AEP Texas has joined with the Electric Reliability Council of Texas (ERCOT) in requesting Rio Grande Valley residents take steps to conserve electricity today.  While reliability conditions in the Valley have improved this morning, those conditions could change suddenly prompting the need to interrupt electric service for area residents.

At 4:47 p.m. on Wednesday, ERCOT instructed electric transmission providers in the Valley to interrupt service following unplanned power plant outages.  The sudden loss of generation made it necessary for ERCOT, in its role as grid operator, to issue the directive to shed electric load in order to protect the transmission system in that area.

Approximately 120,000 customers in the AEP Texas service territory were impacted at the peak of the controlled rotating outages.   The number of controlled outages dropped significantly within 20 minutes or less and continued to decrease until about 6:29 p.m. when ERCOT instructed the transmission providers to terminate the remaining rotating outages.  The dynamic nature of the event, however, resulted in the outage information system used by AEP Texas to post current outage numbers to fall behind in updating restoration progress.

As of 9:20 a.m. on Thursday morning, approximately 2,000 customers in the Edinburg area and approximately 800 in the Harlingen area were without power as a result of distribution-related issues unrelated to the load shed directed by ERCOT on Wednesday.

“ERCOT reports that generation levels in the Valley are improving; however, that could change suddenly as the day continues,” said Bruce Evans, AEP Texas vice president of Distribution Operations.  “Additionally, AEP Texas crews replaced a blown lightning arrestor on a series capacitor bank, which resulted in a 345-kV transmission line from the Rio Hondo to Ajo area going offline.  That transmission line returned to service about 9:25, but these developments reinforce the need to encourage conservation in the Valley throughout the day.”

Consumers can help ensure the system is able to continue serving current power needs by taking the following steps to reduce demand:

• Keep thermostats as high as is comfortable, preferably no lower than 78 degrees.
• Turn off and unplug non-essential lights and appliances.
• Avoid running large appliances, such as washers, dryers and electric ovens, especially during peak demand hours of 6-9 a.m. and 4-8 p.m.
• Close shades and blinds to reduce the amount of sunlight and heat entering through windows.
• Large consumers of electricity should consider shutting down or reducing non-essential production processes.