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Vegetable production in greenhouses is associated with a high global warming potential (GWP). By using alternative heat sources, the CO 2 eq emissions are lowered. In Hinwil, Switzerland a promising project of the waste incineration plant KEZO and the vegetable producer Primanatura AG was started, where formerly un-used waste heat is used to heat a...
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... cultivation of vegetables in greenhouses normally leads to high fossil energy consumption and therefore a high global warming potential (GWP) per kg product compared to non- heated production. However, in Switzerland certain vegetables are, due to climatic condi- tions, mainly grown in greenhouses. This is the case for cucumbers in summer and lettuce in winter. For both products, a considerable higher GWP is attributed to products from heated greenhouses compared to field-grown products (Jungbluth, 2000). Therefore a great potential exists for alternative heating sources like wood pellets or district heating. In the year 2009 a promising project for a greenhouse heated with so far unused waste heat from a waste incineration plant in Hinwil, Switzerland was initiated. The waste incineration plant KEZO already produces electricity and maintains a district heating net- work for the nearby industry and households. However, there is still some hot steam with a temperature of about 55 °C left. This steam is too cold to be used in the district heating net- work and was therefore so far not used. It had to be chilled down actively by an air-cooled condenser to maintain the negative pressure needed for an efficient energy conversion. With the construction of the nearby greenhouse of Primanatura AG, an accepter for this waste heat was found. The system is shown in Figure 1. The greenhouse project enhanced the energy efficiency of the waste incineration plant. Be- sides the utilisation of so far unused heat, the overall electricity production of the waste incineration plant could be increased. The net productivity improvement is credited to the fol- lowing three effects: (1) the load of the ventilator of the air-cooled condenser can be decreased when heat is deducted by the greenhouse. This leads to an average economisation of 40 kW; (2) the productivity of the turbine is increased because the negative pressure of the off-steam is optimised. Therefore more energy is converted into electric power, leading to an average increase of productivity of 90 kW; (3) the waste heat needs to be pumped to the greenhouse. The pumps consume electric power, on average 20 kW. Overall, the productivity of the waste incineration plant is increased by 110 kW. The objective of this study is a comparison of cucumbers and lettuce grown in the greenhouse of the Primanatura AG with cucumbers and lettuce grown in fuel oil heated greenhouses. The goal of this study is to compare the global warming potential (GWP) of vegetables from a greenhouse heated with waste heat from a waste incineration plant to vegetables from a greenhouse heated with fuel oil. Therefore cucumbers, in Switzerland typically grown in greenhouses during the summer half-year, and lettuce produced in the winter months are studied. All inputs such as seedlings, fertilizers and pesticides are considered as well as field processes, infrastructure, heat, electricity, other used materials, the transportation of the products to the point of sale and waste disposal. As the studied products cucumbers and lettuce are usually not cooked, no cooking processes are considered. Transportation from the point of sale to the household is not considered as well, as it is highly depending on the individual behaviour of customers. The system boundaries also include the heat and power production at the waste incineration plant. The functional unit is 1 kg of cucumber or lettuce, respectively. The primary data for the vegetable production and the greenhouse infrastructure are provided by the Primanatura AG. Additional data for conventionally heated greenhouses are taken from the guidance of the official reference method for nutrient balancing at farm level in Switzerland (agridea, 2008) and from Jungbluth (2000). Data for the heating system and the associated additional electricity generation are provided by the waste incineration plant KEZO. The most important data are summarised in Table 1. For secondary data, the ecoinvent inventory V2.1 database is used (Swiss Centre for Life Cycle Inventories, 2009). Direct field emissions, mainly from fertilisation, are calculated according to Nemecek & Kägi (2007). In the ecoinvent database, heat and power from waste incineration plants are considered as emissions free. Three reasons are: (1) the main function of a waste incineration plant is the waste incineration itself. Electric power and heat are by-products; (2) heat is produced in any case. The overall emissions of the waste incineration plant would not be lower if the electric power and heat would not be used; (3) electricity and heat utilisation create only a small part of the income of the waste incineration plant. In this special case, the by-products electric power and heat can be considered as emission free (Doka, 2009). The greenhouse heating system with waste heat increased the efficiency of the waste incineration plant. The additional electricity generation is only achieved due to the construction of the greenhouse, as there are no other possible accepters of this low temperature waste heat. Therefore the additional electricity is considered as a credit for the vegetable production. This additional electricity substitutes electricity that would otherwise have been produced from other sources. The substituted electricity is represented with the power production mix from the Union for the Co-ordination of Transmission of Electricity (UCTE). The UCTE is a predecessor of the European Network of Transmission System Operators for Electricity (ENTSO-E) 1 . Switzerland’s national grid company, Swissgrid, was a member of the UCTE and is now member of the ENTSO-E. The global warming potential (GWP) with a time horizon of 100 years according to Intergovernmental Panel on Climate Change – IPCC (2007) was considered. The analysis was performed using the software EMIS (Environmental Management and Information System) developed by Carbotech AG (Dinkel, 2009). Figure 2 and 3 show a comparison of fuel oil heated and waste heat heated greenhouse production for cucumbers and lettuce, respectively. The results show that fuel oil is the main source for CO 2 eq emissions of cucumber and lettuce production from fuel oil heated greenhouses. It is responsible for almost 90 percent of the total CO 2 eq emissions of both products. In total, 1.741 kg of CO 2 eq is ...
