It's summer in the Lone Star State and the Electric Reliability Council of Texas (ERCOT) is setting power demand records again.
For two consecutive hours Wednesday, ERCOT systemwide demand surpassed the previous record that was set last Monday. Peak demand reached 70,531 megawatts (MW) between 3 and 4 p.m. CDT Wednesday and then blew past that new record with 70,572 MW of demand between 4 and 5 p.m. This topped Monday's record by 403 MW.
According to ERCOT, for the Monday peak, 56.93% of the power used came from natural gas-fueled plants; 26.57% came from coal; 8.04% was from wind; 7.05% was from nuclear; and 1.4% came from other sources such as hydropower, renewables and diesel. Data was not yet available for the Wednesday peaks.
Those figures represent a 68-32% ratio of natural gas versus coal use. To put that in perspective, for all of 2014, which is the most recent full-year data available from the U.S. Energy Information Administration, Texas had a natural gas-to-coal use ratio of 43-57%.
ERCOT's Seasonal Assessment of Resource Adequacy for this summer, released in May, projected 78,434 MW of total generation capacity to serve projected peak demand of 70,588 MW. This includes 680 MW of new natural gas-fired generation resources that were expected to begin operating by summer peak; 410 MW of new planned wind generation capacity (counted at 12% availability); and another 7 MW of planned grid-level solar generation capacity (counted at 80%).
Dan Woodfin, ERCOT director of system operations, said the grid was continuing to meet heightened demand driven by air conditioning as temperatures climbed to the high-90s. "These hot summer days always put our grid to the test, and we have had sufficient generation available to carry us through these high-demand periods," Woodfin said.
On Wednesday ERCOT said another demand record could be on the way for Thursday between 3 and 6 p.m. "Based on current projections, we also don't expect any issues [Thursday]," Woodfin said. "That will depend in part on whether generation, including wind, remains available at levels similar to what we saw [Wednesday]."
One megawatt is enough generation to serve about 200 homes during peak demand, which generally occurs between the hours of 3 and 7 p.m. on hot summer days. August is typically the hottest summer month in Texas, and demand usually increases during this time.
Previous ERCOT demand records have been set on Aug. 5, 6 and 10 in 2015 and Aug. 3, 2011. Last Monday's demand record was the first to break the 70,000 MW barrier.