Article

Sustainable greenhouse production with minimised carbon footprint by energy export

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Abstract

Consumer and trade organisations demand year-round healthy diets including fresh, high quality vegetables from local producers. However, greenhouse gas emissions (GHG) of heating high-tech greenhouses in northern countries are higher than transporting vegetables produced in southern Europe in unheated tunnels. The aim of this work was to assess GHG emissions when renewable energy sources were used for heating and cooling a solar collector greenhouse (SCG) in comparison with a conventional greenhouse (RG). Thermal energy generated in the SCG from solar energy was stored in an insulated water tank and different strategies were examined: no reused energy; reused energy; reused energy and excess energy transfer. Based on the semi-closed climate control strategy set in SCG and associated higher CO2 concentrations, higher marketable yields were achieved (+22%) compared to the production in the RG. The results further showed that the cumulative energy demand of the SCG can be lowered by approximately 44% compared to that needed in the RG. The carbon footprint (CF) and the water use efficiency were improved by 24% and 28%, respectively. If excess thermal energy generated by the SCG could be considered as export energy, a negative carbon footprint of -0.7 CO2-eq kg-1 can be reached. The latter case shows that the CF can be reduced to levels of unheated greenhouses. As such, vegetable production in solar collector greenhouses can be more sustainable than in conventional greenhouses since energy and water, as well as fertiliser and associate CO2 emissions, can be saved.

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... A new approach to crop cultivation, called the "Next Generation" greenhouse cultivation, combines design, technology and climate control with the aim of improving greenhouse energy use (De Gelder, Poot, et al., 2012). Lastly, the use of alternative energy sources does not in itself reduce greenhouse energy use, but it can meaningfully reduce a greenhouse's carbon footprint (Ntinas et al., 2020). ...
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... The greenhouse with LEDs of 200 µmol m -2 s -1 required an energy input 1,388 MJ m -2 , which is 527 MJ m -2 less than a comparable greenhouse in Chapter 4 (the LED greenhouse without temperature adjustment in Figure 4.8). Although specific simulations are required to explain the causes for this energy use reduction, around 300 MJ m -2 of it can be attributed to the use of heat harvesting (Ntinas et al., 2020), around 30 MJ m -2 to the extended use of thermal screens (Dieleman & Kempkes, 2006), and around 100 MJ m -2 to the use of blackout screens (De Gelder, Poot, et al., 2012). ...
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... Several measures have also been identified, with the aim of reducing the floricultural industry's climate impacts. One example addresses the mitigation of greenhouse gas (GHG) when using green houses, especially in the northern hemisphere, suggesting alternative renewable energy sources (Ntinas et al., 2020). ...
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... Currently, finned tube heat exchangers are used in closed and semi-closed greenhouses for dehumidification and energy generation [1,2]. Even though these greenhouses contribute to sustainable production, the equipment in the roof area of such greenhouses provokes a light reduction of between 3 and 11%. ...
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... It follows, that the aquaponic units may be separated without harming either aquaculture or hydroponics and that both can also operate independently from each other. Optionally, the evaporated water in the hydroponics (greenhouse) can be regained via cooling/condensation traps as condensate 89 or desalination/distillation technologies (e.g. reverse osmosis) 90 and returned to the aquaculture unit to minimise the overall water consumption of the system (cf. ...
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... Besides, according to the National Climate Change Committee: Iran INDC (Department of Environment, 2015), Iran is supposed to decrease their CO 2 emission to 4% below business as usual (BAU) levels by 2030. Therefore, to achieve sustainable greenhouse development, it is essential to consider greenhouse energy consumption, CO 2 emission and cost efficiency (Ntinas, Dannehl, Schuch, Rocksch, & Schmidt, 2020). There are a wide variety of greenhouse types (Vanthoor et al., 2012), ranging from solar passive greenhouses mostly used in China (Ahamed, Guo, & Tanino, 2018a;Chen, Li, Li, et al., 2018, b;Xu, Du, & van Willigenburg, 2018) to high-tech greenhouses in Europe (Van Beveren, Bontsema, van Straten, & van Henten, 2015a, b). ...
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A confined closed greenhouse (CGH) was applied to save energy and to investigate how tomatoes respond to specific microclimatic con-ditions. As such, new dynamic set-points for precise climate control were used in the CGH compared to those applied in a conventional greenhouse. Based on the reduced ventilation frequency in the CGH, the results showed that higher levels of mean temperature, CO2 concentration and relative humidity were achieved. Although the light interception was increased in the CGH, these changing micro-climatic conditions resulted in higher rates of photosynthesis and an associated faster crop growth. This means that the mean plant height was increased by 1.5 m, which was the decisive factor to increase the total yield by 21.4 % in relation to that produced in the conventional greenhouse. The new microclimatic environment caused by the CGH promoted the accumulation of primary and secondary plant compounds in tomatoes such as soluble solids (by 9 %), lycopene (by 22 %), ß-carotene (by 21 %), phenolics (by 8 %) and L-ascorbic acid (by 26 %) compared to conventional produced tomatoes. Compared to existing greenhouse systems, the results suggested that a CGH can be used to produce tomatoes in a sustainable way, where the water use and the energy use efficiency can be improved by 71 % and 43 %, respectively.
