New Combined Heat and Power System to Turn Methane Gas into Electricity, Recaptures Waste Heat for Use in Sewage Processing
May 02, 2012
The City of Schenectady’s Water Pollution Control Plant unveiled a $7 million project today that will allow the facility to save a significant amount of energy. It includes a combined heat and power (CHP) system that produces biogas and uses an internal combustion engine to create electricity.
The New York State Energy Research and Development Authority (NYSERDA) provided a $1 million award toward the cost of the CHP project.
“By generating electricity from biogas and capturing the extra heat to help with processing waste, the City of Schenectady is getting a two-for-one deal in clean energy,” said Francis J. Murray Jr., President and CEO of NYSERDA. “Combining anaerobic digestion and CHP makes sense at any facility that processes a large amount of organic waste materials. The city should be commended for its effort to reduce its energy costs and greenhouse gas emissions.”
With the new equipment, the plant will generate an estimated 1,800 megawatt-hours of electricity per year from the biogas – enough to power more than 275 private homes for a year. This will offset the energy costs of the plant and, combined with other improvements, save an estimated $300,000 in energy costs each year.
“The city is very pleased to see the wastewater treatment achieve greater energy efficiency while continuing its modernization efforts,” said Schenectady Mayor Gary McCarthy. “I want to thank NYSERDA for its generous support in helping the plant serve our local residents the best way it can.”
The CHP system uses anaerobic digestion, a process that breaks down biological materials, to produce the biogas. At the plant, sewage is treated and the thickened sludge is mixed and heated to allow the waste to break down and generate methane. The methane is purified and combusted to generate electricity.
In an added energy-efficiency feature, the Schenectady equipment recaptures the waste heat from burning fuel and reuses it to enhance the digestion process and provide heat to two buildings. The entire process also reduces odors and results in a finished product that can be used for compost.
The Schenectady plant treats an average of 14 million gallons per day of wastewater. The plant serves about 85,000 area residents in all -- not only the city but also Scotia, Alplaus, Glenville and portions of Niskayuna and Rotterdam.
The CHP system was part of a $7 million rehab of the facility, which dates back to the early 1900s and was still using equipment that was more than 50 years old. Work also included new technology that reduces the water content of sludge before processing, new equipment to insulate and seal the anaerobic chamber and equipment to remove acidic hydrogen sulfide from the biogas, which protects equipment from corrosion.
A U.S. Department of Energy grant of $600,000 helped to pay for some of the work at the plant, as well as a general energy-efficiency study for the city.
NYSERDA, a public benefit corporation, offers objective information and analysis, innovative programs, technical expertise and funding to help New Yorkers increase energy efficiency, save money, use renewable energy, and reduce their reliance on fossil fuels. NYSERDA professionals work to protect our environment and create clean-energy jobs. NYSERDA has been developing partnerships to advance innovative energy solutions in New York since 1975.
Last Updated: 05/14/2013