness of the proposed method.