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

Purpose

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

Method

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

Results and discussion

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

Conclusions

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

Shift in the marginal supply of vegetable oil

Background, Aims and Scope

The consequential approach to system delimitation in LCA requires that consideration of the technologies and suppliers included are ‘marginal’, i.e. that they are actually affected by a change in demand. Furthermore, coproduct allocation must be avoided by system expansion. Vegetable oils constitute a significant product group included in many LCAs that are intended for use in decision support. This article argues that the vegetable oil market has faced major changes around the turn of the century. The aim of this study is to study the marginal supply of vegetable oil as it has shifted to palm oil and describe the product system of the new supply.

Methods

The methods for identification of marginal technologies and suppliers and for avoiding co-product allocation are based on the work of Weidema (2003). The marginal vegetable oil is identified on the basis of agricultural statistics on production volumes and prices. A co-product from palm oil production is palm kernel meal, which is used for fodder purposes where it has two main properties: protein and energy. When carrying out system expansion, these properties are taken into account.

Results

The major vegetable oils are soy oil, palm oil, rapeseed oil and sun oil. These oils are substitutable within the most common applications. Based on market trends, a shift from rapeseed oil to palm oil as the marginal vegetable oil is identified around the year 2000, when palm oil turns out to be the most competitive oil. It is recommended to regard palm oil and its dependent co-product palm kernel oil as the marginal vegetable oil. The analysis of the product system shows that the demand for 1 kg palm oil requires 4.49 kg FFB (oil palm fruit) and the displacement of 0.035 kg soybeans (marginal source of fodder protein) and 0.066 kg barley (marginal source of fodder energy).

Discussion

The identification of the marginal vegetable oil and the avoidance of co-product allocation by system expansion showed that several commodities may be affected when using the consequential approach. Hence, the product system for vegetable oils is relatively complex compared to traditional LCAs in which average technologies and suppliers are applied and in which co-product allocation is carried out by applying an allocation factor.

Conclusions

This article presents how the marginal vegetable oil can be identified and that co-product allocation between oils and meal can be avoided by system expansion, by considering the energy and protein content in the meal, which displaces a mix of the marginal sources of energy and protein for animal fodder (barley and soy meal, respectively).

Recommendations and Perspectives

The implication of a shift in the marginal vegetable oil is significant. Many LCAs on rapeseed oil have been conducted and are being used as decision support in the bio energy field. Thus, based on consequential LCA methodology, it is argued that these LCAs need to be revised, since they no longer focus on the oil actually affected.

     

Accounting for overfishing in life cycle assessment: new impact categories for biotic resource use

Purpose

Overfishing is a relevant issue to include in all life cycle assessments (LCAs) involving wild caught fish, as overfishing of fish stocks clearly targets the LCA safeguard objects of natural resources and natural ecosystems. Yet no robust method for assessing overfishing has been available. We propose lost potential yield (LPY) as a midpoint impact category to quantify overfishing, comparing the outcome of current with target fisheries management. This category primarily reflects the impact on biotic resource availability, but also serves as a proxy for ecosystem impacts within each stock.

Methods

LPY represents average lost catches owing to ongoing overfishing, assessed by simplified biomass projections covering different fishing mortality scenarios. It is based on the maximum sustainable yield concept and complemented by two alternative methods, overfishing though fishing mortality (OF) and overfishedness of biomass (OB), that are less data-demanding.

Results and discussion

Characterization factors are provided for 31 European commercial fish stocks in 2010, representing 74 % of European and 7 % of global landings. However, large spatial and temporal variations were observed, requiring novel approaches for the LCA practitioner. The methodology is considered compliant with the International Reference Life Cycle Data System (ILCD) standard in most relevant aspects, although harmonization through normalization and endpoint characterization is only briefly discussed.

Conclusions

Seafood LCAs including any of the three approaches can be a powerful communicative tool for the food industry, seafood certification programmes, and for fisheries management.     

A review of life cycle assessments on wind energy systems

Purpose

Several life cycle assessments (LCAs) of wind energy published in recent years are reviewed to identify methodological differences and underlying assumptions.

Methods

A full comparative analysis of 12 studies were undertaken (ten peer-reviewed papers, one conference paper, and one industry report) regarding six fundamental factors (methods used, energy use accounting, quantification of energy production, energy performance and primary energy, natural resources, and recycling). Each factor is discussed in detail to highlight strengths and shortcomings of various approaches.

