Author(s): Ramzy Kahhat Abedrabbo y otros
(Español) There is increasing interest in assessing the environmental impacts of consumer electronics using methods such as life cycle assessment (LCA) and material flow analysis (MFA). Both assessment methods depend on quantifying the materials and parts contained in these products, i.e., the bill of Attributes (BOA). While there has been significant work to develop commercial and public databases detailing material and energy flows in production processes, there have been no comparable efforts to characterize BOA. Further, such assessment is complicated by rapidly evolving production processes and product design and consumption trends. This study was undertaken to assess the degree of change in product attributes commonly used as inputs for LCA for a common consumer electronic product: laptop computers. The analysis includes (1) temporal evolution of BOA for a consistent product type over multiple generations (14.1″ laptops) and (2) variability in a fixed year within a product type (laptops of different sizes). In total, eleven laptop computers were disassembled and characterized based on function, components, and materials. In addition, the study included measurement of silicon die area for all product motherboards and thirty dynamic random access memory (DRAM) cards produced over the period 1999–2011. Results reveal trends important for assessing and designing greener consumer electronics. The fundamental dynamic is the extent technological progress is used to improve functionality versus reduce material and energy footprint. For a variety of attributes, it was found that material footprint did not change significantly over the period 1999–2008, suggesting that improvements in functionality roughly balanced efficiency gains. In particular, total mass and material shares were roughly constant over the period studied. Battery mass, hard disk drive mass, and DRAM die area all decreased per unit of functionality (kWh, GB, MB) over time, but showed roughly constant totals per year. Initial benchmarking to other electronics (netbook, tablet, smartphone) is included here, but further work is needed to determine if the observed pattern in material intensity and functionality is continued over time. This trend, if robust, is important because (1) the BOA inputs to LCA or MFA for an established form factor are surprisingly constant over time, improving temporal robustness of assessment results, and (2) one cannot assume that dematerialization will automatically lead to material and energy reductions for consumer electronics. There is a need for concerted effort from the LCA community to characterize and model BOAs. As collecting BOA data is labor intensive, heuristics can potentially play an important role to streamline analysis. The product attributes that were most consistent over time and across product class for the case study, like material composition, may be good candidates for streamlining data collection and product characterization. However, potential predictors of silicon die area tested here were highly variable and more sensitive to change over time. The most promising estimation methods were those that focused on measuring the area of the five largest integrated circuits (for all motherboards, just five chips contained as much as 30–70% of all die area) and estimating the rest using an average die area per chip ratio. However, given the uncertainty in all tested heuristics, their application to an LCA or MFA should be used with caution.
Open linkAuthor(s): Ian Vázquez Rowe y otros
(Español) Land use changes (LUCs) constitute a crucial source of environmental impact in production systems, which are mostly associated with greenhouse gas (GHG) emissions. This circumstance is especially important for the agricultural sector, since these imply an important proportion of the total GHG emissions occurring worldwide. Wine and grape production is a key sector in Spain, representing the largest surface area at European level. In the past decades, important wine related LUCs have been observed due to changes in farming methods/type, number of Denominations of Origin, and the establishment of larger wineries that have enhanced exports. The current study presents a temporally based Life Cycle Assessment (LCA) study of the Ribeiro appellation in NW Spain, in which the gradual changes in the land use, as well as the technological improvements are analyzed in detail in order to understand how the environmental profile of this specific wine producing area has shifted in the past two decades (i.e., from 1990 to 2009). On the one hand, phenomena such as afforestation and agricultural intensification are analyzed throughout the appellation to estimate the impact due to GHG emissions linked to LUCs, based on IPCC standards. On the other hand, trends linked to technological improvements, operational changes, such as changes in the use and management of plant protection agents or fertilizers or the change in the energy sources for machinery on the vineyards, were assessed in detail.
Open linkAuthor(s): Ian Vázquez Rowe y otros
(Español) Wastewater treatment plants (WWTPs) are regarded as units designed for the efficient removal of organic matter and nutrients from polluted wastewaters, avoiding their discharge into the environment. Despite these benefits, they have also been found to be highly energy intensive, with consequent increased emissions in terms of greenhouse gases and other environmental impacts. Therefore, it has become imperative to monitor thoroughly the overall functioning of WWTPs from an integrated perspective with the aim of understanding how these can improve their eco-efficiency. In this case study, a group of 113 WWTPs located in regions across Spain were analysed using the methodology that combines life cycle assessment (LCA) and data envelopment analysis (DEA). The aim of this work was to determine the operational efficiency of each unit in order to obtain environmental benchmarks for inefficient plants. Thereafter, the environmental gains linked with the inputs reduction proposed for the DEA model for each unit were computed in order to verify eco-efficiency criteria. The operational complexity of WWTPs resulted in several identified factors affecting their efficiency which are discussed in depth, including the size of the facility, the climatic influence, the influent load and the over- or underuse of the plant.
Open linkAuthor(s): Ian Vázquez Rowe y otros
(Español) In an international context characterised by the promotion of renewable sources to face an increasing energy demand, grape marc is an organic co-product of the vinification process whose potential as an energy source has been underexploited. This study analysed the production chain of grape marc pellets and evaluated, through an attributional Life Cycle Assessment based on primary data from field experiments, the overall environmental performance of using grape marc pellets for heat production, as well as its comparison with alternative fossil and renewable energy resources. A sensitivity analysis was carried out concerning the type of fuel used for drying, the methodological approach to solve multi-functionality, as well as the influence of the water content of grape marc. The combustion and drying of pellets were found to be the main contributors to the environmental impacts, although a crucial influence of methodological choices on co-products management was observed. The use of wood chips for drying and an optimization of the pellets loading rate in the combustion process are the main improvement recommendations. Overall, results showed that the production of pellets from grape marc for heat production purposes is a promising technology from an environmental perspective, which is always superior to alternative fuels at the endpoint impact level. Compared to fossil fuels, its main advantage lies in the reduced contribution to climate change. When compared to mixed wood chips, it has an advantage regarding the contribution of agricultural land occupation. For policy support purposes, however, this study should be complemented by further analyses focussing, for instance, on market-driven consequences of large scale implementation. The results were shown to be dependent on the midpoint and endpoint impact categories. Their comprehensive interpretation led to the overarching clear recommendation to adapt the impact assessment categories and models and the approach to deal with multi-functionality to the geographical and market specificities features and to assure maximum transparency in the communication of results.
Open linkAuthor(s): Samy García Torres
(Español) Asesor: Ramzy Kahhat
Tesis para optar el título de Licenciado en Ingeniería Civil
Resumen:
En el Perú, los proyectos de construcción tienen un papel importante a nivel nacional, reflejando un notable crecimiento en los últimos años. Una de las causas de este crecimiento es el incremento de la población y la necesidad que existe de tener una vivienda. El crecimiento en el sector construcción significa progreso para el país a nivel económico, sin embargo, resulta importante indicar que existen desventajas que radican en problemáticas enfocadas al medio ambiente. Asimismo, existe una falta de preocupación, poca sensibilización e información sobre temas que conciernen a los impactos negativos al ambiente. Por tal motivo, este estudio utiliza la herramienta de Análisis de Ciclo de Vida para estimar los impactos ambientales de una vivienda unifamiliar limeña durante todas las etapas de su ciclo de vida, desde la extracción y manufactura de materiales, construcción y uso hasta el fin de vida. Los indicadores ambientales analizados en este estudio son: consumo de energía primaria, emisiones o desechos al suelo, uso de recursos, consumo de combustibles fósiles, potencial de calentamiento global, potencial de acidificación , criterios de salud humana, potencial de eutrofización y potencial de formación de smog. Los resultados del estudio reflejan la relevancia de la etapa de uso y pre-uso (en especial manufactura de materiales) en el ciclo de vida de la vivienda seleccionada, sobretodo para el consumo de energía primaria, consumo de combustibles fósiles y potencial de calentamiento global. En las etapas de pre-uso y uso, el consumo de energía primaria fue de 3,432 GJ y 4,480 GJ respectivamente. De la misma forma, los otros indicadores analizados presentan mayor impacto en estas dos primeras etapas, por ello existe la necesidad de tomar iniciativas en la aplicación de nuevas tecnologías y procedimientos que permitan reducir los niveles de impacto generados, considerando además la etapa de fin de vida.
Author(s): Ramzy Kahhat Abedrabbo y otros
(Español) Currently, around the globe, environmental and social problems derive from the inappropriate recycling of electronic products. Moreover, improper recycling is not the only issue to address in electronic products. Others include: energy intensity in their manufacture, employment generation related to the international trade in used electronics, and access to technology by low-income communities. Nevertheless, policies and controls created to provide socially and environmentally sound management of used electronics do not match the complexity of the system. In order to understand the e-waste system, particularly used computers, as a whole, a field study was done between 2010 and 2011 in ten Mexican cities. Ninety-five diverse stakeholders were interviewed to uncover factors regarding the decision to waste or trade still-usable computers. Structured analysis was used to create Data Flow Diagrams (DFDs) to describe the critical parts of the system. The results show that perceived value and geographical location determine the rate in which computers are disposed and the opportunities to waste or trade them, including the trade of their materials. Among businesses and other organizations, legislation has a stronger effect. Technological change is another important factor, largely driving the change in materials and new products. Designing policies responding to this diversity may prevent unforeseen problems and stimulate solutions.
Open linkAuthor(s): Isabel Quispe Trinidad y otros
(Español) Purpose: Life cycle assessments (LCAs) of various anchovy (anchoveta) direct human consumption products processed in Peru were carried out, to evaluate their relative environmental performance as alternative products to enhance nutrition of communities with low access to fish products in the country. Methods: LCA was carried out for fresh, frozen, canned, salted and cured anchoveta products, both at plant gate and featuring local and national distribution over non-refrigerated, chilled and fully refrigerated distribution chain. The functional unit used was 1 kg of fish in the final product. Results and discussion: Results demonstrate that, in environmental terms, more-refined products (cured and canned anchoveta products) represent a much higher burden than less- refined products (fresh, frozen and salted). Although this is a likely result, the magnitude of this difference (4 to 27 times when expressed as an environmental single score) is higher than expected and had not been quantified before for salted and cured products, as far as we know. This difference is mainly due to differences in energy consumption between types of products. Furthermore, cured and salted products feature larger biotic resource use, when calculated based on the whole fish equivalent, due to higher processing losses/discards. The relevance of taking into account the different transportation and storage needs is highlighted. For those products requiring refrigerated transportation and storage, over a national distribution chain, those activities increase the overall environmental impacts of the products by 55 % (fresh chilled) to 67 % (frozen). However, such an increase does not worsen the environmental performance of fresh and frozen products in comparison to the energy-intensive canned and cured products. Conclusions: It is concluded that a more sustainability-oriented analysis, including the social and economic pillars of sustainability, is required towards decision-making involving promotion of either product for addressing nutritional deficiencies in Peru.
Open linkAuthor(s): Ian Vázquez Rowe y otros
(Español) Attributional LCA, which monitors specific production systems in steady state conditions, is increasingly used in fisheries to assess the environmental profile of fleets and seafood supply chains. However, this approach is not pertinent to assess the environmental consequences of (large scale) policies. In contrast, consequential LCA (CLCA) has been successfully implemented in other sectors to assess the expected changes in environmental impacts of a given production system and other (marginal) production systems that may be affected in response to changes driven by policy or strategic decisions. CLCA commonly combines LCA with economic models to simulate the interactions occurring between the analysed systems. However, the use of these models may not be the most appropriate approach to follow for fisheries. Hence, it seems feasible that CLCA should be combined with stock prediction tools rather than with economic models, to determine how changes in stock sizes and quota restrictions may cause variations in the environmental impact of fishing fleets.
Open link