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
Inventory for greenfield and infill housing systems was compiled from various local sources to represent
construction, operation and transportation to the extent that they were able to be characterised. Hybrid Input-
Output (I-O) energy data for embodied, operational and transportation energy was adapted from a contemporary
study of alternative housing types in Australia by Crawford and Fuller (2011). As hybrid I-O studies
calculate on an energy basis, to obtain a more complete picture of environmental impacts, the embodied energy
for each of the two housing styles was broken down into constituent material quantities such that the
total embodied energy reflected the value being modelled from Crawford and Fuller (2011). Representative
material quantities for greenfield housing construction were obtained from a residential case study of similar
housing in Crawford (2011). For infill style housing material inputs were obtained from a bill of quantities
for a concrete apartment building (OECD, 1999). Operational energy was represented as the NSW average
energy mix of coal fired electricity 90% and gas 10% (Dart Energy, 2011). Transportation energy was represented
as the proportional mix of train versus car travel taken by households in each urban system, with one
passenger car allocated to each household.
2.5 Combining agricultural and urban impacts
To combine impacts, reference is made to scenarios 1 and 2 (Figure 2) respectively. For scenario 1, total
environmental impacts included the addition of one hectare of greenfield housing with the amount of land in
the marginal location associated with the same production yield as displaced Sydney farms. Scenario 1 therefore
combined impacts from 1ha of greenfield housing with impacts from LF4. Total impacts for scenario 2
included the addition of 1 ha of a Sydney farm, plus 1 ha-equivalent of infill housing. For scenario 2, the
environmental impacts from 1 ha equivalent of infill housing was combined with the average impacts from
LF1 and LF2. As these scenarios each require lettuce to be modelled at the Sydney market, inputs included,
in addition to farm processes, post-harvest operations such as washing of lettuce, coolroom operation, transportation
and fabrication of capital equipment for transport, sheds and coolrooms.
3. Results
3.1 Lettuce at farm and lettuce at Sydney market
Preliminary data are indicating that field grown lettuce (LF1, LF2 and LF4) exhibit similar GWPs with
results ranging between 1.5 to 1.9x10 4 kg CO2-e/ha (0.25-0.35 kg CO2-eq per kg lettuce). Hydroponic lettuce
(LF3) exhibited significantly larger GWP at 10.9x10 4 kg CO2-e/ha (0.58 kg CO2-eq per kg lettuce), primarily
due to the contribution to farm inputs from electricity. LF1, LF2 and LF3 exhibited increases in GWP of 6 to
9 percent when factoring inputs to deliver the lettuce to the Sydney market. GWP for interstate farm LF4
increased 40 percent to 2.1x10 4 kg CO2-e/ha.
3.2 Urban housing style comparison and combined impacts
Figure 3 illustrates the GWP for both greenfield and infill urban housing systems (without any horticultural
implications) and provides comparison to the impacts from each of the farms. Embodied, operational
and transportation energy are included in the total per hectare results for each of the urban systems. Per hectare
results for greenfield housing systems exhibited the largest GWP at 44 kg CO2-e/ha, over twenty-fold
Figure 3. GWP for the two housing systems Figure 4. GWP for Scenarios 1 and 2,
and farms LF1 to LF4, per hectare. per hectare
152
kg CO2-e xE4
50
40
30
20
10
0
Inner Outer
urban urban
mid-rise detached
apartment house
LF1 LF2 LF3 LF4
kg CO2-e xE4
50
40
30
20
10
0
Scenario 1 Scenario 2