Matching Items (16)
Description
Current policies subsidizing or accelerating deployment of photovoltaics (PV) are typically motivated by claims of environmental benefit, such as the reduction of CO2 emissions generated by the fossil-fuel fired power plants that PV is intended to displace. Existing practice is to assess these environmental benefits on a net life-cycle basis, where CO2 benefits occurring during use of the PV panels is found to exceed emissions generated during the PV manufacturing phase including materials extraction and manufacture of the PV panels prior to installation. However, this approach neglects to recognize that the environmental costs of CO2 release during manufacture are incurred early, while environmental benefits accrue later. Thus, where specific policy targets suggest meeting CO2 reduction targets established by a certain date, rapid PV deployment may have counter-intuitive, albeit temporary, undesired consequences. Thus, on a cumulative radiative forcing (CRF) basis, the environmental improvements attributable to PV might be realized much later than is currently understood. This phenomenon is particularly acute when PV manufacture occurs in areas using CO2 intensive energy sources (e.g., coal), but deployment occurs in areas with less CO2 intensive electricity sources (e.g., hydro). This thesis builds a dynamic Cumulative Radiative Forcing (CRF) model to examine the inter-temporal warming impacts of PV deployments in three locations: California, Wyoming and Arizona. The model includes the following factors that impact CRF: PV deployment rate, choice of PV technology, pace of PV technology improvements, and CO2 intensity in the electricity mix at manufacturing and deployment locations. Wyoming and California show the highest and lowest CRF benefits as they have the most and least CO2 intensive grids, respectively. CRF payback times are longer than CO2 payback times in all cases. Thin film, CdTe PV technologies have the lowest manufacturing CO2 emissions and therefore the shortest CRF payback times. This model can inform policies intended to fulfill time-sensitive CO2 mitigation goals while minimizing short term radiative forcing.
ContributorsTriplican Ravikumar, Dwarakanath (Author) / Seager, Thomas P (Thesis advisor) / Fraser, Matthew P (Thesis advisor) / Chester, Mikhail V (Committee member) / Sinha, Parikhit (Committee member) / Arizona State University (Publisher)
Created2013
Description
Water resource management is becoming increasingly burdened by uncertain and fluctuating conditions resulting from climate change and population growth which place increased demands on already strained resources. Innovative water management schemes are necessary to address the reality of available water supplies. One such approach is the substitution of trade in virtual water for the use of local water supplies. This study provides a review of existing work in the use of virtual water and water footprint methods. Virtual water trade has been shown to be a successful method for addressing water scarcity and decreasing overall water consumption by shifting high water consumptive processes to wetter regions. These results however assume that all water resource supplies are equivalent regardless of physical location and they do not tie directly to economic markets. In this study we introduce a new mathematical framework, Embedded Resource Accounting (ERA), which is a synthesis of several different analytical methods presently used to quantify and describe human interactions with the economy and the natural environment. We define the specifics of the ERA framework in a generic context for the analysis of embedded resource trade in a way that links directly with the economics of that trade. Acknowledging the cyclical nature of water and the abundance of actual water resources on Earth, this study addresses fresh water availability within a given region. That is to say, the quantities of fresh water supplies annually available at acceptable quality for anthropogenic uses. The results of this research provide useful tools for water resource managers and policy makers to inform decision making on, (1) reallocation of local available fresh water resources, and (2) strategic supplementation of those resources with outside fresh water resources via the import of virtual water.
