Located three kilometres off Toronto Island and below 55 metres of water, sits the first ever underwater compressed air energy storage system.
Officially unveiled November 18, Hydrostor’s system is connected to Toronto Hydro’s electricity grid where it will remain until a two-year pilot study is complete. The project represents years of effort designing and building the underwater storage unit and the onshore energy conversion centre. The system is expected to improve power quality and resiliency for island residents and engineers will be monitoring its performance through a variety of tests.
The technology works by running electricity through a compressor and converting it into compressed air. The compressed air is sent underwater where it is stored in large balloon-like structures, made out of the same type of material used in marine lift bags to raise shipwrecks. When electricity is needed again, the weight of the water pushes the air to the surface through a large pipe. An expander coverts the air back into electricity.
At peak output the storage unit is capable of powering approximately 330 homes (660kW). Depending on how much power is drawn, the system can currently run for a little over an hour, although future expansion of the underwater air cavity will increase this duration.