Results

Several potential issues are found concerning the way LCA methods are used for assessing energy performance and environmental impact of wind energy, as well as dealing with natural resource use and depletion. The potential to evaluate natural resource use and depletion impacts from wind energy appears to be poorly exploited or elaborated on in the reviewed studies. Estimations of energy performance and environmental impacts are critically analyzed and found to differ significantly.

Conclusions and recommendations

A continued discussion and development of LCA methodology for wind energy and other energy resources are encouraged. Efforts should be made to standardize methods and calculations. Inconsistent use of terminology and concepts among the analyzed studies are found and should be remedied. Different methods are generally used and the results are presented in diverse ways, making it difficult to compare studies with each other, but also with other renewable energy sources.     

Parameterized tool for site specific LCAs of wind energy converters

Purpose

The purpose of this project was to provide a parameterized LCA tool that allows performing site specific life cycle assessments for different wind energy converter types by varying a limited number of relevant parameters. Hereby, it addresses the limited transferability of WEC LCA results to other sites as well as the increasing demand for such data.

Methods

Basis of the work was an extensive primary data collection at the respective production facilities and other relevant stakeholders like site assessment, service etc. Most of the required data was available at first hand and was completed with data from literature and LCA databases. Based on this data, a complex parameterized material flow model has been built and different product variants have been pre-defined within the model, including relevant production processes and upstream. The pre-definition of these product variants allows reducing the minimum number of parameters that need to be configured for site specific LCAs from a total of over 330 to just nine parameters.

Results and conclusions

In the future, choosing the right type of technology for specific sites will become more important; especially in the face of increasing land use conflicts and increasing competition between renewable energy technologies. Site and technology specific LCAs prove to be a valuable tool for this assessment. Tools like the presented significantly reduce the effort required for performing these LCAs. Additionally, they can be used for various other purposes like environmental assessments of different repowering scenarios and eco design.     

Life cycle assessment evaluation of green product labeling systems for residential construction

Purpose

Life cycle assessment (LCA) is a tool that can be utilized to holistically evaluate novel trends in the construction industry and the associated environmental impacts. Green labels are awarded by several organizations based on single or multiple attributes. The use of multi-criteria labels is a good start to the labeling process as opposed to single criteria labels that ignore a majority of impacts from products. Life cycle thinking, in theory, has the potential to improve the environmental impacts of labeling systems. However, LCA databases currently are lacking in detailed information about products or sometimes provide conflicting information.

Method

This study compares generic and green-labeled carpets, paints, and linoleum flooring using the Building for Environmental and Economic Sustainability (BEES) LCA database. The results from these comparisons are not intuitive and are contradictory in several impact categories with respect to the greenness of the product. Other data sources such as environmental product declarations and ecoinvent are also compared with the BEES data to compare the results and display the disparity in the databases.

Results

This study shows that partial LCAs focused on the production and transportation phase help in identifying improvements in the product itself and improving the manufacturing process but the results are uncertain and dependent upon the source or database. Inconsistencies in the data and missing categories add to the ambiguity in LCA results.

Conclusions

While life cycle thinking in concept can improve the green labeling systems available, LCA data is lacking. Therefore, LCA data and tools need to improve to support and enable market trends.     

Global characterisation factors to assess land use impacts on biotic production

Purpose

The inclusion of land-use activities in life cycle assessment (LCA) has been subject to much debate in the LCA community. Despite the recent methodological developments in this area, the impacts of land occupation and transformation on its long-term ability to produce biomass (referred to here as biotic production potential [BPP]) — an important endpoint for the Area of Protection (AoP) Natural Resources — have been largely excluded from LCAs partly due to the lack of life cycle impact assessment methods.

Materials and methods

Several possible methods/indicators for BPP associated with biomass, carbon balance, soil erosion, salinisation, energy, soil biota and soil organic matter (SOM) were evaluated. The latter indicator was considered the most appropriate for LCA, and characterisation factors for eight land use types at the climate region level were developed.

