Life cycle assessment of commodity chemical production from forest residue via fast pyrolysis

Purpose

This life cycle assessment evaluates and quantifies the environmental impacts of renewable chemical production from forest residue via fast pyrolysis with hydrotreating/fluidized catalytic cracking (FCC) pathway.

Methods

The assessment input data are taken from Aspen Plus and greenhouse gases, regulated emissions, and energy use in transportation (GREET) model. The SimaPro 7.3 software is employed to evaluate the environmental impacts.

Results and discussion

The results indicate that the net fossil energy input is 34.8 MJ to produce 1 kg of chemicals, and the net global warming potential (GWP) is ?0.53 kg CO₂ eq. per kg chemicals produced under the proposed chemical production pathway. Sensitivity analysis indicates that bio-oil yields and chemical yields play the most important roles in the greenhouse gas footprints.

Conclusions

Fossil energy consumption and greenhouse gas (GHG) emissions can be reduced if commodity chemicals are produced via forest residue fast pyrolysis with hydrotreating/FCC pathway in place of conventional petroleum-based production pathways.     

Wax production from renewable feedstock using biocatalysts instead of fossil feedstock and conventional methods

Background, aim, and scope

Using renewable feedstock and introducing biocatalysts in the chemical industry have been suggested as the key strategies to reduce the environmental impact of chemicals. The Swedish interdisciplinary research program “Speciality Chemicals from Renewable Resources—Greenchem” is aiming to develop these strategies. One target group of chemicals for Greenchem are wax esters which can be used in wood coatings to replace paraffin wax made from fossil crude oil. The aim of this study was to conduct a life cycle assessment of wax esters based on rapeseed oil produced by biocatalysts (enzymes). The scope was to compare the environmental performance of wax esters with paraffin wax produced by conventional methods.

Materials and methods

The study has a cradle-to-gate perspective and the functional unit is “1-kg wax product ready to use in a wood coating product.” Extensive data collection and calculations have been performed for the wax esters, whereas existing life cycle inventory data have been used for the paraffin wax.

Results

The energy input into the wax ester production is about one third of the energy input in paraffin wax production. However, the wax ester has a higher contribution to the global warming potential (GWP) due to high emissions of nitrous oxide from rapeseed cultivation. Referring to a cradle-to-grave perspective, including waste incineration, the contribution to the GWP will, however, be 3.5 times higher from paraffin wax. Wax ester makes a higher contribution to the acidification and eutrophication potential, due to emissions from soil from rapeseed cultivation, but five times lower contribution to the photochemical ozone creation potential. From a land-use perspective and a global warming point of view, it is more efficient to produce paraffin wax and grow high-yielding, short-rotation coppice (Salix) to replace fuel oil than it is to grow rapeseed for wax ester production.

Discussion

Overall, this study shows the importance of studying the environmental performance of a product not only from a gate-to-gate perspective but, instead, considering the environmental performance from cradle-to-gate. The biocatalytic production of the wax ester consumes less energy than the conventional chemical method, but the raw material step, cultivation of rapeseed contributes much to both acidification and eutrophication. When the waste treatment step is included, the contribution to GWP, however, for paraffin wax will be 3.5 times higher than for the wax ester.

Conclusions

From a gate-to-gate perspective, replacing conventional chemical processes by biocatalysts using enzymes leads to energy savings and reduces emissions. However, from a cradle-to-gate perspective, the use of renewable feedstock, such as rapeseed oil, may counteract some of these benefits. Concerning the GWP benefit from using renewable feedstock instead of fossil feedstock, the final waste treatment step must be included, thereby applying a cradle-to-grave perspective.

Recommendations and perspectives

The introduction of biocatalysts as a key strategy in reducing the environmental impact from the chemical industry is supported by the results in this study. On the other hand, it is not obvious that the key strategy of using renewable feedstock in chemical production per se leads to benefits concerning all environmental impact categories. Thus, much more attention needs to be paid to the choice of potential renewable feedstock options, the minimization of energy inputs, and the biological emissions from the soil in the cultivation of feedstock crops, improved gas cleaning in nitrogen fertilizer production plants, and the alternative use of the arable land, in optimizing the overall environmental benefits of an increased use of renewable feedstock in the chemical industry.     

Design of recycling system for poly(methyl methacrylate) (PMMA). Part 1: recycling scenario analysis

Introduction

In this series of papers, we present a poly(methyl methacrylate) (PMMA) recycling system design based on environmental impacts, chemical hazards, and resource availability. We evaluated the recycling system by life cycle assessment, environment, health, and safety method, and material flow analysis.

