AUSTIN (KXAN) — People without power currently could be forced to remain without power through Tuesday, according to an emergency update from Oncor.

“The Texas power system is currently facing an unprecedented shortfall of electric generation,” Oncor said in a statement. “The Electric Reliability Council of Texas (ERCOT) has requested Oncor and utilities across the state to implement controlled power outages to reduce high demand and protect the integrity of the electric grid.

“We are asking all Oncor customers to be prepared to be without power for an extended period of time.”

All Texas electric utilities could face similar extended outages, ERCOT said in a news briefing Monday morning.

“These outages will continue until there’s sufficient generation being able to be brought back online to meet the demands on the system,” said Dan Woodfin, ERCOT’s senior director of system operations. “At this time we anticipate that we’ll need to continue these control outages at some level for the rest of today and at least first part of [Tuesday], perhaps all day tomorrow.”

Just before 4 p.m. Monday, Abbott tweeted the Public Utilities Commission tells him 500,000 residential customers are having power restored at this time. He expects more positive news this evening.

What’s happened to the Texas power grid?

Gov. Abbott maintains the power grid is not broken, but said that parts of the grid had to be shut down, including natural gas and coal generators.

ERCOT gave a more detailed assessment of its facilities Monday morning.

“Going into the event we had a significant number of natural gas fuel generators that were unavailable,” Woodfin explained. “And we had some wind turbines that were out due to the ice buildup.”

Woodfin said the outages began as rotating outages but ERCOT had to switch to controlled outages — which can be much, much longer — due to the magnitude of the demand.

ERCOT says emergency plan was adequate

ERCOT, in responding to a question from News 4 San Antonio, said it felt its emergency plan has been fine — there’s just been record demand.

“Would you say that your emergency plan was inadequate?” asked Jaie Avila of News 4.

“Not at all,” Woodfin said. “The plan actually has worked. There’s just insufficient supply of generation on the grid, very high demand on the grid. The plan is intended to preserve the reliability of the grid as a whole.”

“You have to go back to the 1940s or something, to see these kind of conditions,” Woodfin added. “This event was well beyond kind of the design parameters or or even as extreme as you would normally planned for.”

FAQs from Oncor

Q: Why is my power out?

There are two major issues affecting many of customers right now: winter storm outages and controlled power outages directed by ERCOT, which serve to reduce high demand and protect the integrity of the electric grid. Due to the fast moving nature of these two power emergency events, we are not currently able to break down the difference in outages on our Oncor Outage Map.

Q: When will my power be restored?

Given the unique combination of lack of generation and historic winter storm damage, estimated restoration times are not yet known. For outages related to the winter storm, our crews continue working around the clock to restore power. However, continued winter impacts such as extreme cold, treacherous road conditions and ice buildup is impacting progress.

Controlled outages related to grid supply and demand have been significantly extended due to the current emergency grid conditions and severe cold weather. In order to preserve the reliability of the grid, ERCOT has said that additional generation will be needed before power can be restored.

These outages are taking place across the service territory and ERCOT has said they could be required through Tuesday. We are asking all Oncor customers to be prepared to be without power for an extended period of time.

Q: Why are some homes out for hours and others for minutes or not at all?

Again, there are two major issues affecting many of customers right now: winter storm outages and controlled power outages directed by ERCOT. We are using all designated power lines for controlled outages so that hospitals and other critical infrastructure remains intact and system stability is preserved. This means that customers near critical facilities, or those in limited areas where rolling outages won’t take place in order to maintain grid stability, may not experience outages, while those farther from these facilities or areas may be out multiple times or for longer instances.

Additionally, during instances of substantial generation drop, there are safeguards built into the system that drop power loads automatically in order to prevent cascading widespread outages, or ultimately a blackout. These are designed to be shorter term drops that are reset quicker than controlled outages to prepare for the next response opportunity.

Q: When will power generation plants come back on-line?

Due to the severe winter storm, we do not know and it is outside of our control. Conditions for power generation continue to be very serious and the combination of winter weather and reduced generation is unprecedented in the state of Texas. We are prepared for emergency operations to continue for at least several days.