During the extreme summer heat, Texas’ electrical grid can be put under strain as Texans try to cool off.
From time to time to help manage the supply of electricity with the demand, the Electric Reliability Council of Texas (ERCOT), the agency that manages the state’s power grid, may ask Texans to conserve power during peak hours. At other times, they may issue OCNs warning of conditions that may require future conservation or action.
But what do they all mean and how should Texans respond?
OPERATING CONDITION NOTICE (OCN)
ERCOT describes an OCN as “the first of four levels of communication issued in anticipation of a possible Emergency Condition,” or “an operating condition in which the safety or reliability of the ERCOT System is compromised or threatened.”
An OCN is the warning that there are conditions present that may result in further action being taken in the future to protect the power grid, but there is not yet an Emergency Condition where ERCOT is asking Texans to conserve power or requiring utility services to shed load through controlled power outages.
Following an OCN, ERCOT may issue three other communications indicating the increasing likelihood of an Emergency Condition including advisories, watches and finally, an emergency notice to declare that ERCOT is operating in an Emergency Condition.
ENERGY EMERGENCY LEVELS
When electricity demand is greater than the supply, ERCOT begins emergency operations to prevent an uncontrolled system-wide outage. To prevent uncontrolled outages ERCOT may issue calls for conservation, deploy reserves or implement controlled outages to reduce demand on the system.
There are three levels of Energy Emergency Alerts and each level provides ERCOT with resources to protect the power grid.
Energy Emergency Level 1: Operating reserves have dropped below 2300MW and are not expected to recover within 30 minutes. Conservation is critical and there is a risk of controlled outages. “ERCOT can call on all available power supplies, including power from other grids, if available.”Energy Emergency Level 2: Operating reserves have dropped below 1750MW and are not expected to recover within 30 minutes. Conservation is critical and there is a risk of controlled outages. “ERCOT can reduce demand on the system by interrupting power from large industrial customers who have contractually agreed to have their electricity turned off during an emergency.”Energy Emergency Level 3: Operating reserves have dropped below 1430MW and are not expected to recover within 30 minutes. Conservation is critical and controlled outages are underway. “ERCOT will order transmission companies to reduce demand on the electric system. This is only used as a last resort. This is typically done through [controlled] rotating outages and temporary interruptions of electric service. In extreme circumstances, more prolonged outages may be required.”
ERCOT said they have initiated controlled outages four times in their history including on Dec. 22, 1989, April 17, 2006, Feb. 2, 2011, and most recently from Feb. 15-18, 2021.
Visit ercot.com for up-to-date grid conditions and more detailed information on actions taken during emergency conditions. To receive real-time emergency notifications, you can download ERCOT’s mobile app, follow ERCOT on Twitter or subscribe to an alerts list here.
