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Comparing global warming potential, energy use and water consumption from growing tomatoes in Sweden, the Netherlands and the Canary Islands using life cycle assessment Jonatan Högberg MSc Thesis, 2010! #$%&'()*+,-.( /.0,*+1,-)* -2

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Comparing global warming potential, energy use and water consumption from growing tomatoes in Sweden, the Netherlands and the Canary Islands using life cycle assessment Jonatan Högberg MSc Thesis, 2010! #$%&'()*+,-.( /.0,*+1,-)* -2 - emissioner vid sanering av fastigheten Trädgården 1:124 (Hexionområdet) Examensarbete inom Civilingenjörsprogrammet JOHANNA HECTOR Institutionen för Energi- och miljö Miljösystemanalys CHALMERS TEKNISKA HÖGSKOLA Göteborg, Sverige 2009 Environmental Systems Examensarbete Analysis2009:15 Chalmers University of Technology Sweden, Gothenburg ESA report no.: ESA 2010:2 ISSN no.: Environment Department SIK - Swedish Institute for Food and Biotechnology Sweden, Gothenburg Abstract Tomatoes consumed in Sweden originate mainly from Sweden, Spain and the Netherlands, and it is not obvious which tomatoes are best from an environmental point of view. This MSc thesis report use the framework of Life cycle assessment to compare global warming potential and energy use when growing tomatoes in the different countries, including transport to and storage and retail in Sweden. Data was collected from two growers in Sweden, one in the Canary Islands and one in the Netherlands. The results show that Swedish tomatoes emits the least amount of greenhouse gases, as long as they are heated with bio fuels, and that Spanish tomatoes use the least amount of energy, per kg tomatoes sold in Stockholm, Sweden. Contents 1 Introduction Outline of the report Tip to the inexperienced report-reader Method Short explanation of LCA Calculations Goal & Scope Purpose and targets Accounting LCA Cradle to Gate system model Present system Growing of fresh and industrial tomatoes Greenhouses Soil and hydroponic growth systems Systems descriptions Comparability with other greenhouses in the same regions Bio fuels in Swedish greenhouses Functional unit System boundaries Geographical Time horizon Cut-off criteria Included parts in the system model Farm Transports Warehouse Retail Important excluded parts in the system model Data collection Gathering of data References Fuel Transport Electricity Fertilisers Miscellaneous Description of farm system models Farm system 1, Swedish fossil heat Farm system 2, Swedish waste heat Farm system 3, Netherlands, waste and fossil heat Farm system 4, Spanish, open field Farm system 5, Swedish bio heat (theoretic) Results 20 6 Discussion System model exclusions Transport The tomato farms in Sweden The tomato farm in the Netherlands The tomato farm in the Canary Islands Comparison between Swedish and Dutch farms Best option: GWP Best option: Energy use Future improvements Future research Conclusions Best options for the Swedish consumer 1 Introduction The public awareness of environmental problems have increased over the last few years. One of the most discussed environmental problems is climate change, largely due to reports and projections on global warming caused by our society and possible future effects of it. Huppes and colleagues (2006), as reviewed in Tukker, A. & Jansen, B. (2006), find that climate gas emissions related to food consumption are 31% of the total household emissions. One environmental issue in food consumption in Sweden is consumption of vegetables that either have to be grown in heated greenhouses or transported here from more favorable climates. The most common of the greenhouse vegetable in Sweden is the tomato, which is consumed all year around despite the cold climate. Tomatoes consumed in Sweden usually originate from either Sweden, the Netherlands or Spain. From an environmental point of view it can be hard to choose the most climate friendly origin since the Swedish tomatoes are grown in heated greenhouses but not transported very far while the Spanish ones are transported a long way but produced without heated greenhouses, and the tomatoes from the Netherlands are produced in heated greenhouses but not transported as far as the Spanish tomatoes. Earlier studies in this field include Möller Nielsen, J. (2008) 1 whose resent study of Swedish greenhouse tomatoes show predicted greenhouse gas emissions of 0.94 kg CO2-equvalents per kg tomatoes for 2008; Lagerberg Fogelberg, C. & Carlsson-Kanyama A. (2006) who show that the emissions from Swedish tomatoes in 2005 were 2.7 kg CO2-eq., and the emissions from tomatoes grown in Holland in 2005 were 2.9 kg CO2-eq. per kg tomatoes; Antón, A. (2005) whose study on mediterranean greenhouses show that Spanish tomatoes account for between 81 and 120 g CO2-eq per kg tomatoes, depending on the growth technique used. One important reason for the large difference between tomatoes grown in 2005 and 2008 in Sweden is the shift in the main fuel used to heat the greenhouses, from fossil fuels to bio fuels. However, these studies do not include impact from transport, and it is not obvious how much the transport affects the total impact from growing and selling tomatoes in Sweden. Thus, there is need for a comparing study of the climate impact caused by growing tomatoes on a large scale in Sweden, the Netherlands and Spain, including impact from transport to Sweden. This report uses the framework of Life Cycle Assessment (LCA) to compare Global Warming Potential (GWP), energy use and water consumption of five different tomato farming systems, originating from four different tomato growers in Sweden, the Netherlands and the Canary Islands, including impact from transport, storage and retail to/in Stockholm, Sweden. 