By Jonny Wakefield
February 05, 2015
A Canadian clean energy startup believes the key to reliably storing and discharging commercial volumes of renewable power lies 70 metres beneath Lake Ontario.
Toronto-based Hydrostor, Inc. is the latest company to take an innovative crack at the tricky task of storing intermittent forms of energy like wind and solar.
The company has already successfully stored wind energy in giant, underwater balloons at its facility on Lake Ontario, and hopes to begin work soon on a commercial underwater compressed air energy storage (UW-CAES) facility off the Caribbean island of Aruba.
The system centres on large marine salvage balloons anchored underwater.
The company uses an air compressor powered by a renewable energy source to pump air through a pipe connected to the salvage balloons, CEO Curtis VanWalleghem explained to the Financial Post.
Heat produced from the compressor is stored in a reservoir. To release power during times of high demand, a valve is opened and the air reheated.
"When the valve is opened, the weight of the water all around that air cavity forces the air to come up to the lower pressure," VanWalleghem told the Post. That process then turns a turbine.
It's a modified version system known as pumped hydro—the basic physics behind a hydroelectric dam reservoir.
The difficulty of storing wind and solar for periods of peak demand has been one of the major impediments to more widespread adoption of renewables.
Hydrostor notes that in many grids, peak demand can be as high as 20 per cent over average consumption. While coal, gas and other fuels can be easily stored and burned to meet that demand. Storing wind and solar is not as simple.
Many Canadian companies are working to reliably store power generated by intermittent renewables—including using flywheels and specialized batteries.
Hydrostor claims its system will lead to "renewable energy on demand, even after the sun sets and the wind dies down."
The company hopes to replicate its success in Canada with a commercial scale facility in Aruba, which aims for 100 per cent renewable power by 2020.
The company signed an agreement with a power producer in that country in 2013. The project would be tied to a 30-megawatt wind farm.