The Electric Reliability Council of Texas is trying to increase the amount of power it can quickly access in response to a new risk report showing the region has a 20 percent chance of conditions that could lead to blackouts if it faces peak loads comparable to those seen during Winter Storm Elliott last December.
It's a big ask but not impossible, said Michael Webber, a professor of energy resources at the University of Texas at Austin.
"Generally speaking, industry shuts down plants for a reason — usually related to cost and pollution," he said. " ERCOT asking to open plants that were shut down because stakeholders complained about the pollution puts the owners and operators in a tough spot."
As it tries to find another 3,000 megawatts of power for its winter reserves, ERCOT is looking specifically to CPS Energy's decommissioned J.T. Deely Power Plant, keeping a Denton plant owned by Garland Power & Light open over the winter and stepping up the use of demand-response conservation programs among its list of possible sources.
CPS said Tuesday it was not considering restarting the Deely plant.
"We made a commitment to our community that those would be retired," the city-owned utility said of the Deely plant's two coal-fired units. "We continue to move forward with the implementation of our generation plan to power our community through 2030."
ERCOT brought back some plants under a similar request in 2011, but it was only for about 400 megawatts of generation from plants that had been temporarily closed — or "mothballed" — rather than decommissioned.
Risk Assessment
"Our request to procure capacity in advance of winter is part of our continued commitment to maintain grid reliability and resiliency," ERCOT President and CEO Pablo Vegas said in a statement. " ERCOT is not projecting energy emergency conditions this winter season, but we want to be prepared and ensure all available tools are readily available if needed."
The added capacity would put the grid's risk of emergency below the 10 percent probability level, which is an accepted industry standard.
ERCOT's risk assessment for the winter, which was published Monday, said potential risks this winter are greater than last season due to rising demand for power and not enough new sources of power to "fully serve the higher net peak loads."
When ERCOT ran the same analysis a year ago, the probability was 7 percent, ERCOT Chief Operating Officer Woody Rickerson said Tuesday at the Gulf Coast Power Association conference in Austin.
"We feel like that 20 percent probability is just not acceptable," he said. "It's too high."
During the winter, the 8 a.m. hour can be particularly challenging because that's when customers are powering up to start the day, increasing demand while temperatures are still low and before solar panels start producing energy.
A similar problem played out during the summer, but with the crunch time in the evening. Solar energy supply dropped as the sun went down during record heat and the grid's demand repeatedly nearly outpaced supply, a situation that led to a string of requests for Texans to conserve.
In its new risk assessment, ERCOT also noted what it called "a large increase" in the number of plants set to be retired or being routinely shut down for the winter.
"There are currently 15 units expected to be out of service, representing a loss of 1,283 MW of winter-rated capacity," it said.
Power Sources
In its request for proposals for more reserves, the grid operator identified what it considered acceptable types of power generation for it to tap. The first category included power plants set to be retired by the start of the winter season. That list included seven plants with units capable of about 550 total megawatts of generation.
Such "mothballed" plants are those closed for some time but that still have equipment in place. Rather than shutting down for the winter, ERCOT is asking operators to keep those plants running a little longer, said Joshua Rhodes, an energy expert and research scientist at the University of Texas at Austin.
The biggest contribution of that type identified by ERCOT would be from Talen Energy's 292-megawatt coal-fired Barney M. David plant in Corpus Christi. Talen has said it plans to close the plant, exit coal generation and invest more in renewables.
ERCOT also identified two plants capable of producing about 140 megawatts of power that are set to be routinely closed for the winter that it instead wants to keep operational. But that's not as simple as flipping a switch, Rhodes said of plants that are basically being put to sleep for the season.
"It costs money to be ready. So we'd have to keep them awake," he said, adding that such plants could face an operational challenge. "If those power plants have been gone offline every winter, they might not be as weatherized as we may need."
As was seen during Winter Storm Uri in 2021, plants that lack necessary weatherization may not be operable during extreme cold.
But ERCOT identified its largest single possible source of power as the two retired units that once provided 840 megawatts of coal-fired power from CPS Energy's Deely plant near Calaveras Lake, which was shut down Dec. 31, 2018.
The utility has made its stance on coal clear, its board also voting more recently to shutter one of the units at its J.K. Spruce Power Plant by the end of 2028 and converting that plant's second unit to run on natural gas.
Complicating Factors
Austin's Decker Creek Power Station, a gas-fired plant, is also on ERCOT's winter wish list and once produced 428 megawatts of power. It closed in 2020 amid Austin Energy's efforts to lower that utility's carbon emissions.
Rhodes pointed out that the complexities of bringing such plants back into operation range from bringing in the natural gas or coal they consume to ensuring they have water for cooling and finding the staff to run them.
"There are some pretty big plants that have retired but it takes time to dismantle a power plant," he said. "I don't know the status of these plants. Some, all the parts might be there ... some of it might be able to be returned online."
CPS said the Deely plant is still intact, however.
ERCOT is also asking plants that are in the process of being brought online to start up earlier than planned. It didn't specifically identify any such plants.
Lastly, ERCOT lists demand-response programs as another potential way to increase power reserves. Such voluntary programs allow utilities to tap into customers' thermostats to reduce demand and sometimes pay large industrial users to shut down operations during periods of tight supply.
ERCOT says proposals are due by Nov. 6. The grid operator will announce its selections on Nov. 23 and secure the added power from Dec. 1 through Feb. 29, 2024.
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