LCA Food 2012 in Saint Malo, France! - Manifestations et colloques ...

PARALLEL SESSION 2A: LAND USE 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
Table 1. Input data to milk study
Factor Value
Milk production per cow 8000 kg ECM per year
Replacement rateText 25%
Meat produced per kg ECM 0.0057 kg
Rapeseed oil produced per kg ECM 0.028 kg
GHG emissions for substituted meat production 22 kg CO2-eq.
GHG emissions for substituted rapeseed oil production 0.8 kg CO2-eq.
Table 2. Feed production
Product Yield a (kg/ha yr) Area (ha)
Ley 4230 120
Grazing 4000 70
Spring barley 2440 54
Winter wheat 3228 40
Broad beans 2026 54
Rapeseed cake 1693 40
a a
Yields for barley and wheat are given at 86% dry matter content (DM), rapeseed 91% and broad beans 85% DM. Ley yield is in
total solids (TS), with losses during harvest and ensiling subtracted
The 200 ha arable farm had a 7-year crop rotation (Table 3) that included ley twice, to be used as green
manure (field beans, oats, ley, winter rapeseed, winter wheat, ley, rye). In the reference scenario, ley and
straw were ploughed back into the soil.
Table 3. Arable crop rotation
Crop Yield a (kg/ha yr)
Field beans 2400
Oats 3200
Ley 6000
Winter rapeseed 2000
Winter wheat 3500
Ley 6000
Rye
a
Crops dried to 86% DM except ley, which is in kg DM
3200
2.3 System boundaries
An overview of the production systems with energy self-supply is shown in Figure 1. The system boundary
was set at the farm-gate for products produced on the farm (exception: biomass which is transported to
fuel production facilities and back is included). Feedstock for energy carrier production is forwarded to conversion
facilities (“Conversion processes”-box in Figure 1). Residual products from the conversion processes,
such as ashes and digestion residues, were assumed to be returned to the fields as fertilisers. Byproducts
from the conversion processes were accounted for (“Substituted production”-box in Figure 1). The
system was compared with a reference system, in which the milk production process was supplied with energy
produced with fossil fuels. Mining, extraction, refining, distribution and consumption of the fossil fuels
were included.
2.4 Energy demand
The annual energy demand for the milk farm was 300 GJ electricity (0.14 MJ/kg milk), 115 GJ for grain
drying and 95 GJ for hating of buildings. Annual tractor fuel demand was 460 GJ.
In the arable farm, heat was supplied to the residential building (dimensioned capacity 7.4 kW) the hot
water system (1.2 kW), the workshop (1.7 kW) and the grain dryer (227 kW). The total annual tractor fuel
demand was 414 GJ, electricity demand was 51 GJ and heat demand 290 GJ.
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