Home > Austin, Weather > State electric grid strains amid record heat; Austin breaks 86-year-old record

State electric grid strains amid record heat; Austin breaks 86-year-old record

August 25, 2011

statesman

It was so hot Wednesday that power plants across the state stuttered amid high demand, prompting the manager of the electric grid for much of the state to order about 100 large industrial customers to shut down for more than two hours as electricity reserves dipped dangerously low.

In Austin, temperatures Wednesday reached 106 at Camp Mabry — the 70th day of triple-digit heat, breaking an 86-year-old record.

The Electric Reliability Council of Texas declared a Level 2 power emergency at 3:10 p.m. after overstressed plants produced 5,000 fewer megawatts of power than expected. It was the second time this month that ERCOT had declared such an emergency. On Aug. 4, ERCOT cut off all the interruptible customers and deployed about 400 megawatts of power in emergency reserves, spokeswoman Dottie Roark said.

ERCOT, which manages the electric grid for three-fourths of the state, has been warning customers all week to conserve power.

As power plants have been running at full capacity through this record hot summer, breakdowns have been common, Roark said.

In addition, wind generation Wednesday was 880 megawatts, compared with 1,450 megawatts Tuesday and 1,840 megawatts Monday.

“Until we get a break in the temperature and the drought, we’re just going to have more days like this,” Roark said.

Demand for electricity peaked at 66,552 megawatts, 1,742 megawatts short of an all-time record set earlier this month.

On Tuesday, when ERCOT urged residents to conserve electricity, usage peaked at 67,136 megawatts.

The opening of schools in Austin this week was not to blame for the spike in usage, officials said. Austin Energy spokesman Ed Clark said the estimated load of Austin schools is about 50 megawatts, the power equivalent of 6,000 homes.

Clark said schools are dismissed during the typical peak hour of usage, which is 4 to 5 p.m. statewide and 5 to 6 p.m. in Austin. In addition, a drop in temperature of just a few degrees can lead to enough decrease in air conditioning usage to offset the load of schools, Roark said.

An outage during Wednesday’s afternoon commute affected more than 4,000 Austin Energy customers, mostly in Central and West Austin. Clark attributed the outages to circuit trouble at a substation. He said they had nothing to do with the state’s grid troubles, though he said the malfunctions that caused the outages could have been heat-related. Power was restored to all customers by about 8:30 p.m., he said.

That ERCOT would need to call for rotating power outages is unlikely, Roark said. But, if cutting off interruptible customers doesn’t do enough to keep Texas from its summertime capacity of 73,000 megawatts, there will be no choice.

Rotating outages are a temporary interruption of power — typically 15 to 45 minutes at a time — that prevent uncontrolled, cascading blackouts.

ERCOT has never called for rotating outages in the summer, Roark said.

If ERCOT ordered rotating outages, local distributors such as Austin Energy would have 10 minutes to begin the controlled outages.

The last rotating outage in Austin came in February when a severe cold snap knocked out 80 of the state’s 550 generating units.

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