Environmental footprint of cooking fuels: a life cycle assessment of ten fuel sources used in Indian households

Purpose

Cooking energy is an essential requirement of any human dwelling. With the recent upsurge in petroleum prices coupled with intrinsic volatility of international oil markets, it is fast turning into a politico-socio-economic dilemma for countries like India to sustain future subsidies on liquefied petroleum gas (LPG) and kerosene. The aim of this paper is to evaluate and compare the environmental performance of various cooking fuel options, namely LPG (NG), LPG (CO), kerosene, coal, electricity, firewood, crop residue, dung cake, charcoal, and biogas, in the Indian context. The purpose of this study is to find environmentally suitable alternatives to LPG and kerosene for rural and urban areas of the country.

Methods

The study assessed the cooking fuel performance on 13 ReCiPe environmental impact categories using the life cycle assessment methodology. The study modeled the system boundary for each fuel based on the Indian scenario and prepared a detailed life cycle inventory for each cooking fuel taking 1 GJ of heat energy transferred to cooking pot as the functional unit.

Results and discussion

The cooking fuels with the lowest life cycle environmental impacts are biogas followed by LPG, kerosene, and charcoal. The environmental impacts of using LPG are about 15 to 18 % lower than kerosene for most environmental impact categories. LPG derived from natural gas has about 20 to 30 % lower environmental impact than LPG derived from crude oil. Coal and dung cake have the highest environmental impacts because of significant contributions to climate change and particulate formation, respectively. Charcoal produced from renewable wood supply performs better than kerosene on most impact categories except photochemical oxidation, where its contribution is 19 times higher than kerosene.

Conclusions

Biogas and charcoal can be viewed as potentially sustainable cooking fuel options in the Indian context because of their environmental benefits and other associated co-benefits such as land farming, local employment opportunities, and skill development. The study concluded that kerosene, biogas, and charcoal for rural areas and LPG, kerosene, and biogas for urban areas have the lower environmental footprint among the chosen household cooking fuels in the study.     

A life cycle comparison of disposal and beneficial use of coal combustion products in Florida

Background, aim, and scope  Beneficial use of coal combustion products (CCPs) in industrial or construction operations has the potential to minimize environmental and human health impacts that would otherwise be associated with disposal of CCPs in the life cycle of coal used for electricity generation. To assess opportunities for reducing impacts associated with four CCP materials considered in this study, fly ash, bottom ash, boiler slag, and flue gas desulfurization (FGD) material, this paper reports results of expanding a life cycle inventory of raw material and emissions (part 1 of this series of papers) by performing life cycle impact assessment on five scenarios of CCP management. Materials and methods  SimaPro 5.1 software (PRé Consultants) was used to calculate comparative environmental impacts of all scenarios using CML2001 and Environmental Design of Industrial Products 1997 midpoint impact assessment methods and Heirarchist and Individualist levels of the Eco-indicator 99 end point method. Trends were compared for global and local environmental and human health impact categories of global warming, acidification, smog formation, human toxicity, and ecotoxicity. Results  In each impact category, beneficial use of fly ash, bottom ash, and FGD material resulted in a reduced impact compared to disposal of these materials. The extent to which beneficial use reduced impacts depended on several factors, including the impact category in consideration, the magnitude of potentially avoided impacts associated with producing raw materials that CCPs replace, and the potential impact of CCP disposal methods. Global warming impacts were reduced by the substitution of fly ash for Portland cement in concrete production, as production of Portland cement generates large quantities of CO₂. However, for categories of global warming, smog formation, and acidification, impact reductions from CCP beneficial use are small, less than 6%, as these impacts were attributable, in greater part, to upstream processes of coal mining, transportation, and combustion. Human toxicity and ecotoxicity categories showed larger but more varied reductions, from 0% to 50%, caused by diverting CCPs from landfills and surface impoundments. Discussion  When comparing beneficial use scenarios, the four impact assessment methods used showed similar trends in categories of global warming, acidification, and smog formation. However, results diverged for human toxicity and ecotoxicity categories due to the lack of consensus among methods in classification and characterization of impacts from heavy metal release. Similarly, when assessing sensitivity of these results to changes in assumptions or system boundaries, human toxicity and ecotoxicity categories were most susceptible to change, while other impact categories had more robust results. Conclusions  Impact assessment results showed that beneficial use of CCPs presented opportunities for reduced environmental impacts in the life cycle of coal combusted for electricity generation, as compared to the baseline scenario of 100% CCP disposal, although the impact reductions varied depending on the CCPs used, the ultimate beneficial use, and the impact category in consideration. Recommendations and perspectives  As regulators and electric utilities increasingly consider viability and economics of the use of CCPs in various applications, this study provides a first-basis study of selected beneficial use alternatives. With these initial results, future studies should be directed towards beneficial uses that promise significant economic and environmental savings, such as use of fly ash in concrete, to quantify the currently unknown risk of these applications.     

