Flywheels to be deployed

A Massachusetts utility is planning to build a 20 MW flywheel plant in New York. Spinning flywheels that found use in pottery to running steam engines now will be deployed to smooth out the electricity flow, and do it fast and clean.

Beacon Power's flywheels - each weighing one ton, levitating in a sealed chamber and spinning up to 16,000 times per minute - will make the electric grid more efficient and green, the company says. Beacon's flywheel plant will act as a short-term energy storage system for New York's electrical distribution system, sucking excess energy off the grid when supply is high, storing it in the flywheels' spinning cores, then returning it when demand surges.

The job is done now mainly by fossil-fuel powered generators that are one-tenth the speed of flywheels and create double the carbon emissions. The carbon emissions saved over the 20-year life of a single 20-megawatt flywheel plant are equal to the carbon reduction achieved by planting 660,000 trees, says the company.

Flywheels also figure into the emerging renewable energy market, where intermittent energy sources such as wind and solar provide power at wildly varying intensities.

Flywheels are rotating discs or cylinders that store energy as motion, like the bicycle wheel that keeps rotating long after a pedal's been turned. They still have technological hurdles like friction to surmount. A one-ton flywheel has to be durable enough to spin smoothly at exceptionally high speeds. To avoid losing stored energy to friction, the flywheel levitates between magnets in a vacuum chamber.

Despite their potential, flywheels have not taken off as expected. Is it simply a case of not exploring all avenues under the illusion of ‘plentiful’?