Gas Generators “Significantly Vulnerable” to Failure

As We know.

Gas-fired power plants are not as reliable as grid planners believe and this is a “significant vulnerability” for the electric grid and consumers, the Union of Concerned Scientists said Tuesday in a new issue brief examining thermal generation failures in extreme temperatures.
Gas plants accounted for 63% of the generating capacity forced offline by severe weather during Winter Storm Elliott in 2022, and 56% of the capacity offline during Winter Storm Uri in 2021 when almost 250 people died in Texas amid rolling blackouts, according to the issue brief, “Calling into Question the Reliability of Gas Power Plants.”
The report recommends grid operators consider new approaches to accounting for the contributions of thermal resources, and for regulators to make more information available about the cause of generator failures. Some investment in weatherization may be needed, but UCS energy analyst and report co-author Paul Arbaje cautioned against the “vicious cycle” of investment in new gas-fired resources.

Despite growth in renewable resources, natural gas still provides about 40% of U.S. electricity generation annually and 43% of its generating capacity, according to UCS.

“The energy system’s overreliance on gas is problematic for many reasons,” said UCS Senior Energy Analyst and report co-author Mark Specht. “Our analysis found that gas plants were disproportionately vulnerable to failure.”

Gas plants accounted for most of the failed capacity in all five recent extreme winter weather events, and they failed “disproportionately in comparison with gas’s percentage of total installed capacity, indicating that they are more susceptible to extreme winter weather than are other resource types.”

During Winter Storm Elliott, 90.5 GW in the Eastern Interconnection failed to run or operated at reduced capacity, the Federal Energy Regulatory Commission and North American Electric Reliability Corp. concluded in a joint report. Gas-fired capacity accounted for 63% of the outages, followed by coal and lignite at 23%, oil at 4%, wind at 4%, and nuclear, solar and hydroelectric at 1% each.

The UCS issue brief looks at gas plant operations in both summer and winter, as well as direct impacts and associated fuel supply issues. Gas plants face most issues in the winter, when equipment freezing can impact valves, water lines, inlet air systems and sensing lines, said UCS. Mechanical and electrical issues can also impact wiring and the mechanical wear of valves, while rubber and silicone seals can become brittle.

Summer temperatures also threaten gas plant reliability, said UCS. High temperatures can reduce “both the efficiency and the maximum generating capacity of gas plants,” according to the paper, while droughts can force plants to reduce output or shut down if they are dependent on water for cooling.

“Extreme weather events have become more frequent and intense putting the U.S. power grid and broader energy system under significant pressure,” Arbaje said. Gas plants are “not up to the task of supplying power when it’s needed most,” he said. And further investment in them “continues the vicious cycle of releasing heat-trapping emissions that exacerbate climate change impacts and in turn strain the electric grid.”