HOUSTON, Dec 11 (Reuters) - An extended cold spell across much of Texas pushed power use to a third December record on Tuesday morning, according to preliminary data from the state's power grid operator.
Power demand on Tuesday morning reached 53,690 megawatts in the hour ending at 8 a.m. CDT (1400 GMT), surpassing the 52,279 MW record set Saturday evening, according to the website for the Electric Reliability Council of Texas (ERCOT), the state's primary grid.
A day earlier, power use of 51,484 MW broke the December 2011 record of 50,100 MW.
The latest December peak is 7 percent above the 2011 record.
Real-time power prices rose briefly to nearly $300 per megawatt-hour in some areas of the state during the early morning hours Tuesday.
The state continues to warm up from a weekend winter storm that pushed temperatures 25 to 30 degrees below normal for mid-December in Houston, San Antonio and Dallas, Texas' largest cities.
Although the state experienced a fairly mild summer, ERCOT has now set new monthly power demand records in October, November and December.
Electricity use in Texas has been growing faster than generation is being built, shrinking the region's reserve margin and increasing the prospect of rolling outages when supplies are stretched, the grid operator has warned.
Regulators have made numerous market changes to encourage new generation in the state, but they remain divided on a long-term solution.
ERCOT's recent focus has turned to state power use and working to better understand how the state's growing economy impacts electric consumption.
Texas normally sees peak cold-weather power demand in January or February. December's record power demand has surpassed the grid agency's winter forecast of less than 50,000 MW under normal weather conditions.
ERCOT's winter consumption record is 57,265 MW set on Feb. 10, 2011, during an extreme statewide cold spell. The state's all-time peak use of 68,305 MW occurred in August of the same year during a prolonged heat wave and drought.
One megawatt can power about 500 homes during mild weather conditions and about 200 homes during high-demand summer months, ERCOT said.
Power producers in Texas include Luminant, a unit of privately held Energy Future Holdings, NRG Energy , Calpine Corp, NextEra Energy and Exelon Corp.