Comparative life cycle assessment and life cycle costing of lodging in the Himalaya

Purpose

The main aim of the study is to assess the environmental and economic impacts of the lodging sector located in the Himalayan region of Nepal, from a life cycle perspective. The assessment should support decision making in technology and material selection for minimal environmental and economic burden in future construction projects.

Methods

The study consists of the life cycle assessment and life cycle costing of lodging in three building types: traditional, semi-modern and modern. The life cycle stages under analysis include raw material acquisition, manufacturing, construction, use, maintenance and material replacement. The study includes a sensitivity analysis focusing on the lifespan of buildings, occupancy rate and discount and inflation rates. The functional unit was formulated as the ‘Lodging of one additional guest per night’, and the time horizon is 50 years of building lifespan. Both primary and secondary data were used in the life cycle inventory.

Results and discussion

The modern building has the highest global warming potential (kg CO_2-eq) as well as higher costs over 50 years of building lifespan. The results show that the use stage is responsible for the largest share of environmental impacts and costs, which are related to energy use for different household activities. The use of commercial materials in the modern building, which have to be transported mostly from the capital in the buildings, makes the higher GWP in the construction and replacement stages. Furthermore, a breakdown of the building components shows that the roof and wall of the building are the largest contributors to the production-related environmental impact.

Conclusions

The findings suggest that the main improvement opportunities in the lodging sector lie in the reduction of impacts on the use stage and in the choice of materials for wall and roof.

     

Comparative life cycle assessment of three biohydrogen pathways

A life cycle assessment was performed to quantify and compare the energetic and environmental performances of hydrogen from wheat straw (WS-H₂), sweet sorghum stalk (SSS-H₂), and steam potato peels (SPP-H₂). Inventory data were derived from a pilot plant. Impacts were assessed using the impact 2002+ method. When co-product was not considered, the greenhouse gas (GHG) emissions were 5.60 kg CO_2eq kg⁻¹ H₂ for WS-H₂, 5.32 kg CO_2eq kg⁻¹ H₂ for SSS-H₂, and 5.18 kg CO_2eq kg⁻¹ H₂ for SPP-H₂. BioH₂ pathways reduced GHG emissions by 52-56% compared to diesel and by 54-57% compared to steam methane reforming production of H₂. The energy ratios (ER) were also comparable: 1.08 for WS-H₂, 1.14 for SSS-H₂ and 1.17 for SPP-H₂. A shift from SPP-H₂ to WS-H₂ would therefore not affect the ER and GHG emissions of these BioH₂ pathways. When co-product was considered, a shift from SPP-H₂ to WS-H₂ or SSS-H₂ decreased the ER, while increasing the GHG emissions significantly. Co-product yield should be considered when selecting BioH₂ feedstocks.     

Comparative life cycle assessment and social life cycle assessment of used polyethylene terephthalate (PET) bottles in Mauritius

Purpose

Improper disposal of used polyethylene terephthalate (PET) bottles constitute an eyesore to the environmental landscape and is a threat to the flourishing tourism industry in Mauritius. It is therefore imperative to determine a suitable disposal method of used PET bottles which not only has the least environmental load but at the same time has minimum harmful impacts on peoples employed in waste disposal companies. In this respect, the present study investigated and compared the environmental and social impacts of four selected disposal alternatives of used PET bottles.

Methods

Environmental impacts of the four disposal alternatives, namely: 100 % landfilling, 75 % incineration with energy recovery and 25 % landfilling, 40 % flake production (partial recycling) and 60 % landfilling and 75 % flake production and 25 % landfilling, were determined using ISO standardized life cycle assessment (ISO 14040:2006) and with the support of SimaPro 7.1 software. Social life cycle assessments were performed based on the UNEP/SETAC Guidelines for Social Life Cycle Assessment of products. Three stakeholder categories (worker, society and local community) and eight sub-category indicators (child labour, fair salary, forced labour, health and safety, social benefit/social security, discrimination, contribution to economic development and community engagement) were identified to be relevant to the study. A new method for aggregating and analysing the social inventory data is proposed and used to draw conclusions.

Results and discussion

Environmental life cycle assessment results indicated that highest environmental impacts occurred when used PET bottles were disposed by 100 % landfilling while disposal by 75 % flake production and 25 % landfilling gave the least environmental load. Social life cycle assessment results indicated that least social impacts occurred with 75 % flake production and 25 % landfilling. Thus both E-LCA and S-LCA rated 75 % flake production and 25 % landfilling to be the best disposal option.