Results and discussion

Most of the indicators assessed address land-use impacts satisfactorily for land uses that include biotic production of some kind (agriculture or silviculture). However, some fail to address potentially important land use impacts from other life cycle stages, such as those arising from transport. It is shown that the change in soil organic carbon (SOC) can be used as an indicator for impacts on BPP, because SOC relates to a range of soil properties responsible for soil resilience and fertility.

Conclusions

The characterisation factors developed suggest that the proposed approach to characterize land use impacts on BBP, despite its limitations, is both possible and robust. The availability of land-use-specific and biogeographically differentiated data on SOC makes BPP impact assessments operational. The characterisation factors provided allow for the assessment of land-use impacts on BPP, regardless of where they occur thus enabling more complete LCAs of products and services. Existing databases on every country’s terrestrial carbon stocks and land use enable the operability of this method. Furthermore, BPP impacts will be better assessed by this approach as increasingly spatially specific data are available for all geographical regions of the world at a large scale. The characterisation factors developed are applied to the case studies (Part D of this special issue), which show the practical issues related to their implementation.     

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.     

Utilization of recovered wood in cascades versus utilization of primary wood—a comparison with life cycle assessment using system expansion

Purpose

A cascading utilization of resources is encouraged especially by legislative bodies. However, only few consecutive assessments of the environmental impacts of cascading are available. This study provides answers to the following questions for using recovered wood as a secondary resource: (1) Does cascading decrease impacts on the environment compared to the use of primary wood resources? (2) What aspects of the cascading system are decisive for the life cycle assessment (LCA) results?

Methods

We conducted full LCAs for cascading utilization options of waste wood and compared the results to functionally equivalent products from primary wood, thereby focusing on the direct effects cascading has on the environmental impacts of the systems. In order to compare waste wood cascading to the use of primary wood with LCA, a functional equivalence of the systems has to be achieved. We applied a system expansion approach, considering different options for providing the additionally needed energy for the cascading system.

Results and discussion

We found that the cascading systems create fewer environmental impacts than the primary wood systems, if system expansion is based on wood energy. The most noticeable advantages were detected for the impact categories of land transformation and occupation and the demand of primary energy from renewable sources. The results of the sensitivity analyses indicate that the advantage of the cascading system is robust against the majority of considered factors. Efficiency and the method of incineration at the end of life do influence the results.

Conclusions

To maximize the benefits and minimize the associated environmental impacts, cascading proves to be a preferable option of utilizing untreated waste wood.     

Life cycle assessment of construction materials: the influence of assumptions in end-of-life modelling

Purpose

The nature of end-of-life (EoL) processes is highly uncertain for constructions built today. This uncertainty is often neglected in life cycle assessments (LCAs) of construction materials. This paper tests how EoL assumptions influence LCA comparisons of two alternative roof construction elements: glue-laminated wooden beams and steel frames. The assumptions tested include the type of technology and the use of attributional or consequential modelling approaches.

Methods

The study covers impact categories often considered in the construction industry: total and non-renewable primary energy demand, water depletion, global warming, eutrophication and photo-chemical oxidant creation. The following elements of the EoL processes are tested: energy source used in demolition, fuel type used for transportation to the disposal site, means of disposal and method for handling allocation problems of the EoL modelling. Two assumptions regarding technology development are tested: no development from today’s technologies and that today’s low-impact technologies have become representative for the average future technologies. For allocating environmental impacts of the waste handling to by-products (heat or recycled material), an attributional cut-off approach is compared with a consequential substitution approach. A scenario excluding all EoL processes is also considered.

Results and discussion

In all comparable scenarios, glulam beams have clear environmental benefits compared to steel frames, except for in a scenario in which steel frames are recycled and today’s average steel production is substituted, in which impacts are similar. The choice of methodological approach (attributional, consequential or fully disregarding EoL processes) does not seem to influence the relative performance of the compared construction elements. In absolute terms, four factors are shown to be critical for the results: whether EoL phases are considered at all, whether recycling or incineration is assumed in the disposal of glulam beams, whether a consequential or attributional approach is used in modelling the disposal processes and whether today’s average technology or a low-impact technology is assumed for the substituted technology.

Conclusions

The results suggest that EoL assumptions can be highly important for LCA comparisons of construction materials, particularly in absolute terms. Therefore, we recommend that EoL uncertainties are taken into consideration in any LCA of long-lived products. For the studied product type, LCA practitioners should particularly consider EoL assumptions regarding the means of disposal, the expected technology development of disposal processes and any substituted technology and the choice between attributional and consequential approaches.     

