Green Cheese Energy Intensity and GHG Emissions of Integrated Dairy&Bio‐fuels Systems in Wisconsin Douglas Reinemann Horacio Aguirre‐Villegas Louis Armentano Victor Cabrera John Norman Simone Kraatz Franco Milani Josh Posner Thais Passos Fonseca
Oct 15th, 2010
GHG
Dairy Feed Dairy Herd
Crops
Biomass
Bio‐fuels Industry
GHG
FerSlizers
Bio‐fuel
Manure GHG
Dairy Feed Bio‐fuel Milk
GHG
On‐Farm Processes
Bio‐fuel
GHG
Milk
Manure GHG
BioGas, Electricity
GHG
Dairy Products Milk
Green Cheese Model ‐ Objec(ves 1) InvesSgate synergies and opportuni(es to reduce energy intensity and environmental impact of dairy and bio‐fuels producSon. 2) Provide guidance to: a) Individual farms to i) choose technologies and management pracSces to reduce energy intensity and environmental burden of milk producSon; ii) prepare for carbon credits market b) Policy makers regarding implicaSons of specific technologies on WI energy and GHG balance, aiming beZer resource allocaSon 3) Compare efficiency and environmental impact of dairy producSon systems in WI vs. other regions 4) Expand Life Cycle Assessment database of agricultural products
The “Green Cheese” Model
Desired milk produc(on
Inputs
Model Components
Informa(on Inputs
2b.Biogas genera(on 1a.Dairy herd
Machinery
2a.Manure handling
Herd characteris(cs Lacta(ng cows forage intake
Fer(lizers 1b.Diet composi(ons
3.Crop produc(on
Other characteris(cs of the system
Outputs
Land area CO 2 for feed
Chemicals
4.Bio‐fuels produc(on
Milk Meat
GHG Biogas
Nutrient losses Bio‐fuels
Green Cheese: Model Components and Boundaries
Fuels and energy Process, embedded, and cumula(ve energy and GHG emissions
System Boundary
Scenarios • 5 dairy diets – 3 forage bases • 3 levels of co‐products from bio‐fuels – Dry disSllers grains and solubles (DDGS) – Soybean meal (SBM) Diet
Corn silage DMI
Alfalfa silage DMI
Concentrates
CADS
29%
29%
DDGS = Soybean meal
CSDG
36%
22%
Max. DDGS
CSSB
36%
22%
Max. Soybean meal
ASDG
22%
36%
Max. DDGS
ASSB
22%
36%
Max. Soybean meal
• 2 manure treatments – without anaerobic digesters – with anaerobic digesters (and biogas producSon)
Results • GHG emissions (kg CO2‐eq/kg ECM) • Energy intensity (MJ/kg ECM) • Net energy intensity = Energy inputs – Energy outputs
ECM = energy corrected milk to 4% fat and 3.3% protein CO2‐eq = carbon dioxide equivalent
GHG emissions from Milk ProducSon (kg CO2‐eq/kg ECM) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 CADS
CSDG
CSSB
ASDG
ASSB
Diets
AccounSng for bio‐fuels, displacement of fossil fuels; no biogas AccounSng for bio‐fuels and biogas, displacement of fossil fuels and natural gas
Net Energy Intensity of Milk ProducSon (MJ/kg ECM)
2.5 1.5 0.5 ‐0.5 ‐1.5 ‐2.5 CADS
CSDG
CSSB
ASDG
ASSB
Diets
AccounSng for bio‐fuels energy and fossil fuels displacement; no biogas AccounSng for bio‐fuels and biogas energy, displacement of fossil fuels and natural gas
Land use, GHG emissions, and energy intensity of milk production for selected diets. All values presented in relation to Diet CADS (100%).
Environmental Impacts of Integrated Milk and Bio‐fuels ProducSon (no biogas) 140% 120% 100% 80% 60% 40% 20% 0% CADS Land area use
CSDG
CSSB GHG emissions
ASDG
ASSB
Energy intensity
Diets
Land use, GHG emissions, and energy intensity of milk production for selected diets. All values presented in relation to Diet CADS (100%).
Environmental Impacts of Integrated Milk and Bio‐fuels ProducSon (with biogas) 140% 120% 100% 80% 60% 40% 20% 0% ‐20% ‐40% ‐60% ‐80% ‐100% ‐120% ‐140% CADS
CSDG
Land area use
CSSB GHG emissions
ASDG
ASSB
Energy intensity
Diets
Main Conclusions • Effects of anaerobic digesters for on‐farm biogas generaSon: – ReducSons in GHG emissions by 0.25 kg CO2‐eq/kg ECM – ReducSons in energy intensity by 2.57 MJ/kg ECM
• The minimum GHG emissions and energy intensity per kg of milk occurred in the system that: – used anaerobic digesSon on the farm and – maximized feeding of DDGS (and ethanol producSon) • This scenario also resulted in the largest required land area; • Tradeoffs need to be considered.
PotenSal Impacts of Biogas • Farms with more than 200 cows in Wisconsin: ~ 40% of WI milk producSon ~ 4.5 billion kg of milk/year potenSal on‐farm energy producSon (from biogas): ~ 11.5 billion MJ/year almost 3% of Wisconsin’s Natural Gas consumpSon (~ 400 billion MJ/year)
correspondent potenSal of savings on GHG emissions: ~ 1 billion kg CO2‐eq/year almost 10% of the 10.9 billion CO2‐eq from Wisconsin’s Agriculture sector (esSmated by the World Resources InsStute, 2007)
Thank you! Thais Passos Fonseca: passosfonsec@wisc.edu Horacio Aguirre Villegas: aguirreville@wisc.edu Douglas Reinemann: djreinem@wisc.edu