Conclusions

Two dimensions of sustainability (environmental and social) when investigated using the Life Cycle Management tool, favoured scenario 4 (75 %?% flake production and 25 % landfilling) which is a partial recycling disposal route. One hundred percent landfilling was found out to be the worst scenario. The next step will be to explore the third pillar of sustainability, economic, and devise a method to integrate the three dimensions with a view to determine the sustainable disposal option of used PET bottles in Mauritius.     

Comparative life cycle assessment of rapeseed oil and palm oil

Background, aim and scope  

The environmental effect of globalisation has been debated intensively in the last decades. Only few well-documented analyses of global versus local product alternatives exist, whilst recommendations on buying local are vast. At the same time, the European Environmental Agency’s Third Assessment concludes that the resource use within the EU is stabilising at the expense of increased resource use for import of products to the EU. Taking its point of departure in vegetable oils, this article compares rapeseed oil and palm oil as a local and a global alternative for meeting the increasing demand for these products in the EU. By using detailed life cycle assessment (LCA), this study compares the environmental impacts and identifies alternative ways of producing rapeseed oil and palm oil to the EU market in order to reduce environmental impacts.     

Comparative life cycle assessment of uses of rice husk for energy purposes

Purpose  

Recently, the Thai government has been advancing the expanded use of biomass as an alternative source of energy substituting it for the fossil fuels that have been shown to be harmful to the environment. Rice husk, one of the main sources of biomass in Thailand, has already been used as an energy source in many different applications and has been successful in reducing the consumption of fossil fuels. At present (2011), the main use of rice husk in Thailand is as fuel to generate electricity. However, rice husk can potentially be used to produce other forms of energy such as cellulosic ethanol. This paper compares the environmental performance of the current main use of rice husk for energy purposes in the Thai context, i.e., for electricity generation with the prospective use, i.e., for cellulosic ethanol production. The results from this study will identify the more environmentally friendly option for use of rice husk for energy purposes.     

Comparative life cycle assessment of reused versus disposable dental burs

Purpose

Health care infection control has led to increased utilization of disposable medical devices, which has subsequently led to adverse environmental effects attributed to health care and its supply chain. In dental practice, the dental bur is a commonly used instrument that can be either reused or used once and then disposed. To evaluate the disparities in environmental impacts of disposable and reusable dental burs, a comparative life cycle assessment (LCA) was performed.

Methods

The functional unit was defined as one reusable dental bur, where the maximum instances reused was 30 (or in the case of a disposable, the equivalent functional unit would be 30 disposable dental burs). The system boundary included all cradle-to-grave aspects of both single-use and reused burs, including raw material extraction, manufacturing, packaging, distribution, reuse, and disposal. Primary data included the following: operating parameters for ultrasonic cleaning, manual cleaning, and autoclaving of the burs. The secondary data for raw material extraction and production of dental bur and packaging were obtained directly from life cycle inventory databases. Sensitivity analyses were also performed with respect to ultrasonic and autoclave loading.

Results and discussion

Findings from this research showed that when the ultrasonic and autoclave were loaded optimally, reusable burs had 40 % less of an environmental impact than burs used on a disposable basis. When the autoclave and ultrasonic were loaded to approximately two-third capacity, four environmental impact categories favored reusable burs (i.e., ozone depletion, smog, respiratory effects, exotoxicity), and four impact categories environmentally favored disposables (i.e., acidification, eutrophication, carcinogenics, and non-carcinogenics). When the autoclave and ultrasonic were loaded to approximately one-third capacity, reusable dental burs posed more negative environmental impacts in eight of nine environmental impact categories when compared to disposable burs.

Conclusions

Operational efficiency of ultrasonic and autoclave cleaning equipment should be emphasized to enhance the environmental performance of bur reuse. In fact, improper loading of the ultrasonic and autoclave can lead to greater adverse environmental impacts than if the burs were treated as disposables. The environmental and economic impacts associated with bur reuse are expected to be similar with other dental devices that are designated as disposable but are capable of being reused (e.g., scalpels, forceps).     

