Friday, September 16, 2011

Drought Spawning La Niña Continues To Next Year - Could Pose Problems for Texas Power Plants

La Niña, which contributed to extreme weather around the globe during late 2010 and 2011, has re-emerged in the tropical Pacific Ocean and is forecast to gradually strengthen and continue into winter and next spring.

Forecasters with NOAA’s Climate Prediction Center have now upgraded last month’s La Niña Watch to a La Niña Advisory indicating there will be a continuation of warmer and drier than normal conditions across the southern tier of the United States and wetter than normal conditions in the Pacific Northwest and Ohio Valley from now through at least late spring 2012.

“This means drought is likely to continue in the drought-stricken states of Texas, Oklahoma and New Mexico,” according to Mike Halpert, deputy director of the Climate Prediction Center. “La Niña also often brings colder winters to the Pacific Northwest and the northern Plains, and warmer temperatures to the southern states.”

The strong 2010-11 La Niña contributed to record winter snowfall, spring flooding, the record shattering heat wave and extreme drought across the United States during late 2010 and 2011 to date, as well as other extreme weather events throughout the world, such as heavy rain in Australia and an extremely dry equatorial eastern Africa.

La Niña is a naturally occurring climate phenomenon located over the tropical Pacific Ocean and results from interactions between the ocean surface and the atmosphere. During La Niña, cooler-than-average Pacific Ocean temperatures influence global weather patterns. La Niña typically occurs every three-to-five years, and back-to-back episodes occur about 50 percent of the time. Current conditions reflect a re-development of the June 2010-May 2011 La Niña episode. While La Niña is a naturally occurring climate phenomenon climatologists believe global warm has enhanced weather extremes associated with this climate cycle.

If the La Niña drought in Texas continues well into next spring and summer, some power plants could be forced to stop operating according to a statement from the Electric Reliability Council of Texas, the state's electric grid operator.

TexasTrib: "If we don't get any rain between now and next summer, there's potentially several thousand megawatts of generation that wouldn't be available and would be affected," said Kent Saathoff, an official with the Electric Reliability Council of Texas (ERCOT) in an interview on Thursday. (To provide context, ERCOT manages about 84,400 megawatts of generation capacity. Also, the coal-plant closures and changes announced earlier this week by the power generator Luminant amount to 1,300 megawatts.)

So far, Saathoff said, "it's not a major issue." But if no rain falls by spring, "we will be very concerned at that point," he said.

Nuclear, coal and natural gas plants need vast amounts of water to cool equipment — which is why the South Texas Project, for example, has large reservoirs on-site. Much of the water used by power plants is discharged back into ponds or rivers after it is used for cooling.The drought, already the worst single-year dry spell in recorded Texas history, seems set to continue, given the return of La Niña, an intermittent Pacific Ocean phenomenon that generally makes Texas drier.

This summer, one large plant had to reduce operations at night so that it could operate fully during the day when the power is most needed, Saathoff said. There were two issues: extreme heat made it harder for the water to cool down enough to be discharged, and the drought reduced the volume of cooler water available in a reservoir that would have helped reduce the temperature of the discharged water.

A number of plants, Saathoff said, are already "piping in water from nearby rivers that they may not normally get water from," especially in East Texas near the Trinity and Sabine rivers.

"Unfortunately, you can't manufacture water," Saathoff said, adding that the plants that have been reported as being "in the most jeopardy," should the drought continue, include a coal plant and several gas plants. One option for mitigating the situation, he said, could be to revive mothballed power plants to help handle the demand on the electric grid.

Clara Tuma, a spokeswoman for the Lower Colorado River Authority, a major water supplier, said that power plants and other large water customers, like cities, could be subject to mandatory cutbacks if the drought gets bad enough. Right now, she said, "There is no mandatory curtailment for LCRA customers at this time, but if the drought continues it is likely we will reach the stage of the water management plan where cutbacks are required."

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