NRG Evaluates Alternative Sites for 262-MW Puente Project

NRG Lists Alternate Sites for Natural Gas-Fired Project

NRG Energy (NYSE: NRG) on Dec. 21 filed with the California Energy Commission a list of alternative sites for its Puente Power Project (P3) and reasons why its preferred site at the Mandalay Generating Station (MGS) is still the best option.

NRG is pursuing an Application for Certification (AFC) at the commission filed April 15 under its NRG Oxnard Energy Center LLC subsidiary. The original application indicated that analysis of alternative sites for P3 is not a strict legal requirement. It was documented further in Section 5 of the AFC that alternative sites could not meet the project objectives, namely the obligations of the executed power sales contract between NRG and Southern California Edison (SCE). For these reasons, an alternatives analysis was not presented in the AFC.

In an August 2015 report, commission staff indicated that analysis of alternative site locations may be warranted, and identified two possible alternative sites. The alternative sites identified by the CEC staff are:

  • Site 1: Ormond Beach Generating Station (OBGS)
  • Site 2: Existing location of Mandalay Generating Station Units 1 and 2

The City of Oxnard also requested that CEC staff and NRG review alternative sites for the development of P3. The city initially introduced five potential alternative sites. It subsequently refined the suggested sites, and included a sixth site for consideration. These six alternative sites are:

  • Site 3: Sanitation District Flower Field
  • Site 4: Beedy Street
  • Site 5: Power Machinery/Camino Real Business Park
  • Site 6: Del Norte and East 5th Street Industrial Park
  • Site 7: Mission Rock Energy Center
  • Site 8: Ormond Beach Parcels (various locations near Edison Drive/Hueneme Road)

Although NRG said it continues to believe that analysis of alternative sites is not required, it has reviewed the alternative sites suggested by the CEC staff and the city and compared them to the proposed project site.

It noted that SCE issued the 2013 Local Capacity Requirements Request for Offers for the Moorpark Sub-Area (Track 1) in September 2013. SCE sought to procure between 215 MW and 290 MW of electrical capacity in the Moorpark Sub-Area of the Big Creek/Ventura local reliability area to meet long-term local capacity requirements by the beginning of 2021, due to the expected retirement of once-through cooling generating facilities.

The P3 project is designed to:

  • fulfill NRG's obligations under its 20-year Resource Adequacy Purchase Agreement with SCE, requiring development of a 262-MW nominal net output of new, more flexible and efficient natural-gas generation at the site of the existing MGS;
  • provide an efficient, reliable, and predictable power supply by using a simple-cycle, natural-gas–fired combustion turbine to replace the existing once-through cooling generation;
  • support the local capacity requirements of the California Independent System Operator Big Creek/Ventura Local Capacity Reliability area;
  • develop a 262-MW nominal net power-generating plant that provides efficient, operational flexibility with rapid-start and fast-ramping capability to allow efficient integration of renewable energy sources in the California electrical grid; and
  • have the project designed, permitted, built, and commissioned by June 1, 2020.

The interconnection for this project will need to be to the 220-kV transmission lines that are part of the Moorpark Sub-Area of the Big Creek/Ventura Local Reliability Area. Therefore, all of the alternative sites were reviewed to assess distance to this interconnection.

The proposed site is within the boundaries of MGS, which is an existing natural-gas–fired steam electric generating facility. Among its advantages is that NRG has site control of the project and laydown areas at this site. The proposed site has sufficient and useable space available for the project. The project will be sited on approximately 3 acres in the northern portion of the 36-acre parcel. The project will re-use and re-purpose several existing MGS facilities, including the administration building, warehouse, water storage tanks, and ammonia tank that are outside of the 3-acre power block site, but within the MGS property. An additional 2 acres within the MGS property will be used for construction laydown, offices, and parking. Site access is easily afforded from Harbor Boulevard, local streets, and Highway 101.

The new generating unit will tie into the existing Mandalay Switchyard, owned by SCE, using one of the breaker positions that will be vacated when MGS Units 1 and 2 are removed from service. No new offsite electrical linears will be required. Natural gas is supplied by Southern California Gas and the P3 project will connect to a new gas metering station within the MGS. No new offsite gas linears will be required for the site, NRG noted in the Dec. 21 filing.

MGS is an existing natural-gas–fired steam electric facility owned by NRG California South LP. It consists of two conventional steam turbine units (Units 1 and 2) and one gas combustion turbine unit (Unit 3). MGS Units 1 and 2 were constructed in the 1950s, and have a combined generating capacity of 430 MW. Cooling water for Units 1 and 2 is ocean water conveyed via the 2.5-mile-long Edison Canal from the Channel Islands Harbor. On an annual basis, MGS withdraws substantially less water than its design capacity, due to its low generating capacity use (3.9% average capacity factor for years 2010 to 2014).

MGS Units 1 and 2 are subject to the California State Water Resources Control Board’s OTC Policy. Regardless of the proposed development of P3, the cooling system for MGS Units 1 and 2 must be modified to comply with the OTC Policy compliance date of Dec. 31, 2020. If P3 is approved and developed, MGS Units 1 and 2 would be retired, although not necessarily demolished, by the completion of commissioning of P3. The existing MGS backup-diesel generator, located near the warehouse building, would also be retired. Demolition of MGS Units 1 and 2 is not needed to accommodate development of P3.

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 is connected to the neighboring SCE 66-kV switchyard, and provides local reliability. Unit 3 will continue to operate and will not be affected by the P3 project.

This article was republished with permission from

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