Comparative life cycle assessment of graphitic carbon nitride synthesis routes

Graphitic carbon nitride (g-C₃N₄) has gained great interest as a visible-light-activated photocatalyst. As an emerging nanomaterial for environmental applications, its competitive performance and environmentally responsible synthesis are critical to its success. A powerful tool for informing material development with reduced environmental impacts is life cycle assessment (LCA). In this study, LCA is used to evaluate the environmental impacts of g-C₃N₄ nanosheet produced via eight existing synthesis routes. The results reveal electricity as the main contributor to the cumulative impacts of all eight g-C₃N₄ syntheses. There are opportunities to reduce energy demand, and consequently the synthesis impacts, by revising synthesis procedures (i.e., removing or reducing time of use of a piece of equipment), optimizing the calcination step (i.e., faster heating rate, lower heating time, lower temperature), and moving to cleaner electricity sources. Further, benchmarking the environmental impacts of g-C₃N₄ nanosheets to a well-established metal-based photocatalyst, titanium dioxide nanoparticles (nano-TiO₂), reveals mixed comparative results. The synthesis method substantially influences the comparative impacts. Considering use-phase benefits of activating g-C₃N₄ with visible wavelength light emitting diodes compared to ultraviolet (UV) wavelengths for nano-TiO₂ results in a 52% energy demand reduction (in kWh). Performance of g-C₃N₄ compared to a high-energy disinfection approach (i.e., conventional UV) reveals an inability to meet drinking water disinfection standards for viral load reduction (4-log reduction) with any mass of g-C₃N₄, given its high embodied resource footprint. This work establishes a foundation to inform and direct g-C₃N₄ nanosheets toward improved sustainable development.     

Comparative life cycle assessment of fired brick production in Thailand

The International Journal of Life Cycle Assessment - Fired bricks are an essential construction material in Thailand where the majority of fired brick kilns use rice husk as feedstock. Given the...     

Application typologies for life cycle assessment

Different lists of application areas for life cycle assessment are reviewed together with some suggestions for a typology of these application areas. It is concluded that the scope of a life cycle assessment is determined by the area of validity of the decision with respect to time, space, and interest groups affected. On this basis, six application areas are distinguished. It is further concluded that the application area has limited influence on the inventory analysis and impact assessment phases, although these may be influenced significantly by the decision-maker and the complexity of the trade-offs between the involved environmental impacts. The reporting format for a life cycle assessment depends on the socio-economic importance of the decision, the intended audience, and the time available for decision making.     

Methodologies for social life cycle assessment

Goal, Scope and Background  

In recent years several different approaches towards Social Life Cycle Assessment (SLCA) have been developed. The purpose of this review is to compare these approaches in order to highlight methodological differences and general shortcomings. SLCA has several similarities with other social assessment tools, although, in order to limit the expanse of the review, only claims to address social impacts from an LCA-like framework are considered.     

Parameterised inventories for life cycle assessment

Background and Objective  

Life cycle assessment (LCA) is a highly data intensive undertaking, where collecting the life cycle inventory (LCI) data is the most labour intensive part. The aim of this paper is to show a method for representing the LCI in a simplified manner which not only allows an estimative, quantitative LCA, but also the application of advanced analysis methods to LCA.     

Comparative life cycle assessment and financial analysis of mixed culture polyhydroxyalkanoate production

A life cycle assessment and financial analysis of mixed culture PHA (PHA(MC)) and biogas production was undertaken based on treating an industrial wastewater. Internal rate of return (IRR) and non-renewable CO(2)eq emissions were used to quantify financial viability and environmental impact. PHA(MC) was preferable to biogas production for treating the specified industrial effluent. PHA(MC) was also financially attractive in comparison to pure culture PHA production. Both PHA production processes had similar environmental impacts that were significantly lower than HDPE production. A large potential for optimisation exists for the PHA(MC) process as financial and environmental costs were primarily due to energy use for downstream processing. Under the conditions used in this work PHA(MC) was shown to be a viable biopolymer production process and an effective industrial wastewater treatment technology. This is the first study of its kind and provides valuable insight into the PHA(MC) process.     

Comparative life cycle assessment of first- and second-generation ethanol from sugarcane in Brazil

The International Journal of Life Cycle Assessment - The use of bagasse and trash from sugarcane fields in ethanol production is supposed to increase the ethanol yield per hectare, to reduce the...     

Environmental life cycle assessment for rapeseed-derived biodiesel

Purpose

Biofuels have received special research interest, driven by concerns over high fuel prices, security of energy supplies, global climate change as well as the search of opportunities for rural economic development. This work examines the production of biodiesel derived from the transesterification of crude rapeseed oil, one of the most important sources of biodiesel in Europe, paying special attention to the environmental profile-associated to the manufacture life cycle (i.e., cradle-to-gate perspective).

