Life cycle assessment-based selection of a sustainable lightweight automotive engine hood design

Purpose

This study presents a life cycle assessment (LCA)-based sustainable and lightweight automotive engine hood design and compares the life cycle energy consumption and potential environmental impacts of a steel (baseline) automotive engine hood with three types of lightweight design: advanced high strength steel (AHSS), aluminum, and carbon fiber.

Methods

A “cradle-to-grave” LCA including the production, use, and end-of-life stages is conducted in accordance with the ISO 14040/14044 standards. Onsite data collected by Chinese automotive companies in 2015 are used in the assessment. The Cumulative Energy Demand v1.09 method is applied to evaluate cumulative energy demand (CED), and the International Panel on Climate Change 2013 100a method is used to estimate global warming potential (GWP 100a).

Results and discussion

Among the different lightweight designs for the engine hood, the aluminum design is the most sustainable and has the lowest CED and GWP (100a) from a life cycle perspective, which is based on a lifetime driving distance of approximately 150,000 km. In addition, the AHSS design is also sustainable and lightweight. The carbon fiber design results in higher CED and GWP (100a) values than the steel (baseline) design during the life cycle but results in the largest CED and GWP (100a) savings through waste material recycling. The AHSS design exhibits the best break-even distance based on CED and GWP (100a) within 150,000 km.

Conclusions

Sensitivity analysis results show that the lifetime driving distance and material recycling rate have the largest impacts on the overall CEDs and GWPs of the three lightweight designs.

     

Life cycle assessment of waste strategies for used lubricating oil

Purpose

The study aimed to evaluate the environmental impacts of used lubricating oil (ULO) recovery in the largest oil consumer country in Africa, Egypt. The main questions were: What are the impacts of the different waste management strategies for the recovery of used lubricating oil and which waste management strategy is more eco-friendly?

Methods

Life cycle assessment (LCA) was employed to model the environmental impacts of the two waste management approaches for used lubricating oil recovery in Egypt: recycling by re-firing and recovery by co-firing. The model was applied to assess the impacts of one of the largest ULO recovery units in the Middle East and North Africa (MENA) region and the only operating unit in Egypt. The following impact categories were included: global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), carcinogens potential (CP), ecotoxicity potential (ETP), respiratory inorganic formation potential (RIFP), respiratory organic formation potential (ROFP), radiation potential (RP), ozone layer depletion (OLD), mineral depletion (MD), land use (LU) and fossil fuel depletion (FFD).

Results and discussion

Results indicated that recycling by re-refining strategy is more environment-friendly. De-asphalting, de-aromatization and de-waxing processes are the main processes that affect the environmental impacts of lubricating oil production in both strategies, due to the use of hazard materials and toxic solvents in these processes. Fuel gas and fuel oil used as a fuel in the refinery and power units are the main contributors affecting the environmental impacts in case of recycling by re-refining strategy. The highest impacts were detected on FFD, followed by RIFP, GWP, AP, EP, ETP and CP in both strategies; no impacts were detected on RP, OLD and MD.

Conclusions

It can be concluded that recycling by re-refining of ULO is the more eco-friendly approach. This strategy is more energy conservative, saves a diminishing fossil fuel resource and reduces burdens on the environment. ULO containing high percentages of additive remnants such as viscosity index improvers and pour point depressants which represents a valuable resource and its proper management should be given the most attention.

     

Life cycle assessment to evaluate the environmental performance of new construction material from stainless steel slag

Purpose

Many new opportunities are explored to lower the CO₂ emissions of the cement industry. Academic and industrial researches are currently focused on the possibility of recycling steel production residues in the cement industry, in order to produce new “low-carbon” binders for construction materials. The purpose of this paper is to assess the environmental benefits and costs of steel residue valorisation processes to produce a new binder for construction materials.

Methods

Among other stainless steel slags (SSS), argon oxygen decarburisation (AOD)-slag has the potential to be recovered as a binder during the production of new construction materials. Alkali activation and carbonation processes can, in fact, activate the binding properties of the AOD-slag. However, AOD-slag is today only recycled as low-quality aggregate. For the present study, three different types of construction blocks (called SSS-blocks) were developed starting from the AOD-slag (one block through alkali activation and two blocks through carbonation). The data from the production of the three construction blocks have been collected and used to perform a life cycle assessment (LCA) study, comparing SSS-block production with the production of traditional paver ordinary Portland cement (OPC) concrete.

