By Brandon Mulder

February 15, 2021 - Update: Texas electric grid operators have launched rotating blackouts across the state after power demand reached an all-time high early Monday morning.

Rotating blackouts are "controlled, temporary interruptions of electric service" enacted as a last resort in an effort to conserve power and meet statewide demand. The Electric Reliability Council of Texas warned that some traffic lights and other infrastructure may be without power during this time.

According to a tweet from the organization, which manages the statewide flow of electric power, Texas set a new record power demand of 69,150 megawatts late Sunday. The record is more than 3,200 megawatts higher than the previous record set in 2018.

Earlier: Texas electric grid operators are eyeing emergency response measures as increasingly colder temps force residents to place a greater demand on the state's electricity grid.

The most extreme measure the Electric Reliability Council of Texas could take is calling for rotating blackouts across the state, wherein local electric providers would be asked to shave down energy usage by certain amounts.

"Although rotating outages could be required as early as Sunday night, they become more likely Monday and Tuesday," said Dan Woodfin, senior director of system operations for the Electric Reliability Council of Texas.

Rotating blackouts would be employed after the grid exhausts all other measures. Grid operators monitor the system's operating reserves, or how much electric generation exceeds demand. As that margin grows narrower, grid operators enact three emergency response stages before turning to rotating blackouts as a last resort.

Level 1 of the Energy Emergency Alert protocol is enacted when operating reserves are reduced to 2,300 megawatts. At that stage, the grid can trigger an emergency response service that allows it to tap a portion of its 1,100 megawatt emergency reserve.

Level 2 of the Energy Emergency Alert protocol is enacted when the system's operating reserves drop below 1,750 megawatts, at which point it can deploy the remainder of its emergency reserve.

The final level of the emergency alert protocol is reached when the grid's operating reserve is reduced to 1,000 megawatts. If grid operators foresee those levels dropping below the 1,000 megawatt threshold for longer than 30 minutes, then they ask the state's transmission owners and utilities to reduce electrical output by a certain amount.

As of Sunday afternoon, the system's operating reserve levels were at around 4,200 megawatts.

"The real intent of doing these rotating outages is to preserve the reliability of the system as a whole, so we kind of have to respond to whatever happens on the system," Woodfin said.

Each energy distributor can use its own discretion for how it reduces its load. Often, Woodfin said, this will cause utilities to cut power from certain neighborhoods for 15 to 30 minutes on a rotating basis.

"ERCOT determines how much is necessary to reduce the demand on the system, and then we tell the entities that own the transmission and distribution wires that they need to reduce the overall demand on the system by, say, 1,000 megawatts," he said.

To avoid that measure, grid operators will continue to ask residents to reduce their individual energy usage. Recommended measures include:

    - Reducing heaters to 68 degrees
    - Closing shades or blinds to better insulate windows
    - Turning off or unplugging nonessential appliances
    - Avoiding the use of large appliances
    - Minimizing the use of electric lights.

Large electricity consumers are asked to consider closing operations or shutting down non-essential functions.