Purpose

Previous recycling systems have not focused on highly functional plastics such as PMMA, partly because of lower available volumes of waste PMMA compared with other commodity plastics such as polyethylene or polypropylene. However, with the popularization of PMMA-containing products such as liquid crystal displays, the use of PMMA is increasing and this will result in an increase in waste PMMA in the future. The design and testing of recycling systems and technologies for treating waste PMMA is therefore a high research priority. In this study, we analyze recycling of PMMA monomers under a range of scenarios.

Methods

Based on the differences between PMMA grades and their life cycles, we developed a life cycle model and designed a range of scenarios for PMMA recycling. We obtained monomer recycling process inventory data based on the operational results of a pilot plant. Using this process inventory data, we quantified life cycle greenhouse gas (LC-GHG) emissions and fossil resource consumption, and we calculated the LIME single index.

Results and discussion

PMMA produces more than twice the amount of GHG emissions than other commodity resins. Through scenario and sensitivity analyses, we demonstrated that monomer recycling is more effective than mechanical recycling. Operational modifications in the monomer recycling process can potentially decrease LC-GHG emissions.

Conclusions

Highly functional plastics should be recycled while maintaining their key functions, such as the high transparency of PMMA. Monomer recycling has the potential to achieve a closed-loop recycling of PMMA.     

Life cycle assessment of potential energy uses for short rotation willow biomass in Sweden

Purpose

Two different bioenergy systems using willow chips as raw material has been assessed in detail applying life cycle assessment (LCA) methodology to compare its environmental profile with conventional alternatives based on fossil fuels and demonstrate the potential of this biomass as a lignocellulosic energy source.

Methods

Short rotation forest willow plantations dedicated to biomass chips production for energy purposes and located in Southern Sweden were considered as the agricultural case study. The bioenergy systems under assessment were based on the production and use of willow-based ethanol in a flexi fuel vehicle blended with gasoline (85 % ethanol by volume) and the direct combustion of willow chips in an industrial furnace in order to produce heat for end users. The standard framework for LCA from the International Standards Organisation was followed in this study. The environmental profiles as well as the hot spots all through the life cycles were identified.

Results and discussion

According to the results, Swedish willow biomass production is energetically efficient, and the destination of this biomass for energy purposes (independently the sort of energy) presents environmental benefits, specifically in terms of avoided greenhouse gases emissions and fossil fuels depletion. Several processes from the agricultural activities were identified as hot spots, and special considerations should be paid on them due to their contribution to the environmental impact categories under analysis. This was the case for the production and use of the nitrogen-based fertilizer, as well as the diesel used in agricultural machineries.

Conclusions

Special attention should be paid on diffuse emissions from the ethanol production plant as well as on the control system of the combustion emissions from the boiler.     

Life-cycle assessment of continuous pad-dyeing technology for cotton fabrics

Purpose

China is the largest producer of textile-dyeing products in the world. The production of these materials consumes high amounts of water and energy and results in the discharge of huge amounts of pollutants. This study aimed at evaluating the life-cycle environmental impacts of the textile-dyeing industry and determining the key processes for mitigating life-cycle environmental impacts efficiently and effectively, which will benefit the application of cleaner production technologies.

Methods

A life-cycle assessment was performed according to the ISO 14040 standard series. The system investigated includes the dyeing process and final disposal and the transportation of raw material, energy production, and transportation. The functional unit is 10,000 m of cotton fabric, which weighs 2,000 kg. Our study encompasses three types of data. The data regarding the production process and the major raw materials, necessary energy, and the source of the energy, as well as the emissions of some pollutants, were provided by a textile-dyeing enterprise in Jiangsu Province. The data regarding transport were generated using the GaBi version 4.3 database. Some emission factor data such as those on CO₂, CH₄, and N₂O emissions were obtained from the literature. Resources, energy consumption, and emissions are quantified, and some of the potential environmental effects were evaluated using the CML2001 method built into the GaBi version 4.3 database.

Results and discussion

Scouring and oxygen bleaching, dyeing, stentering and setting, wastewater treatment, and incineration are the key processes in terms of global warming potential, acidification potential, photochemical ozone creation potential, and eutrophication potential. It will therefore be useful to enhance the recycling of water, control the consumption of additives and dyes, and conserve energy as much as possible. Through scenario analysis, we note that motorized shipment should be used instead of shipment by trucks, when conditions permit.

Conclusions

To promote energy conservation and the clean production of continuous pad-dyeing technology for cotton fabrics, other environmental impact categories besides the impact of the water system should be given focus. Additional work can be performed on the following: considering a consumption-based perspective of the entire process, uncertainty in data on life-cycle inventory, the evaluation methodology employed, temporal and spatial variation, the normalized toxicity of dyes and additives, and weighting methods.     

