- Email: [email protected]
Understanding Full Life-cycle Sustainability Impacts of Energy Alternatives
Available online at www.sciencedirect.com
ScienceDirect Energy Procedia 107 (2017) 309 – 313
3rd International Conference on Energy and Environment Research, ICEER 2016, 7-11 September 2016, Barcelona, Spain
Understanding Full Life-cycle Sustainability Impacts of Energy Alternatives Barry A. Benedict* Mechanical Engineering Department, University of Texas at El Paso, El Paso, TX 79968, USA
Abstract Pragmatic and reliable methods for assessing sustainability remain difficult for many organizations. Further, understanding the three elements of sustainability over the full life cycle of products and processes is essential. In some cases, understanding environmental issues is the easiest area. However, economic and social issues are less well understood. Life Cycle Sustainability Analysis is a framework for reviewing all three areas and enabling not only full coverage but understanding balancing and interactions between the elements. This paper reviews the three elements of sustainability, life cycle assessment, and analysis and evaluation of the three elements over a life cycle. These frameworks will be described so as to facilitate development of ways to help decision makers present proposals and illustrate results. Means are presented to enable illustration of findings to both expert and non-expert audiences. Specifically, uses of the life cycle sustainability triangle and the life cycle sustainability dashboard will presented. Examples will be presented for a comparison of solar PV panels. Other examples include alternative energy sources in Mexico to 2050, contrasting alternative vehicles, and electricity scenarios in the UK to 2070. The paper is intended to help practitioners better understand linkages between the three elements of sustainability and ways to analyze them. © 2017 2016Published The Authors. Published by Elsevier Ltd. © by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license Peer-review under responsibility of the scientific committee of the 3rd International Conference on Energy and Environment (http://creativecommons.org/licenses/by-nc-nd/4.0/). Research. under responsibility of the scientific committee of the 3rd International Conference on Energy and Environment Research. Peer-review Keywords: Sustainability, life cycle assessment, energy Introduction.
* Corresponding author. Tel.: +1 (915) 747-5604. E-mail address: [email protected]
1876-6102 © 2017 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the scientific committee of the 3rd International Conference on Energy and Environment Research. doi:10.1016/j.egypro.2016.12.158
310
Barry A. Benedict / Energy Procedia 107 (2017) 309 – 313
1. Introduction Lifecycle sustainability assessment [1] reviews environmental issues, cost, and social issues over the life of a project, product [2], [3], or policy. These three elements taken together provide the basis for assessing sustainability. Fig. 1 shows elements of a typical life cycle assessment (LCA). Basically, a life cycle assessment considers everything that happens because of the project, product, or process. A typical life cycle consists of raw materials, material processing, manufacturing, assembly, product use and end of life, usually with transportation between steps. This is often called cradle to grave, as it begins with finding and extracting raw materials, and it concludes with disposal of the item when it is no longer useful.
. Fig. 1. Basic elements of Life Cycle Assessment.