Usage of skin care products and risk of rheumatoid arthritis: results from the Swedish EIRA study

Introduction

The aim of this study was to investigate the association between exposure to cosmetics, often containing mineral oil, and the risk of developing rheumatoid arthritis (RA). The study was performed against the background that occupational exposure to mineral oil has recently been shown to be associated with an increased risk for RA in man, and that injection of or percutaneous exposure to mineral-oil-containing cosmetics can induce arthritis in certain rat strains.

Methods

A population-based case-control study of incident cases of RA was performed among the population aged 18 to 70 years in a defined area of Sweden during May 1996 to December 2003. A case was defined as an individual from the study base, who received for the first time a diagnosis of RA according to the 1987 American College of Rheumatology criteria. Controls were randomly selected from the study base with consideration taken for age, gender and residential area. Cases (n = 1,419) and controls (n = 1,674) answered an extensive questionnaire regarding environmental and lifestyle factors including habits of cosmetic usage. The relative risk of developing RA was calculated for subjects with different cosmetic usage compared with subjects with low or no usage. Analysis was also performed stratifying the cases for presence/absence of rheumatoid factor and antibodies to citrulline-containing peptides.

Results

The relative risks of developing RA associated with use of cosmetics were all close to one, both for women and men, for different exposure categories, and in relation to different subgroups of RA.

Conclusion

This study does not support the hypothesis that ordinary usage of common cosmetics as body lotions, skin creams, and ointments, often containing mineral oil, increase the risk for RA in the population in general. We cannot exclude, however, that these cosmetics can contribute to arthritis in individuals carrying certain genotypes or simultaneously being exposed to other arthritis-inducing environmental agents.     

Marlo’s windows: why it is a mistake to ignore hazard resistance in LCA

Purpose

Hazard-resistant materials for homes promise environmental benefits, such as avoided waste and materials for repairs, which can be overlooked by scoping in life-cycle assessment (LCA) approaches. Our motivation for pursuing this research was to see how incorporating these avoided losses in the LCA could impact choices between hazard-resistant and traditional materials.

Methods

Two choices common in home construction were analyzed using an LCA process that incorporates catastrophe modeling to consider avoided losses made possible with hazard-resistant materials. These findings were compared to those based on a similar LCA that did not consider these avoided losses. The choices considered were standard windows vs. windows with impact-resistant glass and standard windows with no opening protection vs. standard windows with impact-resistant storm panels.

Results and discussion

For the window comparisons, the standard products were environmentally preferable when avoided losses from storm events were not considered in the LCA. However, when avoided losses were considered, the hazard-resistant products were environmentally preferable. Considering avoided losses in LCAs, as illustrated by the window choices, can change which product appears to be the environmentally preferable option. Further, as home service life increases, the environmental net benefit of the hazard-resistant product increases.

Conclusions

Our results show the value of an LCA approach which allows more complete scopings of comparisons between hazard-resistant materials and their traditional counterparts. This approach will help translate the impacts of hazard-resistant products into the more familiar language used to talk about “green” products, enabling more informed decisions by product manufacturers, those who develop building certification systems and codes, researchers, and other building industry stakeholders.     

Genomic analysis reveals that Pseudomonas aeruginosa virulence is combinatorial

Background

Pseudomonas aeruginosa is a ubiquitous environmental bacterium and an important opportunistic human pathogen. Generally, the acquisition of genes in the form of pathogenicity islands distinguishes pathogenic isolates from nonpathogens. We therefore sequenced a highly virulent strain of P. aeruginosa, PA14, and compared it with a previously sequenced (and less pathogenic) strain, PAO1, to identify novel virulence genes.

Results

The PA14 and PAO1 genomes are remarkably similar, although PA14 has a slightly larger genome (6.5 megabses [Mb]) than does PAO1 (6.3 Mb). We identified 58 PA14 gene clusters that are absent in PAO1 to determine which of these genes, if any, contribute to its enhanced virulence in a Caenorhabditis elegans pathogenicity model. First, we tested 18 additional diverse strains in the C. elegans model and observed a wide range of pathogenic potential; however, genotyping these strains using a custom microarray showed that the presence of PA14 genes that are absent in PAO1 did not correlate with the virulence of these strains. Second, we utilized a full-genome nonredundant mutant library of PA14 to identify five genes (absent in PAO1) required for C. elegans killing. Surprisingly, although these five genes are present in many other P. aeruginosa strains, they do not correlate with virulence in C. elegans.