A life cycle assessment case study of ground rubber production from scrap tires

Purpose

The number of scrap tires generated in China has grown dramatically every year. Generation of ground rubber from scrap tires is the dominant management option in China. It is necessary to assess the environmental impacts of ground rubber production from scrap tires to provide technical advices on a cleaner production.

Methods

Production of ground rubber from recycled scrap tires consist of three steps: rubber powder preparation, devulcanization, and refining. A process life cycle assessment (LCA) of ground rubber production from scrap tires is carried out, and Eco-indicator 99 method coupled with ecoinvent database is applied to evaluate the environmental impacts of this process.

Results and discussion

During the ground rubber production stage, the impact factor of respiratory inorganic is the most serious one. Devulcanization has the highest environmental load of about 66.2 %. Moreover, improvement on the flue gas treatment contributes to a cleaner production and a more environmental-friendly process. Applying clean energy can largely reduce environmental load by about 21.5 %.

Conclusions

The results can be a guidance to reduce environmental load when producing ground rubber from scrap tires. Meanwhile, increasing energy efficiency, improving environmental protection equipment, and applying clean energy are the effective measures to achieve this goal.     

Life cycle assessment of medium density particleboard (MDP) produced in Brazil

Purpose

The wood panel industry is one of the most important forest-based industries in Brazil. The medium density particleboard (MDP) is currently produced and consumed worldwide and represents about 50 % of the wood panel industry in Brazil. Unlike other regions, Brazilian MDP is produced from dedicated eucalyptus plantations and heavy fuel oil is an important energy source in MDP manufacture, which may result in a different environmental profile. This paper presents a life cycle assessment of MDP panel produced in Brazil and suggests improvement opportunities by assessing alternative production scenarios.

Methods

The cradle-to-gate assessment of 1 m³ of MDP produced in Brazil considered two main subsystems: forest and industrial production. Detailed inventories for Brazilian eucalyptus production and MDP industrial production were collected as a result of technical visits to Brazilian MDP producers (foreground systems) as well as literature review (mainly background systems). The potential environmental impacts of MDP were assessed in terms of seven impact categories using CML (abiotic depletion, acidification, global warming, eutrophication, and photochemical oxidation) and USEtox (ecotoxicity and human toxicity) impact assessment methods in order to identify the main hotspots.

Results and discussion

The industrial production was responsible for most of the impacts in all impact categories, except ecotoxicity (EC). The main hotspots identified were the use of heavy fuel oil (HFO) as a thermal energy source in MDP manufacture and the production of urea–formaldehyde (UF) resin used as synthetic adhesive. Glyphosate herbicide application in soil in forestry operations was the main responsible for the impacts in EC. Scenarios for HFO substitution were assessed and results showed that substituting HFO for in-mill wood residues or diesel leads to reduced environmental impacts.

Conclusions

The identification of the main hotspots in the MDP life cycle can assist the wood panel industry to improve their environmental profile. Further research should focus on UF resin production in order to reduce its environmental impacts as well as the possibility of using alternatives resins. Other sources of wood for MDP production could also be investigated (e.g., pine wood and wood residues) to assess potential improvements.     

Design of recycling system for poly(methyl methacrylate) (PMMA). Part 2: process hazards and material flow analysis

Introduction

In this series of papers, we present a design of poly(methyl methacrylate) (PMMA) recycling system considering environmental impacts, chemical hazards, and resource availability. We applied life cycle assessment (LCA), environment, health, and safety (EHS) assessment as well as material flow analysis to the evaluation of the recycling system.

Purpose

Recycling systems for highly functional plastics such as PMMA have not been studied sufficiently. Along with the popularization of PMMA-containing products such as liquid crystal displays (LCDs), the use of PMMA is steadily increasing, which will result in more waste of PMMA in the next decades. In this study, pyrolysis process for recycling waste PMMA into methyl methacrylate (MMA) monomer was examined, considering not only general environmental impacts quantified by life cycle assessment but also local environment, health, and safety hazards, and raw material availability.

Methods

Process EHS hazards assessment was applied to quantify the local effects of the PMMA monomer recycling process. Process hazards are strongly connected with the hazardous properties of chemical substances and stream conditions within the process. Two alternative cooling methods exist, and their difference was analyzed by LCA and EHS assessment. Besides the process hazard, the availability of waste PMMA must be an important point for the feasibility of implementing the PMMA monomer recycling process. The available amount can be quantified by analyzing the material flow of PMMA-containing products. PMMA contained in LCDs as light guide panels was selected as a feasible source of waste PMMA, and the quantity of PMMA flows in the society was evaluated.