There are many potential benefits to application of life cycle sustainability assessment. A few are included in the following: Organizes data in structured form Clarifies tradeoffs Enables consideration of full range of impacts Stimulates innovation Helps decision makers Enables comparative analyses Life cycle sustainability assessment has some overlap with the topics of resilience, asset management, and risk assessment. One recent study has shown that sustainability and resilience are becoming more closely aligned in highway infrastructure [4]. The author has been studying these linkages, and it appears that all have a common core of data needs and life cycle concerns. For example, asset management already calls for a life cycle cost analysis. Coupling life cycle sustainability assessment with scenario planning can enable consideration of uncertainty and assure more robust designs, products, and policies. The major drivers for change include social, technological, environmental, economic, and political. LCA software such as GaBi, Simapro, and OpenLCA have databases and others can be imported. There are free databases, but some require payment of a fee to access them. These are average data from the specific industry and activity and/or product. There are in excess of 70,000 databases. Of course, if accessible and cost effective, local data is preferable. One useful view is the dashboard approach. This uses color coding to indicate results from very good (typically bright green) to very bad (typically bright red), with shadings between the extremes. This enables a quick view of the overall performance and alternatives. Also, results can be shown within each of the three elements environmental life cycle impacts, life cycle costs, and social life cycle assessments. One can better understand the contributions to overall performance and identify points of redesign. 2. Example of solar PV modules The analysis of PV panels [5] is included as a means of illustrating the process and results. It is illustrative of a review of components that might ultimately fit within a larger energy study. The study contrasted production of
Barry A. Benedict / Energy Procedia 107 (2017) 309 – 313
solar PV modules in two German cases and one in Italy. The functional unit selected as the basis of comparison was the square meter. The study used Simapro databases for average values. For example, 21,286 kg of tap water, 4.71 kWh electricity, and 0.11 kg copper, were required for one square meter. Local data that was collected included data on all raw materials for the German site, as well as aggregated electricity use. For the Italian site, some data was available on raw materials, but most came from existing databases. For the life cycle cost analysis, a questionnaire was developed and distributed. Some data was obtained, with other data acquired from databases. One interesting finding showed a significant difference in energy requirements, with the German sites at 0.751 kWh/m2 and the Italian site at 4.711 kWh/m2, both from direct data For the Social LCA, several metrics were used. For workers (segmented by age, gender), the study considered these impact categories: Discrimination; Child labor; Wages;Working hours; Social benefit; and Health conditions.
Fig. 2. Dashboard Illustration of Three PV Modules [].
Results from the study were typically presented in dashboard format. Fig. 2 is an example. This figure contrasts the three sites and times for module construction. For each case, environmental LCA (ELCA), life cycle costs (LCC), and social life cycle assessment (SLCA) are included. Those areas in bright green indicate the most favorable performance, with colors approaching red representing the least desirable performance. The color in the central circle suggests the overall performance for that case. 3. Example contrasting energy scenarios to 2050 in Mexico This study [6] combines scenario planning with life cycle sustainability assessment. Eleven scenarios were developed based on different technologies, electricity mixes, and climate change targets. Further, the study identified seventeen sustainability metrics. They indicate a number of interesting results. For example, they state “…the business-as-usual scenario, mostly based on fossil fuels, is unsustainable regardless of the preferences for different sustainability criteria. “[6] They summarize results as “Overall, the most sustainable scenarios are those with higher penetration of renewables (wind, solar, hydro, geothermal and biomass) and nuclear power. These electricity pathways would enable meeting the national greenhouse gas emission targets by 2050 in a more sustainable way than envisaged by the current policy. However, some trade-offs among the sustainability criteria are needed, particularly with respect to the social impacts. These trade-offs can be explored easily within the decisionsupport framework. This would reveal how different stakeholder preferences affect the outcomes of sustainability assessment, thus contributing to more informed decision and policy making." [6] The tradeoffs mentioned will require engagement of the various stakeholders to develop plans that are balanced. 4. Example contrasting alternative vehicles This recent study [7] compares several types of vehicles across a number of performance measures embedded
