Flywheels Could Be Key to Renewable Storage

Industrial Flywheel

By Jonny Wakefield

November 20, 2014

An Ontario company believes a piece of technology in use since before the age of steam could improve the efficiency of 21st century power grids.  

Temporal Power Ltd.'s flywheel system is one of a dozen technologies being tested by the province's Independent Electricity System Operator (IESO) to help regulate electricity supply and demand.  

The company builds massive steel flywheels that spin at 12,000 rpm and weigh 4,000 kilograms.

According to the Globe and Mail, ten of Temporal's flywheels have been regulating around two megawatts worth of Ontario's power grid at an IESO facility northwest of Toronto since July, discharging power when it's needed and storing it when it's not. 

Temporal CEO Cam Carver told that this is the first time flywheels have been used on a Canadian power grid.

Flywheel technology will be familiar to anyone who has used a potter's wheel, the Globe and Mail notes, and is a key component of steam engines.  

The wheels are charged by electric motors hooked up to the power grid, and can switch back and forth between receiving power and generating power on a on-demand basis. 

Like many other power authorities, IESO is looking for the best way to store energy from non-traditional sources. In the IESO tests, the flywheels are up against several types of batteries and a system that stores power as hydrogen. 

Flywheels are similar to batteries, but store energy kinetically rather than chemically.

As grids move towards a more diverse energy mix, IESO is looking for ways to balance ambient power like wind and solar with sources like coal, natural gas and nuclear.

With those power sources, more energy can be produced on-demand, as need increases. Not so with wind and solar.

According to Canadian Geographic, around 32 per cent of the energy produced in Ontario comes from wind and solar, and more projects are in the works.

Efficient storage of power generated by wind and solar is considered a clean energy "holy grail," allowing grid operators to meet demand regardless of whether the wind blows or the sun shines.

Carver told the Globe and Mail that flywheels are a technology that can help grids balance energy supplies and demand.

"Sometimes you have too much and you want it off, sometimes you have too little and you want more," he said. "It's a constant balancing act."