1 Möller Nielsens report, Energin & koldioxiden i svensk växthusodling TOMAT LCA (only available in swedish), can be recommended as a good source of information on how tomatoes are grown in Sweden in 2008 and the climat impact from the business. 1 SV NL ES January May August December Figure 1: Times during the year when tomatoes are harvested at the growers studied in this report. Sweden (SV), the Netherlands (NL) and the Canary Islands (ES). Sweden and the Netherlands grow in the summer because they need the warmth and the light. In Spain they grow in the winter because it is too hot and dry in the summer. The aim of the report is: To compare climate impact, energy use and water use caused by consumption of tomatoes in Sweden, depending on whether they originate from Sweden, the Nehterlands or Spain. 1.1 Outline of the report This report consist of an Introduction, a Goal and Scope section, a Data collection section, a Results section, a Discussion section and a Conclusions section. The Method section holds descriptions of the methods used to produce the results in the report. The Goal and Scope section is present in all LCA reports and contains specific information of the system and the methods used to analyse it. It also includes a description of the purpose and targets of the report. This section contains most of the information on what was done, why it was done and how it was done. The Data collection section has two main purposes; it contains all the data used to produce the results and a description of how the data was gathered. The Results section contains the results of the calculations, and it is the foundation on which the two last sections are built. In the Discussion section, the results are theoretically analysed and discussed. Included here is also a discussion on possible limitations in the research and on suggestions for future improvements in the tomato growing industry. The Conclusions section holds the conclusions drawn from the discussion. 2 1.1.1 Tip to the inexperienced report-reader For anyone who is mostly interested in the results of this report, and is not used to the art of report reading, I recommend first reading the Short explanation of LCA in the Method section, and then skipping ahead to the Results section, followed by Discussion and Conclusions. The Method and Goal & Scope sections can afterwards be read for better understanding, whereas the Data collection section is more for future reference and transparency reasons. 3 2 Method The method used to calculate the results was Life Cycle Assessment, or LCA. It is a standardised framework documented in ISO and ISO (ISO 2006) which is used to calculate environmental impact. LCA was used in this report because it is a method that can capture the emissions and resource use from the whole life cycle of the production. LCA is commonly used when calculating different kinds of environmental impact from production or services, for example from production of food. 2.1 Short explanation of LCA LCA is a tool for calculating environmental impact caused by a specified product or service (referred to as the system). The impact is calculated for a chosen function of the product; e.g. traveling one km by car or consuming one kilo of tomatoes. All the emissions and resources used throughout the life cycle are added together, including those caused by the production of sub-components; e.g. the production of the steel used in the car or the fertilisers used to grow the tomatoes. The different emissions may be added together using weighting tables and the results are presented in a number of impact categories; e.g. global warming potential, eutrophication and acidification. In this report I have used the impact category Global warming potential over 100 years (GWP100) and energy use, both which will be defined in the Goal and Scope chapter. The water consumption has not been calculated using this approach, only the water used by the grower for watering the tomato plants is accounted for. Doing a complete LCA on a product is often very time consuming since you need to find out the emissions of the producer, and the emissions of the sub-contractors, and of their sub-contractors, etc.. For this reason you are often forced to exclude parts of the life cycle from the calculations, focusing on the main flows and the parts