Citations
... In this research, Switzerland was selected as the case study. In Switzerland, the agricultural greenhouse area has expanded by 22 % in the recent decade, from 385 to 471 ha [41] and a successful project of using waste heat from an solid waste incinerator for heating vegetable greenhouses has already been implemented [24]. ...
... The heated flow from the stream turbine cycle condenser in municipal solid waste incinerators offers low-grade waste heat at approximately 55 • C. This waste heat is unsuitable for many applications due to its low temperature [24], but it is still applicable for heating agricultural greenhouses. Biogas plants hold significant potential [13], with manure alone providing feedstock for up to 1500 agricultural biogas facilities. ...
The rising demand for greenhouse cultivation poses a challenge in providing environmentally friendly energy to maintain favorable greenhouse indoor conditions. This research presents an optimization model to identify cost-optimal symbiotic pathways to replace the import of three key greenhouse crops (tomato, cucumber, lettuce) with local greenhouse production. The proposed solutions involve greenhouses that can meet these crops' heat and CO 2 demands via industrial symbiosis. Switzerland is investigated as the case study, and the (waste) heat suppliers are municipal solid waste incinerators, cement production plants and biogas plants. Upgrading bio-methane production plants are also considered potential CO 2 suppliers. The objective is to minimize the discounted cost when replacing 25%-100 % of vegetable imports with local agricultural greenhouses, considering availability of suitable land as well as waste heat and CO 2 suppliers. Optimization results suggest prioritizing northeast and west Switzerland for greenhouse development, due to the availability of suitable land and proximity of waste heat and CO 2 suppliers. Waste incinerators could provide 50%-70 % of the necessary heat, while Organic Rankine cycle in cement plants could generate 63 % of the electricity of supplementary lighting demand of greenhouses. While tailored for Switzerland, the optimization framework's general formulation can be adapted also to other regions to optimize greenhouses' heat and CO 2 demands. The optimization code is provided open source for associated applications.
... Several studies have investigated the supply of greenhouse heating utilizing waste heat sources. Marton et al. (2010) investigated the industrial symbiosis between a municipal solid waste incinerator (MSWI) and a tomato production greenhouse in Switzerland, where waste heat of the plant condenser is used to heat the greenhouse space. They showed that there are many environmental benefits in this type of symbiotic relationship. ...
... MSWIs, which are mainly close to urban areas, include low-quality waste heat potential in the hot stream of the steam turbine cycle condenser (about 55 • C). This waste heat cannot be utilized for many other purposes because of its low-temperature range (Marton et al., 2010), but it is still appropriate for heating agricultural greenhouses. Hence, MSWIs also have particular importance. ...
Despite the many benefits of greenhouses, it is challenging to meet their heating demand, as greenhouses belong to the most energy‐intensive production systems in the agriculture sector. Industrial symbiosis can bring an effective solution by utilizing waste heat from other industries to meet the greenhouse heat demand. This study proposes an optimization framework by which optimum symbiotic relationships can be identified. For this aim, the spatial analysis is integrated into an optimization model, in which geographical, technical, and economic parameters are considered simultaneously to identify the optimal location for developing new agricultural greenhouses. The objective function is to minimize the heating costs, that is, the investment cost of piping and electricity cost for pumping heat‐carrying fluid from supplier to demand. The model is applied to the case study of Switzerland, and currently existing municipal solid waste incinerators, cement production plants, and biogas plants are considered potential waste heat sources. Results show that the import of tomato, cucumber, and lettuce to Switzerland can theoretically be replaced by vegetable production in new waste‐heat supplied greenhouses (zero import scenarios). Accounting for the economy of scale for pipeline investment costs leads to selecting large‐scale greenhouses with a cost reduction of 37%. The optimization results suggest that 10% of the greenhouses needed to satisfy the total domestic demand for lettuce, tomato, and cucumber could be placed on a suitable land plot in the direct vicinity of a waste heat source, with low costs of waste heat supply.