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The classic methods for energetic evaluation of greenhouses are not sufficient to completely and precisely evaluate the components of a closed installation consisting of a greenhouse, solar techniques and heat storage. Therefore it is necessary to extend the spectrum of methods. For this purpose a few evaluation parameters of climate and solar technique can be instrumented. First of all the tightness of the greenhouse covering is investigated. Due to low air exchange (<0,3) the heat loss is reduced. This results, together with thermal screens, in higher humidity of greenhouse air. Therefore the strategy of vapor passing double screens is suitable to transport the water vapor in the roof zone without losing large quantities of sensible heat. During this process a significant increase of the V-enthalpy value (+116%) and simultaneously a slight growth of the V-air-value (+10%) is shown. The new V-enthalpy value makes it possible to have a combined view of sensible and latent heat flow during the evaluation of thermal screens because the insulation effect is taken into account as well as impermeability in relation to water vapor. Furthermore, it was determined that the heat consumption can be reduced up to 59% by using a double screen. In order to evaluate the efficiency of the heat pump, separate examinations of cooling and heating were executed to find the results for efficiency ratios of 4.9 (cooling) and 4.5 (heating). Furthermore, a significant influence of the auxiliary drive (e.g. circulation pumps) on the efficiency of the heat pump system was proofed. For cooling and dehumidification in the greenhouse, finned tube heat exchangers, situated in the roof zone, are suitable. The resulting induced light reduction (5%) can be compensated through additional yield. In addition, the efficiency of the roof cooling grows. This is based on the natural convection combined with increasing transpiration, which allows a latent cooling part until 35% and a collector’s efficiency up to 0.8. Using 50% collector area in the greenhouse system, an export of the stored heat is recommended for the remaining greenhouse area. Here, a solar fraction for heating support of 60% can be expected. As a storage concept, an above ground heat storage (1 m³/m²) is recommended. This requires at least a thermal insulation of the water surface area. Even low levels of insulation already allow a significant improvement in thermal insulation during low temperature storage systems. Another focus of the investigation aims to find out if further developments, of the method for heat requirement calculation of greenhouses, are possible. Therefore to begin with, a comparison between methods of building- and greenhouse techniques was made, whereas the method, according to the DIN 4701 and DIN EN 12831, proved to be inadequate. In contrast, the established Ucs-method (also called DeltaT-method) uses, at least during the day, a standard efficiency of conversion from solar heat into sensible heat. But there is no differentiation between the cultivated culture, the leaf area index or the irrigation type. The effort from thermal heat to evaporation remains undifferentiated as well. In this case transpiration measurements of adult tomato plants show that even at night, large amounts of thermal heat (40%) can be converted into latent heat. This indicates that the heat consumption of greenhouses can significantly be increased. Along with this, it is possible to extend the Ucs-method by using the enthalpy of air for a correction factor (hx) that depends on evaporation. This factor describes the increase of heat consumption through evapotranspiration and needs to be allocated with the heat consumption coefficient of a greenhouse without plants and irrigation (Ucs,dry). Taking the example of tomato cultivation, nocturnal hx factors of 1.8 and 2.1 were determined. Alternatively, the interpretation of the heat load in the greenhouse could be executed by using the so called enthalpy loading number (τ). This parameter uses just like the correction factor method, the enthalpy difference between internal and external air in order to take into account sensible, as well as, latent heat. For this, the example of the tomato cultivation shows nocturnal τ values of 2.6 (without screen), 1.5 (single screen) and 0.8 (with double and side wall screen). Prospectively, an advanced development of the indicated enthalpy models (hx and τ) at full-day conditions should be performed. Furthermore, it needs to be clarified to which extent energetic storage effects, resulting of the water vapor that emerged at daytime, affect the current nocturnal enthalpy state. In addition, case studies with different leaf areas, types of irrigation and insulation situations should be carried out. Hence groups for cultivar or cultivation types and greenhouse systems can be derived.
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The use of low-impact energy sources for greenhouse cultivations is growing quickly due to environmental demands, constrained by the increased price of fossil energy sources, market demand for low cost greenhouse production, and need for air pollution reduction. This paper demonstrates via environmental analysis the efficiency of a Photovoltaic-Geothermal Heat Pump integrated system (PV-GHP) as a greenhouse heating system, compared to a conventional hot air generator using liquefied petroleum gas (LPG-HG). The tests were carried out in twin experimental greenhouses in the Mediterranean area (Valenzano-Italy). In order to evaluate the environmental performance of a heat pump system with electricity supplied from the national grid, a scenario (GHP Geothermal Heat Pump) was realised. The microclimatic conditions in the two greenhouses, the thermal energy produced, and the electricity consumption were analysed. Furthermore, in order to evaluate the long-term environmental impact, an environmental analysis was conducted using life cycle assessment (LCA) methodology, carried out according to standard UNI EN ISO 14040. The interpretation of the results using method CML2001 (Centre of Environmental Science, Leiden, Netherlands) showed that neither system is more advantageous from an environmental point of view and that the GHP scenario has the higher environmental burdens. Limiting the analysis to the emissions responsible for the greenhouse effect, the plant with the geothermal heat pump and photovoltaic panels reduces carbon emissions by 50%. In order to assess the sustainability of the geothermal heat pump plant, the estimated payback-time for energy and for carbon emissions were 1 year and 2.25 years, respectively.
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Background Low fruit and vegetable (FV) intake is a leading risk factor for chronic disease globally, but much of the world’s population does not consume the recommended servings of FV daily. It remains unknown whether global supply of FV is sufficient to meet current and growing population needs. We sought to determine whether supply of FV is sufficient to meet current and growing population needs, globally and in individual countries. Methods and Findings We used global data on agricultural production and population size to compare supply of FV in 2009 with population need, globally and in individual countries. We found that the global supply of FV falls, on average, 22% short of population need according to nutrition recommendations (supply:need ratio: 0.78 [Range: 0.05–2.01]). This ratio varies widely by country income level, with a median supply:need ratio of 0.42 and 1.02 in low-income and high-income countries, respectively. A sensitivity analysis accounting for need-side food wastage showed similar insufficiency, to a slightly greater extent (global supply:need ratio: 0.66, varying from 0.37 [low-income countries] to 0.77 [high-income countries]). Using agricultural production and population projections, we also estimated supply and need for FV for 2025 and 2050. Assuming medium fertility and projected growth in agricultural production, the global supply:need ratio for FV increases slightly to 0.81 by 2025 and to 0.88 by 2050, with similar patterns seen across country income levels. In a sensitivity analysis assuming no change from current levels of FV production, the global supply:need ratio for FV decreases to 0.66 by 2025 and to 0.57 by 2050. Conclusion The global nutrition and agricultural communities need to find innovative ways to increase FV production and consumption to meet population health needs, particularly in low-income countries.
