A different kind of water power

There are balloons full of energy under Lake Ontario.

Actually, the balloons are full of compressed air and are part of a pilot project by Hydrostor, a Canadian energy firm. The company is testing the concept of storing compressed air in balloons under water, then releasing the air as strong wind to turn generator turbines during times of peak demand or fuel shortages.

The 30-by-120-foot test installation includes six balloons that hold enough air to drive a 660-kilowatt generator. When air is needed, a valve is opened and the water’s pressure whooshes the air out of the balloons and into the turbine.

The system can remain in service twice as long as a lithium-ion battery pack delivering the same amount of power, Hydrostor says, while costing half as much.  Balloons can be sized to a specific location, with the balloon size shrinking in tandem with the water’s depth; the deeper the water, the greater the pressure, and the smaller the balloons needed.

Hydrostor says it’s developing projects in several countries.