Texans shiver as Arctic cold cuts power

Millions of people in Texas have woken without heat again, as power failures continued to plague the state following a historic winter storm that has killed 21 people so far.

Texas Governor Greg Abbott and other top officials in the state, the country's second largest, are demanding answers from operators and leaders at the Electric Reliability Council of Texas (Ercot), an energy cooperative responsible for 90 per cent of the state's electricity.

The storm has killed at least 21 people across four states, and the cold is not expected to let up until this weekend. The weather has shuttered COVID-19 inoculation centres and hindered vaccine supplies.

"We knew a week in advance this storm was coming," Abbott said during an interview on KLBK television, the CBS affiliate in Lubbock. "Ercot should have had a backup plan."

Lina Hidalgo, the top executive in Harris County, which encompasses Houston, warned residents to brace for prolonged problems.

"Let me give it to you straight," she wrote on Twitter Tuesday night. "There's a possibility of power outages even beyond the length of this storm."

Texas' deregulated energy market gives little financial incentives for operators to prepare for the rare bout of intensely cold weather, critics have said for years.

Natural gas wells and pipelines in Texas, the country's biggest energy-producing state, do not undergo the winterisation of those farther north - resulting in many being knocked offline by the prolonged freezing weather.

Abbott demanded that state lawmakers investigate what went wrong and pass reforms to the Electric Reliability Council of Texas, which oversees the electricity grid.

The storm has knocked about a third of the state's generating capacity offline. The power grid in Texas relies heavily on natural gas, responsible for nearly half the electricity generated.

Over 4 million people in Texas were without power as of late Tuesday, including 1.4 million people in the Houston metropolitan area. A quarter of homes in Dallas were dark.

President Joe Biden assured the governors of states hit hard by storms that the federal government stands ready to offer any emergency resources needed, the White House said in a statement.

Storms dumped snow and ice from Ohio to the Rio Grande through the long Presidents Day holiday weekend, and treacherous weather was expected to grip much of the United States through Friday.