Device aims to smooth power plans on Big Island
A shock absorber is for wind power
WAIMEA, Hawaii » A trailer-size electronic device that smoothes the flow of wind-generated electricity could greatly increase the amount of wind power used on the Big Island and at many other sites around the world, said Warren Lee, president of Hawaii Electric Light Co.
The Electronic Shock Absorber was to be dedicated today in a test deployment at HELCO's 1.2-megawatt Lalamilo wind farm near Waimea on the Big Island.
One of the problems with wind is gusts, Lee said. A gust of wind means a gust of power, which is bad for delicate electrical equipment.
During a visit to a Big Island power control room about four years ago, engineer Karl Stahlkopf actually saw instrument readouts of gusts -- to his surprise.
A vice president at HELCO's parent company, Hawaiian Electric Co., Stahlkopf had recently arrived from California, where such fluctuations were rare.
"I notice fluctuations in the frequency. That's quite unusual," he said.
A Big Island technician told him he was seeing power "knocking around" from wind farms at the northern and southern ends of the island.
On a return flight to Honolulu that day, Stahlkopf used the back of an Aloha Airlines magazine to sketch out the device that was to become the PureWave Electronic Shock Absorber. Patented by HECO, the device is manufactured by S&C Electric Co. of Chicago.
Very large wind farms have been operating on the mainland for decades, but their power flows into enormous regional electrical grids with capacities of tens of thousands of megawatts, Stahlkopf said. Wind power fluctuations there disappear amid the multiple sources of energy.
The Big Island has a capacity of only about 200 megawatts, Stahlkopf said. Any roughness in wind power there shows up on the small, isolated grid.
Besides islands, other locations that can benefit from smoother wind power are those that are "weakly supported" -- few connections to a grid -- and areas with a lot of sensitive electronic equipment, Stahlkopf said.
The device Stahlkopf created is designed to control power after it is collected from about 60 small wind turbines at Lalamilo but before it enters the grid.
The device fits into three compartments inside a 30-foot trailer. The first compartment holds computers and other controls that watch for problems that need attention.
The second compartment holds inverters, devices that change excess alternating current to direct current for storage, then back to alternating current when the excess is released.
The final compartment holds "supercapacitors," electrical storage devices originally developed in the Soviet Union to work in the cold of Siberia where batteries failed.
Compared with normal capacitors like those in a television, supercapacitors can hold very large amounts of power. They can hold and release it hundreds of thousands of times.
Two types will be used in the demonstration shock absorber at Lalamilo, said S&C* project manager Gerry Keane. Supercapacitors from a German and an American company will be used so their performance can be compared.
The S&C design is modular, so a shock absorber can be scaled up to a 60-foot trailer and several trailers can be used side by side, Keane said.
While the shock absorber will be used at Lalamilo to smooth bumps in power, it can also be used to create power bursts, Keane said.
CORRECTION
Wednesday, January 18, 2006
» S&C Electric Co. manufactures an "electronic shock absorber" that could facilitate wind-generated electricity. The company was incorrectly identified as C&S in a Page A1 article yesterday.
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