Houston Storm Hit Most-Stressed US Grid With Power Outages at 140,000

(Bloomberg) -- Windows are still falling from skyscrapers in downtown Houston after a historic wind storm whipped through the city last week. And days after the disaster, more than 140,000 customers in the area remain without power.

Most of those homes and businesses are served by CenterPoint Energy Inc. The utility operates the most stressed local power grid in the country.

That’s according to data from Whisker Labs Inc., which developed technology to monitor grid faults and other issues. The company’s residential sensors showed that in April, CenterPoint’s territory in Houston and surrounding areas had the highest count of problems out of any of the six dozen major utilities tracked.

While there’s little protection against the kind of intense wind that hit Houston, widespread outages and prolonged recoveries are more likely to occur on grids that have already been stressed, said Bob Marshall, chief executive officer of Whisker Labs. The outages left around 1 million homes and businesses without power across the state the night of May 16.

“The overall stress of the grid is very concerning,” Marshall said. Whisker Labs has deployed 700,000 sensors to homes across the US to track voltage swings.

“At the rate the grid is getting stressed, in five years the same storm may be catastrophic,” he said. “If the grid can’t handle ‘normal’ weather, it will struggle even more in very severe weather, which results in even more damage and longer recovery.” 

Power-Quality Problems 

What happened in Houston is emblematic of widespread issues across the country. As the US grid is tested by extreme weather and increasing demand, aging infrastructure is giving way to higher counts of grid faults. The problem is one of poor power-quality, or when the flow of electricity powering lights and appliances is being delivered at an uneven or unpredictable pace, which can lead to dangerous surges, sags, brownouts and outages. 

CenterPoint said its focus now is “on restoring service to its customers as safely and as quickly as possible to meet the needs of our communities.” In an emailed statement to Bloomberg News, the company said it has invested more than $6 billion in its electric grid since 2019 to “help meet the region’s ever-increasing electric demands.” 

On Monday, the company said that some of the power outages in its area, which are expected to be substantially restored by Wednesday evening, are taking longer to fix because of secondary issues caused by unseen damage or overloaded systems.

Whisker Labs data point to underlying stress, which can be exacerbated by a storm, on the localized, household level. Utilities don’t typically report this type of granular data, at least not publicly.

In April, customers in CenterPoint’s territory in Houston and surrounding areas experienced an average of 1.79 events per household, according to the Whisker Labs figures. Those events include grid faults, or even the briefest brownouts that can cause digital clocks to flicker. The count was more than double the national average of 0.6 events. 

Derecho

In general, extreme weather will tend to increase the frequency of power-quality issues. 

Such were the conditions facing Houston when on May 16 winds reached speeds of as high as 100 miles (161 kilometers) per hour. The supercell that struck the city formed in a derecho that swept from Texas to Florida, according to Bill Bunting, deputy director of the US Storm Prediction Center. Derechos are rapidly moving lines of thunderstorms that can travel long distances and cause billions of dollars in damages owing to their strong winds that blow in a straight line as opposed to rotating like tornadoes. 

More than 900,000 of CenterPoint’s electric customers lost power at the peak of the damage from the storm. As of Tuesday midday, at least 139,835 CenterPoint customers were still without electricity, according to PowerOutage.us. 

In the hours before the storm on May 16, CenterPoint’s system was humming along with temperatures hovering around 80F (27C) and wind speeds of roughly 10-15 mph in Cypress, Texas, just northwest of Houston.

Whisker Labs data shows the storm moving in just after 6 p.m., as wind speeds began to jump. 

Voltage readings started to swing on eight sensors within a mile of each other. Lightning struck four times from 6:03 p.m. to 6:14 p.m., causing voltage to plunge. Some sensors lost power during the storm and stopped sending readings. Whisker Labs has more than 12,000 sensors deployed in CenterPoint’s territory.

As climate change sparks more extreme weather, grids across the country are being tested by lightning strikes, storms and equipment failures. That’s happening just as demand is expected to grow at an unprecedented clip this decade, with more power needed for electric vehicles and data centers that run artificial intelligence. Without a build up in infrastructure, that’s a potent combination of factors that leaves Americans more vulnerable to longer-lasting power failures. 

“The grid’s got to be resilient to the weather conditions that it’s going to face,” Marshall said. 

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