Compressed Air Energy Storage (CAES) organisation Hydrostor have released the Hydrostor Terra, which is a long-duration bulk energy storage system that is expected to compete head-to-head with new natural gas plants.

Hydrostor Advanced Compressed Air Energy Storage (A-CAES) demonstration facility in Toronto, Ontario.

Using Terra, utilities and electricity system operators can cost-effectively and reliably address the issues of reserve capacity, peak shaving, transmission congestion and renewables integration - enabling the transition away from fossil-fuel generation at half the cost of competing battery technologies.

According to president and CEO of Hydrostor Curtis VanWalleghem, the market response to Terra thus far has been tremendously positive.

"Hydrostor Terra is an industry-changing breakthrough in cost-competitive bulk energy storage," VanWalleghem said.

"We are engaged with several utilities around the world to deploy systems rated at hundreds of megawatts, delivering gigawatt-hours of storage at durations ranging from four hours up to multiple days.

"Battery technologies can't compete with new natural gas plants, but Terra does - the value proposition for utilities is compelling, and for us that's translating into projects."

Terra's design gives it an advantage over traditional CAES systems, which have been limited due to needing underground geological formations for siting, as well as relying on gas to generate heat during operation. 

These limitations do not feature on the Terra though, as it can be utilised at any site close to a body of water - including inner city and urban areas, and its adiabatic design also recycles the heat it produces making it truly emission-free.

The system works by converting off-peak electricity to compressed air, which is stored in a proprietary isobaric purpose-built underground cavern.

During the charge cycle, heat generated from the compressors is stored in a patented adiabatic thermal management system, and the heat it later used to increase the air temperature prior to expansion - boosting overall round-trip efficiency.

At discharge, compressed air is converted back to electricity, on demand, at peak times.

Hydrostor has an EPC (engineering, procurement and construction) partnership with engineering and design firm AECOM, and according to Travis Starns, AECOM's business development manager for energy storage, the company has already conducted a full technical review of the Terra technology.

"AECOM is uniquely positioned to evaluate storage technologies for the utility sector, given the company's expertise and extensive experience in developing and integrating new technologies within the power industry," Starns said. 

"Following our due diligence, we are excited to work together with Hydrostor in offering a complete turnkey solution within the growing energy storage market."

Hydrostor recently also formed a partnership with Canadian developer NRStor to jointly develop utility-scale energy storage projects across Canada.