Texas power demand to exceed planned supply midafternoon July 13: ERCOT

The Electric Reliability Council of Texas forecasts power demand to exceed planned supply on July 13, beginning around 2:45 pm CT and ending around 5:15 pm CT, and it appealed to the public to curtail demand from 2 pm to 9 pm.

Around 11 am CT July 13, ERCOT forecast load to peak at 78.9 GW for the day at 5:10 pm CT, when total planned supply would total just 78.2 GW.

As of 11:45 am CT, the ERCOT systemwide hub average price was $716.40/MWh, up from the five-year average of $26.13/MWh for that date.

CustomWeather forecast ERCOT's population-weighted average high temperature to be 101.1 F on July 13, compared with the normal high of 94.6 F.

Conservation 'a reliability tool'

In its appeal for conservation, ERCOT said the July 13 situation resembles that of July 11, when Texas individuals and businesses met record power demand by cutting energy use by 500 MW.

"Conservation is a reliability tool ERCOT has deployed more than four dozen times since 2008 to successfully manage grid operations," ERCOT said. "This notification is issued when projected reserves may fall below 2,300 MW for 30 minutes or more."

Issues driving the appeal include the heat wave, low wind output, forced thermal outages and developing cloud cover in West Texas reducing solar output, ERCOT said.

ERCOT forecast load to start exceeding planned supply around 2:45 pm, with load at 76.9 GW and planned supply at 76.7 GW.

The widest gap was forecast for around 4:15 pm, with load approaching 78.5 GW and supply at 77.6 GW.

Reliability unit commitments

These numbers are derived from the ERCOT supply and demand graph on the front page of the ERCOT website.

"If you have been watching our graph you will have seen tight conditions like this many times over the past several days," ERCOT spokeswoman Trudi Webster said in a July 13 email.

"This graph shows the supply that the market has committed to provide," Webster said, adding that ERCOT likely will use the reliability-unit-commitment process to serve load as part of its conservative operations strategy.

"Today, there is a LOT of variability including lower than forecasted wind generation and solar," Webster said. "We want to be respectful of Texans, so we will only call for conservation if we need it."

Around 10 am CT, the ERCOT wind fleet was producing 1,338 MW, compared with forecast output of 1,928 MW at that time and a forecast daily low of 1,426 MW.

At the same time, ERCOT's solar capacity was producing 8,097 MW, compared with forecast output of 8,381 MW.