NRG, Siemens mark finish of initial phase of El Segundo repowering

NRG Energy (NYSE: NRG) and Siemens Energy will celebrate the official grand opening and re-powering of the El Segundo Energy Center, only the second “flex-plant” in the nation, on Sept. 12 in El Segundo, Calif.

New “flex plant” units will provide 550 MW of flexible, natural gas-fueled capacity to the California grid, the companies said in a Sept. 10 announcement. These units provide critical backup support for renewable energy sources, such as wind and solar, the companies added. They will also help California meet mandatory greenhouse gas standards by using 30% less natural gas than the units they replaced.

Already home to the nation’s first “Flex-Plant” in Lodi, the state, along with NRG Energy and Siemens Energy, will now commemorate the repowering and modernization of the El Segundo Energy Center, the second Flex-Plant to open in California.

Flex-Plants are fast-start power generation plants start quickly enough to back up wind and solar when wind and solar are producing less than their peak capacities. They are uniquely capable of ramping up power to the grid in 10 minutes or less and, they do it with lower emissions than any other plants in existence today. The Flex-Plant 10 at El Segundo also offers significant environmental benefits, including reduced emissions and air cooling instead of ocean-water cooling.

NRG said Aug. 2 that it had entered commercial operation at its El Segundo Energy Center. The El Segundo Energy Center project contributed to various significant environmental benefits, including the retirement of an older 335-MW steam boiler unit constructed in 1964 that relied on ocean water for cooling. The new Energy Center relies on reclaimed water for its state-of-the art, air-cooled, combined cycle operation, reducing the use of potable water at the site by nearly 90%.

Through a 10-year power purchase agreement, Southern California Edison will obtain the entire output of the facility.

NRG plans more repowering work at the El Segundo site

This isn’t the last redevelopment activity for this site. The California Energy Commission is reviewing the proposed El Segundo Energy Center (ESEC) amendment, filed on April 23. The project applicant is El Segundo Energy Center LLC, a subsidiary of NRG.

Originally built in the 1950s, the ESEC was a 1,052-MW plant consisting of four natural gas-fired utility boiler generating units. In 2000, the project owner applied to the commission to demolish and replace Units 1 and 2 with combined cycle Units 5, 6, and 7 and continue the use of once through cooling. The project was certified by the commission in 2005. In 2007, the owner petitioned to amend the 2005 decision to install smaller rapid start combined cycle units using dry cooling technology and designated as Units 5 and 6 and 7 and 8. The commission approved this petition in 2010. This version of the project is the one that commenced commercial operation on Aug. 1.

Under the pending amendment, primary changes include the demolition and replacement of two once-through-cooled natural gas-fired utility boiler units, Units 3 and 4, with one new combined cycle generator (Unit 9), one steam turbine generator (Unit 10) and two simple-cycle gas turbines (Units 11 and 12). This change will eliminate the use of ocean water for once-through cooling at the facility. The proposed changes will also upgrade and improve the ESEC’s existing and approved site infrastructure, provide fast start and dispatch flexibility capabilities to support Southern California grid load balancing and renewable energy integration, and implement improvements to coastal access.

Changes proposed under the amendment include:

  • Shutdown and demolition of Units 3 and 4;
  • Removal and remediation of existing ESEC retention basins;
  • Construction of a new, combined administration, maintenance, and operations support building;
  • Modifications to existing site access; and
  • Improvements to beach access.

Major new equipment will include:

  • (Unit 9) – One NRG fast start combined-cycle generator unit (CC Fast), rated at 222 MW net, using a General Electric natural gas combustion turbine generator designed to achieve 75% of baseload output in 10 minutes;
  • One two-pressure, duct-fired heat recovery steam generator (HRSG) designed for rapid startup with conventional selective catalytic reduction (SCR)/carbon monoxide (CO) catalysts;
  • (Unit 10) – One single-case, non-reheat axial exhaust admission condensing steam turbine generator (STG) rated at 112 MW and designed for non-traditional elevated condensing pressure to minimize cooling system size;
  • One Heller dry cooling tower system;
  • (Units 11 and 12) – Two Rolls Royce Trent 60 generators, rated at 55 MW/unit net, consisting of advanced aeroderivative simple-cycle gas turbines; and
  • One Cleaver Brooks auxiliary boiler consisting of a direct contact spray condenser and a mechanically-induced-draft dry-cooling tower.
About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.