Methods

To do so, a Spanish company with an average annual biodiesel production of 300,000 t was assessed in detail. The Life Cycle Assessment (LCA) study covers the whole life cycle, from the production of the crude rapeseed oil to the biodiesel production and storage. The inventory data for the foreground system consisted of average annual data obtained by on-site measurements in the company, and background data were taken from databases. Seven impact categories have been assessed in detail: abiotic depletion, acidification, eutrophication, global warming, ozone layer depletion, land competition, and photochemical oxidant formation. An energy analysis was carried out based on the cumulative nonrenewable fossil and nuclear energy demand as an additional impact category. Furthermore, well-to-wheels environmental characterization results were estimated and compared per ton-kilometer for the biodiesel (B100) and the conventional diesel so as to point out the environmental drawbacks and strengths of using biodiesel as transport fuel in a 28 t lorry.

Results and discussion

The results showed that the cultivation of the rapeseed was the main key issue in environmental terms (68 %–100 % depending on the category) mainly because of fertilizer doses and intensive agricultural practices required. With regard to the biorefinery production process, pretreatment and transesterification sections considerably contribute to the environmental profile mostly due to electricity and chemical requirements. Concerning the well-to-wheels comparison, using B100 derived from rapeseed oil instead of petroleum-based diesel would reduce nonrenewable energy dependence (?20 %), GHG emissions (?74 %), and ozone layer depletion (?44 %) but would increase acidification (+59 %), eutrophication (+214 %), photochemical smog (+119 %), and land competition.

Conclusions

The information presented in this study could help to promote the use of renewable transport biofuels. However, the extensive implementation of biodiesel (particularly rapeseed oil-derived biodiesel) in our society is enormously complex with many issues involved not only from environmental but also economical and social points of view.     

Comparative life cycle assessment of smartphone reuse: repurposing vs. refurbishment

Purpose

Waste management for end-of-life (EoL) smartphones is a growing problem due to their high turnover rate and concentration of toxic chemicals. The versatility of modern smartphones presents an interesting alternative waste management strategy: repurposing. This paper investigates the environmental impact of smartphone repurposing as compared to traditional refurbishing using Life Cycle Assessment (LCA).

Methods

A case study of repurposing was conducted by creating a smartphone “app” that replicates the functionality of an in-car parking meter. The environmental impacts of this prototype were quantified using waste management LCA methodology. Studied systems included three waste management options: traditional refurbishment, repurposing using battery power, and repurposing using a portable solar charger. The functional unit was defined as the EoL management of a used smartphone. Consequential system expansion was employed to account for secondary functions provided; avoided impacts from displaced primary products were included. Impacts were calculated in five impact categories. Break-even displacement rates were calculated and sensitivity to standby power consumption were assessed.

Results and discussion

LCA results showed that refurbishing creates the highest environmental impacts of the three reuse routes in every impact category except ODP. High break-even displacement rates suggest that this finding is robust within a reasonable range of primary cell phone displacement. The repurposed smartphone in-car parking meter had lower impacts than the primary production parking meter. Impacts for battery-powered devices were dominated by use-phase charging electricity, whereas solar-power impacts were concentrated in manufacturing. Repurposed phones using battery power had lower impacts than those using solar power, however, standby power sensitivity analysis revealed that solar power is preferred if the battery charger is left plugged-in more than 20 % of the use period.

Conclusions

Our analysis concludes that repurposing represents an environmentally preferable EoL option to refurbishing for used smartphones. The results suggest two generalizable findings. First, primary product displacement is a major factor affecting whether any EoL strategy is environmentally beneficial. The benefit depends not only on what is displaced, but also on how much displacement occurs; in general, repurposing allows freedom to target reuse opportunities with high “displacement potential.” Second, the notion that solar power is preferable to batteries is not always correct; here, the rank-order is sensitive to assumptions about user behavior.     

Comparative life cycle assessment of commonly used refrigerants in commercial refrigeration systems