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Barry A. Benedict / Energy Procedia 107 (2017) 309 – 313
within the sustainability elements. The vehicles studied include conventional gasoline (ICV), hybrid, plug-in hybrid (PHEV) with four different all-electric ranges, and full battery vehicles (BEV). Two sources of electricity for charging were considered, including use of the ordinary US grid and use of solar charging stations. Nineteen sustainability indicators are included. Results of this analysis revealed that the manufacturing phase is the most influential phase in terms of socio-economic impacts compared to other life cycle phases. The operation phase is the most dominant phase in the terms of environmental impacts and some of the socio-economic impacts such as human health and economic cost of emissions. [7] Using solar charging stations reduced the economic costs of emissions, and human health impact can be reduced up to forty-five percent and thirty-five percent respectively. “BEV has the lowest greenhouse gas emissions and ecological land footprint per $ of its contribution to the U.S. GDP, and has the lowest ecological footprint per unit of its energy consumption. The only sustainability metric that does not favor the BEV is the water-energy ratio, where the conventional gasoline vehicle performed best.”[7] The sustainability indicators chosen included global warming potential, water withdrawal, energy consumption, hazardous waste generation, particulate matter formation potential, fisheries, grazing, forestry, cropland, and CO2 uptake (environmental); import, gross operating surplus, gross domestic product, and air emission cost (economics); and employment, government tax, injuries, income, and human health (social). Such studies can decide up front the areas where it is believed that significant impacts will occur. In this study, there were indicators that additional employment might occur as electric vehicles made a more significant market penetration. 5. Example of UK electricity options This study [8] compares six basic electricity generating processes, with thirty-six indicators of sustainability. The issue under consideration is the ability of the UK to meet mandated greenhouse gas emissions by 2050, as shown in Fig. 3. The six technologies selected were the following: coal (subcritical pulverized) with and without carbon capture and storage (CCS); natural gas (combined cycle gas turbine, CCGT); nuclear (pressurized water reactor, PWR); solar photovoltaics (PV); wind (offshore); and biomass (wood and Miscanthus pellets). “To meet the GHG emission targets, coal CCS can only play a limited role, contributing 10% to the electricity mix at most; the use of CCS also increases other sustainability impacts compared to today, including worker injuries, large accident fatalities, depletion of fossil fuels and long-term waste storage. This calls into question the case for investing in coal CCS. A very low-carbon mix with nuclear and renewables provides the best overall environmental performance, but some impacts increase, such as terrestrial eco-toxicity.”[8]
Fig. 3. Target UK Emissions [8].
“With equal weighting assumed for each sustainability impact, the scenario with an equal share of nuclear and renewables is ranked best.”[8]. The potential use of weighting is a topic worthy of further dialogue as these techniques are advanced. Every project, policy, or product may have different balancing efforts. This reinforces the need to engage stakeholders in the decision process to assure that any weighting used has gained consensus. It further encourages use of parametric studies. By varying the weighting, the effects on the results can be noted. This will enable consideration of those factors with only small influence on the final results, as well as those to which the final outcomes are very sensitive.
Barry A. Benedict / Energy Procedia 107 (2017) 309 – 313
6. Future uses Given the centrality of sustainability concerns to existing and future energy development, distribution, and use, it seems logical to see increasing use of this tool. In fact, for the development of robust plans and strategies, such approaches are essential. Coupling life cycle sustainability with scenario planning will further assure satisfactory solutions over a range of conditions. Best results can be achieved by direct and continuous engagement of stakeholders in the data gathering, discussions, decisions, and continuous monitoring for success. If the described approach is applied to several approaches to a problem, then these alternatives can be compared on all three dimensions. These can include products, projects, policies, energy systems, as well as subsets of energy systems. If these analyses are done properly, then all costs and impacts will be included, assuring that comparisons are realistic. Several examples have been presented to illustrate applications within several energy areas. Each study chose different indicators for the environmental, economic, and social aspects. There is work to be done to assure most effective utilization. These include, but are not limited to the following: Define areas where data and data sources can be used for all or most of the life cycle assessments Define the most effective ways to link scenario planning to these assessments Determine potential interactions between the various life cycle assessments, where changes in one may impact another. Adopt ways to assure that stakeholders are not only included but are essential to the decisions made. Perform studies to determine sensitivity of results to data used. Study how weighting of indicators may not only change results but also be considered by stakeholders. Taken together, the results included in this paper should encourage future use of these techniques, as well as ways to display results in a manner most useful to stakeholders and decision makers. 