ContributorsAdams, Elizabeth Anne (Author) / Ruddell, Benjamin L (Thesis advisor) / Allenby, Braden R. (Thesis advisor) / Seager, Thomas P (Committee member) / Arizona State University (Publisher)
Created2013
Description
Cities around the globe struggle with socio-economic disparities, resource inefficiency, environmental contamination, and quality-of-life challenges. Technological innovation, as one prominent approach to problem solving, promises to address these challenges; yet, introducing new technologies, such as nanotechnology, into society and cities has often resulted in negative consequences. Recent research has conceptually linked anticipatory governance and sustainability science: to understand the role of technology in complex problems our societies face; to anticipate negative consequences of technological innovation; and to promote long-term oriented and responsible governance of technologies. This dissertation advances this link conceptually and empirically, focusing on nanotechnology and urban sustainability challenges. The guiding question for this dissertation research is: How can nanotechnology be innovated and governed in responsible ways and with sustainable outcomes? The dissertation: analyzes the nanotechnology innovation process from an actor- and activities-oriented perspective (Chapter 2); assesses this innovation process from a comprehensive perspective on sustainable governance (Chapter 3); constructs a small set of future scenarios to consider future implications of different nanotechnology governance models (Chapter 4); and appraises the amenability of sustainability problems to nanotechnological interventions (Chapter 5). The four studies are based on data collected through literature review, document analysis, participant observation, interviews, workshops, and walking audits, as part of process analysis, scenario construction, and technology assessment. Research was conducted in collaboration with representatives from industry, government agencies, and civic organizations. The empirical parts of the four studies focus on Metropolitan Phoenix. Findings suggest that: predefined mandates and economic goals dominate the nanotechnology innovation process; normative responsibilities identified by risk governance, sustainability-oriented governance, and anticipatory governance are infrequently considered in the nanotechnology innovation process; different governance models will have major impacts on the role and effects of nanotechnology in cities in the future; and nanotechnologies, currently, do not effectively address the root causes of urban sustainability challenges and require complementary solution approaches. This dissertation contributes to the concepts of anticipatory governance and sustainability science on how to constructively guide nanotechnological innovation in order to harvest its positive potential and safeguard against negative consequences.
ContributorsFoley, Rider Williams (Author) / Wiek, Arnim (Thesis advisor) / Guston, David H. (Committee member) / Seager, Thomas P (Committee member) / Minteer, Ben A (Committee member) / Arizona State University (Publisher)
Created2013
Description
Life cycle assessment (LCA) is a powerful framework for environmental decision making because the broad boundaries called for prevent shifting of burden from one life-cycle phase to another. Numerous experts and policy setting organizations call for the application of LCA to developing nanotechnologies. Early application of LCA to nanotechnology may identify environmentally problematic processes and supply chain components before large investments contribute to technology lock in, and thereby promote integration of environmental concerns into technology development and scale-up (enviro-technical integration). However, application of LCA to nanotechnology is problematic due to limitations in LCA methods (e.g., reliance on data from existing industries at scale, ambiguity regarding proper boundary selection), and because social drivers of technology development and environmental preservation are not identified in LCA. This thesis proposes two methodological advances that augment current capabilities of LCA by incorporating knowledge from technical and social domains. Specifically, this thesis advances the capacity for LCA to yield enviro-technical integration through inclusion of scenario development, thermodynamic modeling, and use-phase performance bounding to overcome the paucity of data describing emerging nanotechnologies. With regard to socio-technical integration, this thesis demonstrates that social values are implicit in LCA, and explores the extent to which these values impact LCA practice and results. There are numerous paths of entry through which social values are contained in LCA, for example functional unit selection, impact category selection, and system boundary definition - decisions which embody particular values and determine LCA results. Explicit identification of how social values are embedded in LCA promotes integration of social and environmental concerns into technology development (socio-enviro-technical integration), and may contribute to the development of socially-responsive and environmentally preferable nanotechnologies. In this way, tailoring LCA to promote socio-enviro-technical integration is a tangible and meaningful step towards responsible innovation processes.
