Key takeaways:
Hydrostor’s A-CAES stores compressed air in underground caverns using a water column to regulate pressure and optimize energy use
The system provides 8-24 hours of long-duration storage and is scalable to 500 MW with a projected lifespan exceeding 50 years
Current A-CAES projects in Australia, Canada, and the US total 1.2 GW, with a 7 GW pipeline under development
A Canada-based company, Hydrostor Inc., has received The smarter E AWARD 2025 for its energy storage solution, branded as the Advanced Compressed Air Energy Storage System (A-CAES).
In a conventional CAES, electrical energy is used by compressors to pump compressed air into an underground cavern, where it is stored. This compressed air is used later for energy generation. Unlike conventional CAES, this system uses a water column reservoir to regulate and maintain air pressure at different volume capacities. The CAES can be built as a standalone storage system or co-located with solar or wind energy systems.
Mode of Operation
When there is excess energy available from renewable sources, it can be used to power compressors that compress the air. The heat generated in this process is extracted and stored, while the cooled compressed air is stored underground in a rock cavern filled with water. The water is displaced into a reservoir as the air fills the cavern. When the cavern is completely filled with air, the CAES is considered fully charged. When energy is needed, the water flows back into the cavern using gravity, pushing the air back to the surface to drive a turbine and generate power.
Hydrostor’s CAES
Hydrostor claims that A-CAES is scalable to capacities of up to 500 MW and requires around 20 times less land area than a conventional pumped-hydro storage system. The company notes that the system provides 8 to 24 hours of storage duration and recycles the heat generated during compression for the decompression process, allowing for an emission-free operation. Hydrostor also states that the system has a lifespan of over 50 years without performance degradation.
The company reports existing operational commercial projects in Australia, Canada, and the United States, totaling 1.2 GW, with an additional 7 GW in the development pipeline.
