EL SEGUNDO, CA – On September 12th, Siemens Energy and NRG Energy celebrated the official grand opening and repowering of the El Segundo Energy Center, the second Siemens “Flex- Plant” in the nation with a ribbon cutting ceremony and luncheon. Southern California Edison has a 10 year power purchase agreement. The first Siemens “Flex-Plant” is operating at the Lodi Energy Center also in California (See world-gen.com, Featured Articles, Aug/Sept 2012).

Before the ceremony, NRG executives George Piantka and Tim Sisk hosted a press tour for World- Gen editors around the ten acre plant footprint, and shared its history. Along the tour, they pointed out the new 11 foot high undulating sea wall NRG constructed, fronted by a bike path, ocean walkway and native landscaping NRG planted. The plant created 400 jobs and will increase tax revenue by $3 million annually. No tax dollars were used on the project.

NRG was originally issued a license in 2005 for a 630 MW, ocean-cooled baseload plant, but elected to redesign to an aircooled, rapid-response, 550 MW plant. CEC granted approval in July, 2010. Construction began in May, 2011. The new design included two 280-MW Siemens SCC6-5000F Flex Plant 10 combined cycle power islands. Air-cooled condensers replaced the once-through cooling system. Fortuitously, NRG moved ahead of the 2010 state regulation that requires all once-through cooling systems be removed or replaced by 2020.

The air cooled system allows closed-loop circulation of cooling water. Water/steam cycle wastewaters are recycled back to the single-pressure reverse osmosis water storage tank where they are diluted for reuse as evaporative cooler makeup or reprocessed by mobile demineralizers. A zero liquid discharge system has been added to all wastewater discharge from the facility. The West Basin Municipal Water District is providing through an underground pipe the reclaimed water used as feedwater for the steam turbine and the landscaping. Water for domestic use and for firefighting is being provided by the City of El Segundo.

The project involved the removal of units 1&2 at El Segundo and developing two trains of fast start, highly efficient combined cycle power plants. These units are ideal for responding to peak demand and have the capability to provide efficient base-load generation as well. Capable of providing about more than half of its power generation capacity in 10 minutes, these new units are ideal as back-up to California’s non-dispatchable renewable generation.

By Dick Flanagan and Lyn Corum

John Chillemi, Sr VP, CEO David Crane of NRG, and Barry Nicholls, Sr VP at Siemens are joined by other dignitaries representing state and regional energy agencies that permitted the El Segundo project at the ribbon cutting ceremony.

Siemens dedicated El Segundo in California on September 12th.

For El Segundo, Siemens delivered two power islands with each featuring the main components: an SGT6-5000F gas turbine; an SST-800 steam turbine; an SGen6-100A generator; an SGen6-100A- 2P generator as well as a heat recovery steam generator, and an air-cooled heat exchanger. Siemens also supplied the complete electrical equipment and the SPPA-T3000 power plant instrumentation and control system. The company also provided the engineering services and commissioning of the plant.


Plant start-up times are significantly reduced by introducing and integrating fast-start features, including the single- pressure HP drum heat recovery steam generator (HRSGs), full capacity steam bypass systems, and innovative piping warm-up strategies. The plants will provide high power density while requiring a relatively small plant footprint. The unique small footprint aircooled heat exchanger allows these plants to use 90% less water than traditional ramping solutions, and meets the standards of the once-through cooling initiative in California. The Siemens SPPA-T3000 control system provides an easy-to-use control platform for the entire combined cycle power plant. Its fast start capability delivers over half of the plant’s power in 10 minutes and the balance of power in under an hour. This can result in a carbon monoxide reduction of over 200 tons per year when compared to traditional F-class combined cycle plants.

Fast start combined cycle technology does more than offer fast power to the grid. It makes the plant’s start up emissions lower. This technology avoids holding the gas turbine at low load to start, so you ramp up to a low emissions point very fast. This results in 89% less CO per start and 95% less NOx.

NEM’s DrumPlus™ HRSGs are part of the Siemens power island at El Segundo. Allowing the Siemens SGT6-5000F gas turbines unrestricted ramp up, NEM’s ultramodern HRSGs are vital for flexible operation of the plant. The innovative HRSG design allows the Flex-Plant™ 10 to meet the challenging emission regulations for the California power market. El Segundo is one of the first sites to incorporate Siemens Clean-Ramp™ technology which keeps stack emissions low while ramping fast. Plants without Clean-Ramp experience increased emissions during fast transients. This technology keeps the operation clean even when the plant is changing load constantly to compliment renewables.


In partnership with NRG, Siemens followed a detailed safety program for the site. Siemens Project Manager and Project Engineer independently conducted and documented a formal site Safety Walk at every site visit. There were also regular site audits to assure adherence to Siemens and site procedures and prompt action and resolution for any quality incident reports.


All OEM equipment for El Segundo was delivered ahead of construction plan. Siemens assigned a factory load planner to monitor the manufacturing of the gas turbine and steam turbine for all projects to resolve any schedule issues.

Siemens also assigned a project specific specialist to support needs for parts and services. For El Segundo, they developed a logistics plan for special rail car usage and transit clearance and routing to ensure the gas turbine and the generator delivery to site without schedule delays including steam turbines 63 days early, gas turbines 3 days early, HRSGs 42 days early and air cooled heat exchangers (condenser) 21 days early.


NRG personnel received classroom, hands-on operating and maintenance training on site and on the simulator in Orlando. Over 20,000 plant operators have been trained by Siemens since 1990.

Siemens has implemented nine large scale gas turbine projects in California since 1997. The Siemens Energy Solution Portfolio is designed as an environmentally friendlier way to meet the needs of markets with diverse generation and is being widely dispatched in California. From the fast start simple cycle and gas turbines at Marsh Landing to the Flex-Plant 10 combined cycle plants at El Segundo and the Flex- Plant 30 Combined Cycle plant at Lodi, Siemens solutions fit the needs of California with high efficiency for low cost generation, flexibility for fast dispatch, and low emissions for a clean environment.

Siemens has successfully completed over 330 projects worldwide and procured over 70 HRSGs globally since 2000. In the Americas, over 105 turnkey projects have been completed. NRG is a Fortune 500 Company and is the largest IPP with 47,000 MWs. Last December, NRG and Genon, formerly Mirant and RRI Energy, merged.