El Segundo combined cycle offers

300 MW of peaking in 10 minutes

550MW Flex-Plant 10 combined cycle project represents a growing trend in the use of combined cycle technology that has the ability to provide peaking and base load power to complement intermittent renewables.

550MW El Segundo plant

On September 12th, NRG Energy Inc. inaugurated what is only the second combined cycle plant in the US to use Siemens “Flex-Plant” technology. The new facility, in El Segundo, California, represents what is a growing trend among US operators to install plants that have the operating flexibility to back up the growing amount of renewable generation on the grid in markets like California.


The El Segundo Energy Center features two Siemens Flex-Plant 10 fast-start SCC6-5000F 1x1 combined cycle power blocks. Performance highlights include the ability to deliver 300MW in 10 minutes and limit transient NOx emissions during operation to 2 ppm. More specifically:


Rating.  Each power block is rated at 275MW net output (at 85°F design point) for a total plant output of 550MW at 48.9% combined cycle efficiency.


Fast start.  Each SGT6-5000F gas turbine can deliver 150MW of non-spinning reserve peaking power within 10 minutes of startup, for a total of 300MW.


Emissions.  Entire combined cycle block can ramp up and down at 30-35MW per minute while maintaining 2 ppm NOx stack emissions and virtually no CO.


El Segundo combined cycle offers 300 MW of peaking in 10 minutesH-80 dual shaft gas turbine rated over 110MW and 37% efficiencyCombined cycle heat
rates at simple cycle
$/kW plant costs
Prospects for lower
cost and more efficient IGCC power
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The El Segundo Energy Center is the latest move in NRG’s ongoing drive to lower emissions from its thermal generating fleet while at the same time allowing greater use of renewables and the gradual replacement of aging steam units at the site.


The original plant at the El Segundo facility comprised four natural gas fired steam units – Units 1 and 2 which began operating in the 1950s and Units 3 and 4, which had been running since the 1960s.


Units 1 and 2 were retired in 2002 and demolished in 2010 to make way for the two new units. Unit 3 has also since been retired as part of the permitting of El Segundo Energy Center, while the 335MW Unit 4 is still operating.


In addition to helping the integration of renewables, the new plant will enable the site to reduce the consumption of potable water by nearly 90%; allow NRG to meet or exceed the State and South Coast’s strict air quality standards; and require 30% less natural gas per MW produced than the original steam boilers.


Also, the removal of two large oil tanks at the south end of the property will lower the site’s profile and reduce the overall visual impact.

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