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2009 to 2014, the joint research program ZINEG is carried out in Germany. Its main aim is to reduce the consumption of fossil fuels and hence the CO2 emissions up to 90% for production in greenhouses. At Humboldt University the research is focused on using a greenhouse system as solar thermal collector with above-ground heat storage. During the tomato production in 2011, a seasonal energy efficiency ratio (SEER) of 5.1 and a heating seasonal performance factor (HSPF) of 4.4 was achieved using an electrically-driven heat pump utilized for cooling and heating in the collector greenhouse. Approximately half of the solar irradiation was stored into an insulated rainwater-tank. This corresponds to 1.76 GJ/m2. Twenty percent of this solar energy was collected by condensation (originally latent heat) on finned pipes in the roof zone. For heating the collector greenhouse, about 0.53 GJ/m2 of the stored heat was re-used. That means that additional heat might be exported or the cooling surface area can be reduced to one-third. Furthermore, the solar thermal collector greenhouse achieved a primary energy consumption of 147.6 MJ/m2 (considering a full re-use of the stored heat). Simultaneously, the conventional greenhouse achieved a primary energy consumption of 767.1 MJ/m2. That means that the consumption of non-renewable energies (fossil fuels) is reduced up to 81% with the collector system. In further studies an economic assessment regarding energy-saving in semi-closed greenhouses should be performed to estimate the potential of such facilities. http://www.actahort.org/books/1037/1037_20.htm
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Improved energy efficiency and the increased use of renewable energy are important objectives for sustainable greenhouse crop production. Two prototypes of semi-transparentbifacial photovoltaic modules intended for greenhouse roof applications were developed. A module (PV1) using 1500 spherical solar microcells (1.8 mm diameter, crystalline silicon) with 15.4 cells cm(-2) density in 108 mm x 90 mm area was produced. Thirty-nine percent of the area was covered with the cells. The remaining 61% was transparent to allow the most sunlight to enter the greenhouse for promising plant photosynthesis. Similarly, a module (PV2) was made using 500 cells with 5.1 cells cm(-2) density. Thirteen percent of the area of this module was covered with the cells. The peak power output was 540 mW when the PV1 module was irradiated with 1213 W m(-2) sunlight coming directly from the sky and via ground reflection. The peak power output was 202 mW when the PV2 module was irradiated with 1223W m-2 sunlight. The conversion efficiencies from sunlight energy irradiated on the 108 mm x 90 mm area into electrical energy were 4.5% for the PV1 module and 1.6% for the PV2 module. Calculations of the annual electrical energy production per unit greenhouse land area indicated that these modules are potentially suitable for greenhouses in high-irradiation regions where electricity production could be high and winter demand low. (C) 2014 The Authors. Published by Elsevier Ltd. on behalf of IAgrE.
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Greenhouse crops, one of the most innovative examples of modern agriculture, are considered to be one of the highest man-made forms of agricultural activity, due to the high level of both technological and bio-agronomic input. Greenhouse crops are characterised by the use of structures and equipment as well as increased energy resources and water use efficiency in the production processes. The Life Cycle Assessment (LCA) method is an instrument which provides a quantitative estimate of all flows of matter and energy related to the realisation of a product, providing an evaluation of the environmental compatibility and end result of each productive choice. The LCA method can be applied not only to industrial processes but also to agricultural production such as that carried out in greenhouses. The productive choices of the growers in regards to input and materials utilised are principally based on financial factors. The changes brought about as a result of these choices have a long-term effect in terms of the quantity of residuals and quality of the agricultural environment. This paper presents the results of an LCA study conducted on the outcome and importance of critical management and engineering choices in greenhouse agriculture in West European territory. The goal of this research is to provide an objective comparison of the environmental compatibility of horticultural production carried out in varying typology of greenhouses. For this study the three main forms of greenhouses used in Italy have been considered. The three typology of greenhouse are: a pitched roof structure in zinc-coated steel with glass covering; a vaulted roof structure in zinc-coated steel with plastic film covering; and a pitched roof structure in wood with plastic film covering. In order to best analyse the environmental sustainability of greenhouse production, research has been carried out with the active participation of Italian growers in order to acquire credible information regarding the actual consumption of energy and renewable and/or non-renewable resources utilised in greenhouse cultivation of tomatoes.
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A new type of greenhouse with linear Fresnel lenses in the cover performing as a concentrated photovoltaic (CPV) system is presented. The CPV system retains all direct solar radiation, while diffuse solar radiation passes through and enters into the greenhouse cultivation system. The removal of all direct radiation will block up to 77% of the solar energy from entering the greenhouse in summer, reducing the required cooling capacity by about a factor 4. This drastically reduce the need for cooling in the summer and reduce the use of screens or lime coating to reflect or block radiation.All of the direct radiation is concentrated by a factor of 25 on a photovoltaic/thermal (PV/T) module and converted to electrical and thermal (hot water) energy. The PV/T module is kept in position by a tracking system based on two electric motors and steel cables. The energy consumption of the tracking system, ca. 0.51 W m−2, is less than 2% of the generated electric power yield. A peak power of 38 W m−2 electrical output was measured at 792 W m−2 incoming radiation and a peak power of 170 W m−2 thermal output was measured at 630 W m−2 incoming radiation of. Incoming direct radiation resulted in a thermal yield of 56% and an electric yield of 11%: a combined efficiency of 67%. The annual electrical energy production of the prototype system is estimated to be 29 kW h m−2 and the thermal yield at 518 MJ m−2. The collected thermal energy can be stored and used for winter heating. The generated electrical energy can be supplied to the grid, extra cooling with a pad and fan system and/or a desalination system. The obtained results show a promising system for the lighting and temperature control of a greenhouse system and building roofs, providing simultaneous electricity and heat. It is shown that the energy contribution is sufficient for the heating demand of well-isolated greenhouses located in north European countries.
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A semi-closed solar collector greenhouse was tested to evaluate the yield and the energy saving potential compared with a commercial greenhouse. As such, new algorithm for ventilation, carbon dioxide (CO2) enrichment, as well as for cooling and heating purposes initiated by a heat pump, cooling fins under the roof and a low temperature storage tank were developed. This cooling system showed that the collector greenhouse can be kept longer in the closed operation mode than a commercial one resulting in high levels of CO2 oncentrations, relative humidity and temperatures. Based on these conditions, the potosynthesis and associated CO2 fixations within the plant population were promoted during the experiment, resulting in a yield increase by 32%. These results were realized, although the mean light interception by energy screens and finned tube heat exchangers was increased by 11% compared to the reference greenhouse. The energy use efficiency was improved by 103% when the collector greenhouse was considered as energy production facility. In this context, the energy saving per kilogram produced tomatoes in the collector greenhouse is equivalent to the combustion of high amounts of different fossil fuels, where the reduced CO2 emissions ranged between 2.32 kg and 4.18 kg CO2 per kg produced tomatoes. The generated total heat was composed of approximately one-third of the latent heat and over two-thirds of the sensible heat, where a maximum collector efficiency factor of 0.7 was achieved.
