Sunday, July 31, 2011

The grid adjusts...  

To all the wind and solar projects. As I have discussed before, one big obstacle to alternative energy is the fluctuation problem - wind speeds, cloudy weather, etc. To accommodate more variable energy generators the grid has to be able to balance the voltage and frequency with varying supplies and demand.

This is a hot new area for investment and research.
If you think twirling the mass of a family car hundreds of times a second is an unlikely way to keep power grids humming at perfect pitch, think again. Flywheel developer Beacon Power Corp., based in Tyngsboro, Mass., is already making money that way in Stephentown, N.Y., where it operates more than 160 1150-kilogram magnetically levitated flywheel motor-generators. These machines continuously accelerate and decelerate to balance electrical supply and demand and thus keep New York state's grid tuned to 60 hertz.
AC frequency fluctuates from second to second as generators turn on and off and consumer demand varies. When demand exceeds supply, the extra load slows down power plant turbines, thus depressing frequency. Meanwhile, the turbines accelerate whenever supply is in excess. Frequency regulators add or remove power to restore balance.
Beacon's flywheels can regulate frequency with superior speed relative to the dominant method today—throttling power generators up and down. And grid operators are changing outdated rules to favor faster-acting regulators, including flywheels and grid-scale batteries. The prize: priority access to a frequency regulation market worth US $495 million in the United States last year and growing with the expansion of ever-varying wind and solar power.
One challenge will be competition from battery-based frequency regulators, which are cheaper per megawatt to install. Several battery systems are testing the market, including a 20-MW frequency regulating facility that Arlington, Va.–based power firm AES is building in Johnson City, N.Y. The $22 million plant uses lithium batteries from A123 Systems.
Kema's Hawkins agrees that batteries will lose their edge over flywheels under that level of use. "A battery really doesn't like to be totally charged and discharged," says Hawkins, "whereas flywheels can handle a pretty severe duty cycle." But he says that another threat looms, one that could eviscerate the market for frequency regulation: millions of electric vehicles. Plugged in to the grid, they could respond to frequency deviations at the local level.
Pacific Northwest National Laboratory, a unit of the U.S. Department of Energy, proved a similar concept a few years ago, showing that electric water heaters and dryers could correct frequency dips by temporarily turning off their heating elements. In March, PNNL licensed the concept to Texas-based semiconductor start-up Encryptor, which hopes to make chips for appliances.
So in the future, the frequency regulator could be you. [More]
It is developments like this that renew my belief in our ability to weather storms and adapt to new circumstances. It also makes me want to keep an eye on plug-in sales.

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