Environmental impact of thin-film GaInP/GaAs and multicrystalline silicon solar modules produced with solar electricity

Background, aim, and scope  The environmental burden of photovoltaic (PV) solar modules is currently largely determined by the cumulative input of fossil energy used for module production. However, with an increased focus on limiting the emission of CO₂ coming from fossil fuels, it is expected that renewable resources, including photovoltaics, may well become more important in producing electricity. A comparison of the environmental impacts of PV modules in case their life cycle is based on the use of PV electricity in contrast to conventional electricity can elucidate potential environmental drawbacks in an early stage of development of a solar-based economy. The goal of this paper is to show for ten impact categories the environmental consequences of replacing fossil electricity with solar electricity into the life cycle of two types of PV modules. Materials and methods  Using life cycle assessment (LCA), we evaluated the environmental impacts of two types of PV modules: a thin-film GaInP/GaAs tandem module and a multicrystalline silicon (multi-Si) module. For each of the modules, the total amount of fossil electricity required in the life cycle of the module was substituted with electricity that is generated by a corresponding PV module. The environmental impacts of the modules on the midpoint level were compared with those of the same modules in case their life cycle is based on the use of conventional electricity. The environmental impacts were assessed for Western European circumstances with an annual solar irradiation of 1000 kWh/m². For the GaInP/GaAs module, the environmental impacts of individual production steps were also analysed. Results  Environmental burdens decreased when PV electricity was applied in the life cycle of the two PV modules. The impact score reductions of the GaInP/GaAs module were up to a factor of 4.9 (global warming). The impact score reductions found for the multi-Si module were up to a factor of 2.5 (abiotic depletion and global warming). Reductions of the toxicity scores of both module types were smaller or negligible. This is caused by a decreased use of fossil fuels, on the one hand, and an increased consumption of materials for the production of the additional solar modules used for generating the required PV electricity on the other. Overall, the impact scores of the GaInP/GaAs module were reduced more than the corresponding scores of the multi-Si module. The contribution analysis of the GaInP/GaAs module production steps indicated that for global warming, the cell growth process is dominant for supply with conventional electricity, while for the solar scenario, the frame becomes dominant. Regarding freshwater aquatic ecotoxicity scores associated with the life cycle of the GaInP/GaAs module, the cell growth process is dominant for supply with conventional electricity, while the reactor system for the cell growth with the associated gas scrubbing system is dominant for the solar scenario. Discussion  There are uncertainties regarding the calculated environmental impact scores. This paper describes uncertainties associated with the used economic allocation method, and uncertainties because of missing life cycle inventory data. For the GaInP/GaAs module, it was found that the global warming impact scores range from −66% to +41%, and the freshwater aquatic ecotoxicity scores (for an infinite time horizon) range from −40% to +300% compared to the default estimates. For both impact categories, the choices associated with the allocation of gallium, with the electricity mix, with the conversion efficiency of the commercially produced GaInP/GaAs cells, and with the yield of the cell growth process are most influential. For freshwater aquatic ecotoxicity, the uncertainty concerning the lifetime of the reactor system for the GaInP/GaAs cell growth process and the gas scrubbing system is particularly relevant. Conclusions  Use of PV electricity instead of fossil electricity significantly reduces the environmental burdens of the GaInP/GaAs and the multi-Si module. The reductions of the toxicity scores, however, are smaller or negligible. Toxicity impacts of the GaInP/GaAs cells can be reduced by improvement of the yield of the cell growth process, a reduced energy demand in the cell growth process, reduction of the amount of stainless steel in the cell growth reactor system and the gas scrubbing system, and a longer lifetime of these systems. Recommendations and perspectives  Because the greenhouse gas emissions associated with the production of fossil-fuel-based electricity have an important share in global warming on a world-wide scale, switching to a more extensive use of solar power is helpful to comply with the present international legislation on the area of global warming reduction. As reductions in toxicity impact scores are smaller or negligible when fossil electricity is replaced by PV electricity, it is desirable to give specific attention to the processes which dominantly contribute to these impact categories. Furthermore, in this study, a shift in ranking of several environmental impacts of the modules has been found when PV electricity is used instead of fossil electricity. The results of a comparative LCA can thus be dependent of the electricity mix used in the life cycles of the assessed products. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

基于生命周期方法的生活垃圾资源化利用系统生态效率分析

我国生活垃圾产量大但处理能力不足,产生多种环境危害,对其资源化利用能够缓解环境压力并回收资源。为探讨生活垃圾资源化利用策略,综合生命周期评价与生命周期成本分析方法,建立生态效率模型。以天津市为例,分析和比较焚烧发电、卫生填埋-填埋气发电、与堆肥+卫生填埋3种典型生活垃圾资源化利用情景的生态效率。结果表明,堆肥+卫生填埋情景具有潜在最优生态效率;全球变暖对总环境影响贡献最大,而投资成本对经济影响贡献最大。考虑天津市生活垃圾管理现状,建议鼓励发展生活垃圾干湿组分分离及厨余垃圾堆肥的资源化利用策略。     

