Optimal configuration of shared energy storage system in microgrid cluster: Economic analysis and planning for hybrid self-built and leased modes

Abstract

Applying shared energy storage within a microgrid cluster offers innovative insights for enhancing energy management efficiency. This investigation tackles the financial constraint investors face with a limited budget for shared energy storage configuration, conducting a thorough economic analysis of a hybrid model that integrates self-built and leased energy storage modes. It also underscores the significance of energy sharing among microgrids. Departing from conventional single-mode planning approaches, this study explores the synergistic benefits of the self-built and leased modes, focusing on their distinct advantages regarding upfront investment costs and lifecycle returns. Specifically, a step-cost decrement model is established, accurately depicting the economies of scale characteristics of the self-built energy storage mode. Based on this, a shared energy storage system model that integrates self-built and leased modes is proposed. Subsequently, a robust optimization model is formulated for configuring shared energy storage within a microgrid cluster, incorporating considerations of inter-microgrid energy sharing, seasonal variations in net load curves, and associated volatility. The column-and-constraint generation algorithm and strong duality theory are employed to solve the constructed model in two stages. Six distinct scenarios are designed to validate the effectiveness of the method and model proposed in this paper while also assessing the impact of investment budget and uncertain parameters on shared energy storage planning for a microgrid cluster. The results show that the proposed shared energy storage planning model significantly improves the economics of energy storage investment and system operation, even under budgetary constraints. It also reduces the dependency of a microgrid cluster on both shared energy storage and distribution grid when compared to models relying solely on self-built or leased mode. This study can guide investors and microgrid cluster operators in planning and implementing shared energy storage.