If you have not heard of Compressed Air Energy Storage (CAES) yet, you are about to. Canadian firm Hydrostor, a long-duration energy storage solution provider, revealed this week it will develop 1,000 MW of CAES in California, according to a press release.
But what is CAES? It’s a type of battery that uses off-peak or surplus electricity from the grid to produce energy. It does this by using that extra electricity to run a compressor which in turn generates heated compressed air. This air is stored inside a purpose-built underground cavity, where hydrostatic pressure pushes it back to the surface.
There, it is re-heated by the thermal store and directed through a turbine which generates electricity. CAES systems are increasingly growing in popularity, because compared to conventional batteries, they can store energy for longer periods of time and have less upkeep.
Soon, these systems will be helping Californians make the most out of their clean renewable energy. The new Hydrostor facilities will use an updated version of the CAES technology called Advanced Compressed Air Energy Storage (A-CAES) that incorporates components from existing energy systems to produce an advanced, emissions-free storage system. Not only is it low-impact and cost-effective, but it can also be placed anywhere the grid needs it.
“Long-duration storage is essential for decarbonizing the California electricity grid and integrating the renewable energy that is already developed in the state. Our A-CAES technology utilizes only existing, proven components that are repurposed from conventional power generation into an entirely emissions-free and low-impact storage technology,” says Hydrostor CEO Curtis VanWalleghem.
What are the benefits?
Hydrostor’s two major projects now in active development are located in southern Kern County and in Central California. Storing up to 10 GWh of energy, Hydrostor’s batteries will be able to provide an impressive 8-12+ hours of energy storage. This is significantly more than the 1-4 hours that current battery technologies provide.
Moreover, compressed air storage systems have typically offered round-trip efficiencies between 40-52 percent, but for this system, it’s going to be around 60 percent, per Quartz.
These systems can also help enhance power grid stability during peak times or surges in electrical use and require very little maintenance. They also reduce overall wear on the compressor, extending its life significantly. The Hydrostor facilities are expected to last for more than 50 years.
Hydrostor has already built two pilot projects (one at the 1 MW scale and another at 2 MW) in Ontario, Canada. The new projects will now help the state of California achieve its ambitious decarbonization goals.
“As studies have demonstrated, there is a significant need for long-duration energy storage to support California’s decarbonization goals,” Alex Morris, Executive Director, California Energy Storage Alliance, added in the press release.
The two new projects will each be the world’s largest non-hydro energy storage systems.