Underwater balloons: A sustainable energy solution for island communities

Islands face unique challenges when it comes to energy storage and management. Their limited space makes large-scale energy storage impractical, and their distance from the mainland can lead to poor power stability. Moreover, sustainable energy solutions like wind and solar power can be intermittent and unreliable.

Leveraging islands’ unique geographical conditions, Li et al. proposed underwater compressed air energy storage (UWCAES) as a solution to islands’ energy problems. This method works by placing gas storage balloons deep in the ocean and allowing the hydrostatic pressure to naturally compress the air in the balloons, which can then be used as an energy source.

“This technology makes clever use of the natural physical features of the marine environment,” said author Qiang Lu. “It not only keeps the equipment running efficiently and greatly improves the system’s round-trip efficiency, but more importantly, it takes up no valuable land on the islands at all.”

The researchers compared three energy scenarios made up of combinations of wind, photovoltaics, wave energy, batteries, and UWCAES. They found the combination of UWCAES and batteries to be the optimal choice, as the batteries can respond and adapt quickly to power needs, while the UWCAES can stably store large amounts of energy over long periods of time.

On top of power storage, UWCAES offers additional benefits to an island’s energy use. The heat recovered during the compression process can be used for seawater desalination, and the cold energy generated when the compressed air expands can be used for cooling.

“This realizes an integrated supply of electricity, fresh water, cooling, and heating, fully meeting the diverse energy needs of island communities,” Lu said. “Against the backdrop of carbon peaking and carbon neutrality goals, as well as the development of the marine economy, this technology can drive zero-carbon transformation of islands and support the development of deep sea-related industries, boasting significant strategic and market value.”

Source: “Marine-adapted hybrid algorithm driven multi-objective optimization for offshore island integrated energy systems with underwater compressed air energy storage,” by Ji-hong Li, Yao Dong, Xiao-li Chen, Xu Su, Xin-yue Zhou, Yang-wen Wu, and Qiang Lu, Journal of Renewable and Sustainable Energy (2026). The article can be accessed at https://doi.org/10.1063/5.0308317 .

This paper is part of the Data & Model Driven Solutions for Smart and Sustainable Multi-Energy Systems Collection, learn more here .