that are believed to be relevant and possible to investigate. Even though the quality of an LCA is dependent on what is and isn t included in the system model, conclusions can generally still be drawn from the results of an incomplete system model. This is possible due to experience from working with similar systems, and from working with LCA in general. All the parts of the system that are included in the calculations are referred to as the system model, and are said to be inside the system boundary. One should always be careful in how to interpret the results from an LCA since they depend on what is included in the system model. It can, for example, be misleading to compare the results of two different LCA s if the differences in the system model are not taken into account, even if they were made on two very similar, or even identical, products. 4 For a full introduction on how LCA works and is calculated, please read the book Hitchhikers Guide to LCA by H Baumann and A-M Tillman (2004). 2.2 Calculations The calculations in this report were made using the LCA software SimaPro from PRe Consultants. Global warming potential (GWP) is a way to add together the effect that different gases has on the greenhouse effect of the atmosphere. GWP is measured in carbon dioxide equivalents (CO2-eq) and all other gases have their greenhouse effect recalculated into units of CO2-eq. The list of gases are presented and updated by the IPCC and can be found in their assessment reports (Solomon et al. 2006). The most important greenhouse gases, and their relative GWP over a 100 year perspective, are listed below [IPCC-2, 2007, chp 2, p 212]. CO2-1 Methane (CH4) - 25 N2O These numbers are subject to change as the research surrounding the climate move forward, the changes are however usually small. These are the numbers used in the calculations in this report. 5 3 Goal & Scope 3.1 Purpose and targets This report is the result of a MSc thesis project which was initiated by SIK, the research institute for food and biotechnology in Sweden, as a means to get new inventory data on tomato farming. The gathered data was also used in a project involving ICA Sverige AB, a leading food retail company in Sweden, and all the growers who supplied the data were at the time delivering tomatoes to ICA. The purpose of this report is to answer the question; Which tomatoes should be bought by a consumer or retail store purchaser in Sweden, from a pro-climate point of view? The main targets of the report are grocery store purchasers and consumers in Sweden. Secondary targets are the tomato growers and policy makers in Europe and the scientific communities working with food science, climate change and sustainable resource use (energy and water). 3.2 Accounting LCA This LCA is a so-called accounting LCA, meaning that it is comparing and retrospective. The different tomato growers have been analysed separately and the results of the analysis are compared. The calculated impact can be associated with a product or service. Accounting LCA s are commonly used when comparing different products or services. An option would have been to make a consequential LCA, which is also comparing but prospective instead of retrospective. Had this been a consequential LCA then the focus could have been on the change created when choosing one kind of tomatoes over another kind. E.g. when choosing Swedish tomatoes you actively choose not to buy Dutch or Spanish tomatoes, thus decreasing the amount of tomatoes transported through Europe. The primary reason for doing an accounting LCA, instead of a consequential LCA, is that there is no obvious product that can be substituted for tomatoes, except other tomatoes. One could have made a consequential LCA where one include the assumption that when buying tomatoes from one country one doesn t buy tomatoes from another country, but since the origin of tomatoes sold in Sweden vary with season the results would not hold most of the year. 3.3 Cradle to Gate system model The system model used is a cradle to gate model, meaning that production of raw materials (the cradle ) are included but that the product life cycle is not followed all the way to waste/recycling (as it would have been in a cradle to grave model), instead it is cut of at some point (called the gate ). There are several reasons for not doing a cradle to grave model. 6 First, this is a comparing LCA and since tomatoes generally are treated equally once they arrive in the store there would be no addition of interest from the last part of the life cycle. Secondly, it is very complex to find out how tomatoes are generally treated once they leave the store, compared to finding out how they got there. 3.4 Present system This LCA focuses on the present system since the tomato growing business has undergone large changes in terms of energy efficiency and heating methods in recent years, and since it is hard to foresee how the tomato market, and growth systems, will change in the future. 