Texas’ uniquely isolated and deregulated electricity grid has been wobbling on the edge of rolling blackouts this week thanks to extreme heat throughout the state.
At least so far, the grid has survived, despite less wind than expected, some power plants going offline, and near-record levels of demand. It hasn’t been so lucky in the past. The state became a poster child for the risk that extreme weather can pose to electricity generation in 2021 when Winter Storm Uri led to massive and deadly blackouts.
With Texas still facing a potentially deadly combination of extreme weather, homes that rely on electricity for both heating and cooling, and an energy market that has historically underinvested and underemphasized resiliency and is disconnected from the rest of the country, how has the state managed to avoid devastating blackouts during this heat wave — and I can’t stress this enough — so far?
One big reason is that electricity generation hasn’t quite hit the record-breaking levels ERCOT, the grid operator, has feared.
On Tuesday, power peaked at just over 79,000 megawatts, just below the over 80,000 megawatts record demand last summer, despite temperatures at or near 100 degrees — and heat indices approaching an astonishing 120. ERCOT had forecasted a record-setting electricity consumption day, but actual electricity demand fell below its predictions for the late morning and the afternoon.
Highlighting the risk still confronting the state, ERCOT has forecast that demand for power Wednesday will break records though.
“It has been record or near-record heat in South Texas, not so much in North Texas. Even though the ERCOT electric grid is relatively small, it’s been big enough to move power around from where it’s needed less to needed more,” Texas A&M professor and state climatologist John Nielsen-Gammon told me in an email Tuesday afternoon. One big concern with Texas’ grid is that when the entire state is in need of power, it can’t import electricity from the rest of the country, but at least so far, intra-state transfers have been sufficient.
That could be because ERCOT did itself — and Texas — a massive favor by sending out a warning to Texans on Tuesday just asking them “to voluntarily reduce electric use, if safe to do so.”
These kind of informal requests to reduce power consumption at moments of high demand are not uncommon and can work — they’ve been used successfully in New York and California. They’ve even been used before in Texas during the summer, despite the state’s reputation for being more generation-than-conservation friendly compared to its big state peers.
When comparing the disaster in 2021 to today, it’s also helpful to note that a big reason the state struggled back then was large amounts of natural gas generation going offline due to poor winterization.
Summertime brings even higher electricity demand than the winter, but it tends not to pose the same threat to the grid, explained University of Texas researcher Joshua Rhodes.
“The vulnerability in the summer is that everyone has an air conditioner,” Rhodes said.
That same high heat that causes people to crank up their air conditioning also means that solar power tends to be more abundant at the same time. By the late afternoon Tuesday, solar was providing 14.5% of Texas’ electricity, operating at 90 percent of its summer capacity. Meanwhile natural gas was responsible for just over half of Texas’ electricity generation, but operating at 85 percent of its summer capacity.
“Whoever designed it such that solar energy output is high when it is hot outside was brilliant,” University of Texas professor of energy resources Michael Webber tweeted Tuesday afternoon.
Natural gas power plants can underperform due to high heat, Rhodes said, but the risk of catastrophic failure is lower. Texas also schedules power plant maintenance in order to ensure that plants are online during the highest demand portion of the year.
But while natural gas provides the bulk of Texas’ electricity, wind and solar play a substantial and growing role in the state’s power generation. When ERCOT requested that Texans voluntarily reduce power consumption, it cited “higher than normal” power plant outages as well as “low wind generation compared to historic performance during summer peak.”
Like much of the country, fossil-fuel-rich Texas is dependent on renewables to keep the lights (and AC) on. The head of the Public Utility Commission of Texas warned in May that “On the hottest days of summer, there is no longer enough on-demand dispatchable power generation to meet demand on the ERCOT system.”
According to ERCOT figures from Tuesday, the listed summer capacity of coal, nuclear, and natural gas would have fallen short of peak demand, let alone the record demand forecasted on Monday, so solar really has played an important role in keeping danger at bay — and, again, I can’t stress this enough — so far.
As might be expected in a conservative state with a massive energy industry, when it came time to address reliability issues following Uri and record breaking heat last summer, Texas’ elected officials chose to do so in a way that would favor more fossil generation, as opposed to energy efficiency or more extensive demand management. Governor Greg Abbott signed a slew of bills in its past legislative session, including a bill that would set up a program for billions of dollars worth of loans for new gas-fueled power plants, while vetoing a bill that would allow the state to update building codes due to a fight between the governor's mansion and the statehouse over property taxes.
But Texas remains a renewable powerhouse, and like renewable-heavy California with its “duck curve,” Texas faces its own late-day energy crunch, in its case a so-called “armadillo curve,” when solar power drops out of the grid even as demand remains high thanks to continued high temperatures.
At least so far this week, the grid has held up. But summer has only just begun. The National Weather Service projects that “Excessive Heat Warnings may return” in parts of Texas this weekend and early next week. And ERCOT plans every year around power demand peaking in August.
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