Preliminary analysis of long-term storage requirement in enabling high renewable energy penetration: A case of East Asia

Abstract

Integrating a high penetration of renewable energy for developing sustainable and low-carbon electric energy system is becoming a common trend around the world. Many studies have evaluated the energy storage requirement for accommodating variable renewable energy (VRE). However, in the situation of high renewable penetration, there will be a huge potential requirement of long-term energy storage for addressing the seasonal energy imbalance between VRE and load demand. Thus, a key element of evaluating the storage demand in enabling high VRE penetration is identifying the timescales of storage needed and the economic combination of long-term and short-term energy storages. This is neglected in existing researches. In this study, we quantitatively analyse the role of long-term seasonal storage in enabling high VRE penetration. A generation expansion planning model is formulated to optimise the least-cost generation portfolio with a renewable penetration target. Based on the proposed model, an empirical analysis for East Asia in 2050 is performed. The results indicate that (1) long-term storage contributes to addressing the long-term energy imbalance issue, (2) the optimal duration time of long-term storage is around 720 h (a month), and (3) the long-term storage becomes economical when the renewable penetration is above 70% (54.2% VRE penetration).