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With freezing weather sweeping into Texas at the end of this week, subsidiaries of a major pipeline company are threatening to cut off natural gas to the state's largest electricity generator - which could affect the electricity supply to hundreds of thousands of customers - due to an economic dispute dates from last year. February's deadly winter storm.

Vistra Corp. subsidiary Luminant on Wednesday asked the Railroad Commission of Texas, which regulates the state's oil and gas industry, to prevent Energy Transfer LP from shutting down fuel at five Vistra power plants, which produce enough electricity to supply 400,000 Texas homes, businesses and critical infrastructure such as hospitals and schools.

The companies under Energy Transfer, the pipeline company, have told Vistra that gas will stop flowing to five Vistra power plants on Monday unless Vistra pays Energy Transfer $ 21.6 million, according to the application.

"The threat to end the service in the middle of winter is illegal and grossly irresponsible and should be banned by this commission," Vistra said in the complaint to the railway commission.

Vistra called the Energy Transfer initiative, run by billionaire Kelcy Warren, "a form of commercial blackmail."

During last year's winter storm - which caused the near-total collapse of the state's electricity grid, leaving millions without power for days and causing hundreds of deaths - Vistra spent about $ 1.5 billion on natural gas, "double its planned natural gas cost to burn it all." The Texas Navy for an entire year, "the filing states. Vistra paid Energy Transfer more than $ 600 million during the storm," which is more than 96% of all amounts invoiced by [Energy Transfer]. "

The cost of natural gas skyrocketed during the storm as a combination of freezing temperatures across the state and sky-high demand shut down interdependent natural gas plants and power plants to keep electricity afloat.

While many companies lost money during the storm, Energy Transfer earned $ 2.4 billion. Energy Transfer did not immediately respond to a request for comment.