The Hybrid-Flywheel plant stores kinetic energy when electricity is abundant, and returns that power to the grid when there are supply shortfalls.

“It is not a power plant in the conventional sense,” said Frank Burke, the technical director of Schwungrad, the Irish company developing the plant.

“Instead it operates as a shock absorber and dynamic energy support system, absorbing and re-injecting small but highly flexible amounts of power to suit grid requirements.”

How it works

When the sun is shining and the wind is blowing, excess electricity it is used to start the flywheel spinning. Because it floats between two magnets in a vacuum, the wheel stays spinning until it power is needed in the grid. Then that kinetic energy is used to power turbines to generate electricity again.

The flywheels are under two metres in height and operate almost silently.

Viable energy storage technologies are becoming increasingly important as more and more energy is derived from inconsistent sources such as wind and solar.

Grid impact

Flywheel technology has been integrated in the US energy system, and US developer Beacon Power will be assisting Schwungrad with the running of the new plant.

Beacon Power president Barry Brits said: “We are optimistic about the potential in Ireland and Europe for short-duration flywheel energy storage as a key tool to help address the grid system stability impacts of leading implementation of renewable energy sources.

“In this ‘new’ energy storage marketplace, we have been providing these kinds of services in the US for over seven years, have accumulated over eight million flywheel operating hours and delivered more than 300 gigawatt-hours of service to electric grid operators.”

Rival technologies

With no commercialised dominant technology, various methods of energy storage are being trialled around the world. Pump storage – pumping water uphill into large reservoirs when power is abundant and then letting it flow down again to generate power when needed – was reportedly very valuable in preparing for the eclipse in Germany.

In the UK, the Government is supporting a two year trial for Europe’s largest battery – an £18.7m, 10MW behemoth in Bedforshire. And more recently, on Tuesday, Stanford researchers announced a new fast-charging aluminium-ion battery that they claim could be a legitimate option for grid-level storage of renewable energy.

Brad Allen

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