7. Conclusions Life cycle sustainability is a method of analysis that is growing in use. It recognizes changing conditions over time, as well as differing portions of the life cycle. As more uses and analyses are reported, it is projected that others will recognize the value as a technique for both sustainable development and policy enhancement. To assure best use, research will have to continue to improve understanding of numerous elements. These would include, among other elements, the need for data and a better means of assessing social impacts. References [1] M. Finkbeiner, E.M. Schau, A. Lehmann, and M. Traverso, Toward Life Cycle Sustainability Analysis, Sustainability, 2010, 2, 3309-3322, accessed through http://scholar.google.com/scholar_url?url=http://www.mdpi.com/20711050/2/10/3309/pdf&hl=en&sa=X&scisig=AAGBfm3Pj2J9c6I6v_b51Ue3wDGxTMRlqQ&nossl=1&oi=scholarr [2] UNEP, Guidelines for Social Life Cycle Assessment of Products, 2009, accessed through http://www.unep.org/pdf/DTIE_PDFS/DTIx1164xPA-guidelines_sLCA.pdf [3] UNEP, Towards a Life Cycle Sustainability Assessment for Products, 2012, 86 pp The International Journal of Life Cycle Assessment, September 2012, Volume 17, Issue 8, pp 1068-1079 [4] Paolo Bocchini, M.ASCE1; Dan M. Frangopol, Dist.M.ASCE2; Thomas Ummenhofer3; and Tim Zinke, Resilience and Sustainability of Civil Infrastructure: Toward a Unified Approach, Journal of Infrastructure Systems, American Society of civil Engineering, July 1, 2013, Accessed as http://ascelibrary.org/doi/abs/10.1061/(ASCE)IS.1943-555X.0000177 [5] M. Traverso, F. Asdrubali, A. Francis, and M. Finkbeiner, Towards life cycle sustainability assessment: an implementation to photovoltaic modules, Sep 2012 · The International Journal of Life Cycle Assessment [6] Santoyo-Castelazo, E., A. Azapagic, Sustainability Assessment of Energy Systems: integrating Environmental, Economic, and Social Aspects, Journal of Cleaner Production, Vol. 80, October 1, 2014, pp. 119-138 [7] Nuri Cihat Onat, Murat Kucukvar, and Omer Tateri, Towards Life Cycle Sustainability Assessment of Alternative Passenger Vehicles, Sustainability, December, 2014, pp. 9305-9342. [8] Stamford, L., A. Azapagic, Life Cycle Sustainability Assessment of UK Electricity Scenarios to 2070, Energy for Sustainable Development, Vol. 33, Dec. 2014, pp. 194
313
ScienceDirect Energy Procedia 107 (2017) 309 – 313
3rd International Conference on Energy and Environment Research, ICEER 2016, 7-11 September 2016, Barcelona, Spain
Understanding Full Life-cycle Sustainability Impacts of Energy Alternatives Barry A. Benedict* Mechanical Engineering Department, University of Texas at El Paso, El Paso, TX 79968, USA
Abstract Pragmatic and reliable methods for assessing sustainability remain difficult for many organizations. Further, understanding the three elements of sustainability over the full life cycle of products and processes is essential. In some cases, understanding environmental issues is the easiest area. However, economic and social issues are less well understood. Life Cycle Sustainability Analysis is a framework for reviewing all three areas and enabling not only full coverage but understanding balancing and interactions between the elements. This paper reviews the three elements of sustainability, life cycle assessment, and analysis and evaluation of the three elements over a life cycle. These frameworks will be described so as to facilitate development of ways to help decision makers present proposals and illustrate results. Means are presented to enable illustration of findings to both expert and non-expert audiences. Specifically, uses of the life cycle sustainability triangle and the life cycle sustainability dashboard will presented. Examples will be presented for a comparison of solar PV panels. Other examples include alternative energy sources in Mexico to 2050, contrasting alternative vehicles, and electricity scenarios in the UK to 2070. The paper is intended to help practitioners better understand linkages between the three elements of sustainability and ways to analyze them. © 2017 2016Published The Authors. Published by Elsevier Ltd. © by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license Peer-review under responsibility of the scientific committee of the 3rd International Conference on Energy and Environment (http://creativecommons.org/licenses/by-nc-nd/4.0/). Research. under responsibility of the scientific committee of the 3rd International Conference on Energy and Environment Research. Peer-review Keywords: Sustainability, life cycle assessment, energy Introduction.
