Texas grid operator initiates rotating power outages in wake of freezing temperatures

by Paul Ciampoli
APPA News Director
February 15, 2021

In the wake of record-setting freezing temperatures, the Electric Reliability Council of Texas (ERCOT) entered emergency conditions and initiated rotating outages at 1:25 a.m. on Monday, Feb. 15.

Two other grid operators — the Southwest Power Pool (SPP) and the Midcontinent Independent System Operator (MISO) — were also taking steps in response to bitterly cold temperatures. SPP instituted rotating outages on Feb. 15.

“We continue to have communication with our members about this evolving situation and look forward to continuing to work with them to help address this serious situation,” said Joy Ditto, President and CEO of the American Public Power Association.

“A sprawling winter storm continued to sweep across the country on Monday, knocking out power for millions of people as it dumped snow and ice in places where such perilously frigid conditions tend to arrive just once in a generation,” the New York Times reported on Feb. 15.

ERCOT

About 10,500 megawatts of customer load was shed at the highest point, ERCOT said on Feb. 15.

“The entire state was below freezing on Monday, with temperature ranging from 25 degrees in Brownsville in the south to 15 degrees below zero in the Panhandle,” CNN reported in a story posted on its website.

Extreme weather conditions caused many generating units across fuel types to trip offline and become unavailable, ERCOT said, noting that there was over 30,000 MW of generation forced off the system as of the early morning hours of Feb. 15.

“Every grid operator and every electric company is fighting to restore power right now,” said ERCOT President and CEO Bill Magness, in a statement.

Rotating outages will likely last throughout the morning and could be initiated until this weather emergency ends, ERCOT said on Feb. 15.

On Sunday, Feb. 14, ERCOT asked consumers and businesses to reduce their electricity use as much as possible through Tuesday, Feb. 16.

“We are experiencing record-breaking electric demand due to the extreme cold temperatures that have gripped Texas,” said Magness. “At the same time, we are dealing with higher-than-normal generation outages due to frozen wind turbines and limited natural gas supplies available to generating units. We are asking Texans to take some simple, safe steps to lower their energy use during this time.”

ERCOT starts to restore power

Later in the day, ERCOT reported that it was beginning to restore some of the power lost due to the winter weather event in Texas.

As of 4 p.m., approximately 2,500 MW of load was in the process of being restored.

“ERCOT and Texas electric companies have been able to restore service to hundreds of thousands of households today, but we know there are many people who are still waiting,” said Magness. “It’s also important to remember that severe weather, mainly frigid temperatures, is expected to continue, so we’re not out of the woods.”

At the time, the grid operator said it was instructing transmission owners to shed approximately 14,000 MW of load, down from 16,500 MW earlier in the day.

Controlled outages will likely last throughout the evening and into Tuesday, Feb. 16 as ERCOT works to restore the electric system to normal operations.

White House issues emergency declaration

Texas Gov. Greg Abbott on Feb. 14 announced that the White House had issued a Federal Emergency Declaration for Texas in response to the severe winter weather throughout the state. The governor submitted a request for this declaration on Saturday to assist the state in response efforts related to the storm.  

The Federal Emergency Declaration authorizes the Federal Emergency Management Agency to provide emergency protective measures for mass care and sheltering and Direct Federal Assistance for all 254 counties in Texas.

Abbott on Feb. 12 declared a state of disaster in all 254 Texas counties due to severe weather posing an “imminent threat of widespread and severe property damage, injury, and loss of life due to prolonged freezing temperatures, heavy snow, and freezing rain statewide.”

Also on Feb. 12, the Railroad Commission of Texas issued an Emergency Order pursuant to Texas Utilities Code affecting the gas utility systems in the state. The order specified increasing the priority of gas supplies to ERCOT generators.

Public power utilities in Texas

Public power utilities in the state were affected by the outages and took a number of steps to keep their customers up to date with the latest news and ways that they can help conserve electricity.

In the early morning hours of Feb. 15, San Antonio-based CPS Energy noted that as part of its participation in ERCOT and the critical nature of this stage, “we are required to participate in coordinated rotating outages in an effort to prevent larger and more extreme impacts on the Texas grid. CPS Energy is also asking natural gas customers to reduce energy use as well.”

