By Tom Kleckner

A call for conservation, lower-than-expected temperatures and slightly higher-than-expected wind energy helped ERCOT avoid taking emergency actions during scarce conditions last week.

ERCOT asked Texans to reduce their energy usage on Thursday and Friday, projecting peak demand of 72.7 GW and 73.3 GW, respectively. (See ERCOT Sees Tight Conditions, Calls for Conservation.)

The National Weather Service had expected temperatures to reach triple digits in the state’s major metropolitan areas into the weekend. Temperatures ended up being 2 to 4 degrees lower in many of the cities, with rain in some parts of the state helping dampen demand.

ERCOT’s system demand peaked at 68 GW and 68.8 GW on those two days. The latter set a new record for September, elbowing aside the 68.5-GW mark established Sept. 3.

“We are thankful to Texans for helping us conserve,” spokesperson Leslie Sopko said.

On Thursday, wind production was expected to be less than 1.5 GW during the early afternoon hours before coastal winds picked up. However, wind energy contributed an extra half-gigawatt when physical responsive capability was at its lowest.

“When the wind doesn’t blow, it gets interesting,” ERCOT COO Cheryl Mele said last week during the Infocast Texas Renewables Summit. “The driver to the day is how much wind do we have. On our peak days, we’ve definitely had a little less than we did on peak days last year. When [wind] gets down to 2 GW or less, it has an effect on price. We’re all sitting around hoping the wind really does show up.

“Anytime we’re seeing a forecast of less than 2 GW in the afternoon or at peak, it means we’re going to have an interesting day.”

Prices briefly hit triple digits on Thursday during the interval ending at 5 p.m., after settling at just over $5,000/MWh in the day-ahead market. On Friday, prices were in quadruple figures, topping out at about $1,778/MWh during the 2:35-4:45 p.m. time period. Day-ahead prices for Friday’s energy and ancillary services were both about $4,500/MWh for the day.

The Texas grid operator this summer has called two energy emergency alerts, its first in five years. (See “ERCOT CEO Briefs Commission on Summer Performance,” Texas PUC Briefs: Aug. 29, 2019.)

ERCOT began the summer with an 8.6% reserve margin. It set a new all-time peak of 74.7 GW on Aug. 12, and it has recorded 11 other demand marks above the record set a year ago. Last year, ERCOT broke its previous record 14 times.

Austin, home to ERCOT, exceeded 100 degrees Fahrenheit during 27 of August’s 31 days.