Methods for uncertainty propagation in life cycle assessment
Groen, E.A. ; Heijungs, R. ; Bokkers, E.A.M. ; Boer, I.J.M. de - \ 2014
Environmental Modelling & Software 62 (2014). - ISSN 1364-8152 - p. 316 - 325.
sensitivity-analysis - decision-making - lca - model - input - simulation - inventory - output
Life cycle assessment (LCA) calculates the environmental impact of a product over its entire life cycle. Uncertainty analysis is an important aspect in LCA, and is usually performed using Monte Carlo sampling. In this study, Monte Carlo sampling, Latin hypercube sampling, quasi Monte Carlo sampling, analytical uncertainty propagation and fuzzy interval arithmetic were compared based on e.g. convergence rate and output statistics. Each method was tested on three LCA case studies, which differed in size and behaviour. Uncertainty propagation in LCA using a sampling method leads to more (directly) usable information compared to fuzzy interval arithmetic or analytical uncertainty propagation. Latin hypercube and quasi Monte Carlo sampling provide more accuracy in determining the sample mean than Monte Carlo sampling and can even converge faster than Monte Carlo sampling for some of the case studies discussed in this paper.
Reducing the impact of irrigated crops on freshwater availability: the case of Brazilian yellow melons
Brito de Figueirêdo, M.C. ; Boer, I.J.M. de; Kroeze, C. ; Silva Barros, V. da; Sousa, J.A. de; Souza de Aragão, F.A. ; Sonsol Gondim, R. ; Potting, J. - \ 2014
The International Journal of Life Cycle Assessment 19 (2014)2. - ISSN 0948-3349 - p. 437 - 448.
environmental impacts - lca - l. - consumption - products - quality - yield
Purpose This study quantifies freshwater consumption throughout the life cycle of Brazilian exported yellow melons and assesses the resulting impact on freshwater availability. Results are used to identify improvement options. Moreover, the study explores the further impact of variations in irrigation volume, yield, and production location. Methods The product system boundary encompasses production of seeds, seedlings, and melon plants; melon packing; disposal of solid farm waste; and farm input and melon transportation to European ports. The primary data in the study were collected from farmers in order to quantify freshwater consumption related to packing and to production of seeds, seedlings, and melons. Open-field melon irrigation was also estimated, considering the region's climate and soil characteristics. Estimated and current water consumptions were compared in order to identify impact reduction opportunities. Sensitivity analysis was used to evaluate variations in the impact because of changes in melon field irrigation, yield, and farm location. Results and discussion This study shows that the average impact on freshwater availability of 1 kg of exported Brazilian yellow melons is 135 l H2O-e, with a range from 17 to 224 l H2O-e depending on the growing season's production period. Irrigation during plant production accounts for 98 % of this impact. Current melon field water consumption in the Low Jaguaribe and Açu region is at least 39 % higher than necessary, which affects the quality of fruits and yield. The impact of melon production in other world regions on freshwater availability may range from 0.3 l H2O-e/kg in Costa Rica to 466 l H2O-e/kg in the USA. Conclusions The impact of temporary crops, such as melons, on water availability should be presented in ranges, instead of as an average, since regional consumptive water and water stress variations occur in different growing season periods. Current and estimated water consumption for irrigation may also be compared in order to identify opportunities to achieve optimization and reduce water availability impact.
Life cycle assessment of segregating fattening pig urine and feces compared to conventional liquid manure management
Vries, J.W. de; Aarnink, A.J.A. ; Groot Koerkamp, P.W.G. ; Boer, I.J.M. de - \ 2013
Environmental Science and Technology 47 (2013)3. - ISSN 0013-936X - p. 1589 - 1597.