“Rotating outages are necessary to help preserve the integrity of the Texas electric grid,” said Rudy Garza, Chief Customer Engagement Officer for CPS Energy.  “It is crucial that we, along with other Texas utilities, implement rotating outages as directed by ERCOT. The mandatory request for load shed can be subsidized by residential and commercial customers doing what they can to reduce energy use.”

Meanwhile, Texas public power utility Austin Energy on the morning of Feb. 15 said that due to the severity of weather and the condition of the electric grid, rotating outages in the Austin Energy area were lasting longer than the expected duration. “To serve critical loads and protect the overall reliability of the grid, customers experiencing an ERCOT-directed outage will remain out until conditions improve,” it said.
 
“The situation continues to worsen across Texas and here in Austin,” said Austin Energy General Manager Jackie Sargent. “Austin Energy implemented required outages early Monday morning, doing our part to help stabilize the ERCOT grid. The required outages are more extensive than anyone expected and do not allow us to bring affected customers back online at this time. We will continue working with ERCOT and working through our contingency plans to get power back on to customers as soon as the grid allows.”
 
Conservation is still needed by those who have power. Customers are urged to keep electric use to only what is essential for heating and safety, Austin Energy said.

The utility noted that ERCOT declared an Energy Emergency Alert Level 3, calling for rotating outages across the state.  Rotating outages are controlled, temporary interruptions of electrical service implemented by utilities when it is necessary for ERCOT to reduce demand on the system. This type of demand reduction is only used as a last resort to preserve the reliability of the electric system as a whole.

When power is restored, circuits can become overloaded because of lights, electronics and thermostats left on prior to the outage. This is called cold load pickup and can cause a second outage.

Austin Energy said that customers currently without power can help the utility avoid cold load pickup by turning off their thermostats, turning off or unplugging any fixtures or appliances and only leaving on one light to indicate when the power is back on.

A number of other public power communities also proactively kept their customers up to date on the rotating outages.

In a Feb. 15 Facebook post, the City Hall of Denton, Texas, noted that the duration and frequency of outages depends on the severity of the event and the directions provided by ERCOT.

“Due to the severity of the statewide electric supply shortfall, our originally expected 30 min. outage time has been significantly extended,” the post said. “In addition, we are responding to separate outages caused by the record-breaking weather. We are doing everything possible to respond to this event and keep power on for as long as statewide electric supply will allow.”

The City of Denton is served by public power utility Denton Municipal Electric.

Texas public power utility Greeneville Electric Utility System (GEUS) issued a news release on Feb. 15 in which it noted that ERCOT is encouraging all consumers to reduce their electricity usage to the lowest possible. “Your conserving electricity now can improve ERCOT’s grid reliability and possibly avoid prolonged rotating outages and/or blackouts should conditions worsen,” GEUS said.

New Braunfels Utilities also issued a news release noting ERCOT’s declaration of an Energy Emergency Alert Level 3 and detailing steps that customers can take to help reduce electricity usage and manage their utility bills.

“It is very important that all utilities participate in helping reduce strain on the electric grid, and at this time ERCOT has determined that this can only be accomplished by shedding load from the system,” said Gary Miller, General Manager of Texas public power utility Bryan Texas Utilities.

“BTU’s primary concern is the safety and well-being of our customers, and while these outages are certainly not ideal, they are in the best interest of our service territory and the integrity of the Texas electric system as a whole.”

During this period of rolling blackouts, customers are urged to reduce their electric load to the smallest amount possible, by turning off all unnecessary lighting, appliances, and electronic equipment, BTU said. Additionally, businesses should avoid starting equipment that utilizes a large amount of electricity, and postpone any non-essential production processes, it said in a news release.

“ERCOT is doing everything in its power to keep the electric system from going critical. Consumers are asked to lower thermostats & turn off unneeded appliances/lights,” the public power city of College Station, Texas, said in a tweet.

Other Texas public power utilities and communities that issued news releases or leveraged their social media channels to provide updates on the rotating outages included the City of Georgetown, Kerrville Public Utility Board, Floresville Electric Light and Power System and Brownsville Public Utilities Board.

U.S. Department of Energy issues emergency order

On Feb. 14, the U.S. Department of Energy (DOE) issued an emergency order under section 202(c) of the Federal Power Act relaxing environmental restrictions on certain units in ERCOT through Feb. 19. The order was issued by David Huizenga, Acting Secretary of Energy.

