Flywheels to buffer 20 megawatts on grid

Updated on November 13 at 1:11 p.m. PT to clarify and correct technical details.

Big levitated spinning disks will provide electricity to the grid in a project set to begin next month.

Flywheel energy storage company Beacon Power on Tuesday said it plans to begin construction of a 20-megawatt storage facility in Stephentown, N.Y. Provided on a continuous basis, twenty megawatts could power thousands of homes. But flywheels are used only for providing power for short periods.

Rather have many hours of stored energy on standby, the flywheels will store and dispatch bursts of electricity for what's called frequency regulation in the utility industry. Because of fluctuations in power demand, power generators need to deliver power to the grid to maintain a steady signal frequency. Beacon Power's flywheels are designed to provide one megawatt of power for 15 minutes.

George King, supervisor of flywheel assembly at Beacon Power, stands next to the company's 100-kilowatt flywheel.

(Credit: Beacon Power)

With flywheels, electrical energy is converted into mechanical energy and stored by the spinning disks. By absorbing electricity and dispatching it for quick bursts of a few minutes, utilities can maintain the frequenc with a system that uses no fossil fuel and responds quickly, according to Beacon Power.

The project will help the utility better use renewable energy that supplies electricity intermittently to the grid, according to the New York State Public Service Commission.

The installation in upstate New York will be the first large-scale use of Beacon Power's technology, according to the company. The Tyngsboro, Mass.-based company secured a Department of Energy loan guarantee in July for $43 million to partially finance the project.

Until now, Beacon Power has operated two smaller 1-megawatt facilities, where 10 flywheels are placed in a shipping container-size structure. The wheels themselves are made of carbon fiber composites, rather than metal, and spin at 16,000 revolutions per minute. To reduce friction, the mechanical components are stored in a vacuum and levitated with a permanent magnet, according to the company.

Another idea that has been pursued by Google for frequency regulation is using networks of electric-vehicle batteries. Rather than dispatch stored energy from batteries, plugged-in cars could have the charge rate throttled back, which a grid management system could use to maintain frequency.

[Joe Real]

When will our reporters ever learn?

That there is a HUGE DIFFERENCE between MEGAWATTS and MEGAWATT-HOURS!!!! These are never interchangeable. One is a unit of power and the other is unit of energy.

A 20 MEGAWATT flywheel would supply only one second of power depending upon how much kinetic energy it can store. The storage of energy can be rated in Megawatt hours, joules, calories AND never measured in terms of megawatts. Now the rate of energy delivery from storage devices can be measured in terms of megawatts.

[Joe Real]

So let me beg for an answer:

How many megawatt hours or kilowatt hours do these flywheels provide?

[mlamonica]

A one megawatt flywheel can hold 25 kilowatt-hours.