ContributorsWender, Ben A. (Author) / Seager, Thomas P (Thesis advisor) / Crozier, Peter (Committee member) / Fraser, Matthew (Committee member) / Guston, David (Committee member) / Arizona State University (Publisher)
Created2013
Description
Life Cycle Assessment (LCA) quantifies environmental impacts of products in raw material extraction, processing, manufacturing, distribution, use and final disposal. The findings of an LCA can be used to improve industry practices, to aid in product development, and guide public policy. Unfortunately, existing approaches to LCA are unreliable in the cases of emerging technologies, where data is unavailable and rapid technological advances outstrip environmental knowledge. Previous studies have demonstrated several shortcomings to existing practices, including the masking of environmental impacts, the difficulty of selecting appropriate weight sets for multi-stakeholder problems, and difficulties in exploration of variability and uncertainty. In particular, there is an acute need for decision-driven interpretation methods that can guide decision makers towards making balanced, environmentally sound decisions in instances of high uncertainty. We propose the first major methodological innovation in LCA since early establishment of LCA as the analytical perspective of choice in problems of environmental management. We propose to couple stochastic multi-criteria decision analytic tools with existing approaches to inventory building and characterization to create a robust approach to comparative technology assessment in the context of high uncertainty, rapid technological change, and evolving stakeholder values. Namely, this study introduces a novel method known as Stochastic Multi-attribute Analysis for Life Cycle Impact Assessment (SMAA-LCIA) that uses internal normalization by means of outranking and exploration of feasible weight spaces.
ContributorsPrado, Valentina (Author) / Seager, Thomas P (Thesis advisor) / Landis, Amy E. (Committee member) / Chester, Mikhail (Committee member) / White, Philip (Committee member) / Arizona State University (Publisher)
Created2013
Description
Contrary to many previous travel demand forecasts there is increasing evidence that vehicle travel in developed countries may be peaking. The underlying causes of this peaking are still under much debate and there has been a mobilization of research, largely focused at the national scale, to study the explanatory drivers but research focused at the metropolitan scale, where transportation policy and planning are frequently decided, is relatively thin. Additionally, a majority of this research has focused on changes within the activity system without considering the impact transportation infrastructure has on overall travel demand. Using Los Angeles County California, we investigate Peak Car and whether the saturation of automobile infrastructure, in addition to societal and economic factors, may be a suppressing factor. After peaking in 2002, vehicle travel in Los Angeles County in 2010 was estimated at 78 billion and was 20.3 billion shy of projections made in 2002. The extent to which infrastructure saturation may contribute to Peak Car is evaluated by analyzing social and economic factors that may have impacted personal automobile usage over the last decade. This includes changing fuel prices, fuel economy, population growth, increased utilization of alternate transportation modes, changes in driver demographics , travel time and income levels. Summation of all assessed factors reveals there is at least some portion of the 20 billion VMT that is unexplained in all but the worst case scenario. We hypothesize that the unexplained remaining VMT may be explained by infrastructure supply constraints that result in suppression of travel. This finding has impacts on how we see the role of hard infrastructure systems in urban growth and we explore these impacts in the research.
ContributorsFraser, Andrew (Author) / Chester, Mikhail V (Thesis advisor) / Pendyala, Ram M. (Committee member) / Seager, Thomas P (Committee member) / Arizona State University (Publisher)
Created2014
Description
Comparative life cycle assessment (LCA) evaluates the relative performance of multiple products, services, or technologies with the purpose of selecting the least impactful alternative. Nevertheless, characterized results are seldom conclusive. When one alternative performs best in some aspects, it may also performs worse in others. These tradeoffs among different impact categories make it difficult to identify environmentally preferable alternatives. To help reconcile this dilemma, LCA analysts have the option to apply normalization and weighting to generate comparisons based upon a single score. However, these approaches can be misleading because they suffer from problems of reference dataset incompletion, linear and fully compensatory aggregation, masking of salient tradeoffs, weight insensitivity and difficulties incorporating uncertainty in performance assessment and weights. Consequently, most LCA studies truncate impacts assessment at characterization, which leaves decision-makers to confront highly uncertain multi-criteria problems without the aid of analytic guideposts. This study introduces Stochastic Multi attribute Analysis (SMAA), a novel approach to normalization and weighting of characterized life-cycle inventory data for use in comparative Life Cycle Assessment (LCA). The proposed method avoids the bias introduced by external normalization references, and is capable of exploring high uncertainty in both the input parameters and weights.
