11/26/2024

ERCOT Shows High Probability of Rolling Outages in a Winter Storm

Doug Lewin | Nov. 4, 2024

ERCOT Shows High Probability of Rolling Outages in a Winter Storm

Doug Lewin | Nov. 4, 2024

Late last week, ERCOT released its Monthly Outlook of Resource Adequacy. It forecasts that if Texas experienced another Winter Storm Elliott — the freeze that hit Texas two years ago — there would be a 50% probability of rolling outages. 

Peak demand during Elliott hit about 74,000 megawatts. That said, the event occurred on a holiday weekend, when the state uses less electricity, and there’s been a lot of load growth since then. 

ERCOT now believes another Winter Storm Elliott would trigger 87,000 megawatts of electricity demand. The agency says that translates to a 50% chance of triggering an Energy Emergency Alert 3 (EEA3) and rolling outages. 

Not good.

And as this chart shows, the lowest statewide temperature during Uri was seven degrees colder than Elliott’s low; temperatures also stayed below freezing for nine days in February 2021, compared to only two days in December 2022:

ERCOT has previously estimated that demand during Uri would have hit 77,000 megawatts without the horrible blackouts that Texans endured. That number is probably low: ERCOT vastly underestimated demand during Elliott and this year’s Winter Storm Heather. In addition, a team of Texas A&M researchers estimated Uri demand would have been about 82,000 megawatts, and a University of Texas at Austin team estimated it could have reached over 90,000 megawatts. 

ERCOT itself predicts a peak demand of roughly 92,000 megawatts if Texas sees Winter Storm Uri conditions again this winter: 

According to the Monthly Outlook released Friday, that peak would mean a 65% chance of rolling outages

Why is this happening?

Since Winter Storm Uri, policymakers have focused almost exclusively on adding supply to the grid — specifically with new, expensive gas plants. That ignores at least half of the problem.

That first EEA graph above shows that for every 2,500 or so megawatts of energy savings, the risk of outages decreases 10%. A recent Texas A&M study conducted for ERCOT shows energy efficiency alone could slash demand by 23,000 megawatts — a game-changing difference that would help Texas get through extreme weather of all varieties.

Yet Texas still has not focused on demand-side solutions, especially efforts to help Texans install high-efficiency, all-climate heat pumps or to add insulation. The state also has not adequately funded microgrids — even though they add supply, reduce demand, and increase resiliency against winter storms, hurricanes, wildfires, and other climate risks.

In passing Senate Bill 2627 last year, the Legislature voted to invest $1.8 billion in microgrids, but the Legislature appropriated only half of that money, and the PUC is spending that on large gas plants which are still subject to gas shortages during extreme winter storms 

Until Texas focuses on curbing demand, we will continue to face needlessly high risks of outages.

Would blackouts this winter be as bad as in 2021?

ERCOT’s forecast notwithstanding, there are several reasons why Texas is better positioned for winter this year than we were four years ago, and why outages in 2024-25 would not last as long or impact as many people as 2021.

First, power plant weatherization — which the Legislature ordered in 2021 and the PUC and ERCOT have since implemented — is working. It’s not perfect and the state should continue to improve weatherization, but far fewer power plants have dropped offline during recent winter storms. The state’s gas supply, which the Texas Railroad Commission is supposed to oversee, remains a major vulnerability, but power plant weatherization has demonstrably made a difference.

Texas also has a lot more solar and storage resources than we used to. That makes a big difference. Winter storms often follow cloudy, icy fronts with clear skies. Texas actually achieved a record for solar generation during Winter Storm Heather, when the temperature was below freezing. Texas has added well over 20 gigawatts of solar since Uri — just 10 additional gigawatts would’ve reduced the Uri outages by 15%.

Also, during Uri, Texas had only about 200 megawatts of energy storage. We now have more than 10,000 megawatts of storage — 50 times more. This additional solar and storage could have eliminated 35-40% of the Uri outages. 

And as ERCOT noted last week, solar and storage will likely increase 2,583 megawatts just in December this year. Such growth will help keep lights on and heaters running this winter. It demonstrates again why the legislature needs to double-down on the state’s clean energy leadership, not undermine it.

What should be next

Again, there’s more to do. The Railroad Commission needs to weatherize gas supply. The PUC and Texas utilities need to help Texans install heat pumps, insulation, and smart thermostats. And the Legislature and the PUC need to prioritize microgrid funding. 

These things will work with power plant winterization and booming solar and storage resources to make the grid more reliable and resilient. 

No Texan should accept a 65% chance of outages, especially from the repeat of an event that so many of us have lived through — and many others didn’t.

We can do better.