Flywheel Tech Spins for the Grid

A technology that goes back to nearly the dawn of mankind isn't just enduring--it promises to clean up energy production and storage. Time to get reacquainted with the flywheel.

Grid operators usually reserve one percent of their energy generation...just in case. Usually that supply is pretty stable, but it comes from you know where. A shift to renewable wind and solar power, which are by nature intermittent, means that the reserve will likely need to increase to 2 or 3 percent. Here's where Tyngsboro, Massachusetts-based Beacon Power Corporation comes in. Their goal is to fill that gap with their flywheel storage services, competing against the fossil fuel power plants that currently handle what the industry calls frequency regulation.

Science writer Gene Charleton noted that modern flywheels are extremely high tech, spinning at twice the speed of sound. They are essentially giant masses floating on magnetic bearings in a vacuum, spinning. Flywheels don't release emissions and cost far less than coal-fired plants to build.

"One of the big advantages to flywheel storage, beyond the obvious one of no emissions, is the fast response," says Gene Hunt, spokesperson for Beacon Power. "It will respond within a few seconds." They're also scalable. Ten of Beacon Power's 25 kWh flywheels linked together equals one megawatt. Currently Beacon is constructing a 20-megawatt plant in Stephentown, New York near Albany and has plans for a new plant in the Chicago area.

Hunt describes frequency regulation as a shock absorber on the grid that cushions the bumps. If we're really going to make the switch to sustainable energy, we're going to need a lot of shock absorbers.

Image: Beacon Power's flywheel. Credit: Beacon Power.