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Transport from regional production requires less fossil fuel and thus produces lower greenhouse gas emis-sions. In addition, policies fostering the production of re-gional goods support rural development. Tomato consump-tion has increased fast in Europe over the last decade. Inten-sive production techniques such as heated greenhouses and long-distance transport overcome seasonal constraints in order to provide year-round fresh goods. However, studies that evaluate seasonal and off-season production are scarce. Here, we analyzed the carbon footprint of tomato production systems in Austria, Spain, and Italy using a life cycle ap-proach. We collected data from four main supply chains ending at the point of sale in an average Austrian supermarket. We aimed to identify hotspots of greenhouse gas emissions from agricultural production, heating, packaging, processing, and transport. Our results show that imported tomatoes from Spain and Italy have two times lower greenhouse gas emissions than those produced in Austria in capital-intensive heated systems. On the contrary, tomatoes from Spain and Italy were found to have 3.7 to 4.7 times higher greenhouse gas emissions in comparison to less-intensive organic production systems in Austria. Therefore, greenhouse gas emissions from tomato production highly depend on the production system such as the prevalence or absence of heating. Keywords Greenhouse gas emissions (GHGE) . Tomato . Life cycle analysis (LCA) . Regional production . Transport
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The closed greenhouse is a recent innovation in the horticulture industry. Cooling by ventilation is replaced partly (in semi-closed greenhouses) or completely (in closed greenhouses) by mechanical cooling. Excess solar energy is collected and stored to be reused to heat the greenhouse. In temperate climates, this concept combines improved crop production with energy savings. This paper presents an overview of climate, crop growth and development, and crop yield in closed and semi-closed greenhouses. The technical principles of a closed greenhouse are described and the macroclimate and microclimate arising from this are studied. The consequences of the typical growth conditions found in closed greenhouses for crop physiology and crop yield are examined. Finally, the experiences of commercial growers are presented. In temperate climates, closed greenhouses can reduce the use of fossil fuel-derived energy by 25 – 35%, compared with open greenhouses. With high global radiation, the climate in closed greenhouses is characterised by high CO2 concentrations, high air humidity, improved temperature control, and a vertical temperature gradient. An annual increase in production of 10 – 20% is realistic, with reduced amounts of supplied CO2. The yield increase is primarily obtained through increased rates of photosynthesis due to the higher CO2 concentrations in closed greenhouses. To introduce this innovation into practice, knowledge transfer was a key factor for its implementation and the realisation of increased production levels. Future trends will require minimising the use of fossil fuels and increasing the level of control of the production process. Closed and semi-closed greenhouses fit seamlessly into this trend as they allow for a more controlled climate and higher levels of production, combined with savings in fossil fuel use.
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This study presents detailed and comprehensive inventories on the horticultural production of tomato using compost (CM) or mineral fertilizers (M), in both open-fields (OF) and greenhouses (GH), providing information on the environmental impacts and assessing the agronomic viability of the four cultivation options. Life cycle assessment (LCA) was used to calculate the potential environmental impacts of the tomato production cycle per ton of product. The stages in the assessment included: mineral and organic fertilizers production, fertilizers transport, cultivation stage and greenhouse stage. The data were obtained experimentally in pilot fields and in an industrial composting facility using municipal organic waste, both located in the Mediterranean area. The results indicate that replacing a fraction of the mineral fertilizers dosage with compost is a good option, as this did not alter yield or fruit size parameters. Greenhouse protection increased infrastructure materials requirements but enhanced harvest by almost 50% and reduced the water and pesticides requirement. Compost production and greenhouse stages were the most impacting stages. Without subtracting the avoided burdens by composting and not dumping organic waste, the cultivation option OF_M had the lowest and OF_CM the highest impact. When avoided burdens were taken into consideration, the environmental impacts of the four cultivation options varied, depending on the impact category, with bigger differences due to fertilization as a variable rather than the production system.
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The present study investigates the possibility of energy saving during the spring period in a conventionally heated greenhouse, using an innovating hybrid solar energy saving system.The greenhouse was divided in two equal parts (experimental and control), where tomato plants were cultivated hydroponically. The control part of the greenhouse covered the heating requirements exclusively by a conventional heating system. The experimental part used the conventional heating system only when the hybrid solar energy saving system could not maintain the greenhouse air temperature above 16°C. The hybrid solar energy saving system was consisted of a transparent cylindrical polyethylene sleeve filled with water and two perforated polyethylene tubes resting on the top of it. Through these tubes, air was pumped in order to inflate them and to be mixed with the greenhouse air. The use of hybrid solar energy saving system led to an energy saving portion capable of decreasing the greenhouse energy cost. Energy saving between the two parts of the greenhouse was recorded to be 36% from March to May. It has been also calculated that the oil consumption was significantly decreased in the experimental part and for the whole experimental period was 149.08 l, while in the control part reached 233.03 l. The application of this system contributed to smoother variation of the greenhouse air temperature and the rockwool slabs temperature, leading up to a better plant growth
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The environmental impact of greenhouse production in France is poorly documented. Environmental benefits versus drawbacks of greenhouse production are not well known. Assessments that intregrate pesticide toxicology and transfer of mass and energy are scarce. Here, we compared the main types of tomato production, heated, year-round production in plastic houses or glasshouses, and seasonal production under polytunnel. Environmental impacts where assessed by life cycle analysis. Analyses were performed after the construction of a database relating the integrality of matter and energy fluxes, regarding the structure of the system, the inputs for production, and the waste products. Results show that greenhouse heating had the highest environmental impacts, including toxicological impact. For instance, the mean environmental impact of heated crops under plastic or in glasshouses was 4.5 times higher than in tunnels. Furthermore, pesticides in tunnels had a 3- to 6-fold higher impact in terms of terrestrial or aquatic ecotoxicology or human toxicology. Our results were compared with data from other temperate production regions. KeywordsGreenhouse tomato production–Environmental impact–Life cycle impact assessment
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The aim of this paper is to investigate the application of solid oxide fuel cell (SOFC) as the prime mover of a combined heat and power (CHP) system. In this paper, four hybrid systems are proposed to improve the performance of CHP and compare with baseline condition. Capacity design and operation strategy of hybrid systems are applied to a case study of a greenhouse located in Mahabad, Iran and optimized by using technical, economic and environmental objective functions. Levelized cost of energy (LCOE) and CO2 emission rate are considered as the objective functions. For LCOE optimization, three scenarios are considered to evaluate the impacts of future energy prices and CO2 tax. In scenario i (Regional energy prices in Iran without CO2 tax), none of the proposed hybrid systems are competitive with the baseline case and the difference between LCOEs of the best hybrid system and baseline is 2.8 ¢/kWh. In scenario ii (Regional energy prices in Iran with CO2 tax), although the difference between LCOEs decreases to 1.8 ¢/kWh, none of the proposed hybrid systems are beneficial in comparison with the baseline. In Scenario iii (world average energy prices with CO2 tax), in contrast with previous scenarios, optimized LCOEs of two hybrid systems (11.15 and 11.4 ¢/kWh) are lower than baseline LCOE (17.56 ¢/kWh). From CO2 emission point of view, all of the proposed optimized hybrid systems have lower CO2 emission than baseline. Finally, a multi-objective optimization is done to consider both techno-economic and environmental objective functions simultaneously and provide a powerful decision support tool. The results show that yearly CO2 emission of SOFC base CHP hybrid systems are averagely 62% lower than conventional systems. Moreover, they would be economically beneficial in the case of increasing energy prices and environmental limitations.
