California commission okays switch of Carlsbad project to a gas-fired peaker

The California Energy Commission said July 30 that it has approved two amendments for the proposed Carlsbad Energy Center Project (CECP) and approved contingency water plans for two power plants threatened by drought conditions.

The CECP amendments, which are supported by the city of Carlsbad, address community concerns regarding the coastline, while providing reliable fast-response generation to help meet the region’s energy demands, which were impacted by the retirement of the San Onofre Nuclear Generating Station in San Diego County.

The CECP was originally licensed as a 540-MW natural gas-fired combined-cycle generator by the Energy Commission in 2012. Two years later, the owner, NRG Energy (NYSE: NRG), petitioned to modify the project to a 632-MW natural gas-fired, simple-cycle power generator. In addition to the increase in generating capacity, the CECP amendments allow modifications to the proposed plant’s design, construction and operation, as well as the removal of obsolete facilities including a 400-foot exhaust stack at the adjoining Encina Power Station (EPS) complex.

In 2014, Carlsbad reached an agreement with NRG to reduce the profile of the new power plant, remove the old facility and support the city’s goal of returning coastal lands to non-industrial use. Although the CECP’s profile will exceed the city’s height limit, it will be less than the EPS complex and will only occupy about a third of the property’s 95-acre footprint, the commission noted.

Demolition and construction will take about five years at the power plant site. Nearly 100 people will be employed with an estimated peak workforce of more than 275 people. The operational CECP will have a staff of about 18 people.

In other business, the Energy Commission approved petitions allowing the 330-MW GFW Tracy Power Plant to use backup water supplies for operations and the 200-MW Mariposa Energy Project located near Tracy to install temporary storage tanks for its backup water. Both power plants currently have adequate water supplies and are implementing precautionary measures because of the prolonged drought that has hit California.

Carlsbad project went through various changes in recent years

The CECP would be constructed and operated within the existing footprint of the still-operating Encina Power Station (EPS). The EPS is located on approximately 95 acres, adjacent to the southern edge of the Agua Hedionda Lagoon, in the City of Carlsbad in San Diego County. The EPS contains five units, built between 1950 and the late 1970s, and has been operating in this location since the 1950s.

In 2007, Carlsbad Energy Center LLC filed an Application for Certification (AFC) with the commission to construct an air-cooled, natural gas-fired combined cycle facility with steam power augmentation and evaporative air inlet cooling on a portion of the EPS site.  The commission approved the AFC and granted the petitioner a license to construct the CECP in May 2012.

After issuance of the license to construct, negotiations continued between the petitioner, the City of Carlsbad, and San Diego Gas & Electric (SDG&E), resulting in an agreement regarding changes to the approved CECP to address some of the issues raised in the original licensure proceedings. That resulted in the filing of the two current amendment petitions.

  • The first petition sought permission to demolish three above-ground storage tanks – tanks 1 and 2 to the west of a rail corridor, and tank 4 to the south of the approved project boundary. Those tanks would be demolished in addition to tanks 5–7 on the approved project site. Tanks 5–7 were approved for demolition in the 2012 decision.
  • The second petition would change the project to consist of six simple-cycle turbine generators producing approximately 632 MW. After the new project is commercially operational, the exisiting EPS facilities to the west of the railroad tracks would be decommissioned and demolished, and that site would be made available for redevelopment.

The CECP under the original approval would have been a 558-MW (gross) combined-cycle facility configured with two Siemens SCC6-5000F natural-gas fired combustion turbines and a steam-turbine generator. The amended CECP would consist of six General Electric LMS100PA gas turbines. Similar to the old version of the CECP, the amended CECP units would interconnect with SDG&E’s 138-kV and 230-kV switchyard facilities.

The California Public Utilities Commission on May 21 approved the SDG&E Power Purchase and Tolling Agreement for this project, but only at 500 MW and five units. The Carlsbad plant was slimmed down from about 600 MW and six turbines, to about 500 MW and five turbines, based on a utilities commission decision on SDG&E’s actual power needs. Actual construction of the sixth turbine is a bit of a question mark.

The project is expected to come online in conjunction with the retirement of the Encina station at the end of 2017. Once the new units are online, NRG said it expects to begin the process of demolishing the retired Encina plant.

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.