A rare deep freeze in Texas that raised demand for power forced the US state's electric grid operator on Monday to impose rotating blackouts that left more than 2 million customers without electricity.
Power grid operator Southwest Power Pool, which coordinates electricity supply across a vast swath of the country, on Monday declared an "Energy Emergency Alert Level 2" due to energy shortages. Controlled outages are occurring to protect the electric grid from uncontrolled, cascading outages.
Responding to a request from Governor Greg Abbott, President Joe Biden granted a federal emergency declaration for all 254 counties in the state on Sunday, authorising USA agencies to coordinate disaster relief from severe weather in Texas.
These are the first rolling blackouts caused by cold weather since 2011 in Texas.
Ice storms knocked out almost half the wind-power generating capacity of Texas as a rare deep freeze across the state locked up turbine towers. In the Dallas-Fort Worth area it was 5 degrees Fahrenheit.
The storms knocked out almost half of Texas' wind power generation capacity on Sunday.
Frigid temperatures and a parade of storms in the USA follow other instances of extreme winter weather this year that have snarled ports and upended energy markets in Asia and Europe.
More than 3.8 million homes and businesses were without power across Texas on Monday, based on utility outage data compiled by Poweroutage.us.
Odessa in West Texas, one of the largest cities in the Permian Basin, still has power, but San Antonio has lost power with rolling blackouts lasting 10-15 minutes, according to sources on the ground.
"This impressive onslaught of wicked wintry weather across much of the Lower 48 is due to the combination of strong Arctic high pressure supplying sub-freezing temperatures and an active storm track escorting waves of precipitation from coast-to-coast".
"The southern plains are in a cold pattern", said David Roth, a senior branch forecaster at the U.S. Weather Prediction Center.