Electrified Compressors and the Great Texas Blackout (a threat to grid reliability everywhere)

By Ed Ireland -- May 4, 2023

Ed Note: “Electric natural gas compressors contributed to the near collapse of the Texas power grid in 2021,” Ed Ireland argues below. “All U.S. power grids face the same risk.” His first-hand knowledge of this instance of ‘deep decarbonization’ politics gets to the why-behind-the-why of the still-debated Texas blackout, the worst electricity debacle in the history of the industry.

“The anti-fossil fuel movement started pressuring North Texas cities and towns to require electric compressors on natural gas pipelines based on arguments that the air pollution from natural gas-powered compressors was causing increased asthma and other health problems…. I said that electrifying natural gas pipeline compressors was a terrible idea that could affect the availability of natural gas when it was needed most, such as during bad weather events. Unfortunately, I lost that debate….”

A recent article in The Electricity Journal pointed out that the natural gas pipeline network in the U.S. is vulnerable to electricity outages. How can that be? Surprisingly, critical parts of the U.S. natural gas pipeline grid now depend on electricity.

The study, which the authors say is the first rigorous effort to identify the number of U.S. electric compressor stations, examined data from 2008 to 2020 and found that:

During times of high gas demand, electric outages that disable compressors at these stations can significantly reduce gas available to downstream generating stations. In some cases, the resulting outages could be as large as or larger than the most severe single-cause failure currently considered in electric reliability planning (emphasis added).

Of these outages, they determined that several areas of the country were especially vulnerable to electric outages:

California, the Midwest, the Gulf Coast, and the East have high levels of installed electric compressor capacity. New hydraulic models, verified by past events, show that disrupting power to a single pipeline compressor station can force a loss greater than 2 gigawatts of downstream gas generators (emphasis added).

It is not generally known that natural gas pipelines have, little by little and under the radar, become increasingly dependent on electricity. Recall the parable of a frog in a pot of water that is gradually heated to boiling, but the frog overlooks the danger until it is too late. This describes the electrification of natural gas pipelines that occurred so slowly that it was virtually unnoticed.

The electrification of gas pipelines occurred as the compressors, which are required to keep the gas moving through pipelines, were changed from natural gas to electricity. Compressors are necessary to keep the natural gas moving through the pipeline network. The average distance between compressor stations in interstate pipelines in the U.S. varies, but compressors are usually required every 50 to 100 miles. If any of these compressors fail, the entire pipeline shuts down completely.

Based on their findings, the authors suggest that electric utilities immediately incorporate the identified facilities into critical facilities lists. The authors’ findings support the recommendations of a recent study by the National Academies of Sciences, Engineering, and Medicine:

In contrast to well-established reliability reporting and standards for the electrical system, the gas system has almost no reliability transparency or oversight.” Establishing a federal gas reliability organization, comparable to what is now done for electric power, could improve gas reliability by establishing appropriate reliability reporting, incident investigation, and minimum industry standards.

Background

From the beginning of natural gas pipelines, compressors were powered by natural gas. That made sense because the pipelines were full of natural gas, so pipelines powered themselves. But gradually, compressors were electrified so slowly that, to follow the parable, they, like the frog, didn’t notice what was about to happen.

I observed the early phase of the movement to replace natural gas-fired compressors with electric gas compressors starting around 2010 when I was Executive Director of the Barnett Shale Energy Education Council, headquartered in Fort Worth, Texas. As the Barnett Shale developed in the early 2000s, thousands of natural gas wells were drilled, many in urban areas, and pipelines and compressor stations were constructed to carry the natural gas to markets.

The anti-fossil fuel movement started pressuring North Texas cities and towns to require electric compressors on natural gas pipelines based on arguments that the air pollution from natural gas-powered compressors was causing increased asthma and other health problems. In 2012, the Denton City Council invited me to participate in their project to rewrite city ordinances that regulate natural gas drilling and pipelines.

I distinctly recall a public meeting in which I said that electrifying natural gas pipeline compressors was a terrible idea that could affect the availability of natural gas when it was needed most, such as during bad weather events. Unfortunately, I lost that debate, and the City of Denton changed its city ordinances to require electric natural gas compressors within its city limits. Similar ordinances quickly spread to other municipalities within the state of Texas and eventually to other natural gas-producing states that pipelines pass through.

As shown in the map above, the use of electric compressors on gas pipelines has now become so pervasive that the entire interstate natural gas pipeline network is effectively compromised. An interruption in the generation of electricity can cause some natural gas pipelines to shut down, which interrupts other parts of the natural gas pipeline grid and potentially shuts down multiple pipelines.

An early indicator of the problems caused by the electrification of natural gas pipelines was Winter Storm Uri which hit Texas and much of the nation in February 2021. This was detailed in my article “The Texas power grid was minutes from collapsing in 2021 and declaring an emergency in 2022.”

Here’s what happened. The entire state of Texas was hit by Winter Storm Uri, which resulted in all 254 counties in the state experiencing below-freezing temperatures, with much of the state temperatures in the teens and below zero in some areas for almost an entire week. Freezing temperatures affected all forms of electrical generation, starting with frozen wind turbines, freeze-offs at natural gas wells, and even problems with coal-fired generators and nuclear power generation plants.

As the temperatures dropped and people turned up their heat, the demand for electricity exceeded the supply, and rolling blackouts were ordered to maintain the integrity of the electrical grid. The grid operator, ERCOT, ordered rolling blackouts to balance supply and demand. Unfortunately, some local electricity companies did not have good information on the location of natural gas wells and compressor stations, so some blackouts shut down natural gas wells and pipeline compressors. In turn, this reduced the natural gas supply to gas-fired power generators. This caused a death spiral in electricity generation to the point where the Texas grid was within 4 minutes and 37 seconds of completely collapsing.

After Winter Storm Uri, ERCOT and the Texas Railroad Commission (RRC) recognized that they did not have good data on the location of critical natural gas pipeline infrastructure, including natural gas wells with on-site compressors and the location of all natural gas pipeline compressors that operate on electricity, in addition to the critical customers that depend on electricity to maintain their supply of natural gas.

The RRC highlighted the importance of this information by establishing a new department, the Critical Infrastructure Division, which maintains up-to-date data on all infrastructure required to maintain natural gas supplies to power generators. The RRC published new rules that require gas pipeline operators to provide that information and keep it updated on an ongoing basis.

While Winter Storm Uri caused the Texas power grid problems in 2021, such problems can be caused by the destabilizing impact of wind and solar on power grids, for example. If a sudden decline of wind and solar results in disruptions of electricity, natural gas pipelines can be shut down, which causes a domino effect of more power outages. With more power grids sounding alarms about the instabilities caused by wind and solar, power grids are increasingly facing blackouts and the resulting shut-downs of natural gas pipelines that, in turn, can cause a loss of electric generating capacity.

Where do we go from here?

U.S. power grids have been warning that they are destabilized by wind and solar power generation. Add to that the potential problems they may face as a result of the electrification of natural gas compressors, and the tenuous situation becomes clear.

More power grid operators need to consider their own versions of the rules that ERCOT and the Texas Railroad Commission are implementing.

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Ed Ireland, adjunct professor at TCU’s Neeley School of Business, received his B.S. from Midwestern State University and Ph.D. from Texas Tech University. This analysis was originally posted at Thoughts About Energy and Economics (free subscription).