Temporal Power

Flywheel Energy Storage

“With thorough project management and smart engineering by the Angus team, they have been able to condense the schedule and, at the same time, lower our costs.”

 Geoff Osborne, Senior Associate, NRStor

HH Angus and Associates was engaged to provide the detailed electrical engineering and construction management of this flywheel energy storage project at Temporal Power’s Minto facility near Harriston, ON. Flywheel-based energy storage systems do not use fossil fuel and do not produce CO2 or other harmful emissions during operation.

Our electrical team provided consulting engineering to connect Temporal Power’s nominally 2MW of flywheel energy to (and from) the grid at distribution voltage, as well as commissioning of the site.

Grid frequency regulation is required by the IESO in the area northwest of Guelph because of fluctuating electrical load and generation; 2 MW of flywheel capacity can act as a sink or a source of electricity to stabilize frequency.

The vulnerability of the electrical grid and distribution service, as evidenced in the December 2013 ice storm that affected predominantly Ontario, Quebec and the Northeast US, is giving impetus to the move to smart grids, distributed power and storage systems. The Temporal Power facility serves to balance the system frequency, thereby reducing the need to have a more expensive and less responsive generating plant performing that function.

Each of the ten 250 KW flywheels in the plant weighs about 4000 kilos and spins at up to 11,000 RPM.The flywheels operate through five 480V inverters (ie, two flywheels per inverter, with one redundant unit). HH Angus designed and supplied the system that converts the local grid distribution voltage of 44,000V through 347/600V to 480V (and vice versa). In terms of interconnecting to the grid, this is very much like a generator project in that it does ‘generate’ 2MW when requested as frequency is decreasing. But it can also absorb energy when the grid frequency is ‘speeding up’.

Electrical Engineering | Site Commissioning 

Status: Completed 2014

Harriston, Ontario

Detailed electrical engineering and construction management of flywheel energy storage project | 2 MW of flywheel energy to/from the grid | EPC through Angus Power | Flywheel technology balances system frequency 10 X 250kW flywheels


This was a substantial EPC project that married the electrical engineering capacity of HH Angus’ grid connection specialists with the project and risk management experience of our Angus Power team.