Day-Ahead Scheduling of a Gravity Energy Storage System Considering the Uncertainty

Abstract

To overcome the topographic limitations of pumped hydro storage (PHS) system, novel gravity energy storage (GES) technologies are developing. In this paper, a pioneering work on the modeling and scheduling of a GES system is conducted. The GES system stores and releases energy by lifting and lowering concrete bricks. Since the working principle of the GES system is similar to that of a PHS plant, a double-tower based model of the GES system is established. In addition, a day-ahead scheduling model of the GES system is proposed to test the operation of such system. Specifically, the uncertainty of market price is considered with a data-driven distributionally robust optimization method. Some linearization and reformulation techniques are presented to transform the problem into a mixed integer linear programming (MILP) problem which can be solved easily. Numerical experiments indicate that the proposed model can effectively characterize the operation of the GES system. Concrete bricks are lifted up during low-price period and descend under gravity during high-price period to gain benefits. Additionally, the round trip efficiency considerably influences the total profits.