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Κυριακή 17 Νοεμβρίου 2019

The 9th International Conference on Life Cycle Management 2019—Poznań, Poland, 1-4 September 2019 (www.lcm2019.org)

Integrating life cycle assessment (LCA) and life cycle costing (LCC) in the early phases of aircraft structural design: an elevator case study

Abstract

Purpose

The main objective of this paper is to develop a model that will combine economic and environmental assessment tools to support the composite material selection of aircraft structures in the early phases of design and application of the tool for an aircraft elevator.

Methods

An integrated life cycle cost (LCC) and life cycle assessment (LCA) methodology was used as part of the sustainable design approach for the laminate stacking sequence design. The model considered is the aircraft structure made of carbon fiber reinforce plastic prepreg and processed via hand layup-autoclave process which is the preferred method for the aircraft industry. The model was applied to a cargo aircraft elevator case study by comparing six different laminate configurations and two different carbon fiber prepreg materials across aircraft’s entire life cycle.

Results and discussion

The results show, in line with other studies using different methodologies (e.g., life cycle engineering, or LCE), that the combination of LCA with LCC is a worthwhile approach for comparing the different laminate configurations in terms of cost and environmental impact to support composite laminate stacking design by providing the best trade-off between cost and environment. Elevator LCC reduces 19% by changing the material type and applying different ply orientations. Elevator LCA score reduces 53% by selecting the optimum instead of best technical solution that minimizes the displacement. Improving the structural performance does not always lead to an increase in the cost.

Reviewing the potential for including habitat fragmentation to improve life cycle impact assessments for land use impacts on biodiversity

Abstract

Purpose

The biosphere is progressively subjected to a variety of pressures resulting from anthropogenic activities. Habitat conversion, resulting from anthropogenic land use, is considered the dominant factor driving terrestrial biodiversity loss. Hence, adequate modelling of land use impacts on biodiversity in decision-support tools, like life cycle assessment (LCA), is a priority. State-of-the-art life cycle impact assessment (LCIA) characterisation models for land use impacts on biodiversity translate natural habitat transformation and occupation into biodiversity impacts. However, the currently available models predominantly focus on total habitat loss and ignore the spatial configuration of the landscape. That is, habitat fragmentation effects are ignored in current LCIAs with the exception of one recently developed method.

Methods

Here, we review how habitat fragmentation may affect biodiversity. In addition, we investigate how land use impacts on biodiversity are currently modelled in LCIA and how missing fragmentation impacts can influence the LCIA model results. Finally, we discuss fragmentation literature to evaluate possible methods to include habitat fragmentation into advanced characterisation models.

Results and discussion

We found support in available ecological literature for the notion that habitat fragmentation is a relevant factor when assessing biodiversity loss. Moreover, there are models that capture fragmentation effects on biodiversity that have the potential to be incorporated into current LCIA characterisation models.

Conclusions and recommendations

To enhance the credibility of LCA biodiversity assessments, we suggest that available fragmentation models are adapted, expanded and subsequently incorporated into advanced LCIA characterisation models and promote further efforts to capture the remaining fragmentation effects in LCIA characterisation models.

Operationalisation and application of water supply mix (WSmix) at worldwide scale: how does WSmix influence the environmental profile of water supply for different users?

Abstract

Purpose

A worldwide-regionalized water supply mix (WSmix) has been developed for use in life cycle assessment (LCA) studies. The WSmix is the combination of water sources and water technologies to meet a water user need at a specific time (season, month) and location. A global database has been computed to collect information on water sources and users at country and river basin scales. However, its application to LCA case studies at different locations and for different users has not yet been fully tested and analysed. The aim of this study is to operationalise WSmix for application in LCA and to test the added value and usability of WSmix by applying it worldwide to two different systems, a service and a global product, considering different climatic and socio-economic conditions.

Methods

The WSmix is applied to two main water users, the results are analysed, and the variability of the WSmix for 91 countries with different socio-economic conditions is discussed. Some examples of the variability of the water sources mix (WOmix) and the temporal variation at river basin scale are presented.

Results and discussion

The results show that the WSmix has a great influence on the environmental profile of water supply for different users considering different climatic and socio-economic conditions. Moreover, the interdependence between water and energy (i.e. water-energy nexus) is clearly established, which reinforces the importance to link a regionalized WSmix with national/regionalized electricity mix.

Conclusions

In conclusion, the WSmix has been operationalised and applied in LCI databases. Its added value and usability has been demonstrated by applying it at a worldwide scale for two different users. Methodological developments are still required to increase its spatiotemporal resolution, and LCIA methods need to be improved to better consider its different components (including water sources).

