Power use in 2009 slipped 1.3 percent from the previous year as economic activity slowed.
Across the United States, 2010 electricity output rebounded 3.7 percent from 2009, the largest annual jump since 2005. The rise was also attributed to extreme summer weather, according to the Edison Electric Institute.
U.S. electric use last year remained below levels seen before the recession began in late 2007 while Texas power use surpassed 2008's mark, ERCOT said.
Output from wind and coal-fired generation increased last year as new facilities came online, paring the share of power generated by natural gas-fired plants for a third straight year, ERCOT said.
Texas leads the nation in installed wind capacity, which grew to 9,528 megawatts at the end of 2010, up 612 MW from the previous year, ERCOT said.
Wind farm additions are expected to drop dramatically this year as developers await a $5 billion expansion of the transmission network to allow more wind power to flow from remote areas of the state to power-hungry cities.
In April and November, overall wind usage jumped to 12.1 percent and several hourly records were set during the year.
Coal plants supplied 39.5 percent of the power used in Texas last year, up from 36.6 percent in 2009 as four new coal units were completed.
Power from gas-fired generation slipped to 38.2 percent, down from 42.1 percent in 2009 and more than 45 percent back in 2007, according to ERCOT.
Weather played a large part in ERCOT's electric rebound. The region set an hourly winter peak on January 8 of 55,878 MW, nearly 5,000 MW above the previous winter peak set in 2007.
Over the summer, ERCOT set four hourly records, topping out at 65,776 MW on August 23.
Above-normal heat boosted energy use in August by 7 percent compared to 2009 as temperatures in the Dallas area were 4 degrees Fahrenheit hotter and Houston was 1 degree hotter, ERCOT said.
One megawatt can supply about 500 average Texas homes, but only 200 homes during hot weather when air conditioners run for extended periods.