By Flemmich Webb at Green Futures

Stephentown, New York, is set to become home to the world’s first grid-scale flywheel energy storage plant, after Beacon Power Corporation secured the final $43 million needed to complete the project.

The 20MW plant is currently under construction. It is expected to provide approximately 10% of New York’s total frequency regulation capacity on a typical day, storing energy when there is too much in the grid and releasing it when demand rises.

The flywheel will draw electricity from the grid and stores it as rotational energy, by accelerating a cylinder to speeds as great as 16,000rpm. The cylinder sits in a vacuum to minimise energy loss from friction. When demand on the grid is high, the motor is switched into generator mode: the cylinder drives a turbine, creating electricity that is then fed back into the grid.

The US Treasury’s Federal Financing Bank has put up the $43 million loan, which covers 62.5% of the plant’s estimated $69 million cost. Beacon Power has invested the remaining $29 million.

The flywheel has obvious environmental advantages over the conventional coal or gas power stations typically used to maintain the ‘spinning reserve’ required for frequency regulation.

Ian Welch, National Grid’s Head of Research and Development Strategy, has seen Beacon Power’s flywheel demonstration technology in action. He calls it “a unique low carbon solution for good short-term – as in seconds and minutes – frequency control.”

“However,” he adds, “in the longer term [hours], we require other [high capacity] solutions”. One suggestion is pumped hydro storage, where electricity is used to pump water to a high reservoir; when the grid requires more power, the water is released to drive turbines.

This article originally appeared in Green Futures, the magazine of independent sustainability experts Forum for the Future.

Image courtesy of The Stakhanovite Twins on flickr