Last year, natural gas-fueled plants accounted for 57% of the generating capacity in the Electric Reliability Council of Texas (ERCOT) and more than 44% of energy use. As the reliance on gas-fired power grows, ERCOT is working with other organizations to protect against and prepare for a large-scale system-wide blackout.
Although much is made of hurricanes and their impact on the Gulf Coast region, gas supply disruptions in ERCOT are more likely to occur during periods of extended cold weather, ERCOT's Kent Saathoff, an executive adviser, said last week at an Energy Bar Association event in Houston.
The most severe power disruption in ERCOT happened back in December 1989 when 1,000 MW of rotating outages were required. February 2003 saw the last widespread ERCOT reliability event, but that did not require rotating outages, Saathoff said. Rotating outages that occurred in February 2011 (see NGI, Feb. 7, 2011) were due to outages of generating units crippled by cold weather and not the result of gas supply disruptions, he said.
"One of the electric-gas coordination issues that we have become concerned about is if we ever have a system-wide blackout, there are a lot of natural gas facilities that are dependent upon the electric system for compression and control purposes," Saathoff said. "And we certainly would not like to be in a situation where if we did have a blackout that the black start units that we we have -- those would be the units that can start without offsite power -- that they didn't have fuel [natural gas].
"So we've started trying to incorporate the natural gas infrastructure into our electric models so that we can...evaluate whether the loss of a pipeline is a more severe contingency to us than what we have traditionally modeled, the loss of our largest generating plant."
It could take two days to two weeks to recover from a system-wide blackout in ERCOT, Saathoff said. Most of the region's black start power resources are gas-fueled, so it is critical that in such a situation natural gas is available to run these plants. Therefore it's critical to know what gas supply facilities would be available in the absence of electric power.
ERCOT has been working with the Railroad Commission of Texas (RRC) and the Public Utility Commission of Texas to assess the availability of resources in such a blackout situation, Saathoff said.
"In 2012, ERCOT began working with the Texas Pipeline Association and [RRC] to incorporate location of significant gas facilities into the ERCOT electric network model," Saathoff said. "This information will help ERCOT study the potential impact of electric outages on pipelines and pipeline outages on generators."
Many of the gas-fueled power plants in Texas are supplied by more than one pipeline, Saathoff said, which besides giving the generator more market leverage also helps to ensure gas supply in times of system stress.
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