ERCOT official explains rolling power outages

Staff Writer

American Electric Power (AEP) Texas offered an explanation for the rolling blackouts that occurred Wednesday throughout the Rio Grande Valley, impacting approximately 120,000 customers including San Benito residents.

Other communities affected were Rio Hondo, Harlingen, Los Fresnos, McAllen, Port Isabel, Brownsville and several other cities throughout the Valley.

Larry Jones, who handles corporate communications for AEP Texas, said the blackouts were initiated as per an order from the Electric Reliability Council of Texas (ERCOT).

“What happened is there was a sudden, unexpected loss of generation in the Valley,” explained Jones, adding, “That’s not AEP Texas; that’s the generating companies.”

The generating companies are in a competitive business, “so those units have not been identified,” he noted. ERCOT does not provide AEP with information on the units in question due to the competitive nature of the generating companies.

Brian Lloyd, executive director of the Public Utility Commission of Texas (PUC) wrote an open letter directing the Public Utility Commission’s Reliability Monitor and Independent Market Monitor, to “investigate the load shedding event” that occurred that day.

“You should investigate all the conditions leading to this emergency event,” Lloyd stated in the letter.

It also calls for an investigation into ERCOT’s actions and its market participants to determine whether all appropriate laws, rules, requirements and processes were followed.

Terry Hadley, communications director at the PUC, said, “We have done this in the past when generation outages, whether combined with transmission issues or not, have resulted in shortages, we have directed the independent market monitor and ERCOT to go into more detail than usual as to what the cause, or causes were …”

According to Hadley, the mere fact that the Valley experienced rolling outages promoted such investigation.

“It is always a concern, because anytime you have an electric shortage, as part of the market process, that will cause prices to go up,” said Hadley, adding that there are typically legitimate reasons for this, such as high demand during the summer.

Regardless, the job of PUC, the independent market monitor and ERCOT is to investigate the matter to make sure that everyone “is playing by the rules” and “not creating an artificial situation” to change market prices. Still, Hadley alleges that there is “absolutely no evidence” of as much at this point.

During this time of year, there are a number of planned outages. This, Hadley says, is to conduct general maintenance on plants. The time is significant because it’s “when demand is generally lower.”

Wednesday’s outage, however, was unplanned.

ERCOT’s role as grid operator is to manage the flow of power to 24 million customers in Texas, or 90 percent of the electrical workload in the state, according to its website.

Robbie Searcy, communications manager for ERCOT said, “The Valley area in particular has some significant challenges in that the transmission system in that area is really operating at its limit.”

She said, “There are some large projects underway that were [ERCOT] board-endorsed in 2011 that are scheduled to be complete by 2016 that will help enable the import of more power into that area.” This bit of information was also supported by a statement from Hadley.

“There’s some significant generation limitations in the area as well,” she said.

“There are occasions where overall reliability is threatened,” explained Searcy. That means there were situations in the transmission system after the generation losses where: 1.) “We were seeing low voltage;” 2.) “We were really at the … import limit of the transmission system to keep up with demand.”

“When that other unit tripped, we basically saw an emergency situation that could have affected the entire Valley region at one time, and possibly for a longer period of time,” Searcy added.

Jones explained that because of the unexpected loss of generation, ERCOT instructed its transmission providers, one of which is AEP, to initiate the rotating outages.

ERCOT and transmission providers took this action in order to protect the transmission equipment — not the generator — according to Jones, a “nuance” he said is worth noting.

The rolling blackouts which protected the transmission lines are crucial to insuring that equipment does not suffer damage.

ERCOT describes rotating outages as “controlled, temporary interruptions of service initiated by each utility,” calling it a “safety valve.”

The Rio Grande Valley in particular faces its own problems “because there is very limited electric generation and transmission infrastructure” serving the RGV; it “sometimes experiences a high risk of rotating outages, especially on extremely cold or hot days.”

Not following through with the interruptions, “generators would overload and begin shutting down to avoid damage, risking a domino effect of a region-wide outage.”

Such outages “do not typically include critical-need customers,” according to a press release issued by ERCOT.

“What can happen is it can damage the transmission lines, and then it takes time to repair those … which can then result in much more serious and long-lasting outages,” said Jones.

Equipment suffering an overload can be severely damaged or burn, leading to the need to repair or replace it, causing further outages and frustrations to customers.

The duration and location of the controlled outages is guided by the situation and the assignment from ERCOT, according to Jones.

“It’s a balance between the short-term disturbance vs. the potentially longer term and more widespread impact,” explained Searcy.

AEP issued a press release asking customers to take steps to conserve electricity, something Jones calls “more of a suggestion than a plea.”

The suggestion was based mainly on Wednesday’s events and the situation when AEP sent out the press release.

“We just thought it was a wise approach to suggest conservation today,” Jones said Thursday afternoon, adding, “ERCOT has indicated that there is much more optimism in the generation situation today, but that can change.”

Continuing, Jones said that it is still “good practice” to implement conservation on an ongoing basis.

“At this point conditions are good,” said Jones.


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