ContributorsPrado, Valentina (Author) / Seager, Thomas P (Thesis advisor) / Chester, Mikhail V (Committee member) / Kullapa Soratana (Committee member) / Tervonen, Tommi (Committee member) / Arizona State University (Publisher)
Created2015
Description
Advancing sustainable food systems requires holistic understanding and solutions-oriented approaches that transcend disciplines, so expertise in a variety of subjects is necessary. Proposed solutions are usually technically or socially oriented, but disagreement over the best approach to the future of food dominates the dialogue. Technological optimists argue that scientific advances are necessary to feed the world, but environmental purists believe that reductions in consumption and waste are sufficient and less risky. Life cycle assessment (LCA) helps resolve debates through quantitative analysis of environmental impacts from products which serve the same function. LCA used to compare dietary choices reveals that simple plant-based diets are better for the environment than diets that include animal products. However, analysis of soy protein isolate (SPI) demonstrates that certain plant-based proteins may be less preferable for the environment than some unprocessed meats in several categories due to additional impacts that come from industrial processing. LCAs' focus on production risks ignoring consumers, but the food system exists to serve consumers, who can be major drivers of change. Therefore, the path to a sustainable food system requires addressing consumption issues as well. Existing methods for advancing sustainable food systems that equate more information with better behavior or performance are insufficient to create change. Addressing food system issues requires sufficient tacit knowledge to understand how arguments are framed, what the supporting content is, the findings of primary sources, and complex and controversial dialogue surrounding innovations and interventions for food system sustainability. This level of expertise is called interactional competence and it is necessary to drive and maintain holistic progress towards sustainability. Development strategies for interactional competence are informed by studying the motivations and strategies utilized by vegans. A new methodology helps advance understanding of expertise development by assessing levels of expertise and reveals insights into how vegans maintain commitment to a principle that influences their daily lives. The study of veganism and expertise reveals that while providing information to debunk fallacies is important, the development of tacit knowledge is fundamental to advance to a stage of competence.
ContributorsBerardy, Andrew (Author) / Seager, Thomas P (Thesis advisor) / Hannah, Mark (Committee member) / Costello, Christine (Committee member) / Landis, Amy (Committee member) / Wharton, Christopher (Christopher Mack), 1977- (Committee member) / Arizona State University (Publisher)
Created2015
Description
A major obstacle to sustainable solar technologies is end-of-life solar modules. In this thesis, a recycling process is proposed for crystalline-Si solar modules. It is a three-step process to break down Si modules and recover various materials. Over 95% of a module by weight can be recovered with this process. Two new technologies are demonstrated to enable the proposed recycling process. One is sequential electrowinning which allows multiple metals to be recovered one by one from Si modules, Ag, Pb, Sn and Cu. The other is sheet resistance monitoring by the 4-point probe which maximizes the amount of solar-grade Si recovered from Si modules with high throughput. The purity of the recovered metals is above 99% and the recovery rate can achieve between 70~80%. The recovered Si meets the specifications for solar-grade Si and at least 91% of Si from c-Si solar cells can be recovered. The recovered Si and metals are new feedstocks to the solar industry and generate over $12/module in revenue. This revenue enables a profitable recycling business for Si modules without any government support. The chemicals for recycling are carefully selected to minimize their environmental impact and also the cost. A network for collecting end-of-life solar modules is proposed based on the current distribution network for solar modules to contain the collection cost. As a result, the proposed recycling process for c-Si modules is technically, environmentally and financially sustainable.
ContributorsHuang, Wenxi (Author) / Tao, Meng (Thesis advisor) / Alford, Terry (Committee member) / Sinha, Parikhit (Committee member) / Arizona State University (Publisher)
Created2018
Description
Photovoltaics (PV) is an environmentally promising technology to meet climate goals and transition away from greenhouse-gas (GHG) intensive sources of electricity. The dominant approach to improve the environmental gains from PV is increasing the module efficiency and, thereby, the renewable electricity generated during use. While increasing the use-phase environmental benefits, this approach doesn’t address environmentally intensive PV manufacturing and recycling processes.
