chapter 3 inventory of local food systems

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Project CP/59 - “Instruments and institutions to develop local food systems” Transport efficiency of transport modes for import from abroad Another large factor in the total energy and emission bill of food products is the transport efficiency of import from abroad. Import occurs when domestic products are not available or products are not homegrown at all, e.g. tropical fruits. But also inseason there are a lot of food products imported that can also be homegrown. Table 5 shows the calculated levels of energy uses and carbon dioxide emissions for the most used transport modes over longer distances. For each transport mode the average load capacity (ALC) is given. Two parameters play the most important role: (1) the traveled distances: 400 km or import from neighbouring countries, 1500 km or continental transport and 6000 km or intercontinental transport, and (2) the transport mode used: transport by truck, by vessel, by train or by aircraft. Combining these two, for short distances (400 km) bulk transport by vessel seems to be the most sustainable on energy and emission basis (0.41 MJ/kg and 29.77 g CO2/kg), although a lot of food products are difficult to transport in bulk. All other transportation modes are two to three times more energy consuming or emit two to three times more greenhouse gasses. The highest value is for non-bulk transport by inland vessel (1.08 MJ/kg and 79.72 g CO2/kg). For continental transport (1500 km) sea vessels use less energy (0.69 MJ/kg) and emit less CO2 than trucks, electric trains and freight aircrafts (respectively 2.80, 3.88 and 29.43 MJ/kg). Transport by aircraft results in CO2 emissions that are more than 40 times those of trucks. Intercontinental transport results in even higher energy consumption and CO2 emission with 2.75 MJ/kg for sea vessels and 103.33 MJ/kg for freight aircrafts. These calculations are based on averages from literature, so there can be quite large differences when taking into account real loading factors, productive rides, flights in different stages, etc. It also has to be stressed that transport to and from loading points are not included in this study. Production in heated greenhouses versus in open air Differences in energy use for production in greenhouses versus in open air can also make a large variation in total energy consumption. Assuming that most energy is consumed by the heating installations of these greenhouses, we only take into account the energy used for this heating, excluding electricity consumption for e.g. lighting. Of the food items considered in this study only tomatoes and cabbage lettuce are produced both in greenhouses and in open air in Flanders. Based on Maertens and Van Lierde (2003) and Georges et al. (2003) we calculated that the heating of greenhouses uses on average 26.73 MJ/kg tomatoes and 22.90 MJ/kg cabbage lettuce or 1459.41 g CO2/kg tomatoes and 1250.21 g CO2/kg cabbage lettuce. This means that respectively for LFS and MFS for the heating of greenhouses in Flanders, 10 and 18 times more energy is consumed for tomatoes and 9 and 21 times for cabbage lettuce than for non heated production in open air. These figures are yearly averages meaning that for production in winter/off season these ratios are a lot higher and for production in summer/full season these ratios are close to zero. SPSD II - Part I - Sustainable production and consumption patterns - Agro-Food 45
Project CP/59 - “Instruments and institutions to develop local food systems” Combining the previous factors When combining the above mentioned factors like transport efficiency of the consumers’ purchase and of the transport mode for import from abroad and production in heated greenhouses versus in open air, the original energy uses and CO2 emissions from the basic simulation for local and mainstream systems can vary a lot. Consider, for example, the following four scenarios where all factors come together in one final energy figure: (1) inland tomatoes produced in open air, marketed through an LFS, and delivered at a collecting point on walking distance of the consumers house, (2) inland tomatoes produced in open air, marketed through an LFS, and purchased by the consumer 10 km away from his home, by car in a combined shopping trip, (3) inland tomatoes produced in a heated greenhouse, marketed through a supermarket and collected by a consumer by bicycle and finally (4) tomatoes produced in open air in Spain, transported by truck over 1500 km, marketed through a supermarket at 5 km of the consumers house and purchased by this consumer by car in a specific shopping trip. We assume for scenario (2) and (4) that the consumer buys in total 10 kg of products in one shopping trip. This results in: • Scenario (1): 2.83 MJ/kg for buying through an LFS, 0.00 MJ/kg for production in open air, 0.00 MJ/kg for inland production and 0.00 MJ/kg for the consumers’ purchase on foot. This results in a total amount of 2.83 MJ/kg. • Scenario (2): 2.83 MJ/kg for buying through a LFS, 0.00 MJ/kg for production in open air, 0.00 MJ/kg for inland production and 6.83 MJ/kg for the consumers’ purchase by car. This results in a total amount of 9.66 MJ/kg • Scenario (3): 1.17 MJ/kg for buying in the supermarket, 26.73 MJ/kg for production in a greenhouse, 0.00 MJ/kg for inland production and 0.00 MJ/kg for the consumers’ purchase by bicycle. This results in a total amount of 27.90 MJ/kg • Scenario (4): 1.17 MJ/kg for buying in the supermarket, 0.00 MJ/kg for production in open air and 5.47 MJ/kg for the consumers’ purchase by car, 2.80 MJ/kg for the transport from Spain. This results in a total amount of 9.44 MJ/kg. If we take into account some more extreme scenarios, the differences are even larger. Consider the following two scenarios: (5) tomatoes produced in heated greenhouses in France, transported by truck over 400 km, marketed through a LFS and purchased by a consumer through a 10 km shopping trip specifically for shopping and (6) tomatoes produced in Kenya in open air and imported by aircraft over 6000 km, marketed through a supermarket and purchased by a consumer 15 km away from his home, by car in a combined shopping trip. We then compare these two scenarios with the scenario that has the smallest energy use possible in this study, being (7) inland tomatoes produced in open air, marketed through a supermarket and delivered at a collecting point on walking or cycling distance of the consumers’ house. We assume again that for scenario (5) and (6) the consumer buys in total 10 kg of products in one shopping trip. This results in: SPSD II - Part I - Sustainable production and consumption patterns - Agro-Food 46
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