Results and discussion

The analysis showed that SSS-block production through alkali activation and carbonation has the potential of lowering some of the environmental impacts of OPC-concrete. The LCA results also show that the main bottleneck in the alkali activation process is the production of the alkali activators required in the process, while the use of electricity and of pure CO₂ streams in carbonation lowers the environmental performances of the entire process.

Conclusions

The valorisation of AOD-slag to produce new construction materials is a promising route to lower the environmental impacts of cement and concrete industries. This product-level analysis stresses the need of updating the LCI datasets for alkali activators and boric oxide and of widening the scope of the environmental analysis up to system level, including potential economic interactions and market exchanges between steel and construction sectors.

     

Comparative life-cycle impact assessment of concrete manufacturing in Singapore

Purpose

For countries like Singapore that is highly dependent on imported goods, it is essential to consider the consequences of consumption of imported cement and other concrete constituents for a fair carbon trading at global and regional levels. Recently, as a result of reduction in trade barriers and costs of materials and fuels, Singapore does not have much incentive in reducing environmental impacts of these imported goods. However, Singapore has set high environmental targets nationally to reduce impacts from building and construction. In addition to its national efforts, Singapore also needs to take action in trade-related consequences of importing energy-intensive products like cement and aggregates to Singapore. The purpose of this study is to quantify and suggest alternatives for reducing the embodied energy and life-cycle impacts of concrete consumption in Singapore on the basis of current trading volumes of these materials from Singapore’s importers.

Methods

A detailed life-cycle assessment of concrete manufacturing in Singapore is performed to suggest possible ways to reduce the environmental impacts from importing cement and aggregates from Singapore’s trade partners based on an earlier life-cycle inventory developed for Singapore and its neighboring countries. Life-cycle impact assessment (LCIA) impact characterization factors are based on a midpoint-oriented and hierarchist approach as defined by ReCiPe method. Following the LCIA, a scenario analysis is conducted to select the best combination of cement and aggregate importers of Singapore based on their environmental performance.

Results and discussion

Results from the scenario analysis show that overall impacts can be reduced by importing the materials from a nearer source with efficient production technologies and greener fuel mixes. About 10–34 % reduction is estimated in embodied energy, acidification, eutrophication, global warming potential, smog, and health impacts by importing from a closer and technologically greener source.

Conclusions

Despite the limitations due to data and modeling uncertainties, this study constitutes a baseline/benchmark for addressing the current cement and aggregate markets and associated environmental impacts of concrete consumption in Singapore based on historical import quantities of cement and aggregates from neighboring countries of Singapore. In the near future, policy-related action would be influential in achieving Singapore’s national and global environmental targets in buildings and construction sector. Incorporation of an LCA approach into Green Mark Scheme (GMS) by the Building and Construction Authority (BCA) is recommended for Singapore to comply both with its national goals and with its new climate action plan to the UN Framework Convention on Climate Change.

     

Potential emission savings from refrigeration and air conditioning systems by using low GWP refrigerants

Purpose

Refrigeration and air conditioning systems have high, negative environmental impacts due to refrigerant charge leaks from the system and their corresponding high global warming potential. Thus, many efforts are in progress to obtain suitable low GWP alternative refrigerants and more environmentally friendly systems for the future. The system’s life cycle climate performance (LCCP) is a widespread metric proposed for the evaluation of the system’s environmental impact.

Methods

In this paper, the potential emission reductions in the commercial refrigeration and residential air conditioning systems, made possible by shifting towards more environmentally friendly refrigerants in the US, are presented. First, the current LCCP of the most common commercial refrigeration and residential air conditioning systems is calculated. Then, the LCCP of the baseline systems, when using the potential low GWP alternative refrigerants, is presented. This helps to determine the systems which have the highest potential for emission reductions.

Results and discussion

By shifting from the baseline refrigerants, R-404A and R-410A, to the suggested low GWP refrigerants, N-40 and L-41a, in the commercial refrigeration and residential HVAC systems, respectively, a combined drop of 30.43 % in the total emissions (i.e., total equivalent mass of emissions in kg CO_2eq) is obtained. This results from a 50.5 and 28.01 % drop in total emissions from supermarket refrigeration systems and residential air conditioning, respectively.

Conclusions

Shifting to lower GWP refrigerants in the refrigeration and air conditioning systems helps to reduce the total emissions and negative environmental impacts of these systems. Shifting to a secondary circuit commercial refrigeration system using N-40/L-40 and residential air conditioning and heat pump systems using L-41a helps in reducing the total emissions.