greenhouse-gas emissions - environmental consequences - farming systems - slurry - straw - soils - lca
Gaseous emissions from in-house storage of liquid animal manure remain a major contributor to the environmental impact of manure management. Our aim was to assess the life cycle environmental consequences and reduction potential of segregating fattening pig urine and feces with an innovative V-belt system and to compare it to conventional liquid manure management, i.e. the reference. Moreover, we aimed at analyzing uncertainty of the outcomes related to applied emission factors. We compared a reference with two scenarios: segregation with solid, aerobically, stored feces and with liquid, anaerobically, stored feces. Results showed that, compared to the reference, segregation reduced climate change (CC) up to 82%, due to lower methane emission, reduced terrestrial acidification (TA) and particulate matter formation (PMF) up to 49%, through lower ammonia emission, but increased marine eutrophication (ME) up to 11% through nitrogen oxide emission from storage and nitrate leaching after field application. Fossil fuel depletion did not change. Segregation with liquid feces revealed lower environmental impact than segregation with solid feces. Uncertainty analysis supported the conclusion that segregating fattening pig urine and feces significantly reduced CC, and additionally, segregation with liquid feces significantly reduced TA and PMF compared to the reference.
Assessing environmental impacts associated with freshwater consumption along the life cycle of animal products: the case of Dutch milk production in Noord-Brabant
Boer, I.J.M. de; Hoving, I.E. ; Vellinga, Th.V. ; Ven, G.W.J. van de; Leffelaar, P.A. ; Gerber, P.J. - \ 2013
The International Journal of Life Cycle Assessment 18 (2013)1. - ISSN 0948-3349 - p. 193 - 203.
lca - resources - footprint - land
Purpose - The assessment of water footprints of a wide range of products has increased awareness on preserving freshwater as a resource. The water footprint of a product was originally defined by Hoekstra and Hung (2002) as the sum of the volumetric water use in terms of green, blue and grey water along the entire life cycle of a product and, as such, does not determine the environmental impact associated with freshwater use. Recently, several papers were published that describe building blocks that enable assessment of the site-specific environmental impact associated with freshwater use along the life cycle of a global food chain, such as the impact on human health (HH), ecosystem quality (EQ) or resource depletion (RD). We integrated this knowledge to enable an assessment of the environmental impact associated with freshwater use along the life cycle of milk production, as a case for a global food chain. Material and methods - Our approach innovatively combined knowledge about the main impact pathways of freshwater use in life cycle assessment (LCA), knowledge about site-specific freshwater impacts and knowledge about modelling of irrigation requirements of global feed crops to assess freshwater impacts along the life cycle of milk production. We evaluated a Dutch model farm situated on loamy sand in the province of Noord-Brabant, where grass and maize land is commonly irrigated. Results and discussion - Production of 1 kg of fat-and-protein corrected milk (FPCM) on the model farm in Noord-Brabant required 66 L of consumptive water. About 76 % of this water was used for irrigation during roughage cultivation, 15 % for production of concentrates and 8 % for drinking and cleaning services. Consumptive water use related to production of purchased diesel, gas, electricity and fertiliser was negligible (i.e. total 1 %). Production of 1 kg of FPCM resulted in an impact on HH of 0.8¿×¿10-9 disability adjusted life years, on EQ of 12.9¿×¿10-3 m2¿×¿year and on RD of 6.7 kJ. The impact of producing this kilogram of FPCM on RD, for example, was caused mainly by cultivation of concentrate ingredients, and appeared lower than the average impact on RD of production of 1 kg of broccoli in Spain. Conclusions - Integration of existing knowledge from diverse science fields enabled an assessment of freshwater impacts along the life cycle of a global food chain, such as Dutch milk production, and appeared useful to determine its environmental hotspots. Results from this case study support earlier findings that LCA needs to go beyond simple water volume accounting when the focus is on freshwater scarcity. The approach used, however, required high-resolution inventory global data (i.e. especially regarding crop yield, soil type and root depth), and demonstrated a trade-off between scientific quality of results and applicability of the assessment method.
