ERCOT Wins Praise For Keeping Grid Stable During Harvey
September 12, 2017
In a report to the Public Utility Commission of Texas following Hurricane Harvey’s devastating assault on the Lone Star State, ERCOT said that the market functioned as expected and there was sufficient generation to meet demand.
The grid operator’s performance in dealing with the unprecedented storm that landed on Rockport with 130 mile-her-hour winds and dropped more than 50 inches of rain in some parts of the region drew praise from the PUCT. Commissioner Ken Anderson said ERCOT’s efforts in flood-struck Houston were “remarkable,” while Brandy Marty Marquez added, “This is a big test for us, but everyone’s risen to the occasion.”
ERCOT’s ability to ensure grid stability in the wake of catastrophic conditions was grounded in pre-crisis planning.
As the hurricane was approaching, the grid operator worked with transmission service providers to restore or cancel as many planned outages as possible. Additionally, before Harvey made landfall at 10 p.m. Aug. 25, ERCOT activated its internal Disaster Management Team, and its Systems Operations Team worked round-the-clock in a control center designed to withstand hurricane-force winds. Beyond that, ERCOT stayed in contact with market participants with operating and emergency notices beginning Aug. 23.
Since Harvey made landfall, six 345kV transmission lines experienced forced outages, prompting ERCOT to issue a pair of reliability unit commitment instructions. The first, on Aug. 25, was designed to bring extra capacity to ensure grid resiliency in the Lower Rio Grande Valley; the second, issued the following day, directed a unit in Victoria to provide system resiliency and support.
Also, 91 138kV circuits and 138 69kV circuits suffered storm-related forced outages, the large majority of them in the Central Bend area where Harvey came ashore.
As Harvey hit, system demand started to fall. Peak demand was 43,857 MW on Aug. 26; 41,707 MW on Aug. 27; 44,861 MW on Aug. 28; and 48,573 MW on Aug. 29. That is roughly 15,000 to 20,000 MW lower than usual for this time of year, a decline ERCOT attributed to cooler temperatures and outages in the affected areas.
Demand picked back up as Harvey moved on, however, and was projected to reach 56,000 MW over Labor Day weekend – still far below the forecast summer peak of 73,000 MW.
The morning after Harvey’s landfall, the U.S. Department of Energy confirmed there were 258,137 customer outages. That number had risen by about 20,000 a few hours later, and by another 10,000 by 6:30 a.m. Aug. 27. It its 3:30 report, DOE put the total at 306,058. Two days later, it had fallen to 275,584 and continued to drop as power was restored.
In its Sept. 6 report, the department said that the state had 53,237 outages, many of them in the Aransas Pass, Rockport, Victoria, and Port Lavaca/Refugio areas.
PUCT Commissioner Marquez conceded that the state still “has a long way to go” to come back from Harvey. But, she added: “You can’t mess with Texas. We’ll be fine.”