Results and discussion

In the case of PMMA, monomer recycling has less process hazard than the production of fresh MMA from crude oil. The implementation of circulated cooling water could significantly decrease the process hazard in PMMA pyrolysis attributable to chemical hazards. Material flow analysis revealed that the availability of waste PMMA shows a fluctuating trend in the next 20 years because of the sharp peak demand for LCD television sets. The fluctuation is strongly dependent on the lifetime of LCD television sets.

Conclusions

PMMA monomer recycling has a potential to reduce environmental impacts with a less process hazards than fresh MMA production from crude oil. The availability of waste PMMA has a strong relationship with the lifetime of LCD television sets. The multiple and comprehensive assessments can reveal various aspects of a process technology.     

Tackling environmental impacts in simple trigeneration systems operating under variable conditions

Purpose

Environmental concerns have been a growing issue when planning energy supply systems for buildings, as the energy demands (presenting seasonal and daily variations) represent one of the most energy-intensive consumptions in industrialized societies. The optimal operation corresponding to different energy demands of a trigeneration system was analyzed by an integrated methodology combining Thermoeconomic analysis and life cycle assessment, in order to adequately allocate the energy resources and the generated environmental loads to the different energy services produced.

Methods

Thermoeconomic analysis, which is usually used to allocate energy and economic costs, is herein applied to the evaluation of environmental costs and distribution of resources throughout the trigeneration system. Attention is focused on the correct allocation of energy resources and environmental loads to internal flows and final products. Appropriate rules were established to calculate energy and environmental costs.

Results and discussion

Operation of the system considered the possibilities that surplus electricity could be exported to the national grid and part of the cogenerated heat could be wasted if this resulted in a decrease of operation costs and/or environmental loads. The results obtained show a low-cost and low-emission production with respect to the separate production in different operation modes. It was observed that, in specific periods, the trigeneration system operates wasting part of the cogenerated heat, and, in other periods, part of the electricity produced is exported to the electric grid. The trigeneration system operates in these modes because it results beneficial from environmental or economic viewpoints, achieving a lower economic cost or fewer CO₂ emissions.

Conclusions

The methodology presented as well as the allocation method proposal were congruent with the objectives of installing trigeneration systems that supplied energy services with fewer emissions than those of separate production and of equally benefitting the consumers of heat, coolth (“coolth” is used as the noun form of “cool”; opposite of warmth. Not to be confused with cooling, which is the opposite of heating.) (alias cooling energy), and electricity.     

Quantifying anthropogenic mobilization,flows (in product systems) and emissions of fixed nitrogen in process-based environmental life cycle assessment: rationale,methods and application to a life cycle inventory

Purpose

Anthropogenic perturbation of the nitrogen cycle is attracting increasing attention as both an environmental and societal concern. Here, we provide the rationale and propose methods for independent treatment of anthropogenic mobilization, flows (in product systems) and emissions of fixed nitrogen in process-based environmental life cycle assessment.

Methods

We propose a simple methodology for aggregating N flows in life cycle assessment (LCA), with supporting characterization factors for all nitrogen-containing compounds on the Organization for Economic Cooperation and Development High Production Volume Chemical List for which specific chemical formulae are available, as well as all nitrogen-containing flows in the International Reference Life Cycle Data System. We subsequently apply our method and characterization factors to a life cycle inventory data set representing a subset of the consumption attributable to an average EU-27 consumer and compare the results against previously published estimates for nitrogen emissions at the consumer level that were generated using alternative methods/approaches.

Results and discussion

We derive a suite of over 2,000 characterization factors for nitrogen-containing compounds. Overall, the results generated by applying our method and characterization factors to the European Commission Basket-of-Products life cycle inventory data set are consistent with those observed from studies having a similar scope but different methodological approach.

Conclusions

This outcome suggests that anthropogenic mobilization, flows (in product systems) and emissions of fixed nitrogen can, indeed, be systematically inventoried and aggregated in process-based LCA for the purpose of better understanding and managing anthropogenic impacts on the global nitrogen cycle using the methods and characterization factors we propose.     

LCA of energetic biomass utilization: actual projects and new developments—April 23, 2012, Berne, Switzerland

Introduction

In the last years, the use of biomass for energy purposes has been seen as a promising option to reduce the use of nonrenewable energy sources and the emissions of fossil carbon. However, LCA studies have shown that the energetic use of biomass also causes impacts on climate change and, furthermore, that different environmental issues arise, such as land use and agricultural emissions. While biomass is renewable, it is not an unlimited resource. Its use, to whatever purpose, must therefore be well studied to promote the most efficient option with the least environmental impacts. The 47th LCA Discussion Forum gathered several national and international speakers who provided a broad and qualified view on the topic.