Assessing the greenhouse gas emissions from poultry fat biodiesel
Jorgensen, A. ; Bikker, P. ; Herrmann, I.T. - \ 2012
Journal of Cleaner Production 24 (2012). - ISSN 0959-6526 - p. 85 - 91.
life-cycle assessment - fuel - lca
This article attempts to answer the question: What will most likely happen in terms of emitted greenhouse gases if the use of poultry fat for making biodiesel used in transportation is increased? Through a well-to-wheel assessment, several different possible scenarios are assessed, showing that under average conditions, the use of poultry fat biodiesel instead of diesel leads to a slight reduction (6%) in greenhouse gas emissions. The analysis shows that poultry fat is already used for different purposes and using poultry fat for biodiesel will therefore remove the poultry fat from its original use. This implies that even though the use of biodiesel is assumed to displace petrochemical diesel, the 'original user' of the poultry fat will have to find a substitute, whose production leads to a greenhouse gas emissions comparable to what is saved through driving on poultry fat biodiesel rather than petrochemical diesel. Given that it is the production of the substitute for the poultry fat which mainly eliminates the benefit from using poultry fat for biodiesel, it is argued that whenever assessing the greenhouse gas emissions from biodiesel made from by-products (such as rendered animal fats, used cooking oil, etc.) it is very important to include the oil's alternative use in the assessment.
Life cycle assessment of intensive striped catfish farming in the Mekong Delta for screening hotspots as input to environmental policy and research agenda
Bosma, R.H. ; Pham Thi Ahn, ; Potting, J. - \ 2011
The International Journal of Life Cycle Assessment 16 (2011)9. - ISSN 0948-3349 - p. 903 - 915.
production systems - impact assessment - water-use - aquaculture - ponds - fish - lca
Purpose Intensive striped catfish production in the Mekong Delta has, in recent years, raised environmental concerns. We conducted a stakeholder-based screening life cycle assessment (LCA) of the intensive farming system to determine the critical environmental impact and their causative processes in producing striped catfish. Additional to the LCA, we assessed water use and flooding hazards in the Mekong Delta. Materials and methods The goal and scope of the LCA were defined in a stakeholder workshop. It was decided there to include all processes up to the exit-gate of the fish farm in the inventory and to focus life cycle impact assessment on global warming, acidification, eutrophication, human toxicity, and marine (MAET) and freshwater aquatic ecotoxicity (FWET). A survey was used to collect primary inventory data from 28 farms on fish grow-out, and from seven feed mills. Hatching and nursing of striped catfish fingerlings were not included in the assessment due to limited data availability and low estimated impact. Average feed composition for all farms had to be applied due to limitation of budget and data availability. Results and discussion Feed ingredient production, transport and milling dominated most of the impact categories in the LCA except for eutrophication and FWET. Most feed ingredients were produced outside Vietnam, and the impact of transport was important. Because of the screening character of this LCA, generic instead of specific inventory data were used for modelling feed ingredient production. However, the use of generic data is unlikely to have affected the main findings, given the dominance of feed production in all impact categories. Of the feed ingredients, rice bran contributed the most to global warming and acidification, while wheat bran contributed the most to eutrophication. The dominance of both was mainly due to the amounts used. Fishmeal production, transport and energy contributed the most to MAET. The biggest impacts of grow-out farming in Vietnam are on eutrophication and FWET. Water nutrient discharge from grow-out farming was high but negligible compared with the natural nutrient content of the Mekong River. The discharge from all grow-out farms together hardly modified river water quality compared with that before sector expansion. Conclusions Feed production, i.e. ingredient production and transport and milling, remains the main contributor to most impact categories. It contributes indirectly to eutrophication and FWET through the pond effluents. The environmental impact of Pangasius grow-out farming can be reduced by effectively managing sludge and by using feeds with lower feed conversion ratio and lower content of fishery products in the feed. To consider farm variability, a next LCA of aquaculture should enlist closer collaboration from several feed-milling companies and sample farms using their feeds. Future LCAs should also preferably collect specific instead of generic inventory data for feed ingredient production, and include biodiversity and primary production as impact categories.
Inventory analysis of the timber industry in Ghana
Eshun, J.F. ; Potting, J. ; Leemans, R. - \ 2010
The International Journal of Life Cycle Assessment 15 (2010)7. - ISSN 0948-3349 - p. 715 - 725.
life-cycle inventory - renewable resources - lumber production - policy - wood - lca - thinking - forest - needs