... For example, Marton and Kägi have conducted a study concerning the IS between greenhouses and incinerators in Switzerland, where a greenhouse was being heated by the condenser of an incinerator plant. In this study, using life cycle analysis (LCA), they concluded that the global warming potential (GWP) of crops in studied greenhouses is approximately one-tenth of fuel oil-heated ones (Marton & Kägi, 2010). Additionally, Andrews and Pearce investigated the IS between greenhouses and a glass manufacturing plant in Canada. ...
Industrial symbiosis (IS) is known as an effective strategy to reduce resource consumption. Recently, the utilization of efficient energy conversion technologies in symbiotic relations has been suggested to enhance the flow exchange efficiency and economic effectiveness of energy-based industrial symbiosis schemes. In this work, the possibility of improving industrial symbiosis between agricultural greenhouses and waste heat sources in industries is investigated by utilizing the organic Rankine cycle (ORC) in different configurations. For this aim, a modelling tool is developed to analyse the thermo-economic justification of energy-based industrial symbiosis and estimate the possibility of simultaneous waste heat utilization for power generation and greenhouse heating. The results show that the selection of working fluid, capacity and configuration has a significant effect on the successful implementation of ORC technology and can reduce the payback period time to less than 5 years for the proposed case study. However, results indicate that even using an optimized ORC system is not always accompanied by improving the economic effectiveness and justification of IS establishment.
... Several studies have investigated the supply of greenhouse heating demand with waste heat from waste incinerator plants (Marton, Kägi, & Wettstein, 2010), industrial processes (Andrews & Pearce, 2011), district heating systems (Dou et al., 2018;Togawa, Fujita, Dong, Fujii, & Ooba, 2014), and power plants (Lee, Lee, Lee, & Song, 2016;Yu & Nam, 2016). Similar to these examples, biogas plants and greenhouse cultivation systems can be integrated to close the cycle of material and energy flows. ...
The concept of symbiosis, a mutually beneficial relationship, can be applied to food and energy systems. Greenhouse systems and biogas plants are interesting technologies for food–energy symbiosis, because both are usually based in rural areas and offer opportunities for the exchange of materials (e.g., biomass waste from the greenhouse as input to biogas plants) and energy (heat from biogas co‐generation for heating greenhouses). In this paper, the focus lies on manure resources for biogas in Switzerland, because manure amounts are high and currently largely underused. We provide a spatial analysis of the availability of manure as feedstock to biogas plants and heat source for greenhouses. In this feasibility study, we coupled the potential waste heat supply from manure‐based biogas and the greenhouse peak heat demand. We quantified the area‐based greenhouse heating demand for year‐around tomato production (from 0.98 to 2.67 MW ha−1 where the farms are located) and the available heat supply from manure‐based biogas (up to 3,200 GJ a−1 km−2). A total maximum greenhouse area of 104 ha could be sustained with manure‐based biogas heat, producing 20,800 tonnes a−1 tomatoes. This amounts to 11% of the total domestic tomato demand. Although the results are specific to Switzerland, our method can be adapted and also applied to other regions.
... In contrast, Gunady et al. (2012) report dramatically higher at-market results for lettuce on the Perth (Western Australia) market at 3.56 kg CO 2 -e per kg lettuce. Compared to both literature and to this study, results in Gunady et al. (2012) for field lettuce produced within a relatively 'local' market appear high, in the vicinity of European greenhouse lettuce (Hospido et al., 2009;Marton et al., 2010;Mil a i Canals et al., 2008). Possible reasons include the use of an alternative hybrid impact calculation method. ...
Localisation of food production is often advocated as a means to improve food security by creating climate resilient pathways within food supply chains. As a robust evidence-based response to legitimate food security and environmental concerns, the concept of local food remains controversial with limited studies comparing environmental impact trade-offs. This study compares local peri-urban commercial production in a developed city with de-localised production for lettuce, highlighting trade-offs between a spectrum of regionally relevant environmental indicators (global warming potential (GWP), land use, water use and eutrophication). On- and post-farm supply chain variation was assessed using life cycle assessment for product arriving at Sydney's central vegetable market. Three field farms, one outdoor hydroponic and one high technology greenhouse (HTG) were examined. Sensitivity to renewable energy was assessed in the case of the HTG. Peri-urban field produced lettuce delivered to the central market exhibited lower carbon dioxide equivalent (CO2-e) emissions (0.24 and 0.31 kg CO2-e per kg lettuce) compared to remote field (0.48 kg CO2-e) or peri-urban HTG production (0.51 kg CO2-e). Activities including packaging selection and distance to market had a large influence on environmental impacts. Benefits of using renewable energy for HTG production manifested as a reduction in emissions to 0.27 kg CO2-e, placing the HTG as an environmentally competitive alternative to field production. Land and water use were optimised through the use of outdoor hydroponic and HTG production with improvements over field production of up to 80 and 60 percent for land and water use respectively. Examination of a wider range of regionally specific environmental impacts should be considered with any environmental claims on local food, extending analysis beyond a restriction to emissions. Policy frameworks need to consider how trade-offs will be assessed and managed as governments strive for emissions reductions.
