A Major Technology for Long-Duration Energy Storage Is Approaching Its Moment of Truth

The quest for efficient long-duration energy storage is gaining momentum as Hydrostor Inc., a Canadian company specializing in compressed air energy storage, is set to commence construction on its first large-scale plant by the end of 2024. The Silver City Energy Storage Centre in Australia, expected to be operational by mid-2027, will have the capacity to discharge 200 megawatts for up to eight hours. Following this, the Willow Rock Energy Storage Center in California, with a 500-megawatt capacity for eight hours, is slated for construction by late next year.

Long-duration energy storage is crucial for bridging the supply gaps in renewable energy sources like wind and solar. Current lithium-ion batteries typically provide a maximum of four hours of energy storage, whereas the grid will require systems capable of six to twelve hours or more. The U.S. Department of Energy has highlighted the importance of such technologies in achieving a fully decarbonized electricity system and aims to reduce their costs by 90 percent within a decade.

Hydrostor’s technology, which has been operational at a smaller scale in Ontario since 2019, utilizes a process that compresses air and stores it underground, displacing water in the process. When energy is needed, the water pressure forces the air back to the surface, where it is heated and used to generate electricity.

The success of Hydrostor’s projects could set a precedent for the adoption of compressed air energy storage, which, along with flow batteries, is expected to be among the fastest-growing long-duration storage technologies. The company’s advancements come at a time when the global capacity for such storage stands at 1.4 gigawatts, with Hydrostor’s projects poised to significantly increase this figure.

Hydrostor’s progress is being closely monitored as it navigates regulatory approvals and aims to demonstrate the practicality and cost-effectiveness of its technology. The outcome of these projects could influence the future of energy storage and the transition to clean energy sources.