Environmental Life Cycle Assessment of a Swedish Dissolving Pulp Mill Integrated Biorefinery

The pulp industry plays an important role in the structure of the European economy and society. The production of pulp has been traditionally considered an important source of pollution due to the use of large amounts of chemicals, fuels, and water and its intensive energy consumption. Currently, this situation is changing due to the potential use of biomass to produce value‐added products, which minimizes environmental impacts and increases sustainability. This article uses life cycle assessment (LCA) to identify and quantify the environmental impacts associated with a Swedish softwood‐based biorefinery where total chlorine‐free (TCF) dissolving cellulose is produced together with ethanol and lignosulfonates. The system was defined according to a cradle‐to‐gate perspective—that is to say, from forest activities to the output of the biorefinery mill. According to the results, forest activities associated with the production of soft roundwood play a minor role in all the environmental impact categories under study. In contrast, the production of chemicals consumed in the cooking and bleaching stages, the sludge treatment generated in the wastewater treatment plant, and the on‐site energy production system were identified as the elements that negatively contribute the most to all impact categories. The production of steam from biorefinery wastes, biogas, and methanol in external boilers reduces the environmental impact in all categories. Specific actions associated with the reuse of wastes and improved gas treatment systems would improve the environmental profile of this production activity.     

Energy requirements and environmental impacts associated with the production of short rotation willow (Salix sp.) chip in Ireland

Willow Salix sp. is currently cultivated as a short rotation forestry crop in Ireland as a source of biomass to contribute to renewable energy goals. The aim of this study is to evaluate the energy requirements and environmental impacts associated with willow (Salix sp.) cultivation, harvest, and transport using life cycle assessment (LCA). In this study, only emissions from the production of the willow chip are included, end‐use emissions from combustion are not considered. In this LCA study, three impact categories are considered; acidification potential, eutrophication potential and global warming potential. In addition, the cumulative energy demand and energy ratio of the system are evaluated. The results identify three key processes in the production chain which contribute most to all impact categories considered; maintenance, harvest and transportation of the crop. Sensitivity analysis on the type of fertilizers used, harvesting technologies and transport distances highlights the effects of these management techniques on overall system performance. Replacement of synthetic fertilizer with biosolids results in a reduction in overall energy demand, but raises acidification potential, eutrophication potential and global warming potential. Rod harvesting compares unfavourably in comparison with direct chip harvesting in each of the impact categories considered due to the additional chipping step required. The results show that dedicated truck transport is preferable to tractor‐trailer transport in terms of energy demand and environmental impacts. Finally, willow chip production compares favourably with coal provision in terms of energy ratio and global warming potential, while achieving a higher energy ratio than peat provision but also a higher global warming potential.     

Quantifying system uncertainty of life cycle assessment based on Monte Carlo simulation

Background, aim, and scope

Many studies evaluate the results of applying different life cycle impact assessment (LCIA) methods to the same life cycle inventory (LCI) data and demonstrate that the assessment results would be different with different LICA methods used. Although the importance of uncertainty is recognized, most studies focus on individual stages of LCA, such as LCI and normalization and weighting stages of LCIA. However, an important question has not been answered in previous studies: Which part of the LCA processes will lead to the primary uncertainty? The understanding of the uncertainty contributions of each of the LCA components will facilitate the improvement of the credibility of LCA.

Methodology

A methodology is proposed to systematically analyze the uncertainties involved in the entire procedure of LCA. The Monte Carlo simulation is used to analyze the uncertainties associated with LCI, LCIA, and the normalization and weighting processes. Five LCIA methods are considered in this study, i.e., Eco-indicator 99, EDIP, EPS, IMPACT 2002+, and LIME. The uncertainty of the environmental performance for individual impact categories (e.g., global warming, ecotoxicity, acidification, eutrophication, photochemical smog, human health) is also calculated and compared. The LCA of municipal solid waste management strategies in Taiwan is used as a case study to illustrate the proposed methodology.

Results

The primary uncertainty source in the case study is the LCI stage under a given LCIA method. In comparison with various LCIA methods, EDIP has the highest uncertainty and Eco-indicator 99 the lowest uncertainty. Setting aside the uncertainty caused by LCI, the weighting step has higher uncertainty than the normalization step when Eco-indicator 99 is used. Comparing the uncertainty of various impact categories, the lowest is global warming, followed by eutrophication. Ecotoxicity, human health, and photochemical smog have higher uncertainty.