“ERCOT is in the beginning stages of an unprecedented cold weather event brought on by a rare, southward excursion of the jet stream into the South Central United States,” the order states. Temperatures for Sunday and Monday in many parts of Texas are forecasted to drop well below the lowest temperatures experienced in several decades, and abnormally low temperatures are expected to persist for several more days. This weather event is expected to result in record winter electricity demand that will exceed even ERCOT’s most extreme seasonal load forecasts.”

ERCOT had asked the DOE to immediately issue an order, effective February 14, 2021 through February 19, 2021, authorizing “the provision of additional energy from all generation units subject to emissions or other permit limits” in the ERCOT region.

“Given the emergency nature of the expected load stress, the responsibility of ERCOT to ensure maximum reliability on its system, and the ability of ERCOT to identify and dispatch generation necessary to meet the additional load, I have determined that additional dispatch of the specified resources is necessary to best meet the emergency and serve the public interest for purposes of FPA section 202(c),” wrote Huizenga.

“Because the additional generation may result in a conflict with environmental standards and requirements, I am authorizing only the necessary additional generation, with reporting requirements” detailed in the order.

Southwest Power Pool

Meanwhile, due to an unprecedented energy demand during record low temperatures, SPP, Lincoln Electric System’s (LES) regional reliability coordinator, had notified utilities within its regional footprint that energy curtailments are required, LES, a Nebraska-based public power utility, said on Feb. 15.

SPP declared an Energy Emergency Alert Level 3, which means utilities across the SPP region have been instructed to begin rotating planned outages because there is not enough power available to keep up with customer demand, LES noted.

SPP reported late in the afternoon that after directing member utilities to implement controlled interruptions of service shortly after noon on Feb. 15, SPP had restored load to its 14-state region as of 2:00 p.m. Central time. “The grid operator now has enough generation available to meet demand throughout its service territory and to fully meet its minimum reserve requirements,” it said.

The SPP system reached a peak electricity usage of 43,661 MW on Feb. 15 and is required to carry additional operating reserves in excess of load, it noted. After committing all of its reserves and exhausting other avenues such as importing power from other regions, available generation in SPP fell about 641 MW short of demand for a period beginning just after noon. In response, SPP directed its member utilities to implement planned interruptions of service to curtail electricity use by that amount.

Effective at 2:00 p.m., SPP cancelled the Energy Emergency Alert Level 3 it had declared at 10:08 a.m. when its reserves were exhausted and re-entered an EEA Level 2. SPP’s forecasts anticipate that due to high load and persistent cold weather, it is likely its system will fluctuate between EEA Levels 2 and 3 over the next 48 hours and may have to direct further interruptions of service if available generation is inadequate to meet high demand.

At 10:08 a.m.  Central time on Feb. 15, SPP declared an Energy Emergency Alert Level 3 in response to conditions created by persistent and extreme cold across its service territory. An EEA3 signals that SPP’s operating reserves are below the required minimum. SPP has also directed its member utilities to be prepared to implement controlled interruptions of service if necessary to mitigate the risk of more widespread and longer-lasting outages.

LES had asked customers to continue to voluntarily and safely implement one or more energy-saving measures listed on LES.com.

LES later reported that it had stopped controlled outages after only going through two cycles. “While LES hasn’t received additional requests from the Southwest Power Pool to curtail, we ask customers to remain prepared for rotating outages over the next 36 hours,” LES said.

Another public power utility, Omaha Public Power District (OPPD) on Feb. 15 posted a tweet stating that OPPD and other utilities were asking customers to conserve energy now, “as the bitter cold continues in our region.” OPPD president and CEO Tim Burke addressed the polar vortex event in a YouTube video.

“We are asking customers to conserve energy,” Nebraska Public Power District (NPPD) said in a Feb. 15 Facebook post. “The record cold forecast is putting a high demand on the electrical system.”

In Missouri, City Utilities of Springfield reported that it had been told to reduce its electric load within the SPP. This is a combined group of power generating utilities throughout 14 states and all utilities are under similar reduction requirements. “This process has started at this time,” CU noted in a news release.

CU “will begin what is commonly known as a rolling blackout in sections of Springfield. These will last from 30 to 60 minutes in duration and will be executed in different areas of the city. All areas of the City Utilities electric service territory may potentially be impacted.”

