Art Berman Newsletter: March 2021 (2021-2)
Explanations for the outages include lack of generating plant winterization, natural gas shortages from frozen wells and pipelines, and poor grid management. These were all factors but the triggers for the power crisis were the failure of electricity generated by wind and poor planning by the state’s grid operator ERCOT.
Temperatures commonly dip below freezing for a few hours on a few winter days in parts of Texas. Last month, temperatures fell into the low-20 degree Fahrenheit range in south Texas (Figure 1). The mean Houston temperature in February is about 57 degrees Fahrenheit. On February 15, it was 20 degrees.
This was the first time since 2011 that a freeze left so many in the state without power. The weekly energy used for space heating during the 2021 crisis was 56% higher than for the crisis week in 2011.
The storm was not a surprise. The state’s grid management company ERCOT ramped up electric power generation a week in advance. In the early morning of February 15, net generation dropped 15 GW (gigawatt hours) from 68 to 53 GW (Figure 2). By early evening, it had fallen another 9 GW to 44 GW. The result was loss of electric power to millions of homes.
Much of the state’s water relies on electric pumps to move it through pipelines. When electric power was lost, pumps stopped working and there were shortages of water.
What Critics Say
Texas’s governor Greg Abbott blames the state’s grid management company ERCOT for the electric supply shortage. “The Electric Reliability Council of Texas has been anything but reliable over the past 48 hours,” Abbott said. He also blames much of the failure on poor performance from wind and solar energy.
According to critics, a chief cause of Texas’ grid failure was lack of winterization. In a study following the 2011 winter storm, the Federal Energy Regulatory Commission (FERC) identified frozen sensing lines, frozen equipment, frozen water lines, frozen valves, blade icing, and low temperature cutoff limits as key reasons for plants going offline.
The failure to winterize adequately is because most of Texas’ electricity market is deregulated. Traditional, regulated utilities are guaranteed reimbursement for reasonable plant investments like winterizing. Texas is a purely competitive market where consumers reward providers with the lowest prices. There is no incentive for investments that increase consumer prices. The system is not designed for reliability.
For power generators, the laissez-faire market design rewarded companies that could sell electricity inexpensively and still recover their capital costs. But it provided little incentive for companies to spend cash on infrastructure that could protect power plants during sporadic severe cold snaps.Wall Street Journal (February 24, 2021)
California and New England also have deregulated electricity markets with well-publicized failures to provide customers with power during extreme hot and cold weather.
Critics also point to shortages of natural gas or low pipeline pressure that reduced supply to plants that burn gas to produce electricity. Gas provides almost half of Texas’s electricity. Gas production in the Permian basin fell 2.5 bcf/d almost immediately once the February storm arrived in Texas. Water and gas hydrates in natural gas will freeze. When power is cut off, electric pumps that lift gas to the surface and compressors that move gas through pipelines stop. Gas prices reached $600/mmBtu in some spot markets.
Supply of electricity from wind and solar dropped before the winter storm entered Texas. About 16 gigawatts (GW) of renewable energy, mostly wind power, had gone offline as of Tuesday, February 17 according to ERCOT. Wind turbine blades and rotors could not turn because they were covered with ice.
Meanwhile, renewable advocates say that these claims are exaggerated and that the main problem was failure to require thermal (nuclear, gas, coal) plants to be weatherized to withstand cold temperatures.
What the Data Says
On February 8, ERCOT issued a notice for an extreme cold weather event. Its intent was for generators to increase output and for consumers to curtail consumption. What happened was that natural gas net generation increased dramatically before the cold weather entered the state on February 13 (Figure 2). Coal and nuclear increased slightly but wind and solar were generating at about 50% of their normal output levels.
Natural gas electric power generation ramped up 223% from it’s winter average of 14.6 GW to about 36 GW before the power crisis began on February 15 (Figure3).
Wind generation, on the other hand, dropped below its winter average on February 7, a week before the power crisis began (Figure 4). It lost almost 8 GW of output by February 9 and remained less than its winter average even as Texas recovered from the February power crisis.
There was no freezing weather anywhere in the state before February 13. Generation from wind decreased because wind doesn’t blow all of the time.
Figure 5 shows net generation from wind from February 2020 through February 2021. It is cyclic. Peak-to-peak cycles average about 5 days in the winter and 7 days in the summer. Some peaks are greater and some are lesser.
The wind generation peak that occurred on February 7, 2020 in Figure 4 was a greater peak and the next peak 7 days later was a lesser peak. Bad timing. Probably icing of wind turbines was a factor after February 13 but the underlying problem was natural cyclicity. The wind wasn’t blowing when it was needed.