Discussion

In this case study of municipal waste management, it is confirmed that different LCIA methods would generate different assessment results. In other words, selection of LCIA methods is an important source of uncertainty. In this study, the impacts of human health, ecotoxicity, and photochemical smog can vary a lot when the uncertainties of LCI and LCIA procedures are considered. For the purpose of reducing the errors of impact estimation because of geographic differences, it is important to determine whether and which modifications of assessment of impact categories based on local conditions are necessary.

Conclusions

This study develops a methodology of systematically evaluating the uncertainties involved in the entire LCA procedure to identify the contributions of different assessment stages to the overall uncertainty. Which modifications of the assessment of impact categories are needed can be determined based on the comparison of uncertainty of impact categories.

Recommendations and perspectives

Such an assessment of the system uncertainty of LCA will facilitate the improvement of LCA. If the main source of uncertainty is the LCI stage, the researchers should focus on the data quality of the LCI data. If the primary source of uncertainty is the LCIA stage, direct application of LCIA to non-LCIA software developing nations should be avoided.     

Environmental impacts of wooden,plastic, and wood-polymer composite pallet: a life cycle assessment approach

Purpose

Waste recycling is one of the essential tools for the European Union’s transition towards a circular economy. One of the possibilities for recycling wood and plastic waste is to utilise it to produce composite product. This study analyses the environmental impacts of producing composite pallets made of wood and plastic waste from construction and demolition activities in Finland. It also compares these impacts with conventional wooden and plastic pallets made of virgin materials.

Methods

Two different life cycle assessment methods were used: attributional life cycle assessment and consequential life cycle assessment. In both of the life cycle assessment studies, 1000 trips were considered as the functional unit. Furthermore, end-of-life allocation formula such as 0:100 with a credit system had been used in this study. This study also used sensitivity analysis and normalisation calculation to determine the best performing pallet.

Result and discussion

In the attributional cradle-to-grave life cycle assessment, wood-polymer composite pallets had the lowest environmental impact in abiotic depletion potential (fossil), acidification potential, eutrophication potential, global warming potential (including biogenic carbon), global warming potential (including biogenic carbon) with indirect land-use change, and ozone depletion potential. In contrast, wooden pallets showed the lowest impact on global warming potential (excluding biogenic carbon). In the consequential life cycle assessment, wood-polymer composite pallets showed the best environmental impact in all impact categories. In both attributional and consequential life cycle assessments, plastic pallet had the maximum impact. The sensitivity analysis and normalisation calculation showed that wood-polymer composite pallets can be a better choice over plastic and wooden pallet.

Conclusions

The overall results of the pallets depends on the methodological approach of the LCA. However, it can be concluded that the wood-polymer composite pallet can be a better choice over the plastic pallet and, in most cases, over the wooden pallet. This study will be of use to the pallet industry and relevant stakeholders.

     

Rare Earths from Mines to Metals: Comparing Environmental Impacts from China's Main Production Pathways

Over the past decade, China has supplied over 90% of global rare earths, and in doing so bore significant environmental burdens from processing its complex ores. In this study, we used life cycle assessment to quantify environmental impacts for producing 1 kilogram (kg) of 15 rare earth elements from each major production pathway. The scope of assessment included the largest rare earth oxide (REO) production chain in Bayan Obo, as well as lesser known production chains for bastnäsite in Sichuan and in‐situ leaching of kaolin clays in the Seven Southern Provinces of China. This was followed by assessing impacts from the three major metal refining processes: molten salt electrolysis, calciothermic reduction, and lanthanothermic reduction. Among 11 impact categories assessed, results were highest for human toxicity that ranged between 13.1 and 50.4 kg 1,4‐dichlorobenzene‐eq (equivalent)/kg of rare earth metal^?1, followed by eutrophication (0.04 to 1.26 kg phosphate‐eq/kg of rare earth metal^?1), abiotic depletion potential of fossil fuels (592 to 1,857 megajoules per kg of rare earth metal^?1), acidification (0.25 to 0.87 kg sulfur dioxide‐eq/kg of rare earth metal^?1), and global warming (39.1 to 109.6 kg carbon dioxide‐eq/kg of rare earth metal^?1) potentials. Regionally, impacts in Sichuan were lower across all key impact categories than in Bayan Obo: 32% lower for human toxicity, 67% lower for eutrophication, 58% lower for acidification, and 45% lower for global warming. A scenario analysis between the industry average and best available technologies revealed considerable potential to mitigate impacts across all production chains, particularly by improving waste treatment practices.     

