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Assessing the Commercial Feasibility of Manure to Energy
SystemsKraig Westerbeek
AVP, EHSMurphy-Brown LLC
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3. Evaporation pond Sludge Land, Landfill
Manure to Energy?
• Manure from animal operations does have energy value
• Swine manure = app. 8000 BTU / pound
• Animals are not 100% efficient in converting feed energy into body mass
• Relative measure of efficiency is feed conversion (swine 3 : 1)
Manure to Energy?
• Energy not used by animal can be recycled to other forms of useful energy
• While gasification and or combustion are options for some dry manures, anaerobic digestion seems to have the most potential for deriving energy from animal manure
*tpy: tons per yearSource: AMI, 2011
Chicken: 18,750,000 tpy*
Cattle: 13,300,000 tpy*
Swine: 11,650,000 tpy*
Turkey: 3,100,000 tpy* Others (veal, lamb, mutton): 158,500 tpy*
Manure energy: 10,000 – 20,000 MW power equivalence
“Anaerobic digesters, commonly in the form of covered lagoons or tanks, are designed to stabilize manure and optimize the production of methane.”
EPA AgStar – AD101
Number of Operating Anaerobic Digester Projects (US, July 2010)Dairy 126
Swine 24
Poultry 5
Beef 2
Biogas Use for Operational Projects
Cogeneration 78
Electricity 48
Boiler / Furnace Fuel 20
Flared Full Time 15
Unknown Use 7
Pipeline Gas 4
Vehicle Fuel 1
Methanol 1
Energy Production by Anaerobic Digester Systems: 2001-2010 (EPA AgStar)
0
50
100
150
200
250
300
350
400
450
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
Million kWh/yrEquivalent
Swine barn
Develop: Dewatering system to produce dry organic fertilizer
Swine manure is scraped and collected in the surge tank.
Develop: Solids are further dried with waste heat and processed into organic fertilizer or used as fuel for combustion at a biomass plant
Wastewater is pumped to existing lagoon and irrigated with existing irrigation equipment
Biogas
Electricity distributiongrid
Biogas
Digesters
Buffer tank
Generator
Surge tank
Combination of above-ground and in-ground fermentation leverages the cost and engineering advantages of both design.
Manure to Energy – Commercial Feasibility
• Fact: The technical feasibility of creating energy from manure has been proven
• Question: Can energy be created at a cost that makes manure to energy commercially feasible on a large scale?
Commercial Feasibilty
• To be attractive, manure to energy projects must create value for:– Investor (long term, stable return)– Farmer (avoided costs / increased
revenue, improved manure management system)
– Energy User (reasonably priced renewable energy)
Cost of Manure to Energy Systems
• High capital investment typically required (example – swine manure $5-10M per MW electricity)
• Various state and federal renewable energy credits help reduce initial investment
• Operating costs vary depending upon system used, but are significant, particularly if transportation of manure is involved
Revenue from Manure to Energy Systems
• Direct payment for energy based on current market value
• Renewable energy credits – vary from state to state depending upon legislative requirements
• Tax benefits (state, federal)• Carbon credit value (destruction of
methane)
Benefits to Manure Management Systems
• Significant destruction of volatile solids / reduced organic loading on existing system (increased treatment capacity)
• Reduction of total solids leaving a more nutrient dense solids stream
• Potential reduction of odor and emissions
• Reduction of pathogen loads
Commercial Feasibility
• Investments in manure to energy projects are risky due to the constant variability of manure characteristics
• Advances in technology (anaerobic digestion, etc.) have reduced the risks substantially
• State level renewable energy mandates have created a market for manure to energy projects by making returns more attractive
• Depressed carbon market has been a negative
Circle 4 Farms Project
• In the late 1990’s and early 2000’s, our company invested a significant amount of money in an anaerobic digester project at Circle 4 Farms in Utah
• The goal of the project was to capture methane generated from the anaerobic digestion of swine manure and convert it into biodiesel
Circle 4 Project
• The project failed due to problems associated with manure transport and lower than expected manure energy value
• While technically feasible, the economics of the project did not work
• The digesters built for this project are no longer in use
• This project may have worked with today’s renewable energy incentives
Murphy-Brown Strategy
• Instead of investing internal capital in manure to energy projects, MB has sought out partnerships with project developers and investors
• Current projects– Alpental Energy – Utah– Pacolet/Millikan – North Carolina– Ag Power – North Carolina– Roeslein - Missouri
Summary
• The technology is available today to support manure to energy projects – continues to improve with experience
• Economic drivers have been added to provide the necessary revenue to support projects
• The number of manure to energy projects continues to increase
Summary
• I believe manure can compete well in the renewable energy marketplace based on both its price relative to other renewable energy sources, and its reliability in delivering continuous energy
• I expect a continued increase in the number of manure to energy projects