Conclusion

Genes required for pathogenicity in one strain of P. aeruginosa are neither required for nor predictive of virulence in other strains. We therefore propose that virulence in this organism is both multifactorial and combinatorial, the result of a pool of pathogenicity-related genes that interact in various combinations in different genetic backgrounds.     

An extended life cycle analysis of packaging systems for fruit and vegetable transport in Europe

Purpose

The year-round supply of fresh fruit and vegetables in Europe requires a complex logistics system. In this study, the most common European fruit and vegetable transport packaging systems, namely single-use wooden and cardboard boxes and re-useable plastic crates, are analyzed and compared considering environmental, economic, and social impacts.

Methods

The environmental, economic, and social potentials of the three transport packaging systems are examined and compared from a life cycle perspective using Life Cycle Assessment (LCA), Life Cycle Costing (LCC) and Life Cycle Working Environment (LCWE) methodologies. Relevant parameters influencing the results are analyzed in different scenarios, and their impacts are quantified. The underlying environmental analysis is an ISO 14040 and 14044 comparative Life Cycle Assessment that was critically reviewed by an independent expert panel.

Results and discussion

The results show that wooden boxes and plastic crates perform very similarly in the Global Warming Potential, Acidification Potential, and Photochemical Ozone Creation Potential categories; while plastic crates have a lower impact in the Eutrophication Potential and Abiotic Resource Depletion Potential categories. Cardboard boxes show the highest impacts in all assessed categories. The analysis of the life cycle costs show that the re-usable system is the most cost effective over its entire life cycle. For the production of a single crate, the plastic crates require the most human labor. The share of female employment for the cardboard boxes is the lowest. All three systems require a relatively large share of low-qualified employees. The plastic crate system shows a much lower lethal accident rate. The higher rate for the wooden and cardboard boxes arises mainly from wood logging. In addition, the sustainability consequences due to the influence of packaging in preventing food losses are discussed, and future research combining aspects both from food LCAs and transport packing/packaging LCAs is recommended.

Conclusions

For all three systems, optimization potentials regarding their environmental life cycle performance were identified. Wooden boxes (single use) and plastic crates (re-usable) show preferable environmental performance. The calibration of the system parameters, such as end-of-life treatment, showed environmental optimization potentials in all transport packaging systems. The assessment of the economic and the social dimensions in parallel is important in order to avoid trade-offs between the three sustainability dimensions. Merging economic and social aspects into a Life Cycle Assessment is becoming more and more important, and their integration into one model ensures a consistent modeling approach for a manageable effort.     

Spatially explicit fate factors of phosphorous emissions to freshwater at the global scale

Purpose

The location of a phosphorus emission can strongly affect its expected fate in freshwater. To date, in Life Cycle Assessment (LCA), fate factors for phosphorus emissions have been derived for continents or large countries and had limited spatial resolution. These fate factors do not account sufficiently for local variations and are not applicable globally. In this paper, fate factors for freshwater eutrophication are derived for phosphorus emissions to freshwater on a global scale with a half-degree resolution.

Methods

For this purpose, a new global fate model for phosphorus has been developed on a half-degree resolution. The removal processes taken into account are grid-specific advection, phosphorus retention and water use. Aggregated fate factors based on archetypes and on administrative units are presented.

Results and discussion

The derived fate factors represent the persistence of phosphorus in the freshwater environment. The typical fate factor of phosphorus emissions to freshwater is 10?days and can vary more than 2 orders of magnitude among the grid cells (the 5th and 95th percentile are 0.8 and 310?days, respectively). Advection is the dominant removal process of phosphorus in freshwater (67.5%), followed by retention (27.6%) and water use (4.9%).

Conclusions

The results demonstrate inclusion of information on the location of phosphorus emissions to freshwater can improve the comparative power of the fate factor implementation in LCAs. The fate factors enable consistent assessment and comparison of freshwater eutrophication impacts at different locations across the globe.     

