In the waters of Lake Ontario, Canada, a hugely significant energy development is taking place. Hydrostor is a company specializing in underwater compressed energy storage.

Their idea addresses a significant issue facing renewables: the question of how to store energy to be used when the sun is not shining or winds aren’t strong enough.

“The way the grid operates is (at) any moment the amount of demand – how much stuff is plugged in – has to equal how much is being produced, and if ever those get out of balance you start having brownouts and power quality issues, so that’s what it means to… keep the grid ‘in balance’,” Curtis VanWalleghem, Hydrostor’s CEO, told CNBC in a phone interview.

“As we add wind and solar… (it) makes it very difficult to do that because clouds come, gusts of wind surge,” VanWalleghem added.

Hydrostor’s system works in several steps. Electricity is run through a compressor and converted into compressed air. This compressed air is then sent underwater.

“There, we have a whole series of what are effectively balloons, that fill… like lungs under a lake,” he added.

“They fill with air, and when they’re full you stop charging the system and it can sit there indefinitely. When you want power back, again, a valve opens … air comes rushing out, we run through a low pressure turbine called a turbo expander, and that reproduces power back to the grid.”

Energy storage is becoming increasingly important. In the United States, the Office of Electricity Delivery & Energy Reliability states that the development of technology to store electricity so it’s available on whenever it’s needed would be a “major breakthrough in electricity distribution.”

Read the rest at CNBC.com