July 28, 2021

RBN Energy, LLC recently posted a recap of a UT symposium on natural gas performance during Winter Storm Uri, outlining the discussions had during the event “2021 Texas Energy System at the Crossroads: Lessons in the Wake of Major Storms.” RBN’s recap of the symposium – “Can We Just Talk? – Symposium Explores How Natural Gas Fits Into ERCOT Reliability” – confirms the findings regarding the timing of declines of natural gas production in the Enverus report commissioned by TXOGA, showing loss of power as the biggest factor in production declines. 

Key excerpts from the RBN recap include:

• The key to finding an answer to the freeze-off vs. power loss question is to examine the timing more closely than had previously been done by critics of the TXOGA report. From Wednesday to Friday, a combined loss of 5% was not out of line for normal Permian production fluctuations and would not have been material for ERCOT generators. The first major drop (of ~9%) came on Saturday as the storm began to hit West Texas. Then came Sunday, February 14. Permian production dropped by 31% that day, followed by losses of 20% on Monday and 9% on Tuesday. As noted earlier, the power went off at 1:30 AM Monday morning (vertical yellow line). So, certainly, the combined 29% loss on Monday and Tuesday was consistent with TXOGA’s findings that power loss to wellheads, processing plants, and pipelines was the dominant cause of the supply decline.

• But what about Sunday, the largest one-day loss during the crisis (orange-shaded box in Figure 1)? Here, we run into the longstanding and often-debated mismatch between the standard gas day and the calendar day. The gas day pursuant to standards adopted across the natural gas industry runs from 9:00 AM Central Time to 9:00 AM the following day. In other words, seven and a half hours of the Sunday gas day happened after 1:30 AM Monday when the power went off. Given the additional nearly 20% loss on Monday, it would follow that a large portion of the Sunday gas-day loss actually happened after 1:30 AM Monday.

• So the sequence of events finally agreed upon during the symposium was that widespread freeze-offs of wellheads and midstream facilities probably amounted to an aggregate loss of around 20% prior to the power outage, not a catastrophic drop but enough to combine with generating plant freezes, loss of a unit at the South Texas nuclear station, and loss of some wind generation to require rolling blackouts. But then as soon as the blackout occurred, gas supply plummeted — because of the blackout — to make the situation unrecoverable. Thus, the discussions at the symposium really led to an understanding of what happened, and that common view of facts could show what needs to be done.