Prioritizing regionalization efforts in life cycle assessment through global sensitivity analysis: a sector meta-analysis based on ecoinvent v3

Abstract

Purpose

Regionalization in life cycle assessment (LCA) aims to increase the representativeness of LCA results and reduce the uncertainty due to spatial variability. It may refer to adapting processes to better account for regional technological specificities (inventory regionalization) or adding of spatial information to the elementary flows (inventory spatialization) which allow using more regionalized characterization factors. However, developing and integrating regionalization requires additional efforts for LCA practitioners and database developers that must be prioritized.

Methods

We propose a stepwise methodology for LCA practitioners to prioritize data collection for regionalization based on global sensitivity analysis (GSA) using Sobol indices. It involves several GSA to select the impact categories (ICs) that require further inventory data collection (IC ranking), prioritize between inventory regionalization and inventory spatialization (LCA phase ranking), and target specific data to collect. Then we propose a method to derive sector-specific recommendations using statistical tests to prioritize inventory regionalization versus spatialization and the ICs on which to focus inventory data collection. These recommendations are meant to help LCA practitioners and database developers define their strategy for regional data collection by focusing on data that have the highest potential to reduce the uncertainty of the results.

Results and discussion

The applicability of the methodology is illustrated through three case studies using the ecoinvent v3 database and the regionalized impact methodology IMPACT World+: one on prioritizing data collection in a single biofuel product system and two meta-analyses of all product systems in two distinct economic sectors (biofuel production and land passenger transport). Recommendations for regionalization can be derived for an economic sector and appear to be different from one economic sector to another. GSA seems to be more relevant to prioritize regionalization efforts than an impact contribution analysis (ICA) approach often used to prioritize data collection in LCA. However, further improvements, such as accounting for spatial correlations and better computational times for GSA, are required to implement it in LCA.

Conclusions

We recommend using the methodology based on GSA to efficiently prioritize regionalization efforts between ICs and between inventory regionalization and inventory spatialization. We proved that the implementation of IC ranking and LCA phase ranking is computationally feasible and therefore invite current LCA software providers to unlock this new horizon in LCA interpretation. We also invite to expand the meta-analysis to all sectors in an LCA database.

Comparative life cycle assessment of metal arc welding technologies by using engineering design documentation

Abstract

Purpose

The paper aims to analyze and compare the environmental performances of metal arc welding technologies: gas metal arc welding (GMAW), shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW), submerged arc welding (SAW), and flux-cored arc welding (FCAW). Welding is considered one of the most energy-intensive processes in manufacturing. This study was performed in accordance with the international standard ISO 14040/14044 by using attributional life cycle assessment (aLCA).

Methods

The functional unit is defined as the “the development of 1 metre of welding seam (qualified by ASME section IX requirements) to join 25 millimetres thick of metal plates made in carbon steel material and considering a V-bevel configuration.” Different configurations of base/filler materials and standardized bevel geometries have been analyzed as welding scenarios. The inventory considers all inputs (e.g., electric energy and filler material) and outputs (e.g., fume emissions and slags) involved in each welding process. A framework for data collection starting from available project documentation is presented as an innovative solution for the inventory phase. The impact assessment includes the human health, resources (midpoints/endpoint), and ecosystems (endpoint) categories from the ReCiPe (H) and cumulative energy demand (CED) methods.

Results and discussion

This study reveals a notable dominance in terms of the environmental burdens of GTAW and SMAW processes, as they present higher impacts in most of the impact categories. SMAW is the most energy-consuming process, and this aspect is reflected in the environmental performance. Conversely, GMAW presents the least environmental load, accounting for less than one third compared with GTAW in terms of the CED indicator and performing very well in terms of the ReCiPe endpoint indicator. Via analysis of different scenarios, the main outcomes are the following: (i) the use of V bevels significantly increases the environmental load when the metal plate thickness increases and (ii) the use of specific materials such as Inconel alloy exacerbates the environmental concerns associated with welding processes.

Conclusions

The use of project documentation allows robust analysis of welding activity. Sensitivity analysis shows how the range of values for specific parameters (e.g., volts and amps) affects each technology in a different manner. Indeed, those ranges have a limited impact on the result accuracy (up to 20%) for more automatized welding processes (e.g., GMAW, SAW, and FCAW), in which only a small number of parameters are set by the operator, and the operator skills are less influential on the quality of the weld.

Prospective cost and environmental impact assessment of battery and fuel cell electric vehicles in Germany

Abstract

Purpose

The goal of this study was to provide a holistic, reliable, and transparent comparison of battery electric vehicles (BEVs) and fuel cell electric vehicles (FCVs) regarding their environmental impacts (EI) and costs over their whole life cycle. The comprehensive knowledge about EI and costs forms the basis on which to decide which technology should be favored for the future of mobility.

