ERCOT cancels energy emergency alert

August 4, 2011 5:27:53 PM PDT
Consumers and businesses were asked to reduce their electricity use during peak electricity hours from 3 to 7pm Thursday to avert the need for rotating outages. The Electric Reliability Council of Texas, Inc. (ERCOT), system operator for the state's bulk transmission grid, initiated Energy Emergency Alert Level 2 at 2:26pm today due to responsive reserves below 1,750 megawatts (MW). It was then canceled around 6:45pm.

"Interruptible loads -- large customers paid to be dropped in a level 2 emergency have been deployed," said Kent Saathoff, vice president of system planning and operations.

Capacity was expected to be very tight over the peak today -- particularly between 4 and 5pm, which is why ERCOT asked residents and businesses to reduce their energy consumption.

Consumers typically can help by shutting off unnecessary lights and electrical appliances, minimizing the use of air conditioning and delaying laundry and other activities requiring electricity-consuming appliances until later in the evening.

Power Warnings are issued by the electric grid operator, the Electric Reliability Council of Texas (ERCOT), when there is a high risk that rotating outages will be needed to reduce load.

The emergency procedures are a progressive series of steps that allow ERCOT to bring on uncommitted generation and power from other grids. If the situation does not improve, ERCOT will first drop load resources (a market-based demand response program) and other resources under contract to be interrupted during an emergency. Only as a last resort (Power Emergency) to avoid the risk of a complete blackout does ERCOT ask utilities to reduce demand by dropping load through rotating outages.

Rotating outages are controlled, temporary interruptions of electrical service initiated by each utility when supplies of reserve power are exhausted. Without this safety valve, generators would overload and begin shutting down to avoid damage, risking a domino effect of a region-wide outage.

The outages are typically limited to 15-45 minutes before being rotated to a different neighborhood. Some customers may experience longer outages if power surges cause equipment failure during the restoration process. Customers can minimize power surges by turning off appliances, lights and other equipment, except for one task light to determine when power has been restored.

Consumers should contact the utility company/ transmission provider listed on their electric bill for information about power outages at their homes or business, or about rotating outage procedures for their area.

Conservation Tips
Consumers can help by shutting off unnecessary lights and electrical appliances between 3 and 7 p.m., and delaying laundry and other activities requiring electricity-consuming appliances until later in the evening. Other conservation tips from the Public Utility Commission's "Powerful Advice" include:

  • Turn off all unnecessary lights, appliances, and electronic equipment.
  • When at home, close blinds and drapes that get direct sun, set air conditioning thermostats to 78 degrees or higher, and use fans in occupied rooms to feel cooler.
  • When away from home, set air conditioning thermostats to 85 degrees and turn all fans off before you leave. Block the sun by closing blinds or drapes on windows that will get direct sun.
  • Do not use your dishwasher, laundry equipment, hair dryers, coffee makers, or other home appliances during the peak hours of 3 to 7 p.m.
  • Avoid opening refrigerators or freezers more than necessary.
  • Use microwaves for cooking instead of an electric range or oven.
  • Set your pool pump to run in the early morning or evening instead of the afternoon.

Businesses should minimize the use of electric lighting and electricity-consuming equipment as much as possible. Large consumers of electricity should consider shutting down or reducing non-essential production processes.

Rolling outage map

The following points assist in understanding the CNP rolling outage map:

  • The need for rolling outages only occurs during an ERCOT statewide energy emergency and the situation is typically changing at a rapid pace.
  • On the map, the areas marked in red will be part of the predetermined rolling outages during an ERCOT statewide emergency.
  • Areas on the map shaded in blue are on circuits reserved for a different type of grid emergency called Automatic Load Shed. This type of emergency operation involves the automatic disconnection of electric circuits to prevent severe swings in voltage or frequency on the electric grid. This type of event could lead to damages to utility and customer equipment and an extended outage. Because an emergency load shed event could occur during a rolling outage event, the circuits in blue are reserved to respond to that condition.
  • Areas in black are lines that deliver electric service to facilities that serve 911, 211, downtown Houston, the Texas Medical Center, hospitals, Johnson Space Center, the Galleria, Intercontinental and Hobby airports and Ellington Field. As a result, some customers may experience multiple service interruptions while other customers, whose homes or businesses are located on the same circuits as the facilities noted above, may not experience any outages.
  • Planned rolling outages do not affect transmission voltage customers (like those at the Houston Ship Channel). Transmission customers are usually large, industrial consumers who receive electric service through high voltage power lines. Distribution customers, primarily residences and small businesses, require lower voltage electric service and receive service through smaller distribution power lines.
  • Customers who believe they may qualify for inclusion on the critical care residential customer list should contact their REP to request an application. The customer and the customer's physician must complete the application and return it to CenterPoint Energy. However, approval for inclusion on this list does not ensure uninterrupted electrical service, and customers on the critical care residential list are still subject to rolling outages or emergency load shed electric service interruptions. Additionally, in preparation for an anticipated emergency like a hurricane, CenterPoint Energy advises critical care residential customers to make alternate arrangements because power outages are expected.

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