Texas' largest and oldest electric power cooperative on Monday filed for bankruptcy protection, citing the crush of a massive bill from the state's grid operator, following last month's winter storm that left millions without power for days.
Brazos Electric Power Cooperative filed for Chapter 11 after racking up an estimated $2.1 billion in charges, which the state's grid operator, known as ERCOT, said went unpaid.
Brazos, which supplies electricity to more than 660,000 consumers across the state, is one of dozens of providers facing enormous charges stemming from the deep winter freeze.
The company said the fallout threatens utilities and power marketers, which collectively face billions of dollars in blackout-related charges.
Unusually frigid temperatures knocked out nearly half of the state's power plants in mid-February, leaving 4.3 million Texans without heat or light for days and bursting water pipes that damaged homes and businesses.
Brazos and others that committed to provide power to the grid - and could not - were required to buy replacement power as prices soared.
ERCOT triggered the squeeze when it pushed up spot-market rates to $9,000 per megawatt hour over more than four days and levied huge fees for services.
Pre-storm prices were less than $50 per megawatt hour, according to ERCOT data.