NRG submits plan for demolition of two Mandalay units in California

NRG Energy (NYSE: NRG) on Nov. 19 filed with the California Energy Commission a plan for the demolition of Mandalay Generating Station Unit 1 and 2, which will be replaced with new gas-fired capacity on the same site.

The Puente Power Project’s (called the P3 project) Application for Certification (AFC) was filed with the commission on April 15, 2015, and was accepted as “data adequate” in June. NRG Energy Center Oxnard LLC is proposing through the Nov. 19 filing a project enhancement relative to the previously submitted AFC, to include the demolition of the two gas-fired steam-generating units (Units 1 and 2) at the Mandalay Generating Station (MGS).

The AFC assumed that if P3 is approved and developed, MGS Units 1 and 2 would be retired by the completion of commissioning of P3 (in June 2020), and that the units would then be decommissioned and left in place. As a project enhancement with corresponding community benefits, and to improve the visual aspects associated with the development of P3, NRG now proposes to demolish MGS Units 1 and 2 immediately following their retirement and decommissioning.

This improvement is the outcome of continuous evaluation of methods and financial means to improve upon P3 as originally proposed in the AFC, while maintaining the contractual commitments to the load-serving entity, Southern California Edison (SCE), the filing said.

MGS is an existing natural-gas–fired steam-electric facility owned by NRG California South LP. It is located in the City of Oxnard, Ventura County. MGS consists of two conventional steam turbine units (Units 1 and 2) and one gas turbine peaking unit (Unit 3). MGS Units 1 and 2 were constructed in the 1950s, and have a combined capacity of 430 MW.

Units 1 and 2 are cooled by ocean water conveyed via the 2.5-mile-long Edison Canal from the Channel Islands Harbor (also referred to as the Mandalay Canal). The generating station intake is in the Edison Canal. MGS discharges wastewater—consisting of once-through cooling (OTC) water and other process wastewaters—into the Pacific Ocean, via a concrete-and-rock revetted structure immediately offshore of the facility.

MGS Units 1 and 2 are subject to the California State Water Resources Control Board’s OTC Policy. Irrespective of the proposed development of P3, pumping of ocean water for cooling MGS Units 1 and 2 must be reduced or eliminated as of the OTC Policy compliance date of Dec. 31, 2020.

The applicant now proposes to demolish all above-grade structures associated with MGS Units 1 and 2 following their retirement and decommissioning. The demolition of Units 1 and 2 will generally occur in the western portion of the MGS property, south of the three basins and north of the water storage tanks area. The specific sequencing of demolition activities will provide for coordinated removal of MGS Units 1 and 2 and continued operation and maintenance activities related to P3 and MGS Unit 3.

Decommissioning of Units 1 and 2 would commence upon retirement of both units (no later than Dec. 31, 2020), and is anticipated to take approximately six months. Asbestos abatement and above-grade demolition work for MGS Units 1 and 2 is anticipated to take approximately 15 months following completion of decommissioning, and would be completed by late 2022.

MGS Unit 3 is a jet-engine–powered unit that was commissioned in 1970, and has a generating capacity of approximately 130 MW. Unit 3 will continue to operate and will not be affected by P3 or the demolition of MGS Units 1 and 2.

P3 will replace Units 1 and 2 with a new General Electric (GE) Frame 7HA.01 single-fuel combustion turbine generator (CTG) and associated auxiliaries. P3 will be developed on approximately three acres of previously disturbed vacant brownfield land located within the existing boundaries of MGS.

The P3 power block will provide peaking power and is expected to operate at up to approximately 30% capacity factor. Full-load output of the project under expected operating and ambient (temperature/‌relative humidity) conditions will range from approximately 241 net MW to a peak of 271 net MW. The new generating unit will tie into the existing Mandalay Switchyard, owned by Southern California Edison, using one of the breaker positions that will be vacated when MGS Units 1 and 2 are removed from service.

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.