Summary of the topics presented in DF 47

Several aspects of energetic biomass use from a range of projects financed by the Swiss Federal Office of Energy (SFOE) were presented in this Discussion Forum. The first session focused on important aspects of the agricultural biogas production like the use of high energy crops or catch crops as well as the influence of plant size on the environmental performance of biogas. In the second session, other possibilities of biomass treatment like direct combustion, composting, and incineration with municipal waste were presented. Topic of the first afternoon session was the update and harmonization of biomass inventories and the resulting new assessment of biofuels. The short presentations investigated some further aspects of the LCA of bioenergy like the assessment of spatial variation of greenhouse gas (GHG) emissions from bioenergy production in a country, the importance of indirect land use change emissions on the overall results, the assessment of alternative technologies to direct spreading of digestate or the updates of the car operation datasets in ecoinvent.

Conclusions

One main outcome of this Discussion Forum is that bioenergy is not environmentally friendly per se. In many cases, energetic use of biomass allows a reduction of GHG and fossil energy use. However, there is often a tradeoff with other environmental impacts linked to agricultural production like eutrophication or ecotoxicity. Methodological challenges still exist, like the assessment of direct and indirect land use change emissions and their attribution to the bioenergy production, or the influence of heavy metal flows on the bioenergy assessment. Another challenge is the implementation of a life cycle approach in certification or legislation schemes, as shown by the example of the Renewable Energy Directive of the European Union.     

The influence of contaminants in the environmental impact of recovered paper: a life cycle assessment perspective

Purpose

This study aims to analyze and quantify the environmental impacts associated with the production of testliner paper using 100?% recovered paper as fiber raw material, by applying the life cycle assessment principles. A simulation of advanced sorting technology was done to prepare and use batches of raw materials with different levels of contaminants. Comparative studies of environmental impact assessment were focused on the quality of recovered paper, which is decisively influenced by the efficiency of the sorting process. The particularity of the study is that so far it is the only one that analyzes the environmental impact generated by recovered paper quality.

Methods

To analyze the environmental impacts in the scenarios, life cycle assessment methodology was considered. Potential environmental impacts were assessed by using the CML 2009, Dec.07 method developed by the Centre for Environmental Science from the University of Leiden.

Results and discussion

In this study, acidification potential, abiotic resources depletion potential, eutrophication potential, global warming potential, photochemical ozone creation potential, and human toxicity potential were the impact categories analyzed. Considering that the system boundaries refer only to the paper mill that was obtained, all unitary processes involved in the manufacturing of product system influence in varying proportions the impact categories chosen for evaluation. A higher concentration of contaminants leads to a higher amount of energy and water used, and thus, a significant amount of waste and emissions generated. Simulations performed have highlighted the importance of sorting technology that influences the quality of raw material that will be used.

Conclusions

Utilization of recovered paper batches with a low quality contributes to an increased environmental impact associated with the testliner paper manufacturing stage. A low quality of recovered paper will influence energy consumption in different modules of the system (recycled fiber pulp preparation, paper machine, and wastewater treatment), the volume of waste generated, and consequently the emissions released both in air and water.     

Life cycle energy and environmental benefits of a US industrial symbiosis

Purpose

The industrial ecosystem identified in and around the Campbell Industrial Park in Honolulu County, Hawai’i involves 11 facilities exchanging water, materials, and energy across an industrial cluster. This paper highlights the advantages of this arrangement using life cycle assessment to determine the energy and environmental costs and benefits of the existing pattern of exchanges.

Methods

A consequential approach was used to evaluate each material substitution for four environmental impact categories: primary energy use, greenhouse gas (GHG) emissions, acidification, and eutrophication. Each material exchange included avoided production and reduced use of virgin materials, any necessary pre-processing or transportation of local by-products, and avoided treatment or disposal of these by-products.

Results and discussion

All exchanges exhibited positive net savings across all environmental impact categories, with the exceptions of waste oil and tire-derived fuel burned as substitutes for coal. The greatest savings occur as a result of sharing steam between a combined cycle fuel oil-fired cogeneration plant and a nearby refinery. In total, the environmental savings realized by this industrial cluster are significant, equivalent to 25 % of the state’s policy goal for reducing the industrial component of GHG emissions over the next decade. The role of policy in supporting material and energy exchanges is also discussed as the central cluster of two power plants and two refineries share steam and water in part under regulatory requirements.