The Kansas City Board of Public Utilities (BPU) on Feb. 15 reported that it was asking customers to conserve electricity use as much as possible through Wednesday, Feb. 17, at the request of SPP.

The SPP “advises that the region’s coldest weather in decades is creating high demand for electricity. At the same time, the extreme weather is driving high demand for natural gas used to heat homes and businesses, straining the gas supply available to generate electricity, and icy conditions have made availability of wind generation uncertain,” Kansas-based BPU said.

“Everybody must do their part to save electricity the next few days and this in turn will help us make sure the power supply continues to best serve the region’s needs,” said David Mehlhaff, BPU Chief Communications Officer.

Later in the day, BPU reported that beginning on February 15 at 12:10 p.m., BPU began to turn off electricity to blocks of customers for approximately 40 minutes. Once the period concluded, power was restored to the impacted area. The emergency outages will then rotate to another portion of BPU’s service area and power may cycle off and on periodically until the reduction is no longer required by the SPP, BPU said.

MISO also takes action in response to weather

Meanwhile, MISO on Feb. 15 said that sustained frigid temperatures and winter weather impacting the MISO South Region contributed to the loss of generation and transmission. This led to emergency actions in the region’s western portion to avoid a larger power outage on the bulk electric system.  Periodic power outages began early Monday morning for some customers in Southeast Texas.

“We fully committed every available operating asset before the event to lessen the impact on our system, but conditions eventually deteriorated to a point where demand exceeded supply,” said Renuka Chatterjee, executive director – System Operations at MISO. “The accelerated change in conditions led us to our last resort in order to maintain grid reliability and we are in direct communication with our members to support their restoration efforts in the affected areas.”

MISO and its members worked together to identify the worst-case scenarios to limit the effects of temporary power supply interruptions to those areas that will provide the most relief, it said. That plan focused on the forecasted load demand and expert weather forecast as well as the risks associated with generation availability and transmission capacity across the region.

“This was truly a coordinated effort with all of our members to avoid a potentially larger grid outage,” said Daryl Brown, executive director – South Region at MISO.  “We are in direct communication with our members in the affected area to support their restoration efforts.”

Periodic power outages are always the last stage of several emergency procedures and steps taken to maintain grid reliability, MISO said.

Later in the day, MISO declared a Maximum Generation Event – Emergency Event Step 2c in its South Region due to the extreme cold and weather conditions causing high demand on the bulk electric system.

The declaration was effective February 15 at 6 p.m. until 10 p.m. ET. As part of its emergency procedures, MISO directed South Region members to make a public appeal of conservation to their customers to avoid a larger power outage.

“The frigid temperatures have increased the number of uncertainties and conditions are changing to a point where demand could exceed supply,” said Chatterjee. “We’re moving into uncertain territory which is why we are asking the public for assistance.”

MISO said that this is a highly unusual situation with current power demand nearly exceeding what current generation and transmission can supply because of the extreme weather. The situation has been taking a toll on parts of the bulk electric system limiting MISO’s ability to import electricity from neighbors that are in a similar situation, it said.

“Our members regularly provide customers advice on how to conserve regardless of weather conditions,” said Brown. “However, we are specifically asking those customers in the South Region to heed that advice and limit electricity usage to only the most essential functions so we can avoid a larger grid outage.”

The Maximum Generation Event – Emergency Event Step 2c notification includes instructions for Local Balancing Authorities to issue a public appeal to reduce demand. MISO Operating Conditions FAQs provide details on the necessary steps to manage system demand and ensure grid reliability during tight situations. MISO said it woud continue closely monitoring conditions in the South Region for the duration of the winter weather event.

FERC closely monitoring weather conditions

The Federal Energy Regulatory Commission “is closely monitoring the extreme weather conditions occurring in much of the country and the impact they are having on electric reliability,” said FERC Chairman Richard Glick.

“The Commission is in contact with ERCOT, SPP and MISO — as the regions served by these grid operators have been particularly hard hit by record cold and wintry precipitation.  Safeguarding the reliability of the bulk power system is paramount and I have directed FERC staff to coordinate closely with the RTOs/ISOs, utilities, NERC, and regional reliability entities to do what we can to help,” he said. 

“In the days ahead, we will be examining the root causes of these reliability events, but, for now, the focus must remain on restoring power as quickly as possible and keeping people safe during this incredibly challenging situation.”