Science Scene - Flywheel Power Plant

The world's first grid-scale flywheel power plant is opening in Stephentown, New York by the end of this year.  The plant, being built by Beacon Power, will store excess energy from the grid as kinetic energy that will be tapped for electricity when other sources are overloaded or unavailable.

The Smart Energy 25 flywheel system includes a rotating carbon-fiber composite rim, levitated on hybrid magnetic bearings operating in a near-frictionless vacuum-sealed environment. The rim itself is fabricated from a patented combination of high-strength, lightweight fiber composites, including graphite and fiberglass combined with resins, which allow the flywheel to rotate at high speeds (16,000 rpm) and store large amounts of energy as compared to flywheels made from metals. To reach its operational speed, the system draws electricity from the grid to power a permanent magnet motor. As the rim spins faster, it stores energy kinetically. The flywheel can spin for very extended periods with great efficiency because friction and drag are reduced by the use of magnetic bearings in a vacuum-sealed environment. Because it incurs low friction, little power is required to maintain the flywheel's operating speed.

When a grid operator sends a signal that requests the system to absorb power, the Smart Energy Matrix uses power from the grid to drive the motor/generator, which in turn spins up the flywheel. When a signal is sent for electrical power to be provided, the momentum of the spinning flywheel drives a generator and the kinetic energy is converted into electrical energy for release to the grid.