     

Impact of the selection of functional unit on the life cycle assessment of green concrete

Purpose

The objectives of this study are to evaluate life cycle assessment (LCA) for concrete mix designs containing alternative cement replacement materials in comparison with conventional 100% general use cement concrete and to evaluate the interplay and sensitivity of LCA for four concrete mix designs and six functional units which range in degrees of complexity and variables.

Methods

Six functional units with varying degrees of complexity are included in the analysis: (i) volume of concrete, (ii) volume and 28-day compressive strength, (iii) volume and 28-day rapid chloride permeability (RCP), (iv) volume and binder intensity, (v) volume and a combination of compressive strength and RCP and (vi) volume and a combination of binder intensity and RCP. Four reference flows are included in the analysis: three concrete mix designs containing slag, silica fume and limestone cement as cement replacement and one concrete mix design for conventional concrete.

Results and discussion

All three alternative mix designs were evaluated to have lower environmental impacts compared with the base 100% general use cement and so are considered to be ‘green’ concrete. Similar LCA results were observed for FU₁, FU₂ and FU₄, and relatively similar results were obtained for FU₃, FU₅ and FU₆. LCA conducted with functional units which were a function of durability exhibited markedly different (lower) LCA compared with the functional units that did not capture long-term durability.

Conclusions

Outcomes of this study portray the interplay between concrete mix design materials, choice of functional unit and environmental impact based on LCA. The results emphasize (i) the non-linearity between material properties and environmental impact and (ii) the importance of conducting an LCA with a selected functional unit that captures the concrete’s functional performance metrics specific to its application and expected exposure conditions. Based on this study, it is recommended that a complete LCA for a given concrete mix design should entail examination of multiple functional units in order to identify the range of environmental impacts or the optimal environmental impacts.

     

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

Background, Goal, and Scope

Currently, only 40%, or 44.5 million metric tons, of coal combustion products (CCPs) generated in the United States each year by electric utilities are diverted from disposal in landfills or surface impoundments and recycled. Despite promising economic and environmental savings, there has been scant attention devoted to assessing life cycle impacts of CCP disposal and beneficial use. The objective of this paper is to present a life cycle inventory considering two cases of CCP management, including the stages of coal mining and preparation, coal combustion, CCP disposal, and CCP beneficial use. Six beneficial uses were considered: concrete production, structural fills, soil amendments, road construction, blasting grit and roofing granules, and wallboard.

Methods

Primary data for raw material inputs and emissions of all stages considered were obtained from surveys and site visits of coal-burning utilities in Florida conducted in 2002, and secondary data were obtained from various published sources and from databases available in SimaPro 5.1 (PRé Consultants, Amersfoort, The Netherlands).

Results

Results revealed that 50 percent of all CCPs produced, or 108 kg per 1,000 kg of coal combusted, are diverted for application in a beneficial use; however, the relative amounts sold by each utility is dependent on the process operating parameters, air emission control devices, and resulting quality of CCP. Diversion of 50% of all CCPs to beneficial use applications yields a decrease in the total raw materials requirements (with the exception of gravel and iron) and most emissions to air, water, and land, as compared to 100% disposal.

Discussion

The greatest reduction of raw materials was attributed to replacing Portland cement with fly ash, using bottom ash as an aggregate in concrete production and road construction in place of natural materials, and substituting FGD gypsum for natural gypsum in wallboard. The use of fly ash as cementitious material in concrete also promised significant reductions in emissions, particularly the carbon dioxide that would be generated from Portland cement production. Beneficial uses of fly ash and gypsum showed reductions of emissions to water (particularly total dissolved solids) and emissions of metals to land, although these reductions were small compared to simply diverting 50% of all CCPs from landfills or surface impoundments.

Conclusions

This life cycle inventory (LCI) provides the foundation for assessing the impacts of CCP disposal and beneficial use. Beneficial use of CCPs is shown here to yield reductions in raw material requirements and various emissions to all environmental compartments, with potential tangible savings to human health and the environment.

Recommendations and Perspectives

Extension of this life cycle inventory to include impact assessment and sensitivity analysis will enable a determination of whether the savings in emissions reported here actually result in significant improvements in environmental and human health impacts.

