Converting Dairy Manure into Energy. An introduction to anaerobic digestion of farm waste Stefan Grimberg Associate Profes...
Thank you to Floyd Schanbacher
 
Anaerobic Digester Potential Benefits <ul><li>Odor Control  </li></ul><ul><ul><li>Reduced liability </li></ul></ul><ul><li...
 
 
 
 
 
 
 
 
 
 
Plug Flow Digesters <ul><li>Little mixing </li></ul><ul><li>Few mechanical parts </li></ul><ul><li>Simple </li></ul>
Mixed Digesters Mechanical mixing in tank More gas production Slightly higher capital cost
Community Digester Behringen co-fermentation plant in Germany
Digester Feed
Large-scale Digester Performance
Capital Cost of Manure Management Technology Source: AgStar Publication:
Digester economics <ul><li>Dr. Fick’s estimated fixed of $660 per cow is a little low for the farms we are looking at.  </...
Case Study <ul><li>Gordondale Farms, Nelsonville, WI </li></ul><ul><li>750 head dairy </li></ul><ul><li>Sell biogas to uti...
Summary
Martin, 2005
Martin, 2005
Martin, 2005
Martin, 2005
Martin, 2005
Martin, 2005
Martin, 2005
Martin, 2005
Economic Evaluation <ul><li>Capital costs with co/gen: $748,000  </li></ul><ul><li>Annual sale of power: $18,396  </li></u...
Digester Systems Model Digester Solids Sep. Cogen Manure Other Input Biogas Electricity offset Surplus electricity Surplus...
Example  <ul><li>500 cow dairy </li></ul><ul><li>Free stall barn </li></ul><ul><li>Scraped manure </li></ul><ul><li>Includ...
Model Estimate: 500 cow dairy -$1.8 Annual Net Benefit per Cow without excess heat and methane credits $13.54 Annual Net B...
Run Digester Model <ul><li>Demonstrate: </li></ul><ul><ul><li>Effect of size </li></ul></ul><ul><ul><li>Power cost </li></...
Conclusions <ul><li>Anaerobic digestion of manure has significant potential to decrease fossil fuel use in rural areas. </...
 
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Stefan Grimberg: Energy From Cows, Biogas Digesters for Dairy Farms

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Stefan Grimberg of Clarkson University discusses how to capture energy from Dairy Farms.

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Stefan Grimberg: Energy From Cows, Biogas Digesters for Dairy Farms

  1. 1. Converting Dairy Manure into Energy. An introduction to anaerobic digestion of farm waste Stefan Grimberg Associate Professor Dept. Civil Environ. Eng Clarkson University
  2. 2. Thank you to Floyd Schanbacher
  3. 4. Anaerobic Digester Potential Benefits <ul><li>Odor Control </li></ul><ul><ul><li>Reduced liability </li></ul></ul><ul><li>Manure stabilization </li></ul><ul><ul><li>Help with nutrient management </li></ul></ul><ul><ul><li>Soil stability </li></ul></ul><ul><li>Energy generation </li></ul><ul><ul><li>Offset farm electricity requirements from grid </li></ul></ul><ul><ul><li>Sale of extra energy </li></ul></ul><ul><ul><li>Heat generation to reduce fuel required </li></ul></ul><ul><li>Reuse of bedding solids </li></ul><ul><ul><li>Offset bedding cost </li></ul></ul>
  4. 15. Plug Flow Digesters <ul><li>Little mixing </li></ul><ul><li>Few mechanical parts </li></ul><ul><li>Simple </li></ul>
  5. 16. Mixed Digesters Mechanical mixing in tank More gas production Slightly higher capital cost
  6. 17. Community Digester Behringen co-fermentation plant in Germany
  7. 18. Digester Feed
  8. 19. Large-scale Digester Performance
  9. 20. Capital Cost of Manure Management Technology Source: AgStar Publication:
  10. 21. Digester economics <ul><li>Dr. Fick’s estimated fixed of $660 per cow is a little low for the farms we are looking at. </li></ul><ul><li>Tinesdale farm (in Minnesota), with1800 cows, invested about $1,000 per head. </li></ul><ul><li>Good estimate $1,000 per cow? </li></ul><ul><li>At this capital assumption AD system become economical based on sold energy alone at power sale price of $0.09/kWh. </li></ul>(Mehta, 2002)
  11. 22. Case Study <ul><li>Gordondale Farms, Nelsonville, WI </li></ul><ul><li>750 head dairy </li></ul><ul><li>Sell biogas to utility that generates electricity on site, utility owns and operates generator </li></ul><ul><li>Sell at 0.015 $/kWh generated </li></ul>Martin, J.H., 2005. An evaluation of a mesophilic, modified plug flow anaerobic digester for dairy cattle manure. Final report for EPA contract GS10F-0036K
  12. 23. Summary
  13. 24. Martin, 2005
  14. 25. Martin, 2005
  15. 26. Martin, 2005
  16. 27. Martin, 2005
  17. 28. Martin, 2005
  18. 29. Martin, 2005
  19. 30. Martin, 2005
  20. 31. Martin, 2005
  21. 32. Economic Evaluation <ul><li>Capital costs with co/gen: $748,000 </li></ul><ul><li>Annual sale of power: $18,396 </li></ul><ul><li>Avoided annual bedding cost: $60,000 </li></ul><ul><li>Sale of extra solids: $8,600 </li></ul><ul><li>Total benefits: $86,996 </li></ul><ul><li>Payback period: Approx 6 years. </li></ul>
  22. 33. Digester Systems Model Digester Solids Sep. Cogen Manure Other Input Biogas Electricity offset Surplus electricity Surplus heat Spread liquid fraction Solids for bedding Sale of solids Solids field application Heat
  23. 34. Example <ul><li>500 cow dairy </li></ul><ul><li>Free stall barn </li></ul><ul><li>Scraped manure </li></ul><ul><li>Include flush from milking parlor </li></ul><ul><li>Northern NY </li></ul>
  24. 35. Model Estimate: 500 cow dairy -$1.8 Annual Net Benefit per Cow without excess heat and methane credits $13.54 Annual Net Benefit per Cow if excess heat cannot be sold $38.27 Annual Net Benefit per Cow $111,463 Total Annual Benefits $10,000 Onsite Fiber value $16,739 Tax Offset $8,495 Farm savings-Thermal (internal) $25,171 Farm savings-Electric (internal) $4,203 Renewable Energy Tax Credit $7,646 Methane Credit $12,368 Thermal Sales (surplus) $17,707 Electric Sales (surplus) $9,133 Fiber sales Potential Annual Benefits $23,553 Maintenance, Repair Annual Operating Costs $68,774 Total Annual Cap. Cost over 10 yrs $656,180 Digester/Cogen system Capital Cost Cost/Benefit Item
  25. 36. Run Digester Model <ul><li>Demonstrate: </li></ul><ul><ul><li>Effect of size </li></ul></ul><ul><ul><li>Power cost </li></ul></ul><ul><ul><li>Bedding off set </li></ul></ul><ul><li>Any scenarios of interest? </li></ul>
  26. 37. Conclusions <ul><li>Anaerobic digestion of manure has significant potential to decrease fossil fuel use in rural areas. </li></ul><ul><li>Community digesters may be very cost effective due to larger scale and mixed feed composition </li></ul>

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