Los Angeles looks to repower capacity at two gas plants

The Los Angeles Department of Water and Power (LADWP) plans to repower its gas-fired Haynes and Scattergood power plants over the next few years as it moves to drive up plant efficiencies and reduce air and other emissions.

LADWP on Oct. 5 released a draft integrated resource plan (IRP) for 2012 and will be taking public comment on that plan until Oct. 25.

LADWP is the sole owner and operator of the following four electric generating stations in the Los Angeles Basin, called the “in-basin” stations:

  • The largest of the Los Angeles Basin Stations is the Haynes Generating Station, located in Long Beach. Haynes currently consists of eight units (Unit 7 is used for auxiliary power only) with a combined net maximum capability of 1,556 MW and a net dependable capability of 1,525 MW. This station includes a 575 MW combined-cycle generating unit installed in February 2005. The combined-cycle unit includes two combustion turbines and a common steam turbine. The combustion turbines can each operate with the steam turbine independently or together in a two on one configuration (and are counted by LADWP as three generating units). LADWP plans to repower Units 5 and 6 with six 100-MW simple-cycle gas turbine units targeted by June 2013.
  • The Valley Generating Station is located in the San Fernando Valley and began its repowering in 2001 with a simple-cycle, 60.5-MW gas–turbine generator. Repowering was completed in 2004 with the installation of a combined-cycle unit consisting of two gas turbines with heat recovery steam generators, which supplies one steam turbine with a combined net maximum capability of 576 MW. The total net dependable capacity for Valley is 556 MW.
  • The Harbor Generating Station is located in Wilmington and was repowered in 1995 with a combined-cycle generating unit (counted as three units). Five additional peaking combustion turbines were installed in 2002 for a total of eight units. Harbor has a net maximum capability of 466 MW and a net dependable capability of 452 MW.
  • The Scattergood Station is located in Playa del Rey and is comprised of three steam generating units with a net maximum capability of 817 MW and a net dependable capability of 796 MW. Unit 1 and 2 also burn digester gas from the adjacent Hyperion Wastewater Treatment Plant.

“Securing continued local generation capacity is important for grid reliability,” the draft IRP pointed out. “LADWP’s local transmission system cannot be reliably operated without generation from local thermal generating plants. The amount of generation required to provide transmission reliability is termed Reliability Must Run (RMR) generation. RMR generation is incorporated into all of the strategic cases considered in this IRP. The major issues facing the in-basin stations include the need to replace some of the older units that are approaching the end of their service life, compliance with regulations related to ocean water cooling and NOX emissions, and fuel price volatility.”

Natural gas will continue to be the essential fuel for LADWP generation due to abundant supplies of it, the draft said. Natural gas will be used to supply baseload (as is currently used), and will also provide for the integration of intermittent renewable generation. Natural gas is also a major component of LADWP’s coal replacement strategy, which involves opting out of a share of the Navajo coal plant in Arizona in 2015 and a coal-to-gas conversion of the Intermountain power plant in Utah by around 2024.

There is a need to modify or replace some of LADWP’s older gas-fired facilities located at Haynes and Scattergood, the IRP said. These units were primarily built in the late 1950s and the early 1960s and are approaching the end of their service lives. LADWP said it must modernize these plants to maintain system reliability, improve efficiency, and better integrate renewable resources.

The units to be replaced at Haynes and Scattergood are between 44 and 53 years old, and are among the oldest remaining units in LADWP’s generation fleet. LADWP’s local basin transmission system was never intended to be reliably operated without generation from these plants, the draft IRP said. By virtue of their location within the basin transmission system, Haynes and Scattergood generation ensures that loading on basin transmission lines remain within the circuits’ ratings, and system voltage remains within acceptable limits. Minimizing outages at these locations is therefore especially important. Variable-energy resources, such as solar or wind power, can operate on top of existing in-basin gas-fired generation, but the variable resources cannot replace the role local gas-fired generation plays in transmission reliability.

LADWP plans to revamp cooling systems at coastal plants

In addition, the repowering program is necessary to comply with state and federal regulations related to once through cooling as well as local NOX emission mandates. Once-through cooling (OTC) is the process where water is drawn from the ocean, is pumped through equipment at a power plant to provide cooling, and then is discharged back to the receiving water source.

LADWP operates three coastal stations – Scattergood, Harbor and Haynes – that utilize OTC. The combined net capacity of these stations is 2,839 MW. In order to comply with the statewide OTC policy, LADWP has chosen to eliminate OTC and replace it with closed cycle cooling. Interim requirements are necessary until a facility is deemed fully compliant, including the funding by LADWP of mitigation projects to alleviate impacts, such as habitat restoration with the development of wetlands.

In mid-2000, during the statewide energy crisis, LADWP predicted that NOX emissions from the in-basin generating units would exceed the available supply of NOX RECLAIM Trading Credits issued by the South Coast Air Quality Management District (SCAQMD). Although LADWP’s NOX emissions ultimately did not exceed its allocation in 2000, in August 2000 the SCAQMD Hearing Board issued a stipulated order for abatement to the LADWP. Under the order, LADWP was required to perform a series of repowering projects at its in-basin generating stations. The stipulated order was later superseded by a settlement agreement to accommodate scheduling and other issues. This agreement was revised in September 2011 and addresses the current repowering projects at Haynes and Scattergood.

Long term natural gas price forecasts have been revised downwards from last year’s IRP with recent prices reaching very low levels over the last year. However, it is expected that these unusually low prices will eventually reach an equilibrium supply/demand level over the next year as new gas drilling continues to decline and new sources of demand come on-line, the draft IRP said.

Case 2 in the draft IRP has emerged as the Preliminary Draft Recommended Case, with the key attributes of Case 2 including:

  • At least 10% of Los Angeles’ electric needs will be met through new customer energy efficiency measures by 2020.
  • At least 500 MW of capacity reduction through Demand Response programs by 2026.
  • Generate at least 33% of its electricity from renewable resources by 2020 and maintain that level through 2030. Although the draft IRP incorporates one combination set of renewable resources to achieve a 33% Renewable Portfolio Standard (RPS), LADWP said it will not limit itself to only these types and amounts of resources to achieve its goals and needs flexibility in resource development for the best fit for the electrical system.
  • Diversify LADWP’s RPS through incorporating 114 MW of generic renewable resources by 2032. These resources could be technologies such as biomass, ocean tidal power or other emerging technologies.
  • Diversify LADWP’s energy portfolio through a variety of fuels, technologies and power plant sites throughout the western United States to maintain a high level of reliability.
  • Implement advanced reliability improvements.
  • Emphasize local solar by proposing 40% to 50% of solar capacity being locally sited in Los Angeles. This will be accomplished through programs such as the Customer Solar Incentive Program, Feed-in tariffs, and Solar on Los Angeles properties under public/private partnership.
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.