3.5 Growing of fresh and industrial tomatoes Tomatoes can be divided into two groups; tomatoes that are grown for processing in the food industry, and tomatoes that are grown for fresh consumption. There are also many varieties within these two groups, especially among the fresh tomatoes where one, appart from the the classical round tomato, can find many different sizes, shapes and colours ranging from beef tomatoes to cherry tomatoes. This report focus on fresh tomatoes of the classical round sort. Tomatoes aimed for the industry are usually grown on open field, or in soil in primitive greenhouses in warm countries like Spain or Italy. Tomatoes aimed for fresh consumption are grown both in warm countries, that have no need for extra heating, and in colder countries, that need to use heated greenhouses for their production. In intensive tomato production you often use large amounts of fertilisers to increase yield Greenhouses Both warm and colder countries make use of greenhouses to protect the crops from weather. In the warm countries they are often made of plastic sheets or nets and in the colder countries they are made of glass. The plastic helps to shield the plants from the sun in the hottest part of the day, as well as keep the heat and moisture trapped during the night. The glass helps the greenhouses in the north to utilise as much of the heat and sunlight as possible. It is also more important for the growers in the colder countries to isolate their greenhouses since heating is a cost for them, compared to the growers in warmer countries who get all their heating from the sun Soil and hydroponic growth systems In a soil based growth system the plants are grown in soil enriched with fertilisers, fertilisers are also added several times during the growth season. The watering is either done with flooding or some sort of drip irrigation, the later which generally decrease water use. A hydroponic growth system is soilless and the plants are grown in a 7 substrate, for example rock wool, through which water and nutrients are flowing. In modern hydroponic greenhouses the nutrient water is circulated and monitored so that an exact nutrient level can be keept at all times, this generally results in greatly reduced use of fertiliser compared to growing in soil. The substrate is generally thrown away along with the used plants after each growth season. 3.6 Systems descriptions This report covers five different farm systems originating from four different tomato growers, all which are delivering fresh tomatoes to Sweden to be sold in retail stores. Each grower has one system and the extra system is a copy of one of the Swedish systems, using the same data, but with a wood chip furnace as heating source instead of the original heat source. The reason for including the extra farm system is that it represents a common, and presently expanding, heating technology for greenhouses in Sweden. The five different farming systems are: 1. Tomatoes grown in a hydroponic system in greenhouses heated with fossil fuels in southern Sweden 2. Tomatoes grown in a hydroponic system in greenhouses heated with waste heat 2 in southern Sweden 3. Tomatoes grown in a hydroponic system in greenhouses heated with a mix of waste heat (75 %) and fossil fuels (25 %) in the Netherlands 4. Tomatoes grown on open field 3 under plastic nets on the Canary Islands 5. Tomatoes grown in a hydroponic system in greenhouses heated with bio fuels in southern Sweden Comparability with other greenhouses in the same regions All four farms viewed here are assumed to be representative to a general tomato farm in the specific countries using similar growth and heating systems, but the farm on the Canary Islands can not be said to represent a general tomato farm on the Spanish mainland since it is more common with hydroponic growth systems there. Swedish tomatoes are generally grown in the most southern part of Sweden in greenhouses heated by either fossil fuels or bio fuels. The 2 Waste heat is heat from a nearby industry that is produced as a bi-product of the process and thus holds no real value for the industry. The waste heat is regarded as environmentally free in the calculations, meaning that it does not add to GWP. Another way to do it would have been to use economic allocation, i.e. to compare the economic value of the heat and the main product of the process, and then dividing the pollution from the process according to the ratio between the two. This way of calculating would have resulted in higher GWP, but it would depend on what kind of process was used in the actual industry, and also on the value of the main product. 3 Open field means that the plants are grown in soil outdoors. 8 farms presented in this report represents modern Swedish tomato farms in terms of energy efficiency and water consumption. The results also hold for greenhouse gas emissions given that one compares with another greenhouse using the same heating system. Tomatoes from the Netherlands are generally grown with hydroponic systems in greenhouses heated, more or less, directly with natural ga
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