A daily compilation of significant news articles and comment
June 19, 2008
2. Supply –
Desalination process part of new power plant's plans
UNION-TRIBUNE STAFF WRITER – 6/19/08
By Michael Burge
NRG Energy has applied to the California Energy Commission to build a 540-megawatt power plant west of Interstate 5 on the south
The new plant would be on NRG's 95-acre ocean-view property, where it owns and operates the 965-megawatt Encina Power Station. That power plant is best known for its 400-foot-tall smokestack, visible for miles.
The new plant would replace three of Encina's five steam-driven turbines, so the old plant and its stack would remain standing for the foreseeable future.
NRG raised a group of green balloons this week to show the location and height of the new plant and its 140-foot-high smokestacks.
The gas-powered plant would consist of a two-part electrical generating system. Gas would be burned to drive a turbine that produces electricity; then heat from that process would drive a steam turbine to produce more power.
The advantage of such a system is to increase efficiency and electrical output, NRG says.
Although air-cooled, the plant during peak operation would need 500,000 gallons of water a day to generate electricity from its steam turbines, said Tim Hemig, project manager for the proposed Carlsbad Energy Center.
He said the company would likely file an update with the California Energy Commission detailing its desalination proposal next month.
The desalination idea is similar to a proposal by Poseidon Resources to desalinate 100 million gallons a day of ocean water to produce 50 million gallons of drinking water, at the same site but in a separate facility.
Hemig said yesterday that the company can't rely on Poseidon's process, because that plant doesn't have all of its permits.
NRG would rather use reclaimed wastewater from
“The city's reclaimed-water system is fully committed during peak months,” Joe Garuba, the city's municipal projects manager, wrote to the California Energy Commission on April 25.
NRG proposed the air-cooled power station as a way to eliminate environmental problems associated with the Encina station, which uses seawater to cool its steam turbines.
Environmental groups oppose systems such as Encina's because of the marine life it harms. They have supported NRG's new plant because it would be air-cooled.
Those same groups oppose Poseidon's desalination proposal because the process would trap and kill fish, fish eggs and larvae. Poseidon says those impacts would be minimal.
Joe Geever,
“In our opinion, open ocean intakes are a thing of the past,” Geever said. “The flip side is (that) we would be very supportive of
Hemig said NRG agrees that reclaimed water is preferable, but “we have to demonstrate a long-term water supply” as part of its application.
The company already has a permit from the Regional Water Quality Control Board to desalinate as much as 1.44 million gallons a day, he said.
“Our proposal on the new project would be 1.2 million gallons a day” to produce the 500,000 gallons it needs during periods of peak demand, Hemig said.
The proposed plant would operate only during periods of high energy use, or about 40 percent of the year, he said.
NRG would face the same challenges as Poseidon has, but on a smaller scale. Poseidon's project would be 100 times the size of NRG's.
NRG would have to send a maximum of 722,000 gallons of water a day – about the volume of an Olympic-size swimming pool – back to the ocean twice as salty as when it came into its process.
To lower that salt concentration so it does not harm marine life, Hemig said, the company would blend it with 3 million gallons of seawater, bringing it to a normal level.
Hemig said the new power plant would reduce the need for ocean water from the old turbines it will replace by as much as 98 percent.#
http://www.signonsandiego.com/news/northcounty/20080619-9999-1mc19power.html
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