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Almeria (Spain) is one of the most important agricultural centers of vegetable cultivation in Europe. The search for technological innovation has led to the introduction of climate control systems in greenhouses in Almeria to improve productivity during the cold season. Up to now, no studies have analyzed the energy behavior of introducing this technology in this specific region. The objective of the present study is therefore to analyze the energy use and carbon footprint (CF) of the tomato production in heated multi-tunnel greenhouses in Almeria from a life cycle perspective (cradle to regional distribution center approach). The results obtained show that the introduction of heating systems in multi-tunnel greenhouses in Almeria allowed for an increase in the annual productivity per hectare and kilogram below the increment in cumulative energy demand (CED). The on-farm CED and CF were estimated at, respectively, 13.4 MJ and 0.92 kg CO2-eq kg⁻¹ of gross production. The impacts were thus 3.3 and 2.75 times higher than those of the unheated crop. The use of energy and infrastructure (86.1%), fertilizers, and infrastructure (66.9%) were the main hotspots of the heated and unheated tomato crops. With regard to the marketed output and the supply chain, the CF and CED of heated tomatoes were 2.07 kg CO2-eq and 29.30 MJ kg⁻¹, with a non-renewable EROI (energy return on investment) (0.030:1) that was 48% lower than the one obtained with unheated tomatoes. On-farm production (64.1%), transport, and packing (65.9%) were, respectively, the main hotspots in the heated and unheated tomato agri-food systems. The production of heated tomatoes in Almeria may continue to be a better energy option than locally producing the crop in heated greenhouses in northern Europe, as long as other options related to the seasonal local production and changing diets are not taken into account.
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Greenhouses are widely used in the World, especially in the Mediterranean climate, to provide suitable environment in cultivation of different agricultural crops. Significant amount of energy is necessary to produce, process and distribute these crops. Various systems, including steam or hot water radiation system and hot air heater system, are being used in greenhouse heating. A ground source heat pump system, generally seen as a favorable option since it can provide both heating and cooling energy, is considered for a greenhouse in this study. The aim of this study is to evaluate a renewable energy option for the required total energy need of a greenhouse. Grid connected solar photovoltaic panels are selected to assist a ground source heat pump, and generate sufficient electrical energy for lighting. In this way, a nearly zero energy greenhouse concept is foreseen for three different agricultural products. Monthly and annual heating, cooling and lighting energy load of the greenhouse for these agricultural products were computed. The monthly average electricity generation of 66 photovoltaic panels, which cover 50% of the southern face part of the asymmetric roof, was calculated. Annual photovoltaic electricity generation was found as 21510.4 kWh. It was observed that photovoltaic electricity generation can meet 33.2–67.2% of greenhouse demand in summer operation months. Nevertheless, the coverage ratio, calculated by dividing the photovoltaic panels electricity generation to the electricity demand of the greenhouse (heating, cooling and lighting) for each crop, were very high in winter operation months. Yearly coverage ratio values were 95.7% for tomato, 86.8% for cucumber and 104.5% for lettuce. These high coverage ratio values justify the nearly zero energy concept for the considered greenhouse. Economic and environmental evaluation of the considered system were also accomplished. A simple payback time of the crop cultivations was computed between 7.0 and 7.4 years. The energy payback time of the system was found to be 4.9 years and the greenhouse gas payback time value of 5.7 years and 2.6 years were calculated, based on natural gas and coal based electricity generation, respectively.
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Greening the economy has been widely discussed as a new strategy for simultaneously reducing environmental pressures, promoting economic growth and enhancing social well-being. Indicators are one tool that can be used to describe the development of green growth. This paper presents and evaluates the process of attempting to build a set of policy-relevant key indicators of green growth for Finland. The challenges of developing a cross-scale indicator set integrating different sectors and levels of society are identified and discussed. It is argued that both the experts preparing the indicators and the potential users will benefit from a collaborative process that aims not only to build a shared awareness of the key issues of green growth but also to foster a realistic understanding of the strengths and weaknesses of the indicator approach. Key challenges include data availability, right balance between different indicator selection criteria, systemic understanding of the relationships between indicators, and the variable usage contexts of the indicators. Copyright © 2017 John Wiley & Sons, Ltd and ERP Environment
Article
The installation of PV panels on the greenhouse’s roof reduces solar radiation that passes through roof glazing and falls to the plants inside the greenhouse, affecting their lighting and therefore crop growing. In this paper, performance results of energy production and plant growing from installed PV panels on greenhouse roof, are presented. The results are obtained from a cultivation period of lettuce crop inside two greenhouses, one with fixed roof installed photovoltaics and another unit without photovoltaics. Regarding electrical output, PV panels produced 50.83 kWhm⁻² for the characteristic cultivation period of Feb-Mar-Apr, creating also a 20% greenhouse shading. Plant growing results under shading effect were satisfactory, as they were at same level with those of reference greenhouse without PV covered roof. Extending the results for three PV installation modes to one hectare greenhouse, theoretical results were calculated. The considered PV installation modes are the fixed one, with panels placed on south facing greenhouse roof and two sun tracking modes, with PV panels in rows and axis on east-west and north-south direction. The calculations showed that sun tracking PV panels produce more electricity than fixed mode and can result to solar control of the interior space of the greenhouse.
Article
The environmental impacts of strawberries have been assessed in several studies. However, these studies either present dissimilar results or only focus on single impact categories without offering a comprehensive overview of environmental impacts. We applied the product environmental footprint (PEF) methodology to broadly indicate the environmental impacts of various strawberry production systems in Germany and Estonia by 15 impact categories. Data for the 7 case studies were gathered from two farms with organic and two farms with conventional open field production systems in Estonia and from one farm with conventional open field and one farm with a polytunnel and greenhouse production system in Germany. The greenhouse production system had the highest environmental impact with a PEF of 0.0040. In the field organic production systems, the PEF was 0.0029 and 0.0028. The field conventional production systems resulted in a PEF of 0.0008, 0.0009 and 0.0002. Polytunnel PEF was 0.0006. Human toxicity cancer effects, particulate matter and human toxicity non-cancer effects resulted in the highest impact across all analysed production systems. The main contributors were electricity for cooling, heating the greenhouse and the use of agricultural machinery including fuel burning. While production stage contributed 85% of the total impact in the greenhouse, also other life cycle stages were important contributors: pre-chain resulted in 71% and 90% of impact in conventional and polytunnels, respectively, and cooling was 47% in one organic system. Environmental impact from strawberry cooling can be reduced by more efficient use of the cooling room, increasing the strawberry yield or switching from oil shale electricity to other energy sources. Greenhouse heating is the overall impact hotspot even if it based on renewable resources. A ranking of production systems based on the environmental impact is possible only if all relevant impacts are included. Future studies should aim for detailed results across a variety of impact categories and follow product category rules in defining the life cycle stages.
