May’s Texas heat wave exposed the myth of fossil fuel reliability

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Fossil fuel proponents consistently argue that renewables are too intermittent to maintain grid reliability, and that wind and solar generation replace coal and gas, claiming these resources are always available when needed. But the early season heat wave in Texas showed just the opposite.

Renewables were reliably predictable throughout the 10+ day event, while fossil fuel power plants experienced a series of unexpected outages that triggered warnings from the system operator state electric. It’s a lesson that should help change the generational narrative across the country.

The event began May 3, when the Electric Reliability Council of Texas, or ERCOT, warned that the state could see record demand over Mother’s Day weekend (May 7-8) in due to extremely high temperatures, and scheduled maintenance at a number of thermal generation facilities could cut off supplies. Fossil fuel and nuclear power plants typically schedule maintenance and refueling in the spring and fall, when electricity demand is lower.

As part of its preparations, ERCOT said it is asking generators with scheduled maintenance outages to delay them, and those that are offline to return to service if possible. As ERCOT discovered, you can ask, but that doesn’t mean fossil plants can deliver.

The first problem came late Sunday, May 8, when a fire broke out at Unit 8 of the 3,677-megawatt WA Parish plant southwest of Houston, one of Texas’ largest power plants. . The eight-unit plant includes four gas-fired boilers (1-4) and four coal-fired boilers (5-8). Unit 8 capacity totals 610 megawatts; it is the youngest of the plant’s units, entering commercial service at the end of 1982.

NRG, the company that owns the Parish facility, initially told ERCOT that the unit would be offline until the end of May. Information in ERCOT’s forced shutdown database, however, indicates that the unit could be out of service until December.

The WA Parish power station outside Richmond. According to the authors, coal and gas-fired power plants are not as reliable as the industry claims.

Mark Mulligan, Houston Chronicle/Staff Photographer

Then, early on May 9, a second unit in Parish, Unit 7, with a generating capacity of 577 megawatts, was taken out of service. It remained offline until May 19. A total of three of Parish’s four coal units were unexpectedly shut down for several days in May, with Unit 5 shut down May 25-30.

On Monday, May 9, just after the outage of the two parish units, the Texas network was tested. Peak demand exceeded 70,000 megawatts, easily surpassing May’s previous record of around 67,000 megawatts. During peak hours, wind and solar generation provided 37.8% of ERCOT’s total power supply.

For seven consecutive hours during the day, including during the 5 p.m. rush hour, ERCOT’s solar generators alone fed more electricity into the grid than the region’s coal-fired power plants. At peak time, the solar generators produced 7,332 megawatts compared to 7,039 megawatts for coal, a clear indication of the changing dynamics of the system.

Then, on Friday May 13, six gas-fired power plants with a combined generating capacity of more than 2,900 megawatts shut down in the late morning and early afternoon, forcing ERCOT officials to call residents to reduce their electricity consumption.

These issues highlight two issues that undermine the fossil fuel reliability argument.

During the peak hour, ERCOT’s coal-fired generators produced 7,483 megawatts, or only about 63% of their potential capacity, assuming about 11,783 megawatts of coal-fired capacity was online and available to generate electricity. Since those responsible for the system openly demanded additional production, the insensitivity of coal-fired power plants raises questions. Were the factories not able to increase their output? How reliable will they be as the summer heat intensifies and demand increases in the coming months?

The second problem is related to maintenance, a crucial need for fossil fuel power plants but which is forced into an increasingly narrow window between the cold snaps of January and February and the first heat waves of May. ERCOT’s main maintenance months are April and May, but system operators have been forced to ask (and apparently order, in a few cases) factories to delay planned maintenance shutdowns when the heat wave of the onset May of this year has arrived.

May’s heat wave showed that gas and coal-fired power plants might not be as reliable or dispatchable as the fossil fuel industry claims. This summer’s scorching heat and record-breaking electricity demand will continue to test these claims.

Dennis Wamsted ([email protected]) is an energy analyst at the Institute for Energy Economics and Financial Analysis, a research group examining issues related to energy markets, trends and policies. Seth Feaster ([email protected]) is an IEEFA Energy Data Analyst.

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