     

Environmental performance of social housing in emerging economies: life cycle assessment of conventional and alternative construction methods in the Philippines

Purpose

The environmental impact of the social building stock is relevant, particularly in emerging economies. Life cycle thinking is not yet established, however. Locally available, alternative building concepts could potentially reduce the environmental impact of the construction segment. This paper examines the environmental performance of “as-built” low-cost housing for an example of the Philippines, and the potential to reduce its environmental impact through use of three alternative building technologies: cement–bamboo frames, soil–cement blocks, and coconut board-based housing.

Methods

Life cycle assessment models are implemented and evaluated with software SimaPro, using the single-impact indicators global warming potential (GWP) and cumulative energy demand (CED) and the multi-impact indicator Impact2002+. According to EN 15978, the life cycle phase product and construction process (A), use stage (B), end-of-life (C) and supplementary information beyond the building life cycle (D) have been assessed. Theoretically calculated inflows from standard construction procedures used in phase A have been verified with 3 years of empirical data from implemented construction projects. For phases B, C and D, attention was given to service life, use-phase, allocation of waste products, biogenic carbon and land-use assumptions. Scenarios reflect the actual situation in the emerging economy. Processes, such as heat recovery from thermal utilization, which are not existing nor near to implementation, were excluded.

Results and discussion

For an assessment of the phases A–B–C–D with GWP, a 35% reduction of environmental impact for soil–cement blocks, 74% for cement–bamboo frame, and 83% for coconut board-based houses is obtained relative to a concrete reference house. In absolute terms, this relates to a reduction of 4.4, 9.3, and 10.3 t CO₂ equivalents over a service life of 25 years. CED showed higher impacts for the biogenic construction methods coconut board and cement–bamboo frames of +8.0 and +4.7%, while the soil–cement technology was evaluated ?7.1% compared to GWP. Sixteen of 17 midpoint categories of Impact2002+ confirmed an overall reduction potential of the alternative building methods, with the midpoint category land occupation being the exception rating the conventional practice over the alternatives.

Conclusions

It is concluded that the alternative construction technologies have substantial potential to reduce the environmental burden caused by the social housing sector. The service life of the alternative technologies plays a vital role for it. LCA for emerging economies needs to incorporate realistic scenarios applicable at their current state or belonging to the most probable alternatives to ensure valuable results. Recommendations for further research are provided.

     

The influence of durability and recycling on life cycle impacts of window frame assemblies

Purpose

A set of comparative life cycle assessment case studies were undertaken to explore key issues relating to the environmental impacts of building materials. The case studies explore modeling practice for long-life components by investigating (1) recycled content and end-of-life recycling scenarios and (2) service life and maintenance scenarios. The study uses a window unit frames as the object of comparison, allowing for exploration of multiple materials and assembly techniques.

Methods

Four window frame types were compared: aluminum, wood, aluminum-clad wood, and unplasticized PVC (PVCu). These used existing product life cycle inventory data which included primary frame material, coatings, weather stripping sealants, but not glazing. The functional unit was a window frame required to produce 1 m² of visible glazing, with similar thermal performance over a building lifespan of 80 years. The frames were compared using both the end-of-life and recycled content methods for end-of-life scenarios. The models were also tested using custom-use scenarios.

Results and discussion

Well-maintained aluminum window frames proved to be the least impactful option across all categories, in large part due to the credits delivered from recycling and expectations of long-life. Wood window frames had the least variability associated with maintenance and durability. The global warming potential (GWP) of a moderately maintained aluminum assembly was found to be 68 % less than PVCu and 50 % less than aluminum-clad wood. Using a long-life scenario, wood windows were found to have a 7 % lower GWP than the long-life scenario for aluminum-clad woods. Moderately and well-maintained aluminum windows require less energy to be produced and maintained over their lifetime than any of the wood scenarios. Expectations of service life proved to be the most important factor in considering environmental impact of frame materials.

Conclusions

The research shows significant gaps in available data—such as average realized life expectancies of common building components—while further underscoring that recycling rates are a driving factor in the environmental impact of aluminum building products. A modeling shift from the recycled content method to the end-of-life recycling method should promote goals of material recovery over pursuit of material with high recycled content. Hybrid methods, such as the use of Module D, may bridge the divide between these two approaches by providing due credit for use of recycled material, while supporting a design for recycling ethos. Further research is needed on how design and construction decisions affect collection and recovery rates in practice.

     

Life cycle assessment of a steam thermolysis process to recover carbon fibers from carbon fiber-reinforced polymer waste

Purpose

Carbon fibers have been widely used in composite materials, such as carbon fiber-reinforced polymer (CFRP). Therefore, a considerable amount of CFRP waste has been generated. Different recycling technologies have been proposed to treat the CFRP waste and recover carbon fibers for reuse in other applications. This study aims to perform a life cycle assessment (LCA) to evaluate the environmental impacts of recycling carbon fibers from CFRP waste by steam thermolysis, which is a recycling process developed in France.