Environmental performance assessment of hardboard manufacture

Background, aim and scope  The forest-based and related industries comprise one of the most important industry sectors in the European Union, representing some 10% of the EU's manufacturing industries. Their activities are based on renewable raw material resources and efficient recycling. The forest-based industries can be broken down into the following sectors: forestry, woodworking, pulp and paper manufacturing, paper and board converting and printing and furniture. The woodworking sector includes many sub-sectors; one of the most important is that of wood panels accounting for 9% of total industry production. Wood panels are used as intermediate products in a wide variety of applications in the furniture and building industries. There are different kinds of panels: particleboard, fibreboard, veneer, plywood and blockboard. The main goal of this study was to assess the environmental impacts during the life cycle of wet-process fibreboard (hardboard) manufacturing to identify the processes with the largest environmental impacts. Methods  The study covers the life cycle of hardboard production from a cradle-to-gate perspective. A hardboard plant was analysed in detail, dividing the process chain into three subsystems: wood preparation, board forming and board finishing. Ancillary activities such as chemicals, wood chips, thermal energy and electricity production and transport were included within the system boundaries. Inventory data came from interviews and surveys (on-site measurements). When necessary, the data were complemented with bibliographic resources. The life cycle assessment procedure followed the ISO14040 series. The life cycle inventory (LCI) and impact assessment database for this study were constructed using SimaPro Version 7.0 software. Results  Abiotic depletion (AD), global warming (GW), ozone layer depletion (OLD), human toxicity (HT), ecotoxicity, photochemical oxidant formation (PO), acidification (AC) and eutrophication (EP) were the impact categories analysed in this study. The wood preparation subsystem contributed more than 50% to all impact categories, followed by board forming and board finishing, which is mainly due to chemicals consumption in the wood preparation subsystem. In addition, thermal energy requirements (for all subsystems) were fulfilled by on-site wood waste burning and, accordingly, biomass energy converters were considered. Several processes were identified as hot spots in this study: phenol-formaldehyde resin production (with large contribution to HT, fresh water aquatic ecotoxicity and PO), electricity production (main contributor to marine aquatic ecotoxicity), wood chips production (AD and OLD) and finally, biomass burning for heat production (identified as the largest contributor to AC and EP due to NO _X emissions). In addition, uncontrolled formaldehyde emissions from manufacturing processes at the plant such as fibre drying should be controlled due to relevant contributions to terrestrial ecotoxicity and PO. A sensitivity analysis of electricity profile generation (strong geographic dependence) was carried out and several European profiles were analysed. Discussion  Novel binding agents for the wood panel industry as a substitute for the currently used formaldehyde-based binders have been extensively investigated. Reductions of toxic emissions during drying, mat forming and binder production are desirable. The improved method would considerably reduce the contributions to all impact categories. Conclusions  The results obtained in this work allow forecasting the importance of the wood preparation subsystem for the environmental burdens associated with hardboard manufacture. Special attention was paid to the inventory analysis stage for each subsystem. It is possible to improve the environmental performance of the hardboard manufacturing process if some alternatives are implemented regarding the use of chemicals, electricity profile and emission sources in the production processes located inside the plant. Recommendations and perspectives  This study provides useful information for forest-based industries related to panel manufacture with the aim of increasing their sustainability. Our research continues to assess the use phase and final disposal of panels to complete the life cycle assessment. Future work will focus on analysing the environmental aspects associated with plywood, another type of commonly used wood panel.     

A life cycle assessment study of a Canadian post-combustion carbon dioxide capture process system

Purpose

While carbon dioxide capture and storage (CCS) has been widely recognized as a useful technology for mitigating greenhouse gas emissions, it is necessary to evaluate the environmental performance of CCS from a full life cycle perspective to comprehensively understand its environmental impacts. The primary research objective is to conduct a study on life cycle assessment of the post-combustion carbon dioxide capture process based on data from SaskPower’s electricity generation station at the Boundary Dam in Saskatchewan, Canada. A secondary objective of this study is to identify the life cycle impact assessment (LCIA) methodology which is most suitable for the assessment of carbon dioxide capture technology integrated with the power generation system in the Canadian context.

Methods

The study takes a comparative approach by including three scenarios of carbon dioxide capture at the electricity generation station: no carbon dioxide capture (“no capture”), partial capture (“retrofit”), and fully integrated carbon dioxide capture of the entire facility (“capture”). The four LCIA methods of EDIP 97, CML2001, IMPACT2002+, and TRACI are used to convert existing inventory data into environmental impacts. The LCIA results from the four methods are compared and interpreted based on midpoint categories.

Results and discussion

The LCA results showed an increase in the retrofit and capture scenarios compared to the no capture scenario in the impact categories of eutrophication air, ecotoxicity water, ecotoxicity ground surface soil, eutrophication water, human health cancer ground surface soil, human health cancer water, human health noncancer ground surface soil, ozone depletion air, human health noncancer water, and ionizing radiation. The reductions were observed in the retrofit and capture scenarios in the impact categories of acidification, human health criteria air-point source, human health noncancer air, ecotoxicity air, global warming, human health cancer air, and respiratory effects.

Conclusions

Although the four LCIA methodologies significantly differ in terms of reference substances used for individual impact categories, all (TRACI, IMPACT2002+, CML2001, and EDIP 97) showed similar results in all impact categories.     