Article
The adaption of historic European cultivation techniques for unheated winter vegetable production has gained momentum during the last years in Austria. Studies that evaluate ecological and socio-economic sustainability-factors of these production techniques are scarce. In this study, we analyze the greenhouse gas emissions along vegetable supply chains based on a life cycle approach and investigate factors of the socio-economic system towards future market diffusion of these new-old technologies based on the Sustainability Assessment of Food and Agriculture Systems (SAFA) guidelines of the Food and Agriculture Organization (FAO). Data of the supply-chains of lettuce, spinach, scallions and red radish was collected from field trials in different climatic regions in Austria and compared to existing commercial systems in Austria and Italy. The results show, that unheated winter vegetable production is feasible. Greenhouse gas emissions of unheated vegetables are lower with 0.06 to 0.12 kg CO2 equivalent versus 0.61 to 0.64 kg CO2 equivalent per kg fresh product crops from heated systems. Due to small packaging units unheated vegetables show maxima of 0.58 kg CO2 equivalent per kg product. Heated products were outreached by two times when individual shopping trips to the farm were taken into account. Keeping salad frost-free was not found to contribute to a reduction of greenhouse gas emissions compared to conventional systems. The analysis reveals that a diffusion of unheated winter harvest systems depend primarily on 11 interdepending socio-economic factors. An innovative subsidy system and the creation of a positive image of winter harvest from unheated vegetables production together with an increased utilization rate of polytunnel areas and the consultancy for producers and processors are the most influential factors towards a sustainable market diffusion of winter harvest produce.
Article
The horticultural industry consumes increasing amounts of energy and water contributing to greenhouse gas emissions and global warming. The aim of this study was to investigate the energy flow and the environmental impact of different tomato cultivation systems when renewable energy sources are implemented in the production chain. Seven scenarios including heated greenhouses and open-field crops, in Southern and Central Europe, were examined in order to identify potentials to reduce energy costs, greenhouse gas emissions and increase water use efficiency along the cultivation phase. The environmental impact category applied in this work (carbon footprint) is related to global warming potential, which includes the basic emitted greenhouse gases contributing to climate change and uses CO2 as reference gas (CO2-equivalents). Additionally, an energy flow indicator (cumulative energy demand) and an inventory flow indicator (water use), both relevant to climate change, agriculture and energy processes were determined to assess the different scenarios. The main results showed that annual carbon footprint values varied between 0.1 and 10.1 CO2-eq/kg tomato. Annual cumulative energy demand presented values from 0.8 to 160.5 MJ/kg tomato. Water use efficiency values ranged between 25.6 and 60.0 L/kg. Hotspots for all seven scenarios were determined, with fossil fuel consumption accounting for most of the environmental impact, where applicable. Open-field tomato cultivation presented lower greenhouse gas emissions and cumulated energy demand, however water use efficiency values were smaller than in greenhouse scenarios. In greenhouse production, the use of renewable energy sources and an increased marketable yield reduced their greenhouse gas emissions drastically, even to the levels of open-field cultivation.
Article
Globally, there is a shortage of vegetables to meet the requirements of a healthy diet. Greenhouse production can help meet demand for vegetables, but under certain conditions it can be very energy intensive and unsustainable, particularly in cold climates, such as in Canada. Greenhouse producers in Ontario, Canada, which has the highest concentration of greenhouses in North America, have been actively improving the industry to reduce costs and address environmental concerns, but very little is known about the environmental sustainability of the industry. This study not only addresses the gap in life cycle environmental performance of Canadian greenhouse tomato production, it also provides a broader sustainability analysis that could be applied to other regions when considering improvements in the industry. Life cycle assessment (LCA) was used to benchmark Ontario greenhouse tomato production relative to other regions using data from 8 growers. Heating with fossil fuels contributed between 50 and 85% of the total impact for ozone depletion, global warming, smog, acidification, and respiratory effects. Using willow biomass produced in Ontario could reduce global warming impacts of tomato production by 72%. This solution requires approximately 50,000 ha of land to produce the biomass needed for the annual production of 165,000 t of tomatoes in this region, which is about 10 times more land than field tomato production. However, field tomatoes can be up to 50% more water intensive than greenhouse tomatoes. To mitigate these trade-offs, the industry needs to consider both growing biomass on degraded land and industrial symbiosis to recover wastes so that appropriate strategies are implemented to provide environmentally and economically sustainable vegetables. LCA combined with an evaluation of local factors, such as land resources and waste availability for industrial symbiosis, provides a stronger sustainability assessment of trade-offs and opportunities in greenhouse vegetable production.
Article
Jerome believed that the task of the commentator was to convey what others have said, not to advance his own interpretations. However, an examination of his commentaries on the Prophets shows that their contents are arranged so as to construct a powerful, but tacit, position of authority for their compiler. By juxtaposing Jewish and Greek Christian interpretations as he does, Jerome places himself in the position of arbiter over both exegetical traditions. But because he does not explicitly assert his own authority, he can maintain a stance of humility appropriate for a monk. Here, Jerome may have been a more authentic representative of the tradition of Origen than was his rival, for all that he was willing to abjure Origen's theology.
Article
Between 1998 and 2003, the company Ecofys from Utrecht developed and tested a new concept of an integrated climate and energy system that permits permanently closing the ventilation windows of a greenhouse. The technical concept consists of a combined heat and power unit, heat pump, underground (aquifer) seasonal energy storage as well as daytime storage, air treatment units, and air distribution ducts. Active air circulation is one of the key elements for controlling the climate (T, RH, CO2) at crop level. This paper discusses the technical aspects and the results of a trial using a fully closed 1400 m2 demonstration greenhouse for tomato production. Results showed: 1) reduction in primary energy (fossil fuel) use of 20 and 35% respectively for an "island" closed greenhouse and a closed-conventional combination greenhouse, 2) increase in tomato yield of 20%, 3) an 80% reduction in chemical crop protection, and 4) a 50% reduction in use of irrigation water. The energy efficiency was improved by 50%. Finally, some preliminary environmental data will be shown for the first 14,000 m2 of closed greenhouse installed at a commercial greenhouse operation. The concept of a fully closed greenhouse will be discussed in relation to sustainable greenhouse production.