System delimitation in agricultural consequential LCA

Background, aim, and scope

When dealing with system delimitation in environmental life cycle assessment (LCA), two methodologies are typically referred to: consequential LCA and attributional LCA. The consequential approach uses marginal data and avoids co-product allocation by system expansion. The attributional approach uses average or supplier-specific data and treats co-product allocation by applying allocation factors. Agricultural LCAs typically regard local production as affected and they only include the interventions related to the harvested area. However, as changes in demand and production may affect foreign production, yields and the displacement of other crops in regions where the agricultural area is constrained, there is a need for incorporating the actual affected processes in agricultural consequential LCA. This paper presents a framework for defining system boundaries in consequential agricultural LCA. The framework is applied to an illustrative case study; LCA of increased demand for wheat in Denmark. The aim of the LCA screening is to facilitate the application of the proposed methodology. A secondary aim of the LCA screening is to illustrate that there are different ways to meet increased demand for agricultural products and that the environmental impact from these different ways vary significantly.

Materials and methods

The proposed framework mainly builds on the work of Ekvall T, Weidema BP (Int J Life Cycle Assess 9(3):pp. 161–171, 2004), agricultural statistics (FAOSTAT, FAOSTAT Agriculture Data, Food and Agriculture Organisation of the United Nations (2006), http://apps.fao.org/ (accessed June)), and agricultural outlook (FAPRI, US and world agricultural outlook, Food and Agriculture Research Institute, Iowa, 2006a). The framework and accompanying guidelines concern the suppliers affected, the achievement of increased production (area or yield), and the substitutions between crops. The framework, which is presented as a decision tree, proposes four possible systems that may be affected as a result of the increased demand of a certain crop in a certain area.

Results

The core of the proposed methodology is a decision tree, which guides the identification of affected processes in consequential agricultural LCA. The application of the methodology is illustrated with a case study presenting an LCA screening of wheat in Denmark. Different scenarios of how increased demand for wheat can be met show significant differences in emission levels as well as land use.

Discussion

The great differences in potential environmental impacts of the analysed results underpin the importance of system delimitation. The consequential approach is appointed as providing a more complete and accurate but also less precise result, while the attributional approach provides a more precise result but with inherent blind spots, i.e. a less accurate result.

Conclusions

The main features of the proposed framework and case study are: (1) an identification of significant sensitivity on results of system delimitation, and (2) a formalised way of identifying blind spots in attributional agricultural LCAs.

Recommendations and perspectives

It is recommended to include considerations on the basis of the framework presented in agricultural LCAs if relevant. This may be done either by full quantification or as qualitative identification of the most likely ways the agricultural product system will respond on changed demand. Hereby, it will be possible to make reservations to the conclusions drawn on the basis of an attributional LCA.     

Comparative attributional life cycle assessment of European cellulase enzyme production for use in second-generation lignocellulosic bioethanol production

Purpose

The production of cellulase enzymes (CE) has been identified as one major contributor towards the life cycle environmental and economic impacts of second-generation lignocellulosic bioethanol (LCB) production. Despite this knowledge, the literature lacks consistent and transparent life cycle assessments (LCA) which compare CE production based on the three more commonly proposed carbon sources: cornstarch glucose, sugar cane molasses and pre-treated softwood. Furthermore, numerous LCAs of LCB omit CE production from their system boundaries, with several authors citing the lack of available production data.

Methods

In this article, we perform a comparative attributional LCA for the on-site production of 1 kg CE in full broth via submerged aerobic fermentation (SmF) based on the three alternative carbon sources, cases A, B and C, respectively. We determine life cycle inventory (LCI) material consumption using stoichiometric equations and volume flow, supplemented with information from the literature. All LCIs are provided in a consistent and transparent manner, filling the existing data gaps towards performing representative LCAs of LCB production with on-site CE production. Life cycle impact assessment (LCIA) results are determined with SimaPro 8 software using CML 1A baseline and non-baseline methods along with cumulative energy demand and are compared to results of similar studies. Sensitivity analysis is performed both for all major assumptions and for market changes with the application of advanced attributional LCA (AALCA).

