chapter 3 inventory of local food systems

Project CP/59 - “Instruments and institutions to develop local food systems”
Annex: Methods and assumptions used in the calculations of the ecological impact
In general
• Transport energy and emission calculations are based on figures of van Essen et
al. (2003).
• Indirect emissions and energy uses caused by production, maintenance and
dissembling of the vehicles and infrastructure are not included in the energy and
emission factors.
• Traffic jams are also not included, because their effect on the total emissions of
road transport appears to be limited (van Essen et al., 2003).
• No other contributions to the greenhouse gas effect than CO2 emissions are
included. Although there are a lot of other gasses, like methane, that have a high
greenhouse gas effect.
• Manipulation energy uses and emissions like loading and unloading with fork-lift
trucks, etc. are not calculated as these are complex to ascribe to a specific amount of a
specific food item.
• The transport energy use is the energy use per ton-kilometer, summed with the
energy use of refinery, multiplied by the distance traveled and divided by 1000 to get
the final data in MJ/kg food item (van Essen et al. (2003)). The energy use of refinery is
the energy use per ton-kilometer multiplied by the energy ratio for refining. This energy
ratio varies along different kinds of fuel and different oil fields. Here we have set it on
9% for all fuels, based on a comparison of Edwards et al. (2003), Meul et al. (2005) and
van den Brink et al. (1997).
• For transport CO2 emissions a comparable procedure is followed: the energy use
per ton-kilometer is multiplied by the CO2 emission factor of that vehicle, summed with
the CO2 emissions of refinery and then multiplied by the distance traveled and divided
by 1000 to get data in g CO2/kg food item transported.
• For these transport energy and CO2 emission calculations, some estimations had
to be made on transported loads in tons per vehicle, on load factors and on percentage
of productive rides. For most cases averages of these figures are known or standards are
used (Van Essen et al., 2003).
• Precise effects of transport to and from loading points are not known. For this we
used the default energy and emission estimations of Van Essen et al. (2003) in the
calculations.
• All distances are counted double as most rides are back and forth. Exceptions to
these are pick-up and drop-off rounds, these are counted single and as if half of the
whole load is transported during the whole round.
SPSD II - Part I - Sustainable production and consumption patterns - Agro-Food 52