* Corresponding author. Tel.: +1 (915) 747-5604. E-mail address: [email protected]
1876-6102 © 2017 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the scientific committee of the 3rd International Conference on Energy and Environment Research. doi:10.1016/j.egypro.2016.12.158
310
Barry A. Benedict / Energy Procedia 107 (2017) 309 – 313
1. Introduction Lifecycle sustainability assessment [1] reviews environmental issues, cost, and social issues over the life of a project, product [2], [3], or policy. These three elements taken together provide the basis for assessing sustainability. Fig. 1 shows elements of a typical life cycle assessment (LCA). Basically, a life cycle assessment considers everything that happens because of the project, product, or process. A typical life cycle consists of raw materials, material processing, manufacturing, assembly, product use and end of life, usually with transportation between steps. This is often called cradle to grave, as it begins with finding and extracting raw materials, and it concludes with disposal of the item when it is no longer useful.
. Fig. 1. Basic elements of Life Cycle Assessment.
There are many potential benefits to application of life cycle sustainability assessment. A few are included in the following: Organizes data in structured form Clarifies tradeoffs Enables consideration of full range of impacts Stimulates innovation Helps decision makers Enables comparative analyses Life cycle sustainability assessment has some overlap with the topics of resilience, asset management, and risk assessment. One recent study has shown that sustainability and resilience are becoming more closely aligned in highway infrastructure [4]. The author has been studying these linkages, and it appears that all have a common core of data needs and life cycle concerns. For example, asset management already calls for a life cycle cost analysis. Coupling life cycle sustainability assessment with scenario planning can enable consideration of uncertainty and assure more robust designs, products, and policies. The major drivers for change include social, technological, environmental, economic, and political. LCA software such as GaBi, Simapro, and OpenLCA have databases and others can be imported. There are free databases, but some require payment of a fee to access them. These are average data from the specific industry and activity and/or product. There are in excess of 70,000 databases. Of course, if accessible and cost effective, local data is preferable. One useful view is the dashboard approach. This uses color coding to indicate results from very good (typically bright green) to very bad (typically bright red), with shadings between the extremes. This enables a quick view of the overall performance and alternatives. Also, results can be shown within each of the three elements environmental life cycle impacts, life cycle costs, and social life cycle assessments. One can better understand the contributions to overall performance and identify points of redesign. 2. Example of solar PV modules The analysis of PV panels [5] is included as a means of illustrating the process and results. It is illustrative of a review of components that might ultimately fit within a larger energy study. The study contrasted production of
Barry A. Benedict / Energy Procedia 107 (2017) 309 – 313
solar PV modules in two German cases and one in Italy. The functional unit selected as the basis of comparison was the square meter. The study used Simapro databases for average values. For example, 21,286 kg of tap water, 4.71 kWh electricity, and 0.11 kg copper, were required for one square meter. Local data that was collected included data on all raw materials for the German site, as well as aggregated electricity use. For the Italian site, some data was available on raw materials, but most came from existing databases. For the life cycle cost analysis, a questionnaire was developed and distributed. Some data was obtained, with other data acquired from databases. One interesting finding showed a significant difference in energy requirements, with the German sites at 0.751 kWh/m2 and the Italian site at 4.711 kWh/m2, both from direct data For the Social LCA, several metrics were used. For workers (segmented by age, gender), the study considered these impact categories: Discrimination; Child labor; Wages;Working hours; Social benefit; and Health conditions.
Fig. 2. Dashboard Illustration of Three PV Modules [].
