Electric Transmission Texas LLC (ETT) has completed a contract with NGK-Locke, Inc. for a state-of-the-art, sodium-sulfur 4-megawatt NAS battery system, which will be installed in Presidio, Texas. ETT is a joint venture between American Electric Power (NYSE: AEP) and MidAmerican Energy Holdings Company (MidAmerican).

The NAS battery will be the first in Texas and the largest in the United States and represents part of a $67 million overall commitment by ETT to improve transmission reliability in Presidio and surrounding areas.

The battery, along with construction of the Gonzales substation, is currently scheduled to be completed by first quarter 2010 in time for summer peak usage. Cost of the battery and substation is estimated at approximately $23 million. A 60-mi, 69- kV transmission line from Marfa to Presidio is targeted for completion by 2012 with an estimated cost of approximately $44 million.

“Very soon, one of the oldest cities in the United States will be benefiting from one of the world’s newest technology developments,” said Calvin Crowder, ETT president. “This battery installation will enhance electrical service for our customers in this region, and completion of this contract will allow the Presidio area to realize its benefits by next summer. “

The NAS® battery system uses sodium-sulfur battery technology. This technology proposed by ETT for Presidio will provide the following benefits:

Due to its quick response, the battery will address voltage fluctuations and momentary outages.

In the event of an outage on the radial transmission line providing power to Presidio, the battery can supply 4 MW of uninterrupted power for up to 8 hours.

The battery will allow Presidio’s electrical load to receive uninterrupted power from Comisiün Federal de Electricidad (CFE) during emergency situations.

The battery will allow for maintenance on the new transmission line being built to from Marfa to Presidio without loss of electric service.

AEP pioneered the use of the NAS battery in the United States. Following testing at its Dolan Technology Center near Columbus, Ohio, AEP became the first U.S. company to deploy NAS batteries in 2002 when it installed and operated a demonstration unit in Gahanna, Ohio. In 2006, AEP installed a 1.2-megawatt stationary NAS battery near Charleston, W.Va. In 2008, AEP installed three, 2-megawatt NAS batteries: one in Churubusco, Ind.; one in Balls Gap, W.Va.; and one in Bluffton, Ohio.