AES starts California process to replace 1,950-MW Alamitos plant

Replacement gas-fired plant to have a capacity of up to 1,936 MW

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The California Energy Commission is beginning the process, with Jan. 15 notices of the application sent to various parties, of reviewing a recent application from AES Southland Development LLC for the repowering of the Alamitos power plant.

On Dec. 27, 2013, AES Southland Development, a unit of AES Corp. (NYSE:AES), submitted an Application for Certification (AFC) to the commission to modernize the existing Alamitos Generating Station (AGS). The new Alamitos Energy Center (AEC) would be located on approximately 63 acres of privately owned land at the site of the existing power plant in the city of Long Beach in Los Angeles County, Calif.

The existing Alamitos Generating Station Units 1–6 are currently in operation with a net generating capacity of 1,950 MW. All six operating units and the retired Unit 7 would be demolished as part of the proposed project. Construction and demolition activities at the project site are anticipated to last 139 months, from the first quarter of 2016 until the third quarter of 2027, with elements of the new plant phased in as parts of the old plant are shut and ripped out.

The new AEC will consist of four 3-on-1 combined-cycle gas turbine power blocks with twelve natural-gas-fired combustion turbine generators (CTG), twelve heat recovery steam generators (HRSG), four steam turbine generators (STG), four air-cooled condensers, and related ancillary equipment. The AEC will use air-cooled condensers for cooling, completely eliminating the existing ocean water once-through cooling (OTC) system. Getting rid of existing plants using OTC is a high priority for California regulators. It will provide up to 1,936 MW of capacity.

The AEC will interconnect to the existing Southern California Edison (SCE) 230-kV switchyard adjacent to the north side of the property. Natural gas will be supplied to the AEC via the existing offsite 30-inch-diameter pipeline owned and operated by SoCalGas that currently serves the Alamitos Generating Station.

To provide fast-starting and stopping, flexible generating resources, the AEC will be configured and deployed as a multi-stage generating (MSG) facility. The MSG configuration will allow the AEC to generate power across a wide and flexible operating range, serving both peak and intermediate loads with the added capabilities of rapid startup, significant turndown capability, and fast ramp rates (30% per minute when operating above minimum gas turbine turndown capacity).

Once-through cooling shutdowns, increased renewables are key reasons for this project

“As California’s intermittent renewable energy portfolio continues to grow, operating in either load following or partial shutdown mode will become necessary to maintain electrical grid reliability, thus placing an increased importance upon the rapid startup, high turndown, steep ramp rate, and superior heat rate of the MSG configuration employed at the AEC,” said the application. “By using proven combined-cycle technology, the AEC can also run as a baseload facility, if needed, providing greater reliability to meet resource adequacy needs for the southern California electrical system. As an in-basin generating asset, the AEC will provide local generating capacity, voltage support, and reactive power that are essential for transmission system reliability. The AEC will be able to provide system stability by providing reactive power, voltage support, frequency stability, and rotating mass in the heart of the critical Western Los Angeles local reliability area. By being in the load center, the AEC also helps to avoid potential transmission line overloads and can provide reliable local energy supplies when electricity from more distant generating resources is unavailable.”

The application added: “The achievement of the project objectives is contingent on using qualifying technology under the South Coast Air Quality Management District’s (SCAQMD) Rule 1304(a)(2) that allows for the replacement of older, less-efficient electric utility steam boilers with specific new generation technologies on a megawatt to megawatt basis (that is, the replacement megawatts are equal or less than the megawatts from the electric utility steam boilers). Rule 1304(a)(2) requires the electric utility steam boiler be replaced with one of several specific technologies, including the combined-cycle configuration used in the AEC design. Without accessing Rule 1304(a)(2) provisions, the Applicant would be required to acquire emission offset credits for particulate matter and volatile organic emissions and these credits are for all practical purposes unavailable.”

The California Public Utilities Commission (CPUC) confirmed the need for new generation in the Los Angeles Basin in a decision authorizing procurement of between 1,400 MW and 1,800 MW of new electrical capacity in the western Los Angeles sub-area to meet long-term local capacity requirements by 2021 and that at least 1,000 MW but no more than 1,200 MW must be from conventional gas-fired resources (including combined heat and power resources), the application said. Further, the CPUC found a significant need for local generating resources to replace retiring OTC plants in the Los Angeles basin local area under every scenario analyzed by the California ISO.

“The CPUC decision authorizing procurement of between 1,400 and 1,800 MW of new electrical capacity in the western Los Angeles sub-area did not consider any replacement generation for the loss of the San Onofre Nuclear Generating Station (SONGS),” the application added. “It is expected that further procurement authorization from the CPUC will result from its assessment of the electrical capacity needs in the absence of SONGS. As a modern, gas-fired generation plant located at an existing OTC site, the AEC will satisfy these resource and reliability needs.”

Southern California Edison announced in 2013 that it plans to retire the idled San Onofre nuclear plant, setting off a scramble to fill the capacity hole left by that over 2,000 MW facility.

AES working at commission for approval of other repowering projects

This is not the only AES repowering project in California. The California Energy Commission is also working on an application for the Redondo Beach Energy Project of AES Southland Development. The Redondo Beach Energy Project is a proposed natural gas-fired, combined-cycle facility located southeast of the intersection of North Harbor Drive and Herondo Street in Redondo Beach in Los Angeles County.

The new 496-MW facility would replace the existing Redondo Beach Generating Station - which relies on 1950s technology - with a modern, more efficient plant that would utilize about 26% of the existing power plant site. It would use dry-cooling to reduce water use and comply with the State Water Resources Control Board's policy eliminating the use of ocean water for power plant cooling. The existing Redondo Beach Generating Station would be demolished. Construction and demolition activities are scheduled from January 2016 until December 2020.

The California Energy Commission is also handling an application from AES Southland Development for the proposed Huntington Beach Energy Project in Huntington Beach, Calif. This is a 939-MW, gas-fired power project. It would be constructed on a 28.6-acre site located within the footprint of the existing Huntington Beach Generating Station, which would be demolished and removed.

The new Huntington Beach facility would consist of two independently operating, combined-cycle gas turbine power blocks. It would use dry-cooling to reduce water use and comply with the State Water Resources Control Board’s policy eliminating the use of ocean water for power plant cooling. Demolition and construction activities for the project are scheduled between the first quarter of 2015 and the third quarter of 2022.

Barry Cassell
About the Author

Barry Cassell

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 26 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.

Barry can be reached at barryc@pennwell.com.

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