Results from the study were typically presented in dashboard format. Fig. 2 is an example. This figure contrasts the three sites and times for module construction. For each case, environmental LCA (ELCA), life cycle costs (LCC), and social life cycle assessment (SLCA) are included. Those areas in bright green indicate the most favorable performance, with colors approaching red representing the least desirable performance. The color in the central circle suggests the overall performance for that case. 3. Example contrasting energy scenarios to 2050 in Mexico This study [6] combines scenario planning with life cycle sustainability assessment. Eleven scenarios were developed based on different technologies, electricity mixes, and climate change targets. Further, the study identified seventeen sustainability metrics. They indicate a number of interesting results. For example, they state “…the business-as-usual scenario, mostly based on fossil fuels, is unsustainable regardless of the preferences for different sustainability criteria. “[6] They summarize results as “Overall, the most sustainable scenarios are those with higher penetration of renewables (wind, solar, hydro, geothermal and biomass) and nuclear power. These electricity pathways would enable meeting the national greenhouse gas emission targets by 2050 in a more sustainable way than envisaged by the current policy. However, some trade-offs among the sustainability criteria are needed, particularly with respect to the social impacts. These trade-offs can be explored easily within the decisionsupport framework. This would reveal how different stakeholder preferences affect the outcomes of sustainability assessment, thus contributing to more informed decision and policy making." [6] The tradeoffs mentioned will require engagement of the various stakeholders to develop plans that are balanced. 4. Example contrasting alternative vehicles This recent study [7] compares several types of vehicles across a number of performance measures embedded
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Barry A. Benedict / Energy Procedia 107 (2017) 309 – 313
within the sustainability elements. The vehicles studied include conventional gasoline (ICV), hybrid, plug-in hybrid (PHEV) with four different all-electric ranges, and full battery vehicles (BEV). Two sources of electricity for charging were considered, including use of the ordinary US grid and use of solar charging stations. Nineteen sustainability indicators are included. Results of this analysis revealed that the manufacturing phase is the most influential phase in terms of socio-economic impacts compared to other life cycle phases. The operation phase is the most dominant phase in the terms of environmental impacts and some of the socio-economic impacts such as human health and economic cost of emissions. [7] Using solar charging stations reduced the economic costs of emissions, and human health impact can be reduced up to forty-five percent and thirty-five percent respectively. “BEV has the lowest greenhouse gas emissions and ecological land footprint per $ of its contribution to the U.S. GDP, and has the lowest ecological footprint per unit of its energy consumption. The only sustainability metric that does not favor the BEV is the water-energy ratio, where the conventional gasoline vehicle performed best.”[7] The sustainability indicators chosen included global warming potential, water withdrawal, energy consumption, hazardous waste generation, particulate matter formation potential, fisheries, grazing, forestry, cropland, and CO2 uptake (environmental); import, gross operating surplus, gross domestic product, and air emission cost (economics); and employment, government tax, injuries, income, and human health (social). Such studies can decide up front the areas where it is believed that significant impacts will occur. In this study, there were indicators that additional employment might occur as electric vehicles made a more significant market penetration. 5. Example of UK electricity options This study [8] compares six basic electricity generating processes, with thirty-six indicators of sustainability. The issue under consideration is the ability of the UK to meet mandated greenhouse gas emissions by 2050, as shown in Fig. 3. The six technologies selected were the following: coal (subcritical pulverized) with and without carbon capture and storage (CCS); natural gas (combined cycle gas turbine, CCGT); nuclear (pressurized water reactor, PWR); solar photovoltaics (PV); wind (offshore); and biomass (wood and Miscanthus pellets). “To meet the GHG emission targets, coal CCS can only play a limited role, contributing 10% to the electricity mix at most; the use of CCS also increases other sustainability impacts compared to today, including worker injuries, large accident fatalities, depletion of fossil fuels and long-term waste storage. This calls into question the case for investing in coal CCS. A very low-carbon mix with nuclear and renewables provides the best overall environmental performance, but some impacts increase, such as terrestrial eco-toxicity.”[8]
Fig. 3. Target UK Emissions [8].
“With equal weighting assumed for each sustainability impact, the scenario with an equal share of nuclear and renewables is ranked best.”[8]. The potential use of weighting is a topic worthy of further dialogue as these techniques are advanced. Every project, policy, or product may have different balancing efforts. This reinforces the need to engage stakeholders in the decision process to assure that any weighting used has gained consensus. It further encourages use of parametric studies. By varying the weighting, the effects on the results can be noted. This will enable consideration of those factors with only small influence on the final results, as well as those to which the final outcomes are very sensitive.