Environmental life cycle assessment of biodiesel produced with palm oil from Colombia

Purpose

Palm biodiesel life cycle studies have been mainly performed for Asia and focused on greenhouse gas (GHG) intensity. The purpose of this article is to present an environmental life cycle assessment (LCA) of biodiesel produced in Portugal from palm oil (PO) imported from Colombia, addressing the direct effects of land-use change (LUC), different fertilization schemes, and biogas management options at the extraction mill.

Methods

An LC inventory and model of PO biodiesel was implemented based on data collected in five Portuguese biodiesel plants and in a palm plantation and extraction mill in the Orinoquía Region of Colombia. The emissions due to carbon stock changes associated with LUC were calculated based on the Colombian oil palm area expansion from 1990 to 2010 and on historical data of vegetation cleared for planting new palm trees. Five impact categories were assessed based on ReCiPe and CML-IA methods: GHG intensity, freshwater and marine eutrophication, photochemical oxidant formation, terrestrial acidification. A sensitivity analysis of alternative allocation approaches was performed.

Results and discussion

Palm plantation was the LC phase which contributed the most to eutrophication and acidification impacts, whereas transportation and oil extraction contributed the most to photochemical oxidation. An increase in carbon stock due to LUC associated with the expansion of Colombian oil palm was calculated (palm is a perennial crop with higher carbon stock than most previous land-uses). The choice of the fertilization scheme that leads to the lowest environmental impacts is contradictory among various categories. The use of calcium ammonium nitrate (followed by ammonium sulfate) leads to the lowest acidification and eutrophication impacts. The highest GHG intensity was calculated for calcium ammonium nitrate, while the lowest was for ammonium sulfate and poultry manure. Biogas captured and flared at the oil extraction mill instead of being released into the atmosphere had the lowest impacts in all categories (GHG intensity reduced by more than 60 % when biogas is flared instead of released).

Conclusions

Recommendation on the selection of the fertilization scheme depends on the environmental priority. ReCiPe and CML showed contradictory results for eutrophication and photochemical oxidation; however, uncertainty may impair strong recommendations. GHG intensity and photochemical oxidation impacts can be significantly reduced if biogas is flared instead of being released. However, more efficient biogas management should be implemented in order to reduce the impacts further.

     

Setting Priorities within Product-Oriented Environmental Policy

To focus Danish product‐oriented environmental policy, a study applying extended input‐output analysis has been performed, identifying the most important product groups from an environmental perspective. The environmental impacts are analyzed from three different perspectives—the supply perspective, the consumption perspective, and the process perspective—differing primarily in their system delimitation. The top ten environmentally most important product groups (out of 138 industry products and 98 final consumption groups) are listed for each of the three perspectives, using both total environmental impact and environmental impact intensity as ranking principles. The study covers all substances that contribute significantly to the environmental impact categories of global warming, ozone depletion, acidification, nutrient enrichment, photochemical ozone formation, ecotoxicity, human toxicity, and nature occupation. The differences in results between the three perspectives are elaborated and their policy relevance discussed. The top ten product groups account for a surprisingly large share of the total environmental impact of Danish production and consumption (up to 45%, depending upon the perspective). This implies that product‐oriented environmental policy may achieve large improvements by focusing on a rather small number of product groups. Both imported products and products produced for export in general cause more environmental impact than products produced in Denmark for the Danish market. Especially noticeable are the export of meat and ship transport. This leads to the recommendation to include specific policy measures targeting both foreign producers and foreign markets. Because of its relatively large input of labor, public consumption is found to have a much smaller environmental impact intensity than private consumption. The results confirm results of other similar studies, but are more detailed and have lower uncertainty, due to a number of improvements in data and methodology. A short presentation of the methodology is provided as background information, although this is not the main focus of this article.     

Review of impact categories and environmental indicators for life cycle assessment of geotechnical systems

Life cycle assessment (LCA) has only had limited application in the geotechnical engineering discipline, though it has been widely applied to civil engineering systems such as pavements and roadways. A review of previous geotechnical LCAs showed that most studies have tracked a small set of impact categories, such as energy and global warming potential. Accordingly, currently reported environmental indicators may not effectively or fully capture important environmental impacts and tradeoffs associated with geotechnical systems, including those associated with land and soil resources. This research reviewed previous studies, methods, and models for assessment of land use and soil‐related impacts to understand their applicability to geotechnical LCA. The results of this review show that critical gaps remain in current knowledge and practice. In particular, further development or refinement of environmental indicators, impact categories, and cause–effect pathways is needed as they pertain to geotechnical applications—specifically those related to soil quality, soil functions, and the ecosystem services soils provide. In addition, many existing methods emerge from research on land use and land use change related to other disciplines (e.g., agriculture). For applicability to geotechnical projects, the resolution of many of these methods and resulting indicators need to be downscaled from the landscape/macro scale to the project scale. In the near term, practitioners of geotechnical LCA should begin tracking changes to soil properties and report impacts to land and soil resources qualitatively.     

