120 minutes which nearly destroyed Texas’s electricity grid

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Mon Feb 22, 2021

As the temperature plunged to arctic levels around Austin, the electricity demand for heat across the state was soaring. But soon the green dots on the Cineplex-sized screen started flipping to red. Each of these dots represented a regional power generator and they were shutting down. The frequency of 60 hertz is needed for stable electricity flow on the grid. Below 59 and the state’s electrical system would face cascading blackouts which would take weeks or even months to restore. Texas was seconds and minutes away from such a catastrophe.

In order to protect the electrical grids in Texas, Bill Magness, chief executive officer of the grid operator ordered the largest forced power outage in U.S. history.

Texas’s power grid is independent and insular. Its electricity grid is entirely in-state with limited import ability which keeps it away from federal oversight. It is also an energy-only market which means that the grid relies on price signals from extreme power prices to spur investments in new power plants, batteries, and other supplies.

In other words, there is no way to contract power supply to meet the soaring demands. There are no mandates or penalties compelling generators to make supply available when it is needed or to cold proof their equipment for storms.

As the cold began to shut down the supply of natural gas, freezing the instruments at power plants and icing over wind turbines, there was no sufficient supply available to meet demands. Nearly five million homes and businesses were forced into frigid darkness for four straight days ensnaring more than a dozen other states including California.

Nearly a week before the blackouts began, the operator of a wind farm in Texas alerted the grid manager that ice from the impending storm could force it offline. By Saturday, a considerable amount of capacity was already offline, some of it for routine maintenance and some of it due to weather. The reason for this is that Texas peak demand is associated with summer heat and as a result many plants do their routine maintenance in winter.

On Sunday, as the cold deepened, demand climbed abruptly, hitting, and then exceeding the state’s all-time winter peak. At 11 p.m., power plants started to go down and virtually all of the generations falling off the grid came from coal or gas plants.

In the span of 30 minutes, 2.6 gigawatts of capacity had suddenly disappeared from Texas’s power grid, enough to power half a million homes. By that point, the temperature outside had fallen to five degrees Fahrenheit. No one had anticipated this situation.

The generation outages caused frequency to fall as much as 0.5 hertz in a half-hour. Power supplies became so scarce that what were supposed to be rolling blackouts ended up lasting for days at a time leaving millions of Texans without light, heat, and water.

 

 

 

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2021 - Spring - Issue 4
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