Conclusions

The results show environmental benefits of the sharing of by-product resources accrued on a life cycle basis, while for the local context, the reduction of imported fuels and materials helps to reduce the external dependency of Oahu’s remote island economy. The environmental benefits of materials exchanges are often ignored in energy policy, though, as in this case, they can represent considerable savings.     

Comparative life cycle assessment of re-use and replacement for video projectors

Purpose

The current focus of environmental legislation for energy-using products is an efficient energy consumption in the use stage. However, the production and waste treatment of electronic products are also related to environmental impacts in terms of declining metal resources and growing waste streams. This paper investigates the environmental impacts of life time extension versus energy efficiency for the product group video projector using life cycle assessment (LCA).

Methods

The product under study was an average video projector based on three LCD projectors. The studied systems included two possibilities after a regular first usage period: reconditioning for a second use or replacement by a primary successor with an energy efficiency increase of 5 and 10%. All impacts addressed were accounted using the ReCiPe 2008 method. The impact contribution of projector components was identified at midpoint and endpoint levels, while life cycle impacts were calculated with a focus on three impact categories. Furthermore, the amortization period of production emissions was quantified.

Results and discussion

LCA results showed that the use stage dominates life cycle impacts of the global warming potential and primary energy demand. For the metal depletion potential, the production stage accounts for most of the total life cycle load. The highest shares in production emissions were identified for electronic components, namely printed wired boards and integrated circuits. Reconditioning and reuse of a secondary projector resulted in minor environmental impacts compared to the replacement and use of a primary projector with an energy efficiency increase of 5%. The saving potential of the primary energy demand is higher only in the case of a 10% more efficient device as compared to the secondary projector.

Conclusions

The study concluded that production emissions and their amortization period are relevant factors offsetting any environmentally beneficial measures applied during the use phase. The study suggests that life time extension of video projectors can provide higher environmental improvement potentials, while energy efficiency increase during usage is less beneficial, given that major improvements in energy efficiency do not occur. Recommendations are valid for this particular case study. The study suggests that the current focus of mandatory product requirements for energy-using products on energy efficiency increase should be extended to measures of life time extension in order to serve the intent of an integrated product policy.

     

Gender as a factor in an environmental assessment of the consumption of animal and plant-based foods in Germany

Purpose

Due to their production intensity, different foods of animal or plant origin play a crucial role in the assessment of the environmental impacts of human nutrition and diets. Based on a representative nutrition survey in Germany from the year 2006, a life cycle assessment (LCA) was conducted to quantify nutrition-related emissions of animal and plant-based foods (excluding beverages), with a special focus on the socio-demographic factor gender.

Materials and methods

For the study, representative data sets concerning German food production and consumption were used. These were complemented by the Danish LCA Food database and other LCA data to analyse the impact of food imports. As regards environmental impact assessment, global warming potential (GWP) was assessed, which included emissions from direct land use change and land use (dLUC, LU), along with three inventory indicators (ammonia emissions, land use, blue water use). The following food groups were analysed from cradle-to-store and their impacts were evaluated and compared with each other: animal-based foods (meat products, milk products, egg products and fish products), plant-based foods (grain products, vegetables, fruits, potato products, margarine/oils, sugar/sweets). The reference year in the study is the year 2006.

Results and discussion

For all indicators, the results show strong variation between the genders. Even if the physiologically different consumption patterns among men and women are adjusted on a weight basis, men show a higher impact in terms of GWP (CO₂ eq. +25%), ammonia emissions (+30%) and land use (+24%). In contrast, women demonstrate a higher water demand (+11%). These differences are primarily caused by a higher share of meat and meat products in the usual diet of men (+28%) as well as of fruit and vegetables in the diet of women (+40%). If men were to shift qualitatively to the usual diet of women, then 14.8 Mt CO₂ eq. and 60.1 kt ammonia emissions could be saved annually. Within the system boundaries of our study, this would translate into a reduction of 12% of CO₂ eq. and 14% of ammonia emissions. With regard to land use, this equals an area of 15,613?km²?year^?1 (?11%), whereas the total blue water demand would be increased by 94?Mm³?year^?1 (+7%). Limitations within this study are caused by the system boundaries cradle-to-store and are also due to the restricted set of environmental indicators which were analysed. Nonetheless, our results for GWP and land use are in keeping with previous studies. The results concerning ammonia and blue water use are limited when compared with other study results.

Conclusions

The study shows that within one society distinct diet profiles with markedly different environmental impacts are already established. Taking cultural and physiological considerations among the genders into account, these differences could be seen as offering potential opportunities to strengthen sustainable diet profiles. Further research should also consider health impact assessments to ensure that alterations in diet profiles due to environmental constraints do not lead to disadvantageous public health effects. Particular attention should be paid here to potentially undernourished subgroups (such as the elderly, sick people, pregnant women).     

