The Blog

2021-

2021-02-22 c
TEXAS FREEZE III

The Texas Blackout and Preparing for the Past

One lesson of the Texas energy crisis is surely a need to make infrastructure robust to the past in order to better prepare for the future

As I write this, about 500,000 people remain without power in Texas resulting from some of the coldest weather to hit the region in at least 30 years. There will be many investigations as to what happened and how this type of electricity crisis can be avoided in the future. Here I focus on what may be an important factor in the crisis — a failure to fully consider history as a basis for understanding near-term risks. Many years ago I called this “preparing for the past” in the context of extreme weather.

Texas is well known for sweltering summer weather, with corresponding high demands for electricity for air conditioning. But Texas can also experience cold extremes, which require its grid operators to prepare for both increased demand and impacts on generation. According to the New York Times, for 2020 “Texas’ grid operators had anticipated that, in the worst case, the state would use 67 gigawatts of electricity during the winter peak.”

I was curious as to how ERCOT (Electric Reliability Council of Texas) actually defined such a worst case scenario. It turns out that this scenario is based on using an extreme cold period of 2011 as an analogy (see this ERCOT spreadsheet).

The first week of February, 2011 indeed saw an extreme cold front descend throughout the United States, resulting in significant impacts to electricity generation across the Texas region. However, despite its severity, an after-event review estimated that it “was determined to be a one in ten year event for some regions of Texas in terms of low temperature extremes and duration.”

A one-in-ten year event is not generally considered a “worst case scenario” in planning for extreme weather events. For comparison, the insurance industry typically considers one-in-100 and one-in-500 year events to estimate maximum possible losses. And even these rare events could be exceeded. There are always important debates to be had over what level of hardening to build into infrastructure, typically based on cost considerations. But it will surely be a rare case where that level is defined only as the 1-in-10 year event.

It appears that ERCOT based its assessment of preparedness for winter 2020-21 on a historical period of 2004 to 2018. Imagine if Miami based its hurricane preparations on the past 14 years of hurricane experience — decision makers would dramatically underestimate possible risks. To understand climate variability in extreme events requires a long-term perspective, many decades and even longer. However, even without a long-term perspective, he experiences of 2011 did provided clear lessons that the Texas grid was unprepared for a deep cold snap.

Looking a bit further into the past shows that 2011 was far from a worst case scenario. In fact, 1989 saw a cold snap that was considerably more widespread and severe than 2011, leading to an 84% reduction in Texas electricity generation versus a 68% reduction in 2011. According to Bloomberg the Texas weather of the past week, “which caused temperatures to fall two degrees below zero in Dallas on Tuesday -- is far worse than 2011.”

The ERCOT 2020/21 winter weather outlook acknowledged that “there’s enough of a chance for a period of extreme cold that the possibility cannot be discounted – even in what may otherwise be a mild winter.” However, it also emphasized that cold weather was decreasing rapidly in Texas, warning, “You should have strong supporting evidence if forecasting a colder-than-normal (coldest third) season.”

Indeed, a 2020 report by the Texas State Climatologist made little mention of cold weather risks, aside from the fact that they were decreasing, and predicted that, “the expected warming of extreme wintertime temperatures would make typical wintertime extremes by 2036 milder than all but five of the winters in the historic record.” Others argue that extreme cold weather in the continental United States should actually be expected to increase, although the evidence for that hypothesis is weak at this point.

Whether cold outbreaks are decreasing or increasing due to climate change should be beside the point. We know that extreme cold events can still happen and will continue to happen regardless of the precise human effects on climate. We also know that such cold events can be very severe and, as we have seen, can have significant consequences. Climate change is of course important, and we should prepare for an uncertain future. But the recent Texas electricity crisis should remind us that we still need to prepare for climate, not just climate change.

Part of that preparation requires making better use of hindsight. Because if we are not even prepared for the past, it is certain that we won’t be prepared for the future. (read more)

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