by AF 1026 B5 — October 29, 2008—To help reduce energy use and help the environment the City of San Leandro, California, recently approved a contract with Siemens Building Technologies, Inc., to build a 330-kilowatt cogeneration facility at the city’s Water Pollution Control Plant (WPCP).
Expected to cut energy use by 60 percent, the new power plant has the potential to reduce CO2 emissions by 1,500 tons per year. The new facility represents a major step in helping the city meet its goal of reducing San Leandro greenhouse gas emissions by 25 percent below 2005 levels by 2020.
The $5.6 million agreement with Siemens Building Technologies includes design, construction and maintenance for the cogeneration system. Project costs will be covered by WPCP enterprise funds, which according to San Leandro officials are collected annually from city sewer service fees and will be used for maintaining and improving the plant. The new facility will also take advantage of applicable rebates, including a $255,000 Self-Generation Incentive Program (SGIP) rebate from local utility Pacific Gas & Electric (PG&E).
The WPCP treats an average of 6 million gallons per day of municipal and industrial wastewater and is the largest single consumer of electrical energy of all city facilities. Currently, the plant uses PG&E-supplied energy to run wastewater treatment operations. The plant also produces some 96,000 cubic feet per day of methane gas (a greenhouse gas shown to be 21 times more potent than CO2), most of which is burned off and not re-used.
The new co-generation facility will now use all the methane gas to fuel specially designed reciprocating engines (large internal combustion motors) to spin generators that will produce the electricity needed to power the plant and treat the wastewater. In addition, the heat produced by the reciprocating engines will be recycled used to raise the temperature of the water needed in the treatment process. This system is extremely efficient because it uses normally discarded methane to create both electrical energy and heat; hence, the term cogeneration.
For more information, see the Siemens Building Technologies Web site.
