Electricity storage: "(Water) that goes up must come down, spinning (fly) wheel got to go 'round'"

The obvious ways to store electricity are through massive banks of huge batteries, but some truly novel ways to are being developed as well. Constantly rotating flywheels and pumping up water uphill so kit call fall into turbines are two of them. by John Dodge
Written by John Dodge, Contributor

When Blood, Sweat and Tears sang the line from its famous song Spinning Wheel in the late sixties, the rocknroll group must have subconsciously been thinking about innovative ways to store electricity. More on that in a bit.

Utilities constantly struggle with matching the supply of electricity to ever-changing demand. One problem is that until now, electricity has not been stored to help balance generation with usage.

That's wasteful, expensive, harmful to the environment, increases wear and tear on equipment and is a real problem for renewable sources of electricity because it's impossible to align energy demand with when the sun shines or when the wind blows. So the notion of banking electricity has become paramount to wider adoption of wind and solar generation.

At my last magazine, we wrote about the obvious ways to store electricity through massive banks of batteries. But some truly novel ways to store electricity are being developed as well. The song Spinning Wheel captures their essence: "What goes up, must come down (water), spinning wheel (as in flywheels) got to go 'round."

Beacon's Smart Energy 25 flywheel

Constantly rotating flywheels can consume excess power to keep going and discharge power when the grid demands it. Another is pumping water uphill using excess electricity and letting it flow downhill to produce electricity as needed.

Beacon Power just north of Boston is installing farms of carbon fiber flywheels  that spin at 16,000-18,000 revolutions per second (that's about  Mach 2). Their motors use electricity to spin the flywheels which can reliably and quickly discharge electricity up to 20 megawatts when there's the need.

The flywheels also perform a task in the electricity industry known as frequency regulation because the grids are ideally operated at 60 hertz (Hz or cycles per second..50 Hz is standard in Europe). Maintaining 60 Hz stabilizes costs and minimizes wear and tear on equipment, but the frequency tends to jump around when supply is not aligned with demand. The flywheels help stabilize the right frequency.

Besides frequency regulation, flywheels have a range of other applications and the company also has R&D projects with hydro and wind operators. Its president Bill Capp is speaking at GridWeek this week in Washington.

Riverbank Power based in Albany, N.Y. accomplishes much the same thing only its so-called underground  "Aguabanks" push water uphill using excess electricity and let it run downhill to produce power as needed. The company claims it's Aquabank turbines with a "suitable water source" can produce up to 1,000 megawatts.

How Aquabanks work

Riverbank is focused on wind and solar operators and currently has two proposed projects (you have to register to read about its projects. Sigh). For its part, Beacon is more evolved and has functioning flywheel farms on the grid. Its web site has several videos that do a good job explaining how electrical grids work in addition to the flywheels. Riverbank also has some good video, one of which is below.

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This post was originally published on Smartplanet.com

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