利用浮力实现可扩展和可持续的能量存储

Abstract As the global shift to renewable energy accelerates, scalable and sustainable energy storage technologies are becoming increasingly essential. This study presents the Buoyancy Energy Storage System, a novel method that stores surplus energy by submerging buoyant objects in fluids and recovers it via controlled ascent, converting gravitational potential energy into electricity. Based on energy conservation principles and the ideal gas law, analytical relationships for energy storage in both variable-volume and fixed-volume buoyant bodies in liquid and gaseous environments are derived. In liquids, soft floaters exhibit energy capacity positively correlated with internal gas quantity and negatively correlated with descent depth, while rigid floaters store energy in direct proportion to volume and depth. In air, variable-volume floaters display nonlinear dependence on altitude and pressure, whereas fixed-volume systems are influenced by ambient air density and internal volume. These formulations offer a clear physical foundation for designing and scaling this technology. Preliminary economic analysis estimates the Levelized Cost of Storage at $1088–$2908/kWh when deployed at a depth of around 1000 m. These values are indicative and reflect early-stage assumptions, with intentionally conservative estimates to account for uncertainties in materials, marine deployment, and long-term maintenance. Despite limited short-term cost competitiveness, Buoyancy Energy Storage offers long-term potential as a modular, environmentally adaptive, and ultra-large-scale energy storage solution suitable for integrating massive-scale renewable energy into future grids. Notably, the system is conceptually evaluated for its feasibility in capturing and storing the vast kinetic and thermal energy associated with extreme weather events such as typhoons, demonstrating its potential as a resilient energy buffer in coastal and island regions. In addition, based on the distinct behavior of soft bodies at varying depths, this study proposes a novel research direction involving hybrid rigid–soft floater configurations. Preliminary analysis suggests that soft floaters may partially collapse at certain depths, performing negative work during descent and thereby enhancing net energy storage. This presents key optimization challenges regarding submersion depth and the volume ratio between rigid and deformable components, worthy of further investigation by the broader research community.