Methods

The LCA is performed by comparing a scenario where the CFRP waste is recycled by steam-thermolysis with other where the CFRP waste is directly disposed in landfill and incineration. The functional unit set for this study is 2 kg of composite. The inventory analysis is established for the different phases of the two scenarios considered in the study, such as the manufacturing phase, the recycling phase, and the end-of-life phase. The input and output flows associated with each elementary process are standardized to the functional unit. The life cycle impact assessment (LCIA) is performed using the SimaPro software and the Ecoinvent 3 database by the implementation of the CML-IA baseline LCIA method and the ILCD 2011 midpoint LCIA method.

Results and discussion

Despite that the addition of recycling phase produces non-negligible environmental impacts, the impact assessment shows that, overall, the scenario with recycling is less impactful on the environment than the scenario without recycling. The recycling of CFRP waste reduces between 25 and 30% of the impacts and requires about 25% less energy. The two LCIA methods used, CML-IA baseline and ILCD 2011 midpoint, lead to similar results, allowing the verification of the robustness and reliability of the LCIA results.

Conclusions

The recycling of composite materials with recovery of carbon fibers brings evident advantages from an environmental point of view. Although this study presents some limitations, the LCA conducted allows the evaluation of potential environmental impacts of steam thermolysis recycling process in comparison with a scenario where the composites are directly sent to final disposal. The proposed approach can be scaled up to be used in other life cycle assessments, such as in industrial scales, and furthermore to compare the steam thermolysis to other recycling processes.

     

Life cycle environmental assessment of industrial hazardous waste incineration and landfilling in China

Purpose

The improper handling of industrial hazardous waste (IHW), which comprises large amounts of toxic chemicals, heavy metals, or irradiation substances, is a considerable threat to human health and the environment. This study aims to quantify the life cycle environmental impacts of IHW landfilling and incineration in China, to identify its key factors, to improve its potential effects, and to establish a hazardous waste disposal inventory.

Methods

Life cycle assessment was conducted using the ReCiPe model to estimate the environmental impact of IHW landfilling and incineration. The characterization factors for the human toxicity and freshwater ecotoxicity categories shown in the ReCiPe were updated based on the geographies, population, food intake, and environmental conditions in China.

Results and discussion

The overall environmental burden was mainly attributed to the carcinogen category. The national carcinogen burden in 2014 at 37.8 CTUh was dominated by diesel consumption, cement and sodium hydroxide production, direct emission, transportation, and electricity generation stages caused by direct mercury and arsenic emissions, as well as indirect chromium emission. Although the atmospheric mercury emission directly caused by IHW incineration was comparative with the emission levels of developed countries, the annual direct mercury emission accounted for approximately 0.1% of the national mercury emission.

Conclusions

The key factors contributing to the reduction of the national environmental burden include the increasing diesel and electricity consumption efficiency, the reduction of cement and sodium hydroxide use, the development of air pollutant controlling systems, the reduction of transport distance between IHW disposers to suppliers, and the improvement of IHW recycling and reuse technologies.

     

Vehicle lightweighting through the use of molybdenum-bearing advanced high-strength steels (AHSS)

Purpose

The past two decades have seen growing pressure on vehicle manufacturers to reduce the environmental impact of their vehicles. One effective way to improve fuel efficiency and lower tailpipe emissions is to use advanced high-strength steels (AHSS) that offer equal strength and crash resistance at lower mass. The present study assesses the life cycle environmental impacts of two steel grades considered for the B-pillar in the Ford Fusion: A press-hardened boron steel design as used in the previous model of the vehicle and a hydroformed component made from a mix of the molybdenum-bearing dual phase steels DP800 and DP1000.

Methods

Information related to the component masses and grades was provided by Ford. Process models for the steelmaking process, finishing, forming, vehicle use and end of life were created in the GaBi LCA software tool. Sensitivity analyses were conducted on the impact of the hydroforming process for the new component, for which only proxy data were available and on the mix of DP800 and DP1000 in the B-pillar. Results have been presented for the environmental impact categories deemed most relevant to vehicle use.