Lifecycle assessment (LCA), the preferred framework to identify and address environmental hotspots in PV manufacturing and recycling, doesn’t account for time-sensitive climate impact of PV manufacturing GHG emissions and underestimates the climate benefit of manufacturing improvements. Furthermore, LCA is inherently retrospective by relying on inventory data collected from commercial-scale processes that have matured over time and this approach cannot evaluate environmentally promising pilot-scale alternatives based on lab-scale data. Also, prospective-LCAs that rely on hotspot analysis to guide future environmental improvements, (1) don’t account for stake-holder inputs to guide environmental choices in a specific decision context, and (2) may fail in a comparative context where the mutual differences in the environmental impacts of the alternatives and not the environmental hotspots of a particular alternative determine the environmentally preferable alternative
This thesis addresses the aforementioned problematic aspects by (1)using the time-sensitive radiative-forcing metric to identify PV manufacturing improvements with the highest climate benefit, (2)identifying the environmental hotspots in the incumbent CdTe-PV recycling process, and (3)applying the anticipatory-LCA framework to identify the most environmentally favorable alternative to address the recycling hotspot and significant stakeholder inputs that can impact the choice of the preferred recycling alternative.
The results show that using low-carbon electricity is the most significant PV manufacturing improvement and is equivalent to increasing the mono-Si and multi-Si module efficiency from a baseline of 17% to 21.7% and 16% to 18.7%, respectively. The elimination of the ethylene-vinyl acetate encapsulant through mechanical and chemical processes is the most significant environmental hotspot for CdTe PV recycling. Thermal delamination is the most promising environmental alternative to address this hotspot. The most significant stake-holder input to influence the choice of the environmentally preferable recycling alternative is the weight assigned to the different environmental impact categories.
Lifecycle assessment (LCA), the preferred framework to identify and address environmental hotspots in PV manufacturing and recycling, doesn’t account for time-sensitive climate impact of PV manufacturing GHG emissions and underestimates the climate benefit of manufacturing improvements. Furthermore, LCA is inherently retrospective by relying on inventory data collected from commercial-scale processes that have matured over time and this approach cannot evaluate environmentally promising pilot-scale alternatives based on lab-scale data. Also, prospective-LCAs that rely on hotspot analysis to guide future environmental improvements, (1) don’t account for stake-holder inputs to guide environmental choices in a specific decision context, and (2) may fail in a comparative context where the mutual differences in the environmental impacts of the alternatives and not the environmental hotspots of a particular alternative determine the environmentally preferable alternative
This thesis addresses the aforementioned problematic aspects by (1)using the time-sensitive radiative-forcing metric to identify PV manufacturing improvements with the highest climate benefit, (2)identifying the environmental hotspots in the incumbent CdTe-PV recycling process, and (3)applying the anticipatory-LCA framework to identify the most environmentally favorable alternative to address the recycling hotspot and significant stakeholder inputs that can impact the choice of the preferred recycling alternative.
The results show that using low-carbon electricity is the most significant PV manufacturing improvement and is equivalent to increasing the mono-Si and multi-Si module efficiency from a baseline of 17% to 21.7% and 16% to 18.7%, respectively. The elimination of the ethylene-vinyl acetate encapsulant through mechanical and chemical processes is the most significant environmental hotspot for CdTe PV recycling. Thermal delamination is the most promising environmental alternative to address this hotspot. The most significant stake-holder input to influence the choice of the environmentally preferable recycling alternative is the weight assigned to the different environmental impact categories.
ContributorsTriplican Ravikumar, Dwarakanath (Author) / Seager, Thomas P (Thesis advisor) / Fraser, Matthew P (Thesis advisor) / Chester, Mikhail (Committee member) / Sinha, Parikhit (Committee member) / Tao, Meng (Committee member) / Arizona State University (Publisher)
Created2016