Background, Aim and Scope In accordance with the Montreal Protocol and Kyoto Protocols, the refrigeration industry is currently evaluating the environmental performance of using HFCs and the so-called natural refrigerants, such as NH₃ or CO₂, as a long-term substitute for CFCs and HCFCs. The objective of this study is to quantify and compare the environmental impact throughout the life cycle of commercial refrigeration systems using HCFCs, HFCs and natural refrigerants. The function of the system under study is the refrigeration of a standard European supermarket with an average surface area of 2000 m², with a cooling duty of 130 kW over a period of 15 years. Different scenarios have been created involving a combination of the most common refrigerants (HCFCs (R-22), HFCs (R-134a, R-404A, R-407A, R-407C, R-410A, R-507A) and natural ones (R-744 and R-717)), with different commercial refrigeration systems (direct expansion, secondary loop and distributed), for medium and low temperature. For each scenario, an environmental evaluation was carried out, using the Life Cycle Assessment (LCA) methodology, to compare the influence of both the refrigerant and refrigeration system on the overall contribution to impact. Materials and Methods According to ISO 1404X standards, the analysis is performed at the following two levels. 1) Firstly, the emissions accounted for in the inventory stage are sorted into impact categories according to CML to obtain an indicator for each category (mandatory elements). 2) Secondly, the weighting of environmental data to a single unit is applied (optional elements). In compliance with ISO 14042, a sensitivity analysis is performed and three different impact assessment methods (Eco-Indicator’95, Eco-Indicator’99 and EPS’00) are applied in order to analyse their influence on the results. Results The use of natural refrigerants such as R-744 and R-717 in direct expansion and secondary loop systems, respectively, is completely justified from the environmental point of view, taking into account that it offers better results for most impact categories and for all impact assessment methods. The need to promote the use of R-744 has to be stressed, despite the fact that it is presently in an experimental phase, and that its current installation outputs are low, since it has been demonstrated that it will perform better in direct expansion systems from an environmental point of view in a future scenario in which its efficiency equals that of R-404A, in the same way as what occurs with R-717 for secondary loop systems. The need to replace HCFCs by HFCs or natural refrigerants is clearly shown by the contribution to the ozone depletion category. Discussion Energy efficiency of a refrigeration installation is a determinant parameter to assess pollutant emissions to the environment. If we assume a future scenario in which R-744 has an efficiency similar to that of R-404A, then R-744 is seen as the refrigerant which offers a better environmental behaviour in the direct expansion system. Conclusions It can be concluded that this study demonstrates how using the so-called natural refrigerants as a long-term substitute for CFCs and HCFCs, even better than the use of HFCs, is environmentally feasible. Recommendations and Perspectives More investment and research should be carried out with the aim of promoting the use of the so-called natural refrigerants to fulfil the Montreal and Kyoto Protocols. The technology used for R-744 is at a developmental stage, and presently, the efficiency of the installations operating with this refrigerant is lower than those others functioning with HFCs or R-717. In the near future, it will be demonstrated that this natural refrigerant can replace the use of other HFCs. ESS-Submission Editor: Mary Ann Curran (curran.maryann@epa.gov)     

Comparative life cycle assessment of two landfill technologies for the treatment of municipal solid waste

Goal and Scope  The potential environmental impacts associated with two landfill technologies for the treatment of municipal solid waste (MSW), the engineered landfill and the bioreactor landfill, were assessed using the life cycle assessment (LCA) tool. The system boundaries were expanded to include an external energy production function since the landfill gas collected from the bioreactor landfill can be energetically valorized into either electricity or heat; the functional unit was then defined as the stabilization of 600 000 tonnes of MSW and the production of 2.56x10⁸ MJ of electricity and 7.81x10⁸ MJ of heat. Methods  Only the life cycle stages that presented differences between the two compared options were considered in the study. The four life cycle stages considered in the study cover the landfill cell construction, the daily and closure operations, the leachate and landfill gas associated emissions and the external energy production. The temporal boundary corresponded to the stabilization of the waste and was represented by the time to produce 95% of the calculated landfill gas volume. The potential impacts were evaluated using the EDIP97 method, stopping after the characterization step. Results and Discussion  The inventory phase of the LCA showed that the engineered landfill uses 26% more natural resources and generates 81% more solid wastes throughout its life cycle than the bioreactor landfill. The evaluated impacts, essentially associated with the external energy production and the landfill gas related emissions, are on average 91% higher for the engineered landfill, since for this option 1) no energy is recovered from the landfill gas and 2) more landfill gas is released untreated after the end of the post-closure monitoring period. The valorization of the landfill gas to electricity or heat showed similar environmental profiles (1% more raw materials and 7% more solid waste for the heat option but 13% more impacts for the electricity option). Conclusion and Recommendations  The methodological choices made during this study, e.g. simplification of the systems by the exclusion of the identical life cycle stages, limit the use of the results to the comparison of the two considered options. The validity of this comparison could however be improved if the systems were placed in the larger context of municipal solid waste management and include activities such as recycling, composting and incineration.     

Comparative life cycle assessment of conventional and Green Seal-compliant industrial and institutional cleaning products

Purpose  

The goal of this study was to use life cycle assessment (LCA) methodology to assess the environmental impacts of industrial and institutional cleaning products that are compliant with the Green Seal Standard for Cleaning Products for Industrial and Institutional Use, GS-37, and conventional products (non-GS-37-compliant) products.