Barry A. Benedict / Energy Procedia 107 (2017) 309 – 313
6. Future uses Given the centrality of sustainability concerns to existing and future energy development, distribution, and use, it seems logical to see increasing use of this tool. In fact, for the development of robust plans and strategies, such approaches are essential. Coupling life cycle sustainability with scenario planning will further assure satisfactory solutions over a range of conditions. Best results can be achieved by direct and continuous engagement of stakeholders in the data gathering, discussions, decisions, and continuous monitoring for success. If the described approach is applied to several approaches to a problem, then these alternatives can be compared on all three dimensions. These can include products, projects, policies, energy systems, as well as subsets of energy systems. If these analyses are done properly, then all costs and impacts will be included, assuring that comparisons are realistic. Several examples have been presented to illustrate applications within several energy areas. Each study chose different indicators for the environmental, economic, and social aspects. There is work to be done to assure most effective utilization. These include, but are not limited to the following: Define areas where data and data sources can be used for all or most of the life cycle assessments Define the most effective ways to link scenario planning to these assessments Determine potential interactions between the various life cycle assessments, where changes in one may impact another. Adopt ways to assure that stakeholders are not only included but are essential to the decisions made. Perform studies to determine sensitivity of results to data used. Study how weighting of indicators may not only change results but also be considered by stakeholders. Taken together, the results included in this paper should encourage future use of these techniques, as well as ways to display results in a manner most useful to stakeholders and decision makers. 7. Conclusions Life cycle sustainability is a method of analysis that is growing in use. It recognizes changing conditions over time, as well as differing portions of the life cycle. As more uses and analyses are reported, it is projected that others will recognize the value as a technique for both sustainable development and policy enhancement. To assure best use, research will have to continue to improve understanding of numerous elements. These would include, among other elements, the need for data and a better means of assessing social impacts. References [1] M. Finkbeiner, E.M. Schau, A. Lehmann, and M. Traverso, Toward Life Cycle Sustainability Analysis, Sustainability, 2010, 2, 3309-3322, accessed through http://scholar.google.com/scholar_url?url=http://www.mdpi.com/20711050/2/10/3309/pdf&hl=en&sa=X&scisig=AAGBfm3Pj2J9c6I6v_b51Ue3wDGxTMRlqQ&nossl=1&oi=scholarr [2] UNEP, Guidelines for Social Life Cycle Assessment of Products, 2009, accessed through http://www.unep.org/pdf/DTIE_PDFS/DTIx1164xPA-guidelines_sLCA.pdf [3] UNEP, Towards a Life Cycle Sustainability Assessment for Products, 2012, 86 pp The International Journal of Life Cycle Assessment, September 2012, Volume 17, Issue 8, pp 1068-1079 [4] Paolo Bocchini, M.ASCE1; Dan M. Frangopol, Dist.M.ASCE2; Thomas Ummenhofer3; and Tim Zinke, Resilience and Sustainability of Civil Infrastructure: Toward a Unified Approach, Journal of Infrastructure Systems, American Society of civil Engineering, July 1, 2013, Accessed as http://ascelibrary.org/doi/abs/10.1061/(ASCE)IS.1943-555X.0000177 [5] M. Traverso, F. Asdrubali, A. Francis, and M. Finkbeiner, Towards life cycle sustainability assessment: an implementation to photovoltaic modules, Sep 2012 · The International Journal of Life Cycle Assessment [6] Santoyo-Castelazo, E., A. Azapagic, Sustainability Assessment of Energy Systems: integrating Environmental, Economic, and Social Aspects, Journal of Cleaner Production, Vol. 80, October 1, 2014, pp. 119-138 [7] Nuri Cihat Onat, Murat Kucukvar, and Omer Tateri, Towards Life Cycle Sustainability Assessment of Alternative Passenger Vehicles, Sustainability, December, 2014, pp. 9305-9342. [8] Stamford, L., A. Azapagic, Life Cycle Sustainability Assessment of UK Electricity Scenarios to 2070, Energy for Sustainable Development, Vol. 33, Dec. 2014, pp. 194
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