When Power Fails, the Grid is Rarely to Blame

It’s a rare but familiar event: arriving home and the clock is blinking. That happened in a Midland neighborhood last week, when the lights went out in more than 600 homes Friday night because of electrical equipment problems. A more serious power outage affected nearly all of Lubbock for a few hours in July, with malfunctioning equipment again to blame.

The average Texan experiences a few hundred minutes of power outages each year, according to a major report recently by the Brattle Group, which has done consulting for the Texas power grid.

If Texans are already used to the lights going out because of everyday issues like storms, equipment problems or people driving into utility poles, why is there so much fuss about preventing the occasional grid-wide power outage? It’s a question implicitly posed by the Brattle Group’s report, which points out that localized outages “cause customers to lose power 100 times more often” than does the shortage of power plants, which is the preoccupation of power-grid operators as they look to the future.

Rejiggering the Texas electric market to encourage more power supply “may prove to be less cost-effective” than investing to improve local reliability, the Brattle report states.

But regulators argue that preventing grid-wide outages is paramount for the economy and public confidence. Donna Nelson, chairwoman of the Public Utility Commission of Texas, said the issue comes down to public perception.

“People understand squirrels or weather,” she said, referring to two common causes of local power-line failures. “But I think it starts to impede our ability to attract businesses to the state and people to the state if they fear that we don’t have enough electricity.”

The last outage across the Texas grid was in February 2011, when a deep freeze caused a large number of the state’s power plants to fail. Rolling blackouts, generally lasting a few hours in each area, blanketed the state all day. The jitters continued even after the lights came back on for good. 

Such events can prompt extensive press coverage and legislative hearings, noted Sam Newell, a principal at the Brattle Group and the lead author of the group’s report. “The public’s tolerance for rolling outages seems to be very low,” he said.

State Sen. Troy Fraser, R-Horseshoe Bay, who was among the lawmakers examining last year’s deep-freeze crisis, echoed Nelson’s comments.

“If you have an accidental outage caused by somebody running into the [utility] pole, there’s no way we can defend against that. Those things happen,” he said. But “for us to intentionally design a system that we know is insufficient [for] taking care of the needs of the state is not good public policy.”

Michael Webber, associate director of the Center for International Energy and Environmental Policy at the University of Texas at Austin, said in an email that while it is true that Texas homeowners are already accustomed to brief power outages and “the economic damage and risk to our health is pretty small” from events like a tree branch falling on a power line, there are still key technical reasons why a grid-wide failure is worse than a localized problem.

For one thing, grid-wide outages in Texas are most likely to occur on extremely hot summer afternoons because of increased air conditioning.

“There is a non-trivial risk of death, by mostly elderly [people], if the power outage occurs during a heat wave, depriving vulnerable people of air conditioning, refrigerated medicines and so forth,” Webber said.

On a more technical level, when power demand stretches the grid to its limit, overworked power plants can experience equipment malfunctions and trip offline, Webber said.

“In that case, a whole cascading series of failures will occur, with one power plant after another tripping offline,” he said. “Unfortunately, bringing them back online has to be done very slowly, one at a time, which takes many days [or] weeks.”

Even as Texas regulators try to prevent such catastrophes, localized outages are bound to continue. So far this year, Texans have been spared the days-long outages experienced in the Washington, D.C., area after a huge storm rolled through in June. But even small events can cause problems. In Lubbock, for example, a widespread blackout in July triggered a boil-water notice.

Last year, customers of Oncor, a Dallas-based utility, experienced 237 minutes of outages on average, with 170 minutes for Centerpoint customers and 306 minutes for AEP Central customers, according the Brattle Report. The numbers are far below what they were in 2008, according to the report, although it’s unclear if 2008 was an anomaly, and if there has been little discernible improvement since then.

New technology is helping to address the power-line problems, said Catherine Cuellar, a spokeswoman for Oncor. The utility’s rollout of smart meters is nearly complete. Every 15 minutes the meters send signals to a central database, making it easier to tell if there is a problem (and helping Oncor to create a real-time map of power outages).

In 20 percent of cases, Cuellar said, Oncor can spot a problem even before customers begin calling in — a big change from even five years ago. (The system is also set up to detect false positives, such as an electrician temporarily tinkering with the fuse-box.)

The technology represents, she said, “a huge leap forward.”