coupling dairy manure anaerobic digesters with commercial greenhouses – an assessment of technical...
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Proceedings available at: http://www.extension.org/67727 Despite all of the positive environmental benefits of anaerobic digestion, the economics are not sufficient for widespread adoption by US farmers when selling surplus power to the grid. Often farms are only paid the wholesale price (2 to 3 cents/kWh) for electricity, making it difficult to justify generating it in the first place. In addition, typically in the Northeast, approximately 40% of the energy from a digester goes unused (excess heat). Therefore, promising value-added technology/business partnerships need to be evaluated and demonstrated, such as partnering anaerobic digestion with commercial greenhouses. Presentation by: Curt GoochTRANSCRIPT
Coupling Dairy Manure Anaerobic Digesters with Commercial
Greenhouses
Curt Gooch, PE
Tim Shelford, Ph.D.
From Waste to Worth, April 4, 2012
Introduction
• Funding for this project provided by the USDA Hatch formula funds
• Some equipment from NYSERDA
• Three year project with an overall goal of encouraging dairy Anaerobic Digester/commercial greenhouse synergies.
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Overview
• Anaerobic Digestion in NY
• Greenhouse/Cogeneration synergies
• Greenhouse considerations
– Power, Heat and CO2 requirements
– Food Hub Model
• Project objectives
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Anaerobic Digestion Growth in NYS
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On-Farm Anaerobic Digestion in New York State – Current Status
Operating and generating power: 17
Operating and not generating power: 2
Currently down for service: 2
Under construction: 3 (two in start up stage)
Planning/signed RPS: 15
Decommissioned: 5
Of the operating systems:
• 15 Eng-gen sets (5,395-kW)
• 0 Microturbines 5
Electrical Power from AD Cogeneration
• NYS power sales through remote net metering
• Farms in NYS get the avoided cost rate for their surplus power, typically < $0.03/kWh
• Maintenance costs on generation equipment can be $0.015 to $0.022 / kWh.
• No incentive to improve biogas production or generation efficiencies.
• Greenhouses are able to utilize excess energy on-site.
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Waste heat from Cogeneration40% average heat dumped to atmosphere
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Greenhouse/Power Generation Synergies
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Greenhouse/Digester System
9Scott, N.R., Rutzke, C.J., and L.D. Albright. 2005. Energy Conversion Options for Energy-efficient Controlled Environment
Agriculture. HortScience Vol. 40(2):287-292.
Complementary Power Use
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-AA Dairy is a 600 cow dairy, in Candor NY-Summer power usage is cooling
-CEA Greenhouse is a 1/5 acre facility-Winter power usage is primarily supplemental lighting
Greenhouse Lighting
-70% of the light for growing comes from the sun in Ithaca
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-Shade control in the summer is also a critical control
-Supplemental lighting can provide up to 30% of the required winter heating load
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Tip-burn in Lettuce
-Physiological disorder due to too rapid growth
-Renders the product unsalable
-Common in summer months with too much light
Greenhouse CO2 Supplementation
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Greenhouse CO2 Supplementation
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Greenhouse CO2 Supplementation
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-Greenhouses typically heated to:66 to 75 F(19 to 24 C)
-Can cost $10-$20 per
square foot per year (heat+power) in upstate NY
Greenhouse Heating
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Food Hub Operations Model
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One of the main reasons smaller greenhouse operations fail is that it’s difficult to support an expert grower, and maintain all of the necessary infrastructure for food
safety certification.
Food Hub Operations Model
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One option for overcoming this obstacle is to use a centralized or Hub model of operations (Fingerlakes Fresh). In this model seedlings are grown at a centralized facility until they are
ready to be transplanted to their final planting density.
Food Hub Operations Model
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The time of critical care for optimal production is during the seedling stage which can be overseen by a single expert grower.
Centralized seedling production, harvesting and packaging
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Once ready for harvest the plants are trucked back to the centralized
harvesting and packaging plant for processing.
From here the produce from multiple
greenhouses can be shipped out to larger
distributors or directly to grocery chains.
Project Objectives:
1. Develop and validate an analytical energy model of Dairy AD
2. Develop and validate an analytical energy model of commercial greenhouse production
3. Combine the two models4. Use the combined model to investigate several
“what if” scenarios5. Perform an economic analysis of these scenarios6. Distribute the results of the analyses and other
related educational materials
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Acknowledgements:
• USDA• Anaerobic Digester Partners:
-Roach Dairy, Venice Center, NY
-Stonyvale Farms, Exeter, ME
-Sunnyside Dairy, Venice, NY
-Synergy Dairy, Covington, NY
• Greenhouse Partners:-Durham Foods, Port Perry, ON
-Fingerlakes Fresh (Challenge Industries), Ithaca, NY
-Gotham Greens, Brooklyn, NY
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