Life cycle assessment of sponge nickel produced by gas atomisation for use in industrial hydrogenation catalysis applications

Purpose

This paper presents a cradle-to-grave comparative life cycle assessment (LCA) of new gas atomised (GA) sponge nickel catalysts and evaluates their performance against the current cast and crush standard currently used in the industrial hydrogenation of butyraldehyde to butanol.

Methods

A comparative LCA has been made, accounting for the energy used and emissions throughout the entire life cycle of sponge nickel catalysts—ranging from the upstream production of materials (mainly aluminium and nickel), to the manufacturing, to the operation and finally to the recycling and disposal. The LCA was performed following ISO14040 principles where possible, and subsequently implemented in the software package GaBi 4.3. The CML2001 impact assessment methodology was used, with primary focus on comparing catalysts for equivalent greenhouse gasses generated over their lifetime and their relative global warming potential and secondary focus on acidification potential. This is justified as the lifetime is dominated by energy use in the operational phase, and acidification is dominated by the production of nickel for which existing ISO14040 collected data has been used. A sensitivity analysis was used to provide a number of scenarios and overall environmental performances of the various sponge nickels considered when compared to the existing industrial standard.

Results and discussion

It was found that the energy and emissions during the operation phase associated with a given catalyst significantly outweigh the primary production, manufacturing and recycling. Primary production of the nickel (and to a lesser extent molybdenum when used as a dopant) also has a significant environmental impact in terms of acidification potential, but this is offset by operational energy savings over the catalysts’ estimated lifetime and end of life recyclability. Finally, the impact of activity improvement and lifetime duration of sponge nickel catalysts was determined as both total life cycle energy for operational use and as a total life cycle global warming potential.

Conclusions

From this assessment, the newly developed, higher activity spongy nickel catalysts produced by gas atomisation could have a significantly lower environmental impact than the current industry standard cast and crush method. Given the potential environmental benefits of such catalysts, applications in other processes that require a catalyst should also be investigated.     

Cost-effectiveness of bioethanol policies to reduce carbon dioxide emissions in Greece

Purpose

The aim of this study was to evaluate the cost-effectiveness of bioethanol as regards to its carbon dioxide emissions. The production of the raw material accounts for more than 50 % of the total cost as well as having a significant part of greenhouse gases emitted during the entire process. For this reason, special emphasis is given to a change in agricultural land usage influenced by the demand of biofuel. Therefore, we have estimated the extent of policy influence according to its bioethanol cost-effectiveness. A case study on bioethanol production in an ex-sugar factory in the region of Thessaly, Greece, illustrates the above ideas.

Methods

A partial equilibrium micro-economic model of regional supply in the arable farming system of Thessaly was coupled to industrial processing sub-models of bioethanol production from beets and grains. The maximisation of total welfare determines the most suitable crop mix for farmers as well as the lowest cost configurations for industry and, eventually, the minimal level of support by the government for biofuel activity to take off. The environmental performance is assessed under the life cycle assessment (LCA) framework following three interrelated phases: data inventory, data analysis and interpretation. The economic burden to society to support the activity divided by avoided CO₂ eq. emissions indicates the bioethanol cost-effectiveness, in other words, the cost of greenhouse gases emissions savings.

Results

The integrated agro-industry model has been parametrically run for a range of biofuel capacities. A change in direct land use results in lower emissions in the agricultural phase, since energy crops are a substitute for intensive cultivations, such as cotton and corn. A change in indirect land use moderates these estimations, as it takes in account imported food crops that are replaced by energy crops in the region. The savings in cost vary around 160 euros per ton of CO₂ eq. for the basic agricultural policy scenario. The current policy that supports cotton production by means of increased coupled area payment has increased up to 30 % the cost of greenhouse gas savings due to bioethanol production.

Conclusions

An integrated model, articulating the agricultural supply of biomass with ethanol processing, maximises the total surplus that is under constraints in order to determine the cost-effectiveness for different production levels. Results demonstrate that economic performances, as well as the environmental cost-effectiveness of bioethanol, are clearly affected by the parameters of agricultural policies. Therefore, bioenergy, environmental and economic performances, when based on LCA and the conceptual change in land usage, are context dependent. Agricultural policies for decoupling subsidies from production are in favour of cultivation in biomass for energy purposes.     

Characterization of CO2 emissions during construction of reservoir embankment elevation in South Korea

Purpose

The environmentally friendly construction of agricultural infrastructure is much needed for sustainable development because construction is recognized as a cause of environmental degradation. The objective of this study was to estimate and characterize carbon dioxide (CO₂) emissions during construction of agricultural reservoir embankments for the quantitative environmental assessment and management of CO₂ emissions using life cycle assessment method.

