Dec 18 - McClatchy-Tribune Regional News - George Hohmann Charleston Daily Mail, W.Va.

Two-and-a-half years after installing a 77-ton battery in North Charleston, American Electric Power has installed an even larger battery project near Milton.

A 1.2-megawatt battery installed in June 2006 in North Charleston relieves a bottleneck at the utility's Chemical Substation. It is charged at night when electricity demand is low and is discharged into the electric grid during afternoons, when demand peaks.

The North Charleston battery can store enough energy to supply 500 to 600 households for six or seven hours. It is operated by time of day. "We look at our load profiles and winter and heating summer cooling season peaks and operate the battery at times that historically have peak demand," said Phil Moye, spokesman for American Electric Power's Appalachian Power subsidiary.

Now the company has installed two similar batteries in parallel on its Milton-Balls Gap circuit. The two-megawatt installation's primary purpose is to perform similar work -- relieving the load on a transformer. "But a secondary benefit and a fairly new use for this type of technology is a capability called 'islanding,' " Moye said.

"'Islanding' refers to a control setup that allows the battery to provide power to customers even when the normal feed of electricity from the station is interrupted," Moye said. "So if there's a power outage that affects the Milton station, this battery could keep customers in service on its own."

"It's not that the capability of the battery is different," Moye said. "The real difference is the controls." The battery, controls and switching equipment together are called a distributed energy storage system.

The Milton battery can store enough energy to supply about 760 households for six or seven hours.

Also, rather than operating by time of day, the Milton battery will be operated by control to follow the actual load on the line "so when the load reaches a certain point, the battery begins to supplement what the transformer is putting on the line," Moye said.

American Electric Power began using the Milton battery last week to relieve the load on a transformer. "We won't actually do the islanding portion of the battery operation until probably the first couple of weeks of January," Moye said. "They have to test the controls before they actually put it in operation."

Meanwhile, the North Charleston battery "is doing exactly what we intended it to do," Moye said. "It is still effectively relieving the load of the transformer at our Chemical Substation and we will continue to use it for that purpose.

"Ultimately we'll move it to another spot and use it somewhere else and a Patrick Street substation will be built to relieve the load on the Chemical Substation," he said. "The battery was placed at the Chemical Substation to allow us to defer that construction for a few years. That saves the company and its customers money. It's done a very effective job. We haven't had any problems with it."

The North Charleston battery was the first megawatt-class, advanced energy storage technology used on a U.S. distribution system. Total project cost was $2.2 million.

The total cost of the Milton project is about $11 million. Unlike the North Charleston battery, the Milton battery is not located inside a substation. Rather, it is located mid-circuit. Some of the project cost includes site preparation and infrastructure for future construction of a substation.

American Electric Power also plans to install giant batteries in Ohio and Indiana.

NGK Insulators Ltd. of Nagoya, Japan, made the North Charleston and Milton batteries.

The use of batteries on the electrical grid is known as "distributed energy" -- the placement of power sources close to the location of use.

In addition to providing relief for congested systems and "islanding" capability, some believe batteries will be widely used to store wind and solar power and release it when demand is heavy.

According to a Nov. 16 story in the Wall Street Journal, Japan Wind Development Co. started a 51-megawatt wind farm in May and connected it to a 34-megawatt battery complex developed by NGK Insulators Ltd.

"The energy-storage system will have enough capacity to power approximately 26,000 homes by storing the energy generated by the wind farm and then redistributing that power during the day," the Journal reported.

Batteries could be used for this purpose in West Virginia. On Dec. 8 Dominion and Shell WindEnergy Inc. announced the completion of the NedPower Mount Storm wind energy project. The project's 132 wind turbines can generate up to 264 megawatts of electricity -- enough to serve about 66,000 homes and businesses.

During last week's state energy summit at Stonewall Resort, Dominion's Bob Orndorff reported that during initial operation this summer, the project had to be shut down a couple of times because of congestion on the grid.

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