The Electricity Reliability Council of Texas (ERCOT) on August 10 set a record for electricity demand, topping 69,000 MW twice during the afternoon. The peak came as the Energy Information Administration (EIA) noted that Texas also set a record for gas power burn—natural gas usage in its power sector—reaching an average 4.5 Bcf/d through August 11.

The peak came during a recent heat wave, with temperatures across the state topping 100F. Though reserves briefly fell below 2,500 MW, ERCOT was able to weather the episode without any system emergencies. Wholesale prices peaked at $2,250/MWh during the hour period of greatest demand, which hit an all-time high of 69,783 MW.

Both ERCOT and Texas Gov. Greg Abbott called for Texans to curb their power usage until the heat wave abated, turning off unnecessary appliances and turning up thermostats to reduce the load from air conditioning.

Though ERCOT struggled with narrow reserve margins during the early 2010s, it has seen improvements since a widely reported episode in 2011 when another heat wave forced load shedding and ERCOT had to bring several mothballed plants out of retirement to bolster reliability. Since then, ERCOT has added around 10 GW of new capacity, mostly wind and gas-fired, and currently has more than 73,000 MW on the grid. Several large gas plants have come online in Temple, Sherman, and Houston, though the Sherman plant suffered a forced outage earlier this month.

Still, the state is not out of the woods.

ERCOT warned last year that the Obama administration’s Clean Power Plan could force the shutdown of multiple coal plants across the state and threaten reliability. It has not yet issued an analysis of the final rule, but it said last summer that 3.3 GW to 8.7 GW of coal-fired generation was at risk.

The plan could result in “transmission reliability issues due to the loss of generation resources in and around major urban centers, and will strain ERCOT’s ability to integrate new intermittent renewable generation resources,” it said at the time. Gas, meanwhile, would jump to a 53% share of the ERCOT power mix by 2029.

Though the state is suing to block the rule, some observers suggest the burden on the state will be lower under the final rule than with the proposed scheme. Texas’ emissions reduction target was lowered from 39% by 2030 to 34%. What effect that will have on the state’s coal power sector is not clear.

Environmental groups have claimed that a major chunk of the state’s emissions could be cut by retiring its most-polluting plants, but this would include large facilities like Luminant’s 2,250-MW Martin Lake plant near Tatum and NRG’s 2,697-MW W.A. Parish plant near Houston. (A portion of the Parish plant, though, is being retrofitted with carbon-capture technology.)

—Thomas W. Overton, JD is a POWER associate editor (@thomas_overton, @POWERmagazine).