That is important because wind is the second largest contributor to Texas electric power supply after natural gas. Table 1 shows that wind provides approximately 10.8 GW during the winter or 27% of all electric power. When wind dropped 45% before the cold weather arrived, that left a 5 GW deficit.
Figure 6 graphically shows the same data from Table 1. It emphasizes that wind performed worse than any other major energy source for electric power before, during and after the recent Texas power crisis. It further shows that only natural gas and, to a lesser extent, coal had the capacity to significantly ramp up generation for the anticipated cold weather.
I am frankly stunned by those who look at this data and suggest that the problem is that Texas is too reliant on fossil energy.
The real failing of Texas was the reliance upon the natural gas backbone as the firm power source, which of course wasn’t so firm, as they later learned.”David Victor, University of California, San Diego.
What exactly would this political science professor recommend? That people suffer more than they already have from even less available power during extreme weather events?
I am equally distressed by those who categorically declare that this cold weather was because of climate change. Based on what evidence?
I take climate change quite seriously and have published several articles stating that. I do not know any credible weather or climate expert who claims that this or any recent weather disaster is because of climate change. What they say is that it is likely that more extreme weather will characterize the future because of climate change. In fact, there were nine previous storms over the last 120 years that brought even colder weather to Texas than in February 2021. These seem to occur with a cyclicity like the wind patterns show in Figure 5.
Some blame for the crisis has been placed on natural gas shortages. Most of those focus on reduced gas-well production and associated well freeze-offs. Those reflect inexperience in oil and gas production and midstream operations.
Gas does not flow directly from wells to gas generating plants. Water vapor, carbon dioxide, hydrogen sulfide and natural gas liquids must be removed from produced gas before most pipelines will take it. That involves plant processing that commonly takes several days before the gas is ready for pipeline gathering. Supply shortages come days, not hours, after production is suspended. Gas supply shortages during the February freeze were probably because pipeline compressors lost power as the grid shed load and generating plants went off line.
FERC’s evaluation the 2011 electric power curtailments noted:
Gas shortages were not a significant cause of the electric generator outages experienced during the February 2011 event, nor were rolling blackouts a primary cause of the production declines at the wellhead. Both, however, contributed to the problem.FERC
The same is true for water supply. Plants generate electricity by heating water to produce steam that rotates turbines. If electric pumps that supply plants with water lose power, electricity cannot be generated. Water is also used to cool plant equipment so reduced water means that plants must close or face equipment damage from over-heating. This seems especially probable for nuclear power plants.
ERCOT deserves considerable blame for the recent power crisis. Its resource capacity estimates are baffling and inconsistent with net generation data for any fuel source or any period over the last 12 months.
ERCOT’s seasonal average resource adequacy (SARA) estimate for natural gas is 36% higher than the February 14 peak level of 37.5 GW (Figure 7). I assumed that represented installed capacity. I, therefore, filtered the four types of gas generators included in SARA data and used corresponding EIA capacity factors to calculate a maximum deliverable capacity level. That is also shown in Figure 6 and it is -47% less than the February 14 peak level.
Figure 7. ERCOT SARA (seasonal average resource capacity) is 36% higher than February 14 maximum net generation level. Calculated deliverable level is -47% less than February 14 level. Source: ERCOT, EIA & Labyrinth Consulting Services, Inc.
I am left with little confidence in ERCOT’s capacity planning process based on the abundant publicly available data I have examined.
ERCOT cannot, however, control the weather, the intermittency of electricity from wind or the winterizing practices of independent generators. ERCOT is a grid management company, not an electric utility. The grid it manages consists of independent producers that do not report to ERCOT. It is reliant on data they provide for its grid planning and management.
ERCOT must live within the rules set by the Texas legislature. There are clearly changes needed and the governor must lead them. He must also take responsibility for the grid failures that affected millions of Texans. I find nothing that went wrong last month that wasn’t known and documented in 2011.
Electric power grids are complex systems. They are characterized by complicated interrelationships and feedback loops. Changes in one part of the system affects other parts of the system in unpredictable and sometimes disastrous ways. It may be possible to identify a triggering event or series of events for the recent power crisis but there was no single or even primary cause.
I have greatly simplified a complex situation in an effort to identify and discuss the key patterns that available data permits. More will be learned as the event is investigated further.
The obvious conclusions from this crisis are that 27% reliance on wind is a big risk and that Texas’s unregulated electric grid system is a train wreck. I am not confident that either will be addressed any sooner than they were after 2011—ever!
Thanks to Carey King and Brian Maschhoff for helpful discussions during the research for this post.
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