Underwater Compressed Air Energy Storage

Another great innovation in Compressed Air Energy Storage involves compressing the air using pressure provided by submerging a bag filled with air in water. Having worked in underwater salvage I have seen firsthand the ability of compressed air salvage bags to lift large amounts of weight and generate a large amount of mechanical energy. This strong buoyancy of salvage bags also points to one of the main challenges for underwater compressed air energy storage as anchoring the storage devices can physically be a challenge. One company working on an underwater compressed air energy storage device is Hydrostor.

Hydrostor – rather than using geologic formations to store the compressed air, Hydrostor seeks to use an adiabatic compression system (like ADELE) to store compressed air in large underwater air bags. Hydrostor estimates that 50% of the world’s population and most of the largest cities are located near bodies of water appropriate for their technology.  This eases some of the siting restrictions of traditional CAES while providing a scalable storage solution in the 100kW – 10MW range with a discharge time in hours or days without using additional fossil fuels. A 1MW/4MWh demonstration facility is scheduled to begin operation in the summer of 2013. The facility will be located approximately 7km from the shore of Toronto, in Lake Ontario at a depth of 80m (Hydrostor, 2012).

Figure 1 showing the Hydrostor CAES system using underwater air bags (Hydrostor, 2012).

Clearly the summer of 2013 has passed and the demonstration facility, as of yet, has not begun operating. The most recent news about Hydrostor that I can find is a June 2013 article repeating the plan to implement the demonstration facility in 2013 with plans for a 2014 demonstration facility in the Caribbean. Hopefully we will see progress on this very important and interesting project soon.

Works Cited

Hydrostor. (2012). How the Hydrostor System Works. Retrieved January 13, 2013, from Hydrostor: http://hydrostor.ca/technology/