After extreme cold events in 1989 and 2011, Texas was warned to winterize power plants - but many still froze in the latest storms

• Millions of Texans lost power this week as extreme winter weather shut down power plants.
• The event was not unprecedented, as Texas power plants have been disrupted by cold weather before.
• Following disruptions in 2011, federal regulators again warned Texas to winterize its power plants.

The severe winter weather in Texas this week showed some power plants in the state were unprepared for the extreme cold - but it wasn't the first time the state has faced this issue.

Texas has received warnings about its preparedness going back at least three decades.

In 1989 and 2011, Texas experienced significant power disruptions as a result of severe winter storms. Following both events, government regulators recommended power plants in the state prepare their facilities for the extreme cold.

Fast forward to this week, when severe winter storms again disrupted Texas's power plants, causing millions to go without power for several days.

In 2011, federal regulators were already critical of the state's lack of winterizing facilities when it was clear it was needed.

A report prepared by the Federal Energy Regulatory Commission, a federal agency, and the North American Electric Reliability Corporation, a nonprofit, examined electric and natural gas disruptions across the Southwest during the 2011 cold weather event.

It found 210 power generating units under the jurisdiction of the Electric Reliability Council of Texas experienced an outage or disruption over a few days in February 2011, affecting 3.2 million people. ERCOT, a nonprofit, still oversees the state's electrical grid.

The authors of the report also determined that, while especially severe, the 2011 cold event was not without precedent. They found there had been several instances of severe cold weather impacting power prior to 2011, particularly in 1989.

The report said that in that year, following the power disruptions caused by cold weather, the Public Utility Commission of Texas recommended several actions to ensure power plants could withstand extreme weather. Those actions included yearly reviews to check for cold-weather preparedness, maintaining proper insulation, and employee training for cold weather emergency situations.

However, those actions were not mandatory, and more than two dozen of the generators that failed in 1989 failed again in 2011. The report criticized the repeated failures and the fact that power plants were not required to prepare for cold weather following the 1989 event.

ERCOT has yet to announce which generators failed during this week's severe storms, though they have said that information will be released after a review, local outlet WFFA reported.

The 2011 report also said that while power generators and natural gas producers implemented some winterizing procedures, "the poor performance" of many of them "suggests that these procedures were either inadequate or were not adequately followed."

In the report's key findings, the authors said the lack of any direct requirement for power plants to winterize "left winter-readiness dependent on plant or corporate choices."

It also noted that while the severe winter storms are less common in the Southwest than other places, when they do occur, "the cost in terms of dollars and human hardship is considerable."

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