Life cycle assessment of a biobased chainsaw oil made on the farm in Wallonia

Purpose

The environmental issue is a particular concern for chainsaw oils because these fluids represent a total loss system. The aim of this study is to quantify the environmental impacts of a biobased chainsaw oil made on the farm in Wallonia (a region of Belgium) and to compare it with a model mineral chainsaw oil. With this study, the aim is also to participate in the development of the life cycle assessment (LCA) methodology applied to the biolubricant sector since LCAs on these products are quite limited and rarely sufficiently detailed.

Method

In this LCA, the attributional approach is applied. Seven impact categories are studied. The methods for life cycle impact assessment are IPCC, ReCiPe, CML and USEtox. The functional unit is 1 kg of base oil. Seven sensitivity analyses are performed.

Results and discussion

Results indicate that the biobased chainsaw oil made on the farm has a lower impact for the global warming potential, the abiotic depletion potential, the ozone depletion potential and the photochemical oxidation potential. On the contrary, it has larger acidification, aquatic eutrophication and aquatic ecotoxicity potential impacts. Regarding the contribution of the life cycle stages of the biobased chainsaw oil, the agricultural stage causes the highest contribution in all impact categories. For the mineral chainsaw oil, the refining stage is preponderant for all impact categories except for the global warming potential for which the end-of-life stage contributes the most. When taking additives into account, conclusions regarding the comparison between the oils are not reversed. Even if it was necessary to consume more biobased than mineral chainsaw oil, conclusions regarding the comparison of the oils would not be reversed. In the same way, a different allocation procedure for rapeseed oil and rape meal, a different rape seeds yield or different extraction yields in the refining stage of the mineral base oil do not change the results of the comparison. For the biobased chainsaw oil, the substitution of only one active substance in the agricultural stage could result in an important decrease of the freshwater ecotoxicity impact.

Conclusions

The biobased chainsaw oil has a lower impact in four out of the seven impact categories and a higher impact in three impact categories. By providing a detailed LCA on a biobased chainsaw oil, this study contributes to the development of LCA applied to biobased lubricants.     

Environmental and human health impacts of growing genetically modified herbicide-tolerant sugar beet: a life-cycle assessment

There is ongoing debate concerning the possible environmental and human health impacts of growing genetically modified (GM) crops. Here, we report the results of a life-cycle assessment (LCA) comparing the environmental and human health impacts of conventional sugar beet growing regimes in the UK and Germany with those that might be expected if GM herbicide-tolerant (to glyphosate) sugar beet is commercialized. The results presented for a number of environmental and human health impact categories suggest that growing the GM herbicide-tolerant crop would be less harmful to the environment and human health than growing the conventional crop, largely due to lower emissions from herbicide manufacture, transport and field operations. Emissions contributing to negative environmental impacts, such as global warming, ozone depletion, ecotoxicity of water and acidification and nutrification of soil and water, were much lower for the herbicide-tolerant crop than for the conventional crop. Emissions contributing to summer smog, toxic particulate matter and carcinogenicity, which have negative human health impacts, were also substantially lower for the herbicide-tolerant crop. The environmental and human health impacts of growing GM crops need to be assessed on a case-by-case basis using a holistic approach. LCA is a valuable technique for helping to undertake such assessments.     

Environmental Effects of Steam Explosion Pretreatment on Biogas from Maize—Case Study of a 500-kW Austrian Biogas Facility

Potential environmental impacts of biogas electricity from agricultural residues (maize stover) with steam explosion (SE) pretreatment were compared to a typical Austrian biogas system (maize silage) using the method of life cycle assessment. Besides the biogas plant, the system includes substrate production, a combined heat-and-power (CHP) unit, digestate management, and transportation. The stover scenario (including construction and operation of the SE unit) results in lower total climate change impacts than those of the typical biogas system (239 g CO₂-eq/kWh electricity vs. 287 g CO₂-eq/kWh electricity; 100-year global warming potential (GWP)), and this holds also for the other impact categories (e.g., cumulative energy demand, acidification, eutrophication). While uncertainties in other areas could change the results, based on the uncertainty information considered, the overall results for the two scenarios were significantly different. Methane slip emissions from the CHP exhaust account for the largest GWP share in both scenarios. Other large GWP contributions are from substrate production and grid electricity for plant operations. The findings were robust against worst-case assumptions about the energy requirements of the SE pretreatment.     