Methods

Therefore, a holistic and transparent comparative life cycle assessment (LCA), using the ReCiPe 2016 method, and a life cycle costing were conducted. Special attention was paid to the fuel supply infrastructure for BEV and FCV as these have not been sufficiently considered in previous research. The required infrastructure was calculated for six million electric vehicles (EVs) and the EI and costs were allocated proportional on the functional unit of 1 km driven with an EV. Different scenarios regarding electricity mix, range of the BEV, and vehicle lifetime were calculated. In order to ensure transparency, all inventories and calculations were published in the attached Electronic supplementary material (ESM).

Results and discussion

Detailed results were presented for the impact categories global warming potential (GWP), human toxicity potential non-carcinogenic (HTPnc), surplus ore potential (SOP), and particulate matter formation potential (PMFP). Aggregated results for all midpoint impact categories of the ReCiPe method can be found in the ESM. It was shown that BEVs achieve lower EI than FCVs in most impact categories (e.g., GWP: BEV: 1.40E-01, FCV: 1.68E-01 kg CO2-eq./km) and that the total costs of ownership are as well lower for BEVs (68,900 € vs. 130,100 €). Further, it was found that the fuel supply infrastructure—without electricity supply—contributes a considerable amount to the overall impact per kilometer driven (e.g., 3.7% and 3.3% of the GWP for BEV and FCV, respectively).

Conclusions

Considering mid-size vehicles like the VW e-Golf, it was concluded that BEVs have today a better environmental and financial performance than FCVs. However, the range of the BEV is lower than the range of the FCV (200 vs. 530 km) and both technologies have different stages of maturity. Moreover, the study showed that the fuel supply infrastructure is an important contributor to the overall life cycle impacts and that it is therefore indispensable to include the infrastructure in LCA of electric vehicles. Based on the results, recommendations to utilize the advantage of both BEV (high energy efficiency, lower costs) and FCV (long-distance capability) were made.

Water footprint inventory database of Thai rice farming for water policy decisions and water scarcity footprint label

Abstract

Purpose

Rice is a major economic crop which has created local livelihood, careers and incomes in the agricultural sector in Thailand, one of the leading rice producers at global scale. Rice is a key commodity in the agriculture sector requiring the highest portion of water demand, around 40% out of the total sector demand of 65%. This study was aimed to develop the water footprint database of rice farming at the national level to support the information for area-based water management and water footprint label based on the methodology described in ISO14046.

Methods

The water footprint inventory data associated with the 8 main cultivated rice species were gathered in accordance with the ISO 14046 Water Footprint. The statistical data of rice cultivation area and production in 2016 were used as the basis for sampling to cover 62% of the national annual production with a 90% confidence interval. Eight rice species were sampled by simple random sampling method, covering 62% of the national annual production with a 90% confidence interval. The total number of samples was 817, covering 114 samples of Khao Dok Mali 105, 103 samples of Pathumthani 1, 103 samples of Phitsanulok 2, 112 samples of RD41, 112 samples of Chainat 1, 103 samples of RD6, 70 samples of San Pah Tawng 1 and 100 samples of riceberry.

Results and discussion

The study found that the rice cultivation in Thailand had an average water footprint inventory of 1665 m3/t and a water scarcity footprint of 334 m3H2Oe/t paddy rice. One hectare of rice cultivation normally required water around 6340 m3/ha on the average. The results showed that Khao Dok Mali 105 has the highest water scarcity (598 m3H2Oe/t paddy rice) as the Northeastern area where it is cultivated, has the highest water stress index. This was followed by RD6, Riceberry, Phitsanulok 2, Pathumthani 1, San Pah Tawng 1 and RD41. Chainat 1 species has the lowest water scarcity footprint (220 m3H2Oe/t paddy rice).

Conclusions

The replacement of rice with sugarcane/cassava could potentially reduce the water scarcity footprint by more than half. The shifting of cultivation period when the average rainfall was higher could slightly decrease the amount of total water requirements, whereas the implementation of alternate wet and dry farming system instead of continual flooding system would moderately reduce the amount of total water requirements. It is expected to use the water footprint national database for more effective water resource management for rice cultivation and to support the decisions on national water policy and the implementation of water scarcity footprint label.

Computer vision for LCA foreground modelling—an initial pipeline and proof of concept software, lcopt-cv

Abstract

Purpose

The majority of LCA studies begin with the drawing of a process flow diagram, which then needs to be translated manually into an LCA model. This study presents an initial image processing pipeline, implemented in an open-source software package, called lcopt-cv, which can be used to identify the boxes and links in a photograph of a hand-drawn process flow diagram and automatically create an LCA foreground model.

Methods

The computer vision pipeline consists of a total of 15 steps, beginning with loading the image file and conversion to greyscale. The background is equalised, then the foreground of the image is extracted from the background using thresholding. The lines are then dilated and closed to account for drawing errors. Contours in the image are detected and simplified, and rectangles (contours with four corners) are identified from the simplified contours as ‘boxes’. Links between these boxes are identified using a flood-filling technique. Heuristic processing, based on knowledge of common practice in drawing of process flow diagrams, is then performed to more accurately identify the typology of the identified boxes and the direction of the links between them.

