Puente Hills Landfill Gas-to-Energy Facility - "WORLD'S LARGEST LANDFILL GAS-TO-ENERGY PROJECT"

ESA Development LLC (ESA) designed and built the Puente Hills Energy Recovery from Gas (PERG) Plant, incorporating superior technical and economic design. Work on this fast-track, turnkey project was completed in 19 months, and the project began operating in October 1986. Since then, it has been producing 50MW of electricity for customers throughout the Los Angeles region, and has dramatically reduced Methane emissions - a particularly potent greenhouse gas.

The PERG project utilizes landfill gas (LFG) generated by the bacterial decomposition of organic materials contained in municipal solid wastes of the landfill.  The LFG is collected through a piping network embedded in the landfill and transported by compressors applying a vacuum to the collection pipes.  Compressed LFG is processed through booster compressors and into (2) Rankine cycle steam turbine/generators.  The plant is interconnected to a local electrical substation and local power transmission lines, which were provided by regional utility authority (Southern California Edison).  By using boilers to combust the gas and a landfill gas pretreatment system customized for each facility, the Sanitation Districts maintain emission levels well below those required by the South Coast Air Quality Management District. Overall, the Sanitation Districts’ facilities have successfully demonstrated that a landfill gas-to-energy plant can combust low-BTU landfill gas as boiler fuel, reduce air emissions, and provide significant economic benefits for landfill owners.

Puente Hills is the largest landfill in the United States.  Abundant and readily available, landfill methane is a renewable resource with a potential generating capacity of 3,000 MW in the United States and 9,000 MW globally.  In the United State alone, there are currently nearly 600 operating LFG plants with a 1,813 MW capacity.  Another 540 landfills are candidates for LFG generation plants with a 1,212 MW projected capacity.

Plant owner, the Sanitation Districts of Los Angeles County, have made a significant effort to reduce air emissions and develop emissions controls in their solid waste management and wastewater treatment operations.  Ongoing projects include processing landfill gas into compressed natural gas (CNG) for use as an alternative fuel; converting Sanitation Districts' owned transfer trucks for use with alternative fuel; purchasing CNG vehicles, where feasible; and constructing CNG fueling facilities at various Sanitation Districts' locations.  Other landfill gas-to-energy facilities include projects at the Calabasas Landfill (7 MW) and the Spadra Landfill (5 MW).

Technical Summary:

The PERG project utilizes landfill gas (LFG) generated by the bacterial decomposition of organic materials contained in municipal solid wastes of the landfill. The energy content of the gas withdrawn from the landfill is approximately 400 to 500 BTU per cubic foot. The LFG is collected through a piping network embedded in the landfill and transported by compressors applying a vacuum to the collection pipes. The compressed LFG is processed through booster compressors and into two 216,000 lbs/hr steam generators producing steam at 1,350 psig and 1,000oF, which is fed to a steam turbine generator producing 50MW of electricity. The steam cycle consists of three high pressure and two low pressure feed water heaters along with a deaerator system. The boiler water is demineralized through an anion, cation and mixed bed system water treatment system. A cooling tower system handles 32,000 GPM and the entire energy producing facility is situated on 50,000 square feet of land. The plant was interconnected to a local electrical substation and local power transmission lines, which were provided by regional utility authority.

Construction of the plant was completed in 19 months with 2 months allocated to operational start-up and equipment performance verification for each segment of the system. This resulted in a final acceptance in just 21 months.

ESA engineered and designed the facility with a high efficiency steam cycle as just one of the major unique features of this plant. The plant is also automatically controlled from a central control room location utilizing an advanced distributed control system, configured by ESA. This maximized access to operational data and control while eliminating excessive wiring throughout the facility. Using the advanced control software developed by ESA, the plant can be operated with maximum efficiency and reliability.

ESA also removed, redesigned, fabricated and reinstalled approximately 50,000 lineal feet of pipe ranging from A-106 Grade B standard up to A-335, P-11, and P-22 with up to 3-inch wall thickness, and rebuild or supplied approximately 1,000 valves. All plant piping was tested on-site through x-ray and heat treating critical systems. The condensate polishing system was also designed and replaced including new back-washable pleated filters with 1-micron cartridges.

 A complete overhaul of the Turbine Generator rotor and stator was performed, including re-wedging, inspection/testing program, meggar, polarization index, El Cid, doble and hi potential each of the four generators. A new solid-state excitation system and a power stabilizer system was also installed.

Project Performance:

ESA's design and implementation of the SCR and CO systems established this project as the cleanest thermal generating in California to date. And in general this plant has been regarded as the cleanest thermal power plant in the world.

  • All ESA design and supporting calculations were approved by the State of California energy technical consultants. There were no major injuries, and no loss time.
  • Puente Hills is the largest landfill in the United States, and the PERG Plant is the largest landfill to energy center in the world.
  • Since the project began operation in 1986, it has been generating electric power from LFG with greater than 95% availability.
  • The plant emissions are well below the strict emissions standard established in Los Angeles, by the "South Coast Air Quality Management District".
  • In October 1987, a large 6.0 (Richter scale) earthquake struck Los Angeles, centered in Whittier California only 5 miles from the plant. The plant was operating at the time of earthquake and did not sustain any damage, despite wide-spread damage to the surrounding area.
  • ESA's designed maximized the overall plant efficiency producing a heat rate of less than 10,000.

References:

ESA|  Feature Projects:  Puente Hills Energy Recovery from Gas

ESA Energy|  Project Profile:  Puente Hills Energy Recovery from Gas