Article
According to the IPCC, societies can respond to climate changes by adapting to its impacts and by mitigation, that is, by reducing GHG emissions. No single technology can provide all of the mitigation potential in any sector, but many technologies have been acknowledged in being able to contribute to such potential. Among the technologies that can contribute in such potential, Thermal Energy Storage (TES) is not included explicitly, but implicitly as part of technologies such as energy supply, buildings, and industry. To enable a more detailed assessment of the CO2 mitigation potential of TES across many sectors, the group Annex 25 “Surplus heat management using advanced TES for CO2 mitigation” of the Energy Conservation through Energy Storage Implementing Agreement (ECES IA) of the International Energy Agency (AEI) present in this article the CO2 mitigation potential of different case studies with integrated TES. This potential is shown using operational and embodied CO2 parameters. Results are difficult to compare since TES is always designed in relation to its application, and each technology impacts the energy system as a whole to different extents. The applications analyzed for operational CO2 are refrigeration, solar power plants, mobile heat storage in industrial waste heat recovery, passive systems in buildings, ATES for a supermarket, greenhouse applications, and dishwasher with zeolite in Germany. The paper shows that the reason for mitigation is different in each application, from energy savings to larger solar share or lowering energy consumption from appliances. The mitigation potential dues to integrated TES is quantified in kg/MW h energy produced or heat delivered. Embodied CO2 in two TES case studies is presented, buildings and solar power plants.
Article
The water and carbon footprint of the presented dried tomato value chain is compared to the conventional process. The coupling of pre- and post-harvest processes, namely growing and drying respectively, is analyzed for resource consumption optimization. The growing system of tomatoes (Solanum lycopersicon L. cv, Pannovy) in an energy efficient greenhouse (operating as a solar thermal collector) is databased; while the post-harvest process consists of a model-based solar drying system. The thermodynamic operation zones (temperature, humidity and enthalpy) are detailed to apply energy interaction between both processes. The results of the monthly record of a season show that the water footprint was reduced from 91 to 51.1 L kg-1 with a standard deviation from 53.2 to 12.4 L kg-1. The carbon footprint was reduced from 40.2 to 11 kg kg-1 with a standard deviation from 23.9 to 11.4 kg carbon dioxide kg-1. From the observed variation from monthly values, the relevance of the seasonal effect on resources needed for implementing process improvements is highlighted. The use of renewable energy and energy efficiency concepts is shown to have a positive impact when applied at industrial level in 'compound industries' that share sub-processes in the value chains. http://www.sciencedirect.com/science/article/pii/S0959652615005405
Article
This study reports on the carbon, water, and energy footprints of tomatoes grown in a greenhouse in Northern Italy and two possible future variations of heating and carbon dioxide (CO2) fertilization on the current setup. The heat supply in place, consisting of natural gas (NG) and canola oil combustion, is compared to cogeneration and incineration of municipal solid waste for heating and CO2 from industrial exhaust for fertilization. As a benchmark, the current system is also compared to a conventional system, in which heat is delivered solely based on NG. Each kilogram (kg) of fresh tomatoes (“Cuore di Bue” variety) produced in the current greenhouse emits 2.28 kg CO2 equivalents (eq) and uses 95.5 megajoules (MJ) eq energy and 122 liters (L) of water. Relative to the system in place, the carbon footprint (CF) is 57.5% and 18% higher with conventional NG heating and cogeneration and is 40% lower with waste valorization. Further, 33%, 55%, and 63% less energy and 9%, 96%, and 14% less water are used in the conventional, cogeneration, and waste valorization scenarios, respectively. This confirms that there are multiple strategies to reduce the impact of the tomato production under consideration.
Article
The commercial greenhouse has the highest demand for energy as compared to all other agricultural industry sectors. Here, energy management is important from a broad sustainability perspective. This paper presents the state-of-the-art regarding one energy management concept; the closed greenhouse integrated with thermal energy storage (TES) technology. This concept is an innovation for sustainable energy management since it is designed to maximize the utilization of solar energy through seasonal storage. In a fully closed greenhouse, there is no ventilation which means that excess sensible and latent heat must be removed. Then, this heat can be stored using seasonal and/or daily TES technology, and used later in order to satisfy the heating demand of the greenhouse. This assessment shows that closed greenhouse can, in addition to satisfying its own heating demand, also supply the demand for neighboring buildings. Several energy potential studies show that summer excess heat of almost three times the annual heating demand of the greenhouse. However, many studies propose the use of some auxiliary system for peak load. Also, the assessment clearly point out that a combination of seasonal and short-term TES must be further explored to make use of the full potential. Although higher amount of solar energy can be harvested in a fully closed greenhouse, in reality a semi-closed greenhouse concept may be more applicable. There, a large part of the available excess heat will be stored, but the benefits of an integrated forced-ventilation system are introduced in order to use fresh air as a rapid response for primarily humidity control. The main conclusion from this review is that aspects like energy efficiency, environmental benefits and economics must be further examined since this is seldom presented in the literature. Also, a variety of energy management scenarios may be employed depending on the most prioritized aspect.
Article
The environmental impact of the water consumption of four typical crop rotations grown in Spain, including energy crops, was analyzed and compared against Spanish agricultural and natural reference situations. The life cycle assessment (LCA) methodology was used for the assessment of the potential environmental impact of blue water (withdrawal from water bodies) and green water (uptake of soil moisture) consumption. The latter has so far been disregarded in LCA. To account for green water, two approaches have been applied: the first accounts for the difference in green water demand of the crops and a reference situation. The second is a green water scarcity index, which measures the fraction of the soil‐water plant consumption to the available green water. Our results show that, if the aim is to minimize the environmental impacts of water consumption, the energy crop rotations assessed in this study were most suitable in basins in the northeast of Spain. In contrast, the energy crops grown in basins in the southeast of Spain were associated with the greatest environmental impacts. Further research into the integration of quantitative green water assessment in LCA is crucial in studies of systems with a high dependence on green water resources.