Results and discussion

The performance of the image processing pipeline was tested on four flow diagrams of increasing difficulty: one simple computer drawn diagram and three photographs of hand-drawn diagrams (a simple diagram, a complex diagram and a diagram with merged lines). A set of default values for the variables which define the pipeline was developed through trial and error. For the two simple flow charts, all boxes and links were identified using the default settings. The complex diagram required minor tweaks to the default values to detect all boxes and links. An ‘unstacking’ heuristic allowed the diagram with merged lines to be correctly processed. After some manual reclassification of link directions and process types, the diagrams were turned into LCA models and exported to open-source LCA software packages (lcopt and Brightway) to be verified and analysed.

Conclusions

This study demonstrates that it is possible to generate a fully functional LCA model from a picture of a flow chart. This has potentially important implications not only for LCA practitioners as a whole, but in particular for the teaching of LCA. Skipping the steep learning curve required by most LCA software packages allows teachers to focus on important LCA concepts, while participants maintain the benefits of experiential learning by doing a ‘real’ LCA.

Environmental benchmarks for buildings: needs, challenges and solutions—71st LCA forum, Swiss Federal Institute of Technology, Zürich, 18 June 2019

Abstract

Purpose

The 71st LCA forum was held on 18 June 2019 in Zurich, Switzerland, to discuss the current status and future plans of environmental benchmarking for buildings in view of the 1.5 °C target stipulated in the Paris Agreement. The Paris Agreement requires a significant reduction in greenhouse gas emissions, in fact net zero by 2050. One of the priority areas is the building stock, as it is an important source of greenhouse gas emissions. COP23, the International Energy Agency (IEA) and an increasing number of countries are extending their consideration from aspects such as energy consumption and emissions from building operation to the manufacture of construction materials and building construction. The event offered an excellent platform to exchange ideas and thoughts on existing and planned environmental benchmarking schemes for buildings.

Methods

The one day event dealt at first with life cycle assessment (LCA) approaches applied in European, Asian, Australasian and American countries to assess the environmental performance of buildings. Within a round robin test, organised within the IEA EBC (Energy in Building and Communities) Annex 72 project, 22 organisations from 21 countries assessed the environmental performance of one identical building, the be2226 office building located in Lustenau, Austria. The materials, the building technologies and the energy consumption were kept constant. This allowed to identify the main differences in LCA data used and LCA methodology applied in the national contexts. In the LCA forum, eight organisations presented the current state or future plans of an environmental benchmarking system in their home country. The systems were characterised in terms of scope, in particular (a) which types of buildings are covered; (b) which life cycle stages are included; (c) which building elements and which operational energy uses are considered; and (d) which environmental impacts are addressed. Furthermore, the default reference service life and the main source of LCA data were specified and the current or planned benchmark values for greenhouse gas emissions of residential buildings were reported.

Results and discussion

The round robin test revealed the LCA background data as one major source of difference in assessment results. Methodological and modelling choices were less important except for the Danish assessment, which applies a comparatively long reference study period (80 years for office buildings, 120 years for residential buildings) and considering future changes in the electricity mix towards 100% renewables to describe the operational electricity demand during the lifetime of the building. Most benchmarking systems presented are applied on new and retrofit residential, office and school buildings. Other use types such as shops, restaurants, universities or hospitals are covered only in few or just one country. The greenhouse gas emission benchmark for residential buildings (construction and operation) revealed a significant gap between the current level of the building benchmarks on one hand and the target of net zero CO2-eq emissions derived from the 1.5 °C scenarios of IPCC on the other. An online inquiry carried out among the audience during the event showed a preference for a per capita overall budget of 500 kg CO2-eq per year to derive greenhouse gas emission benchmarks for buildings and that life cycle-based benchmarks for buildings should be legally binding.

Conclusions

The 71st LCA forum on environmental benchmarks for buildings showed that the experts present acknowledge the net zero CO2 emission target derived from the 1.5 °C scenarios. Several countries have expertise and experience in assessing the environmental impacts of buildings. However, the current (mostly voluntary) benchmarking schemes are way too weak to support the building sector in contributing significantly to the required CO2 emission turn off. The outlook given by several speakers showed that the current benchmarks will likely be tightened and oriented on the planetary boundaries and on the scientifically defined CO2 emission budgets rather than on the technical or economic feasibility. Finally, the responsibility of governments for defining environmental requirements and targets was stressed. The event, the exchange of ideas and the discussions helped to nurture and hopefully accelerate the developments in the construction sector of the home countries of the experts and government representatives. These developments will contribute to a society whose environmental impacts remain within the carrying capacity of our planet.

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