The project employs two 250-kilowatt fuel cells furnished by FuelCell Energy, Inc. The fuel cells use digester gas as a fuel. The methane content of the digester gas is 62 percent. The project began operation in November 2004.
The project incorporates a waste heat hot water generator and an SCS-designed/ fabricated digester gas pressurization/treatment skid. The skid removes moisture, particulates, hydrogen sulfide, halogenated compounds and siloxanes. The hot water is used to heat the WWTP’s anaerobic digesters, which frees up additional digester gas for power generation. The entire power plant, including digester gas supply and hot water interfaces, are under the control of an SCS-designed/fabricated SCADA system.
The power plant operates in parallel with Southern California Edison (SCE) as a baseload unit. The power plant displaces power otherwise bought from SCE at retail rates. The project qualifies for net metering under CaPUC regulations.
The total power plant capacity is 500 kW. SCS executed the project on a design/construct basis. The project is the largest digester gas fueled fuel cell in California. SCS handled operation/maintenance responsibilities under the power purchase agreements expired and the site was decommissioned in the autumn of 2010.
SCS Engineers’ responsibilities: