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Rochester, NY, United States

Matteson S.,Golisano Institute for Sustainability
Energy | Year: 2014

This paper reviews a published multi-criteria assessment of power systems and proposes new methods for normalization and ranking of criteria indicators. In previous work, the power systems are evaluated and ranked relative to the other systems considered in the assessment. This relative ranking system negatively affects the results in two ways. First, relative ranking tends to skew the results of the assessment, sometimes leading to incorrect conclusions and recommendations. Second, with a relative ranking system, the results lack applicability outside the assessment, since they are entirely dependent on the model from which they originate. This paper addresses these issues and proposes an extension that will combine experience curves, technological progress models, life cycle assessments, and thermodynamics within a dynamic multi-criteria optimization framework in order to create objective bounds for each sustainability indicator. This extension solves the relative ranking issue by creating a single system within which it is possible to rank and compare a variety of power systems, while maintaining relevant results between studies and over different scales. These results provide decision-makers with the information necessary to choose between systems to ensure a more sustainable future for the power sector. © 2014 Elsevier Ltd.

Deng L.,Arizona State University | Babbitt C.W.,Golisano Institute for Sustainability | Williams E.D.,Arizona State University
Journal of Cleaner Production | Year: 2011

The emergence of Life Cycle Assessment (LCA) on the global stage as a design and policy tool increases the importance of assessing and managing uncertainty. This article develops and implements uncertainty methods for hybrid LCA. Hybrid LCA combines a bottom-up construction of the supply-chain based on facility-level data on material/energy use with a top-down economic input-output (EIO) model to account for processes for which direct data were unavailable. For the bottom-up part of the LCA, we account for variability in process and usage pattern data by developing parameter ranges. For the EIO side we develop a method to assess price uncertainty. These methods are explored through a case study examining energy use and carbon dioxide emissions of manufacturing and use of a laptop computer, a 2001 Dell Inspiron 2500. Results show that manufacturing the computer requires 3010-4340 MJ of primary energy, 52-67% less than the energy to make a desktop computer, and emits 227-270 kg CO2. The manufacturing phase represents 62-70% of total primary energy of manufacturing and operation. This indicates, as for desktop computers, that mitigating manufacturing energy use, for example through extending lifespan, can be an important strategy to manage the life cycle energy of laptop computers. Results also indicate that truncation error from excluded processes in the bottom-up process model is significant, perhaps particularly so due to complex supply chains of information technology products. © 2011 Elsevier Ltd. All rights reserved.

Kahhat R.,Catholic University of Peru | Williams E.,Golisano Institute for Sustainability
Resources, Conservation and Recycling | Year: 2012

The management of electronic waste (e-waste) presents new sustainability challenges, prominent among these is informal electronic recycling in the developing world fed by both international and domestic sources. There is a need to mitigate environmental impacts of informal recycling while maintaining social and economic benefits of refurbishment and reuse. The development of appropriate social responses is hindered by critical data gaps, which include lack of data on trade flows of used and scrap electronics, flows invisible to trade statistics of many countries. We address this data gap by proposing and implementing an approach to quantify the exportation of used and scrap equipment from a particular country or region to the rest of the world. The approach is based on material flow analysis and combines collection of primary survey data from residential and business/public sectors with secondary data from available recycling, landfill and computer adoption studies. Exports are estimated through materials balance: exports = generated - reuse - recycling - landfill. The proposed methodology is implemented in a case study of desktop (excluding monitors) and laptop computers in the United States (US) in 2010. Results indicate that 40 million used and scrap computers entered the end-of-life management sector, from which 30% were reused domestically, 6-29% were exported, 17-21% were landfilled in domestic sites and 20-47% were collected for domestic recycling in 2010. The range in results reflects uncertainty arising from inferring end-of-life fate from individual and institutional users. Given sufficient resources to conduct a survey, the proposed materials flow analysis method can be widely applied to other devices and nations. © 2012 Elsevier B.V. All rights reserved.

Gaustad G.,Golisano Institute for Sustainability | Olivetti E.,Massachusetts Institute of Technology | Kirchain R.,Massachusetts Institute of Technology
Resources, Conservation and Recycling | Year: 2012

Aluminum recycling has a number of key environmental and economic benefits. With these energy and cost savings in mind, many producers now have targets of increasing their usage of secondary materials. However, the accumulation of impurities in these recycled material streams may provide a significant compositional barrier to these goals. A growing number of studies and literature suggest that accumulation of unwanted elements is a growing problem; for the case of aluminum, the list of problematic impurities is quite large, including but not limited to Si, Mg, Ni, Zn, Pb, Cr, Fe, Cu, V, and Mn. The removal of unwanted elements in the scrap stream is dictated by the energy considerations of the melt process. Compared to many metals, it is challenging to remove tramp elements from aluminium. Therefore, with no simple thermodynamic solution, producers must identify strategies throughout the production process to mitigate this elemental accumulation. There are a variety of solutions to deal with accumulation of undesired elements; each presents a trade-off between cost and efficacy (tramp removal). Dilution with primary is the most common solution used in industry today; this has a negative impact on recycling as the required dilution results in a compositionally determined cap to recycling rates. This article provides an overview of the expanse of upgrading technologies available at both the industrial and lab-scale to improve aluminum scrap purity and facilitate recycling. © 2011 Elsevier B.V. All rights reserved.

Koomey J.G.,Stanford University | Matthews H.S.,Carnegie Mellon University | Williams E.,Golisano Institute for Sustainability
Annual Review of Environment and Resources | Year: 2013

Until recently, the main environmental concerns associated with ormation and communication technologies (ICTs) have been their use-phase electricity consumption and the chemicals associated with their manufacture, and the environmental effects of these technologies on other parts of the economy have largely been ignored. With the advent of mobile computing, communication, and sensing devices, these indirect effects have the potential to be much more important than the impacts from the use and manufacturing phases of this equipment. This article summarizes the trends that have propelled modern technological societies into the ultralow-power design space and explores the implications of these trends for the direct and indirect environmental impacts associated with these new technologies. It reviews the literature on environmental effects of ormation technology (also with an emphasis on low-power systems) and suggests areas for further research. © 2013 by Annual Reviews. All rights reserved.

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