Wind power will return to Kahuku

More than a year after a battery fire shut down First Wind’s Kahuku Wind energy project, the company is finishing up repairs and plans to restart the facility as soon as late September.

Boston-based First Wind has decided not to replace the battery that had been originally installed to smooth out voltage and frequency fluctuations inherent in wind power, and will instead use another type of technology to even out the power flow.

"We’ve been working hard to bring the proj­ect back online. We hope to begin testing late this month and ideally be back on line by the end of September or early October," said John La­mon­tagne, First Wind spokes­man.

A fire on Aug. 1, 2012, destroyed the battery storage building at the 30-megawatt wind energy proj­ect, forcing First Wind to shut down the entire facility and disconnect it from Hawaiian Electric Co.’s power grid.

The cause of the fire was not determined.

Instead of replacing the batteries, First Wind is installing a dynamic volt-amp reactive system, or D-VAR. The D-VAR system uses patented technology to regulate power fluctuations in both traditional and renewable energy generation systems.

First Wind will use a D-VAR system made by American Superconductor.

"D-VAR systems are proven worldwide to address a range of voltage stability issues and increase the power transfer capacity of utility networks," according to American Superconductor’s website.

HECO engineers have been working with First Wind to make sure the Kahuku proj­ect can be safely hooked back into the utility’s grid using the D-VAR system and other "technical solutions to manage sudden changes in output from the wind farm that could result from varying wind conditions," said Darren Pai, HECO spokes­man.

The Kahuku project and its 12 wind turbines began feeding electricity into the HECO grid in March 2011. The wind farm had been performing as expected up until the time of the fire, La­mon­tagne said. The proj­ect was designed to generate enough energy to provide the needs of 7,700 Oahu households.

HECO signed a 20-year agreement to pay First Wind an average of 22.9 cents a kilowatt-hour for electricity produced by the Kahuku wind proj­ect. The utility pays only for electricity it receives from the proj­ect.

First Wind financed construction of the project, in part, with a $117 million loan guaranteed by the U.S. Energy Department. First Wind is current on its loan payments, La­mon­tagne said.

FIRST Wind also has a second wind energy proj­ect on Oahu and one on Maui.

The company’s 69-megawatt Kawai­loa Wind project northeast of Hale­iwa did not require a battery system because of its proximity to one of HECO’s main 138-kilovolt transmission lines, according to First Wind officials.

The Kahuku project, by contrast, is located near the end of a smaller 46-kilovolt HECO transmission line. The smaller capacity line, combined with the proj­ect’s remote location, means that more needs to be done to protect the local circuit from fluctuations in power output associated with wind energy, the officials said.

The first phase of First Wind’s 51-megawatt Kahe­awa Wind energy proj­ect on Maui is equipped with an Xtreme Power Solutions battery system.

Hawaii has about 175 megawatts of total wind energy capacity on Oahu, Maui and Hawaii island.

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Correction:  There have been three fires at the Kahuku Wind farm — in April 2011, May 2011 and on Aug. 1, 2012. The third fire caused the generator and turbines to be shut down. The battery maker for Kahuku Wind, Xtreme Power, blamed the first two fires on faulty parts supplied by Dynapower Corp. Xtreme Power sued Dynapower for damages stemming from those events, and the two sides settled the case. The cause of the third fire has not been determined. An earlier version of this story reported that Xtreme Power sued Dynapower Corp. over the Aug. 1 fire.