Results and discussion

The life cycle assessment showed that the new DP800/DP1000 B-pillar design has a lower impact for the environmental impact categories assessed. Overall, the global warming potential (GWP) of the new DP800/DP1000 design was 29 % lower than the boron steel design over the full life cycle of the vehicle. The use phase was found to be the major source of environmental impacts, accounting for 93 % of the life cycle GWP impact. The 4 kg weight saving accounts for the majority of the difference in impacts between the two B-pillar designs. Impacts from manufacturing were also lower for the new design for all of the impact categories assessed despite the higher alloy content of the steel. A sensitivity analysis of the hydroforming process showed that even if impacts from forming were 100 % greater than for press hardening, the GWP from production of the new B-pillar design would still be lower than the boron steel version.

Conclusions and recommendations

The molybdenum-bearing DP1000/DP800 B-pillar was found to have lower life cycle and production impacts than the previous boron steel design. The assessment indicates that significant improvements in the environmental impacts associated with the body structure of vehicles could be made through the increased use of AHSS in vehicles without compromising crash performance.

     

Life cycle assessment of Chinese radial passenger vehicle tire

Purpose

We evaluated and quantified the environmental impact of a radial tire product for passenger vehicles throughout the product’s life cycle to identify key stages that contribute to the overall environmental burden and to find ways to reduce these burdens effectively. The study covers all relevant life cycle stages, from the acquisition of raw materials to the production, use, and end of life.

Methods

Data collected onsite in 2014 by one of the largest Chinese tire companies were used in the assessment. The evaluation is presented in terms of individual impact category according to the CML model. Five impact categories (i.e., global warming potential (GWP), acidification potential (AP), photochemical oxidant creation potential (POCP), eutrophication potential (EP), and human toxicity potential (HTP)) were considered. The research was conducted in accordance with the ISO 14040/14044 standards.

Results and discussion

Fuel (gasoline) consumption represents an important contribution to most impact categories, including the GWP, AP, POCP, and EP, during the use stage. The largest contributor to the HTP category is raw material acquisition, mainly because of the impact of the production of organic chemicals. In the end-of-life stage, assuming that 100 % of used tires are collected and recycled to produce reclaimed rubber, the GWP, EP, and HTP contributions are negative, whereas those to the AP and POCP are positive. During the raw material acquisition stage, natural rubber, synthetic rubber, carbon black, and organic chemicals represent the largest contribution to the environmental impact categories. During the production stage, the compound blending process is the largest contributor to the AP and POCP, whereas vulcanizing and testing contribute most to the GWP, EP, and HTP.

Conclusions

Vehicle fuel consumption and its proportion consumed by the tires during the use stage are key factors that contribute to environmental impact during tire life. Further investigations should be conducted to decrease the impact of these factors and improve the environmental performance of tire products.

     

Lead industry life cycle studies: environmental impact and life cycle assessment of lead battery and architectural sheet production

Purpose

This paper will give an overview of LCA studies on lead metal production and use recently conducted by the International Lead Association.

Methods

The lead industry, through the International Lead Association (ILA), has recently completed three life cycle studies to assess the environmental impact of lead metal production and two of the products that make up approximately 90 % of the end uses of lead, namely lead-based batteries and architectural lead sheet.

Results and discussion

Lead is one of the most recycled materials in widespread use and has the highest end-of-life recycling rate of all commonly used metals. This is a result of the physical chemical properties of the metal and product design, which makes lead-based products easily identifiable and economic to collect and recycle. For example, the end-of-life collection and recycling rates of lead automotive and industrial batteries and lead sheet in Europe are 99 and 95 %, respectively, making them one of the few products that operate in a true closed loop. These high recycling rates, coupled with the fact that both lead-based batteries and architectural lead sheet are manufactured from recycled material, have a beneficial impact on the results of LCA studies, significantly lowering the overall environmental impact of these products. This means that environmental impacts associated with mining and smelting of lead ores are minimised and in some cases avoided completely. The lead battery LCA assesses not only the production and end of life but also the use phase of these products in vehicles. The study demonstrates that the technological capabilities of innovative advanced lead batteries used in start-stop vehicles significantly offset the environmental impact of their production. A considerable offset is realised through the savings achieved in global warming potential when lead-based batteries are installed in passenger vehicles with start-stop and micro-hybrid engine systems which have significantly lower fuel consumption than regular engines.

Conclusions

ILA has undertaken LCAs which investigate the environmental impact associated with the European production of lead metal and the most significant manufactured lead products (lead-based batteries used in vehicles and architectural lead sheet for construction) to ensure up-to-date and robust data is publically and widely available.