Methods

Two reservoirs with different foundation treatment and construction components were selected in this study and their characteristics in CO₂ emissions were compared. And CO₂ emissions were calculated separately for each of the following major components: construction materials, equipment, and transport. The basic unit of CO₂ emissions for construction materials was calculated using the 2009 input–output tables in Korea and the basic unit of CO₂ emissions for equipment of transport and construction was also calculated based on the amount of fuel used in a unit time.

Results and discussion

According to the study results, the construction of a water supply process appeared to generate the most emissions among all processes for the two sites. Emissions due to equipment were the highest in site A, while materials generated the most emissions in site B. Differences in emissions are due to differences in the construction process. While the operation time of the equipment in site A increased due to the cofferdam process and a large amount of cement was used in the foundation process in site B.

Conclusions

Characteristic of CO₂ emissions differs with different construction processes and thus construction processes need to be optimized for environmental friendly development of agricultural infrastructure through estimation and characterization of CO₂ emissions.     

A study on the environmental aspects of WEEE plastic recycling in a Brazilian company

Purpose

The high consumption of electrical and electronic equipment motivated by the rapid technological advances seen over the years has lead to an increase in the generation of waste electrical and electronic equipment (WEEE). Such residues contain various dangerous substances and therefore deserve special attention. To that end, the Brazilian Policy on Solid Waste has provided guidelines on integrated and solid waste management, such as consumer electronics, aiming at their appropriate disposal and treatment through reverse logistics. In this context, the present work focuses on studying the recycling of some WEEE plastics.

Methods

This study was conducted using the methodological framework presented in the International Standard ISO 14040:2006 and aimed to determine the life cycle inventory (LCI) of a WEEE plastic recycling process in a company in Brazil. Having collected the data, it was possible to identify and quantify the environmental aspects caused by the recycling process of major plastics (acrylonitrile-butadiene-styrene (ABS) and high impact polystyrene (HIPS). The study was conducted in the only company in Brazil that operates WEEE plastic recycling in large scale.

Results and discussion

Some of the environmental aspects caused during the recycling process of the plastics under study were identified and quantified. As a result, besides presenting the inventory, it was also possible to determine a reduction in the consumption of energy and in CO₂ emissions. When compared to the production of virgin ABS and HIPS, the recycling processes for such plastics showed a reduction in energy consumption by approximately 90% for both plastics and a reduction in CO₂ emissions by approximately 84% for HIPS and 87% for ABS. The plastics recycled by the company retain over 90% of their virgin mechanical properties.

Conclusions

The study shows that recycling is highly relevant and that components present in WEEE received appropriate destination and treatment. Recycling avoids environmental impacts as it prevents WEEE from being disposed of in landfills and as the pellets of recycled plastics can re-enter the supply chain as raw materials. Considering the legislation in Brazil, the stage of collection/transport/treatment of WEEE conducted by the company under study presents strong indications of contributions to the environment, society, and economy of the country.

     

Comparison of product carbon footprint standards with a case study on poinsettia (Euphorbia pulcherrima)

Purpose

A method to quantify the climate impact of products called product carbon footprint (PCF) has been gaining popularity in recent years. However, variations of this method have resulted in several competing standards to guide the carbon calculation process. The aim of the current paper was to compare PCF results when calculated according to the different standards.

Methods

The three leading PCF standards are Publicly Available Specification (PAS) 2050:2011, ISO.DIN 2 14067 and Product Life Cycle Accounting and Reporting Standard (PARS) 2011. These standards were compared conceptually, and a case study was performed in which the PCF of a poinsettia plant produced in Germany was calculated according to all three standards.

Results and discussion

The PCF results were 0.45–0.50, 0.53–0.58 and 0.53–0.59 kg carbon dioxide equivalent according to PAS 2050:2011, ISO.DIN 2 14067 and PARS 2011, respectively. According to all standards, the life cycle stage contributing the most greenhouse gases (GHGs) was the production of the poinsettia plant, and the single process with the highest emissions was the electricity use in the production. It was found that if nonrenewable fuels were used for heating instead of wood chips, then heating would be the highest GHG contributor—accounting for over 80 % of emissions of the total PCF.

Conclusions

A key finding was that both the production system used and the decisions taken by the person carrying out the PCF calculation result in greater differences in the PCF result than the use of different standards. Differences among the three standards could be harmonised by more specific cut-off rules and exclusion criteria with the publication of ISO.DIN 2 14067, as well as the development and use of product category rules.