Sonoma County owns and operates the Sonoma Central Landfill. It is a 120-acre actively filling landfill and is located in Petaluma, California. In 1995 the County determined that there was sufficient landfill gas to warrant expanding their existing 3.2 MW landfill gas-to-energy facility.The design that Landfill Energy Systems (LES) supplied for the Phase I facility was duplicated and Phase II became a replica of the original plant. In addition to the design, LES supplied construction services, equipment procurement and commissioning services for the 3.2 MW facility. The plant is equipped with four CAT 3516 internal combustion engine generator sets and is located adjacent to the Phase I facility.