The role of underground salt caverns for large-scale energy storage: A review and prospects

Abstract

To achieve China's goal of carbon neutrality by 2030 and achieving a true carbon balance by 2060, it is imperative to implement large-scale energy storage (carbon sequestration) projects. In underground salt formations, the salt cavern constructed by the leaching method is large, stable, and airtight, an ideal space for large-scale energy storage. Currently, salt caverns have been widely used for natural gas, crude oil, hydrogen, compressed air, and other energy storages. With the demand for peak-shaving of renewable energy and the approach of carbon peaking and carbon neutrality goals, salt caverns are expected to play a more effective role in compressed air energy storage (CAES), large-scale hydrogen storage, and temporary carbon dioxide storage. Herein the innovation of this paper lies in conducting a comprehensive review of the history, current status, and future development trends of salt cavern energy storage (SCES) technology. Firstly, we provide an overview of natural gas and oil storage in various types of salt caverns worldwide and assess the future prospects for CAES and hydrogen storage. Secondly, we propose a novel model for carbon dioxide storage in salt caverns based on the carbon cycle to effectively address the spatiotemporal disparity between carbon capture and utilization. In the future plans, salt caverns will play a crucial role throughout the entire carbon cycle by facilitating carbon storage, compressed air storage, and hydrogen storage. Additionally, we introduce the concept of utilizing sediment space for large-scale energy storage purposes. Finally, we anticipate the future development of salt caverns for energy storage in China to focus on large-scale, integrated, and intelligent projects, emphasizing their significance in achieving enhanced efficiency and sustainability. Accordingly, this review promotes thorough knowledge of SCES, provides guidance on operating large-scale SCES projects, encourages energy engineers to focus more on SCES research, and provides an overview of advanced technology. This review also provides an important basis and reference for the development and expansion of the SCES industries.