Ontario Grid Takes Flywheels for a Spin

Canada recently powered up its first grid-level flywheel storage system, putting 2 MW worth of flywheels online.

The intermittent nature of renewable energy makes grid-level storage a necessity, and Ontario’s Independent Electricity System Operator (IESO) – the government owned corporation responsible for operating and maintaining the Ontario grid – thinks that flywheels might be the best way to balance supply and demand while bringing more renewable energy sources online.

IESO recently cut the ribbon on Canada’s first grid-level flywheel storage system. The storage module, made by Ontario’s Temporal Power, consists of ten flywheels that provide a total capacity of 500 kWh. With a response time of less than ten milliseconds, the unit is capable of delivering two megawatts for a fifteen minute period with a round-trip AC to AC efficiency of 85%.

Temporal’s flywheel is made of recycled steel and can be fully recycled at the end of its projected twenty year life, making it a green storage solution on several fronts. It uses no exotic materials, which keeps the cost low. The company claims that its flywheel design requires minimal maintenance and offers the lowest cost of ownership for high-cycling storage applications. Its modules are scalable, so more capacity can be added as needed. Will it keep rotating in the cold winters of the Great White North? Most likely, yes – the flywheel’s operating temperature range is -40oC to +55oC (-40oF to 131oF). In more extreme conditions, the unit can be housed in a climate-controlled building, as shown here:

A flywheel stores mechanical energy in the form of a rotating disk. Unlike batteries, which use toxic chemicals and have limited recharging cycles, flywheels are clean and offer a virtually unlimited number of recharges, even when brought to 100% depth of discharge. With frictionless magnetic bearings and vacuum chambers reducing losses, flywheels are now a viable and efficient source of energy storage. They offer quick response and high power densities – exactly what you need to compensate for short-term fluctuations in power from renewable sources like wind and solar, and to provide frequency and voltage regulation in response to changing loads. 


Energy storage is a multi-faceted field; flywheels offer an environmentally friendly, scalable solution that can be deployed anywhere. Recent advances in technology make them even more reliable and cost effective. While I don’t see flywheels causing a revolution in the energy storage market, they will help pave the way for renewables, and that’s certainly a turn for the better!

Images courtesy of Temporal Power