link available til March 22 2016, http://authors.elsevier.com/a/1STrN3QCo9EQ8c
... The use of heating systems with nonfossil energy and particularly waste heat could be a solution which may reduce both carbon footprint and water stress impacts. Some greenhouses functioning with waste heat are already in operation, for example, the greenhouse attached to a municipal solid waste incineration in Hinwil, 47 and the tropical centers in Frutigen and Wolhusen, Switzerland, 48 which are heated with geothermal heat (warm water effluent from a tunnel) and waste heat from a gas concentration unit respectively. The decision recommendation for food producers would thus be to search for such alternative heat energy sources or to avoid heating as much as possible. ...
Food production and consumption is known to have significant environmental impacts. In the present work, the life cycle assessment methodology is used for the environmental assessment of an assortment of 34 fruits and vegetables of a large Swiss retailer, with the aim of providing environmental decision-support to the retailer and establishing life cycle inventories (LCI) also applicable to other case studies. The LCI includes, among others, seedling production, farm machinery use, fuels for the heating of greenhouses, irrigation, fertilizers, pesticides, storage and transport to and within Switzerland. The results show that the largest reduction of environmental impacts can be achieved by consuming seasonal fruits and vegetables, followed by reduction of transport by airplane. Sourcing fruits and vegetables locally is only a good strategy to reduce the carbon footprint if no greenhouse heating with fossil fuels is involved. The impact of water consumption depends on the location of agricultural production. For some crops a trade-off between the carbon footprint and the induced water stress is observed. The results were used by the retailer to support the purchasing decisions and improve the supply chain management.
Education for sustainable development through activities or seminars is part of the training program for chemical engineering students to strengthen their commitment to the Sustainable Development Goals (SDGs) included in Agenda 2030. Food waste is not only an ethical and economic issue; it also depletes limited natural resources. In terms of the most recognized environmental indicator, food waste generates about 8% of global greenhouse gas emissions. In this regard, curbing the growing trend of over-consumption of goods that we will not consume can have a significant effect on reducing the environmental impact associated with food production.
The evaluation of the environmental impacts associated with non-responsible food consumption address SDGs No. 1, 2, 6, 12 and 13 and creates a framework for discussion on how to prevent food waste and strengthen the sustainability of the food system. The activity included both group activities (search for life cycle characterization factors to estimate the carbon and water footprints of food) and individual activities (collection of food waste data) over several months. When comparing the values of environmental footprints at the beginning and end of the activity, the most rational consumption of meat and dairy products was responsible for the largest proportion of the reduction achieved (70%). The activity was evaluated by the students with an average of 3.40 (between 1 and 4), with a remarkable percentage of students (>75%) who valued the activity positively both in the definition of the different phases of the work and in the monitoring of the results.
Current food production and consumption practices are depleting natural resources and polluting ecosystems at a rate that is unsustainable and are one of the main causes of anthropogenic climate change. If this trend does not change, externalities of food production will be exacerbated in future decades due to population growth and increasing living standards. A shift towards low impact diets has been proposed as part of the solution. The public food sector offers tremendous potential for influencing such a shift; however currently in the UK this potential is only partially exploited as national guidelines for public food procurement avoid promoting the adoption of low impact menus. This doctoral research aims at addressing this shortfall by creating a procedure for the design of low impact primary school menus. This is informed by a life-cycle based tool (the Environmental Assessment Tool of School meals, EATS) that enables catering companies and local authorities to self-assess the environmental impact of a meal in terms of its carbon and water footprint, with the purpose of identifying hotspot meals and comparing alternatives in the design of new menus. The data underlying EATS includes the results of a meta-analysis of the existing literature on the carbon footprint of 110 food products commonly used in the preparation of primary school meals in the UK. To validate EATS, a statistical analysis of the underlying data was performed, feedback from its potential users was collected, three case study analyses were developed, and the results provided were compared with existing studies.
The global impacts of food production
Food is produced and processed by millions of farmers and intermediaries globally, with substantial associated environmental costs. Given the heterogeneity of producers, what is the best way to reduce food's environmental impacts? Poore and Nemecek consolidated data on the multiple environmental impacts of ∼38,000 farms producing 40 different agricultural goods around the world in a meta-analysis comparing various types of food production systems. The environmental cost of producing the same goods can be highly variable. However, this heterogeneity creates opportunities to target the small numbers of producers that have the most impact.
Science , this issue p. 987