Comparing Three Life Cycle Impact Assessment Methods from an Endpoint Perspective

The impact assessment methods Eco‐Indicator 99 (H), Stepwise2006, and ReCiPe2008 (H) are compared with respect to the relative and absolute importance that they assign to the different mid‐point impact categories. The comparison is done by a common monetary valuation of the three endpoints that are common to the three methods: human well‐being, nature, and resources. Land use, global warming, and respiratory inorganic pollutants together make up between 86% and 97% of the overall impacts compared in all three methods. The overall monetarized impacts amount to 30%, 28%, and 165% of the gross domestic product (GDP), respectively. Resource depletion, land use, and global warming explain 99.5% of the positive deviation of ReCiPe2008, relative to the other two methods. The main causes for these differences are investigated and discussed, pointing to possibly questionable calculations and assumptions, for example, regarding the nonsubstitutability of resources and the very long relaxation time for transformed forestland in the relatively new ReCiPe2008 method, which leads us to recommend users to be cautious and critical when interpreting the results. Sensitivity analysis is made for other cultural perspectives and normalization references.     

Life cycle assessment of biogas infrastructure options on a regional scale

A life cycle assessment has been completed of potential biogas infrastructures on a regional scale. Centralised and distributed infrastructures were considered along with biogas end uses of Combined Heat and Power (CHP) and injection to the gas grid for either transport fuel or domestic heating end uses. Damage orientated (endpoint) life cycle impact assessment method identified that CHP with 80% heat utilisation had the least environmental impact, followed by transport fuel use. Utilisation for domestic heating purposes via the gas grid was found to perform less well. A 32% difference in transportation requirement between the centralised and distributed infrastructures was found to have a relatively small effect on the overall environmental impact. Global warming impacts were significantly affected by changes in methane emissions at upgrading stage, highlighting the importance of minimising operational losses.     

Life Cycle Assessment of a Personal Computer and its Effective Recycling Rate (7 pp)

Background, Aims and Scope Telecommunication and information technology, dramatically emerged during the last decade, has generated environmental problems by accelerating mass production, mass consumption, and mass disposal of personal computers (PCs) in Korea. In addition, it has led the Korean new economy. The Korean government has encouraged researchers and industry to study the environmental impact, adequate disposal treatment, and the reasonable recycling rate of an end-of-life personal computer. The main purpose of this research is to investigate the life cycle environmental impact of PCs and to determine the desirable or feasible recycle rate of an end-of-life PC. An LCA on a PC was performed based on different recycling scenario. Target audiences are new product developers, designers, product recovery managers and environmental policy makers who are interested in the environmental impact of PCs and recycling of end-of-life products. Methods A target product is a Pentium IV personal computer made in Korea in 2001, excluding the monitor and peripheral equipment. The procedure of the LCA followed the ISO14040 series. System boundary includes the entire life cycle of the product, including pre-manufacturing (the electrical parts and components manufacturing), manufacturing, transportation, use, and disposal. The LCI and impact assessment database for a PC was constructed using SIMAPRO version 4.0 software and LCI information was compiled by site-specific data and the Korean national database. The LCA was performed on different recycling scenarios: one being that of the current recycling rate of 46%, and the other being the ideal condition of a 100% recycling rate. Results and Discussion Abiotic depletion, global warming, ecotoxicity, human toxicity, acidification, ozone layer depletion, photo-oxidant formation, and eutrophication are adopted as the impact categories. The pre-manufacturing stage was a significant stage for all of the environmental parameters, besides human toxicity potential. PC manufacturing consists of rather simple processes such as assembly and packaging. For improving the environmental performance of PCs, environmental management approaches of design for the environment and green procurement are recommended. The use stage had a significant potential due to the electricity consumption produced by burning fossil fuel. The disposal stage's contribution to environmental impact was largest in human toxicity, and second largest in ozone layer depletion potential. The PC recycling was shown to inhibit all environmental impacts with the exception of the ozone depletion and ecotoxicity potential. The increase of light oil, nitric acid, sulfuric acid, and deoxidating agent consumption during the recycling process contributes to the environmental impact of ozone and ecotoxicity parameters. Current recovery and recycling technologies should be taken into account for enhancing the benefits of recycling. Anyway, the effectiveness of recycling was highlighted by this study. PC recycling reduces the total environmental impact of the product. The PC recycling is recommended to be raised up to at least 63% in order to reduce the environmental burdens of a PC in other life cycle stages. Conclusion and Recommendation This study implies that design for the environment (DfE) in the product design stage and green procurement are recommended for improving the entire environmental performance of electronic equipment such as PCs. The recycling of waste PCs clearly reduces the environmental burden. There are, however, trade-offs among environmental parameters according to the PC recycling rate. Current recycling methods are not effective in reducing ozone depletion and ecotoxicity environmental impact. The product recovery is another key for efficient recycling. Efficient reverse logistics to collect and transport end-of-life PCs should be taken into account to enhance recycling effects. There were several electrical parts not included in this assessment, due to the unavailability of adequate data. Further studies with more detail and reliable inventories for electrical parts and sub-components are recommended. Furthermore, costs of recycling should also be treated in further research.