     

Cradle-to-gate assessment of environmental impacts for a broad set of biomass-to-product process chains

Purpose

This study advocates a modular approach combining unit processes as building blocks to formulate biomass process chains. This approach facilitates a transparent environmental life cycle impact assessment for bio-based products. It also enhances the ability to develop and assess more complex biorefinery systems, identifies critical parameters and offers useful material to support environmental impact assessment in early design stages.

Methods

Twenty-three different products were assessed with regard to the environmental burden associated with their production paths. Life cycle inventories (LCIs) for 32 unit processes were compiled (using information from pilot plants, simulation and literature data) and organized in biomass process chains. Then, 58 study systems were formed based on various combinations of the unit processes, each study system referring to the production of a selected product. Three indicators were used for quantification of the impacts: non-renewable fossil cumulative energy demand (CED), global warming potential (GWP) and water depletion as defined in the ReCiPe method.

Results and discussion

Factors influencing the variation of results even for similar products are discussed (e.g. production path and allocation method lead to a range of GWP values for ethylene production from 0.43 to 3.37 kg CO₂ eq/kg ethylene). For the majority of bio-products, CED has lower values than fossil-based equivalents (average difference 39–70 MJ eq/kg product depending on the allocation method), while mixed trends are obtained for the GWP and water depletion indicators. Assessments also highlight attributes that have a significant effect in the environmental profile of a production path such as the synthesis path, the process chemistry (water intensity) and process-related factors (energy intensity, degree of energy integration/heat recovery).

Conclusions

The analysis of impacts per unit process is able to demonstrate the particular production stages featuring high environmental intensities along a path further hinting to suggestions for amendments and improvements from an overall performance perspective. The study makes a useful source for biorefinery design studies especially in adopting a modular approach to represent and to analyse biomass process chains; it also provides a reference point for comparison (benchmarking) between different process technologies for biomass utilization. Finally, the analysis is compatible with the standards of the LCA methodology, and it is based on the use of the most common LCA databases, which facilitates the comparison of the results with other relevant studies.

     

Do green wooden composites using lignin-based binder have environmentally benign alternatives? A preliminary LCA case study in China

Purpose

Nowadays, formaldehyde emissions from petroleum-based adhesives contribute considerably to environmental problems and are a constraint to the development of forest-based industries. Although many efforts are being made to develop new lignin-based adhesives for panels, very few studies were carried out via life cycle assessment (LCA). This study aims to assess the life cycle of green wooden composites by using hybrid-modified ammonium lignosulfonate (HMAL) as the binder and investigate the possibility of lignin-based binder to be a good alternative.

Methods

This study is a step further of the previous work conducted on HMAL as an alternative binder for medium-density fiberboard (MDF) or, in other words, the wooden composite made from HMAL and wood fiber (WF). LCA was carried out to assess the environmental impacts during the life cycle of the new manufacturing process of HMAL/WF production using ReCiPe 1.08 Endpoint and IPCC global warming potential (GWP) method built into the GaBi version 6.0 software. The production system involved two subsystems: raw material supply and board manufacture. Meanwhile, a comparative LCA of conventional MDF, with three main damage categories and GWP, was also carried out.

Results and discussion

The hydrogen peroxide (H₂O₂) production, electricity, and the HMAL/WF manufacturing stages had the greatest environmental impact. The comparative results pointed out that HMAL/WF production is environmentally superior to conventional MDF in general. Due to the environmental impacts associated with the HMAL binder, a sensitivity analysis was carried out. Suggestions were made for a cleaner production, in which the H₂O₂ dose was reduced to 24 wt%.

Conclusions

H₂O₂ use, energy, and electricity consumption are main contributors to most impact categories, which help us to find the potential improvements of sustainability, choose the appropriate HMAL technology, and optimize the HMAL/WF system. Feasible production processes and life cycle costs are factors that still need to be studied.

     

Methane oxidation,biogenic carbon,and the IPCC’s emission metrics. Proposal for a consistent greenhouse-gas accounting

Purpose

The fifth assessment report by the IPCC includes methane oxidation as an additional indirect effect in the global warming potential (GWP) and global temperature potential (GTP) values for methane. An analysis of the figures provided by the IPCC reveals they lead to different outcomes measured in CO₂-eq., depending on whether or not biogenic CO₂ emissions are considered neutral. In this article, we discuss this inconsistency and propose a correction.

