By Steve Gorman
(Reuters) - Ice storms knocked out nearly half the wind-power generating capacity of Texas on Sunday as a rare deep freeze across the state locked up turbine towers while driving electricity demand to record levels, the state's grid operator reported.
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, authorizing U.S. agencies to coordinate disaster relief from severe weather in Texas.
The winter energy woes in Texas came as bone-chilling cold, combined with snow, sleet and freezing rain, gripped much of the United States from the Pacific Northwest through the Great Plains and into the mid-Atlantic states over the weekend.
An Arctic air mass causing the chill extended southward well beyond areas accustomed to icy weather, with winter storm warnings posted for much of the Gulf Coast region, Oklahoma and Missouri, the National Weather Service said.
The Electric Reliability Council of Texas (ERCOT), the state's grid operator, issued an alert asking consumers and businesses to conserve power, citing record-breaking energy demands due to extreme cold gripping the state.
"We are dealing with higher-than-normal generation outages due to frozen wind turbines and limited natural gas supplies available to generating units," the agency said.
Wind farms in West Texas, stricken by weekend ice storms, were particularly hard hit.
Of the 25,000-plus megawatts of wind-power capacity normally available in Texas, some 12,000 megawatts was out of service as of Sunday morning "due to the winter weather event we're experiencing in Texas," ERCOT spokeswoman Leslie Sopko said.
Wind generation ranks as the second-largest source of energy in Texas, accounting for 23% of state power supplies last year, behind natural gas, which represented 45%, according to ERCOT figures.
Forecasts call for heavy snow and freezing rain to spread across a larger swath of central and eastern sections of the country through Monday, with a storm front in the West likely to dump 1 to 2 feet of snow in the Cascades and northern Rockies through Tuesday, according to the weather service.
(Reporting by Steve Gorman in Los Angeles; Additional reporting by Erwin Seba in Houston and Heather Timmons in Washington; editing by Diane Craft)