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The proposed $5.6 million project at San Leandro's Water Pollution Control Plant is expected to save 60 percent in plant energy use and have the potential to reduce CO2 emissions by 1,500 tons per year. The plan is considered an important component of the town's bid to reduce greenhouse gas emissions by 25 percent below 2005 levels by 2020.
"Any way you look at this project is a win-win," San Leandro Mayor Tony Santos said in a statement announcing the deal. "We are cutting the city's energy costs, reducing the city's impact on global warming, re-using a waste product, namely, grease, and using only funding that is specifically dedicated for this purpose, preserving our General Fund monies for critical city programs."
The treatment plant handles about 6 million gallons a day of municipal and industrial wastewater and uses the most electricity when compared to the city's other facilities. The plant uses PG&E-supplied energy currently to run wastewater treatment operations, and it produces about 96,000 cubic feet per day of methane gas, most of which is burned off and not re-used. The greenhouse gas methane has been shown to be 21 times more potent than CO2.
In contrast, the new co-generation facility would use the plant's methane gas to fuel large internal combustion motors, called reciprocating engines, to power generators that in turn produce the electricity the plant needs to treat the wastewater. Heat from the reciprocating engines would be used to raise the temperature of the water required in the treatment process.
The key elements of the proposed project include three 110-kilowatt generators that are to produce 285 kilowatts of continuous electrical energy needed to power the plant; a gas conditioning facility that would clean and cool the methane from the treatment plant's digester so the gas can be used to fuel the reciprocating engines; and a grease receiving station that would accept additional waste grease from commercial waste haulers to enhance the digester process and increase methane gas production.
The system would enable the facility to recycle grease from companies in the area, improve the performance of the generators and generate revenue from grease disposal fees.
The proposed project must be approved by the city's Community Development Department and obtain permits from the Bay Area Air Quality Management District. If successful in that process, construction would begin in late summer 2009.
Eastern Kentucky University and Siemens also announced an energy saving project that is expected to halve the campus' utility use and save the university $8,000 a day in energy costs.
According to the company, $5 million in upgrades to energy intensive systems would generate more than enough savings to cost-justify what would be a $27 million investment. The project would be financed by a lease to be paid back over a 13-year period from the energy savings guaranteed by Siemens once the system upgrades are completed, the company said.
The university's utility bill is now $6.4 million annually. Siemens said its contract with the university guarantees it will save 24,665,190 kWh of electricity, 89,329 mcf of natural gas, 1,729 tons of coal, 102,585 ccf of water and 138,584 ccf of sewer. During the lifetime of the contract, the university's projected reduction in ghg emissions would be about 76 million pounds, the company said.