Article
In this study we analysed the environmental and economic profile of current agricultural practices for greenhouse crops, in cold and warm climates in Europe, using four scenarios as reference systems: tomato crop in a plastic greenhouse in Spain, and in glasshouses in Hungary and the Netherlands, and rose crop in a glasshouse in the Netherlands. This study is in the context of the EUPHOROS project “Efficient Use of Inputs in Protected Horticulture”. The aim of EUPHOROS project is to improve horticultural production systems in Europe by developing cleaner production alternatives from both an environmental and economic point of view. The methodologies selected for the study were Life Cycle Assessment for the environmental analysis and cost-benefit analysis for the economic assessment. Dutch reference systems used a combined heat and power (CHP) system for the production of thermal energy and electricity. Two approaches were used to study the multifunctionality of CHP: system expansion and energy allocation. The main environmental burdens in the four scenarios were energy consumption, greenhouse structure and fertilizers. Environmental impacts due to energy consumption can be reduced by using co-generation or geothermal water in glasshouses. The structure contribution can be decreased with the improvement of recycled materials and design. Adjustment of fertilizer doses and closed irrigation systems are recommended in Spain and Hungary. The best economic perspectives to reduce inputs are energy savings in glasshouses and reduction of fertilizers in Spain and Hungary. The study shows the importance of including economic and environmental aspects in sustainability studies.
Article
A greenhouse energy and climate model (HortiAlmería) based on the Horticern greenhouse energy model developed by Jolliet et al. (1991) and which includes the treatment of humidity and transpiration used in the Hortitrans model (Jolliet, 1994) was used to design an model a novel system for heating and cooling a semi-closed greenhouse compartment (160 m2) based on fine wire heat exchangers and water storage. Calculations were performed for winter time and two different hypotheses were studied: single energy store without heat pump, heat pump with hot and cold energy stores. Some of the most important aspects analysed were the influence of energy store capacity on heat demand of experimental greenhouse with single energy store, the heat store capacity for different types of heat pumps, the increase in net CO2 assimilated with increasing energy store capacity, increased photosynthesis permitted by partial closure of the greenhouse, the influence of greenhouse light transmission and air tightness on profit from CO2 enrichment, a study of the number of heat exchanger units necessary to achieve the desired conditions. To maintain and enhance thermal stratification in a single thermal store, water has to be added and removed a way that minimises disturbances. This requires two diffusers, one to withdraw cold water from the bottom of the store and the other to introduce warm water at the top. The diffusers should permit a uniform flow across the entire horizontal plan area of the store. A design of such diffusers is presented in the paper.
Article
Multiple web-based calculators have come on the market as tools to support sustainable decision making, but few are available to agriculture. Life cycle assessment (LCA) has proved to be an objective, transparent tool for calculating environmental impacts throughout the life cycle of products and services, but can often be too complex for non-specialists. The objective of this study was therefore to develop an environmental support tool to determine the environmental impacts of protected crops. An effort was made to provide an easy-to-use tool in order to reach a wide audience and help horticulture stakeholders choose efficient options to mitigate the environmental impacts of protected crops. Users can estimate the environmental performance of their crops by entering a limited amount of data and following a few easy steps. A questionnaire must be answered with data on the crop, greenhouse dimensions, substrate, waste management, and the consumption of water, energy, fertilisers and pesticides. The calculator was designed as a simplified LCA, based on two scenarios analysed in detail in previous tasks of the EUPHOROS project and used as reference systems in this study. Two spreadsheets were provided based on these reference scenarios: one for a tomato crop in a multi-tunnel greenhouse under Southern European climate conditions and the other for a tomato crop in a Venlo glass greenhouse under Central European climate conditions. The selected functional unit was one tonne of tomatoes. Default data were given for each reference system for users who did not have complete specific data and to provide results for comparison with users' own results.
Article
If the aim of an LCA is to support decisions or to generate and evaluate ideas for future decisions, the allocation procedure should generally be effect-oriented rather than cause-oriented. It is important that the procedure be acceptable to decision makers expected to use the LCA results. It is also an advantage if the procedure is easy to apply. Applicability appears to be in conflict with accurate reflection of effect-oriented causalities. To make LCA a more efficient tool for decision support, a range of feasible allocation procedures that reflect the consequences of inflows and outflows of cascade materials is required.
Article
Nitrate pollution due to excessive N fertirrigation in greenhouse tomato production is a persisting environmental concern in the Mediterranean region. Driven by productivity rather than sustainability, growers continue to use very high N concentrations of more than 11 mM in greenhouse tomato production. A greenhouse study was conducted in Barcelona, Spain, over two growing seasons to analyze the effect of N concentrations from 5 mM to 11 mM (control) on tomato yield and physical quality. The relative environmental impact was calculated by using the life cycle assessment method (LCA). Our results show that N concentration in the nutrient solution can be reduced from 11 mM (control) to 7 mM under a daily mean drainage volume of 30%. This finding implies a 70% decrease in nitrate leaching without reducing tomato yield or quality. According to life cycle assessment, a reduction of 36% in N fertilizers leads to a 60% decrease in the potential impact of eutrophication, 50% decrease in the potential impact of climate change, and 45% decrease in the potential impact of photochemical oxidants. Lycopersicon esculentum L.–water-use efficiency–LCA–hydroponics
Article
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.
Article
A greenhouse cooling system with heat storage for completely closed greenhouses has been designed, based on the use of a fine wire heat exchanger. The performance of the fine wire heat exchangers was tested under laboratory conditions and in a small greenhouse compartment. The effects of the system on the environmental conditions (temperature and humidity distribution) in the greenhouse were simulated to decide on the final lay out of the system. Finally the system was implemented on a large scale in a pot plant greenhouse complex of 2500 m². The system is being tested under practical conditions and compared to a traditional heating and ventilation system in a comparable reference compartment of 2500 m². This paper describes the set up of the greenhouse system, the first simulation results achieved with the system with respect to environmental conditions and energy use.
2006 IPCC guidelines for national greenhouse gas inventories. Prepared by the national greenhouse gas inventories programme
IPCC. (2006). In H. S. Eggleston, L. Buendia, K. Miwa, T. Ngara, & K. Tanabe (Eds.), 2006 IPCC guidelines for national greenhouse gas inventories. Prepared by the national greenhouse gas inventories programme. Japan: IGES. Retrieved from https://www.ipccnggip.iges.or.jp/public/2006gl/.
Prozessorientierte basisdaten fü r umweltmanagementinstrumente (PROBAS)
ProBas. (2018). Prozessorientierte basisdaten fü r umweltmanagementinstrumente (PROBAS). Retrieved November 25, 2018, from http://www.probas.umweltbundesamt.de/php/index.php.
Guideline VDI 4600 Cumulative energy demand (KEA). Terms, defenitions, methods of calculation
  • Verein Deutscher Ingenieure
Verein Deutscher Ingenieure (VDI). (2012). Guideline VDI 4600 Cumulative energy demand (KEA). Terms, defenitions, methods of calculation. Beuth Verlag GmbH. Retrieved from https://www. vdi.eu/uploads/tx_vdirili/pdf/1807038.pdf.