Methods

We propose a simple framework to account for methane oxidation in GWP and GTP in a way that is independent on the accounting rules for biogenic carbon. An equation with three components is provided to calculate metric values, and its application is tested, together with the original IPCC figures, in a hypothetical example focusing on GWP100.

Results and discussion

The hypothetical example shows that the only set of GWP100 values consistently leading to the same outcome, regardless of how we account for biogenic carbon, is the one proposed in this article. Using the methane GWP100 values from the IPCC report results in conflicting net GHG emissions, thus pointing to an inconsistency.

Conclusions

In order to consistently discriminate between biogenic and fossil methane sources, a difference of 2.75 kg CO₂-eq. is needed, which corresponds to the ratio of the molecular weights of CO₂ and methane (44/16). We propose to correct the GWP and GTP values for methane accordingly.

     

A comparative cradle-to-gate life cycle assessment of three concrete mix designs

Purpose

The concrete industry faces challenges to create concrete mix designs that reduce negative environmental impacts but also maintain high performance. This has led to ‘greener’ cementitious materials being developed which can decrease the use of traditional Portland cement (PC). This study intended to carry out a ‘cradle-to-gate’ life cycle assessment (LCA) on concrete mix designs containing different cementitious blends.

Methods

The aim of this study was to obtain the overall environmental impact, with a particular focus on carbon dioxide (CO₂) emissions of three concrete mix designs: CEM I (100 % PC content), CEM II/B-V (65 % PC content, 35 % Fly Ash (FA) content) and CEM III/B (30 % PC content, 70 % ground granulated blast furnace slag (GGBS) content). Evaluations of the three concrete mixes were performed using ‘SimaPro 8’ LCA software. A comparative cradle-to-gate LCA of these mixes has not currently been explored and could present a new insight into improving the environmental impact of concrete with the use of secondary materials. Recommendations from this work would help the industry make key decisions about concrete mix designs.

Results and discussion

Results show that Mix 2 (CEM II/B-V) and Mix 3 (CEM III/B) could potentially be taken forwards to improve their environmental impacts of concrete production. With respect to optimum mix design, it is strongly recommended that GGBS is selected as the addition of choice for reducing CO₂ emissions. FA does still considerably improve sustainability when compared to PC, but this work proved that inclusion of GGBS environmentally optimises the mix design even further. Advantages of using GGBS include lower CO₂ emissions, a substantial reduction of environmental impacts and an increased scope for sustainability due to the higher PC replacement levels that are permitted for GGBS. Due to mix designs enabling a higher contribution of GGBS additions, it would also indicate an increased positive effect regarding waste scenarios.

Conclusions and recommendations

The main contribution of this work demonstrated that concrete can be produced without loss of performance whilst significantly reducing the negative environmental impacts incurred in its production. The results obtained from this work would help to define the available options for optimising concrete mix design. The only material variations in each mix were the different cementitious blends. So, by determining the best option, a platform to make recommendations can be established based upon cementitious materials.

     

Criteria for the evaluation of life cycle assessment software packages and life cycle inventory data with application to concrete

Purpose

Life cycle assessment (LCA) software packages have proliferated and evolved as LCA has developed and grown. There are now a multitude of LCA software packages that must be critically evaluated by users. Prior to conducting a comparative LCA study on different concrete materials, it is necessary to examine a variety of software packages for this specific purpose. The paper evaluates five LCA tools in the context of the LCA of seven concrete mix designs (conventional concrete, concrete with fly ash, slag, silica fume or limestone as cement replacement, recycled aggregate concrete, and photocatalytic concrete).

Methods

Three key evaluation criteria required to assess the quality of analysis are adequate flexibility, sophistication and complexity of analysis, and usefulness of outputs. The quality of life cycle inventory (LCI) data included in each software package is also assessed for its reliability, completeness, and correlation to the scope of LCA of concrete products in Canada. A questionnaire is developed for evaluating LCA software packages and is applied to five LCA tools.

Results and discussion

The result is the selection of a software package for the specific context of LCA of concrete materials in Canada, which will be used to complete a full LCA study. The software package with the highest score is software package C (SP-C), with 44 out of a possible 48 points. Its main advantage is that it allows for the user to have a high level of control over the system being modeled and the calculation methods used.

Conclusions

This comparative study highlights the importance of selecting a software package that is appropriate for a specific research project. The ability to accurately model the chosen functional unit and system boundary is an important selection criterion. This study demonstrates a method to enable a critical and rigorous comparison without excessive and redundant duplication of efforts.

     

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.