Results and discussion

We find that CE production from pre-treated softwood (case C) provides the lowest environmental impacts, followed by sugar cane molasses (case B) and then cornstarch glucose (case A), with global warming potentials of 7.9, 9.1 and 10.6 kg CO₂ eq./kg enzyme, respectively. These findings compare well with those of similar studies, though great variation exists in the literature. Through sensitivity analysis, we determine that results are sensitive to assumptions made concerning carbon source origin, applied allocation, market changes, process efficiency and electricity supply.

Conclusions

Furthermore, we find that the contribution of CE production towards the overall life cycle impacts of LCB is significant and that the omission of this sub-process in LCAs of LCB production can compromise their representativeness.

     

LCA applied to perennial cropping systems: a review focused on the farm stage

Purpose

Perennial crops globally provide a lot of fruit and other food products. They may also provide feedstock for bioenergy and have been, notably to this end, the subject of several LCA-based studies mostly focusing on energy and GHG balances. The purpose of this review was to investigate the relevance of LCAs on perennial crops, especially focusing on how the perennial crop specificities were accounted for in the farm stage modelling.

Methods

More than 100 papers were reviewed covering 14 products from perennial crops: apple, banana (managed over several years), orange and other citrus fruits, cocoa, coconut, coffee, grape fruit, Jatropha oil, kiwi fruit, palm oil, olive, pear and sugarcane. These papers were classified into three categories according to the comprehensiveness of the LCA study and depending on whether they were peer-reviewed or not. An in-depth analysis of the goal and scope, data origin for farming systems, modelling approach for the perennial cropping systems and methods and data for field emissions helped reveal the more critical issues and design some key recommendations to account better for perennial cropping systems in LCA.

Results and discussion

In the vast majority of the reviewed papers, very little attention was paid on integrating the perennial cropping cycle in the LCA. It is especially true for bioenergy LCA-based studies that often mostly focused on the industrial transformation without detailing the agricultural raw material production, although it might contribute to a large extent to the studied impacts. Some key parameters, such as the length of the crop cycle, the immature and unproductive phase or the biannual yield alternance, were mostly not accounted for. Moreover, the lack of conceptual modelling of the perennial cycle was not balanced by any attempt to represent the temporal variability of the system with a comprehensive inventory of crop managements and field emissions over several years.

Conclusions

According to the reviewed papers and complementary references, we identified the gaps in current LCA of perennial cropping systems and proposed a road map for scientific researches to help fill-in the knowledge-based gaps. We also made some methodological recommendations in order to account better for the perennial cycle within LCA considering the aim of the study and data availability.     

Do wood-based panels made with agro-industrial residues provide environmentally benign alternatives? An LCA case study of sugarcane bagasse addition to particle board manufacturing

Purpose

Sugarcane bagasse is one of the main agro-industrial residues which can be used to produce wood-based panels. However, more investigations related to its environmental performance assessment are needed, focusing on questions such as: Does it provide environmental benefits? What are its main environmental impacts? Could it substitute wood as raw material? Accordingly, this paper presents a life cycle assessment (LCA) study of particle board manufactured with sugarcane bagasse residues.

Methods

The cradle-to-gate assessment of 1 m³ of particle board made with sugarcane bagasse (PSB) considered three main subsystems: bagasse generation, bagasse distribution, and PSB production. For the inventory of PSB, dataset from two previous LCA studies related to the conventional particle board production and the ethanol life cycle for the Brazilian context were used. The allocation criterion for the bagasse generation subsystem was 9.08 % (economic base). The potential environmental impact phase was assessed by applying the CML and USEtox methods. PSB was compared with the conventional particle board manufactured in Brazil by the categories of the CML and USETox, and including land use indicators. Finally, two scenarios were analyzed to evaluate the influence of the allocation criteria and the consumption of sugarcane bagasse.

Results and discussion

All hotspots identified by CML and USETox methods are mainly related to the PSB production subsystem (24–100 % of impacts) due to heavy fuel oil, electricity, and urea-formaldehyde resin supply chain. The bagasse generation subsystem was more relevant to the eutrophication category (75 % of impacts). The bagasse distribution subsystem was not relevant because the impacts on all categories were lower than 1 %. PSB can substitute the conventional particle board mainly because of its lower contribution to abiotic depletion and ecotoxicity. Regarding land use impacts, PSB showed lower values according to all indicators (38–40 % of all impacts), which is explained by the lower demand for land occupation in comparison to that of the traditional particle board.

Conclusions

PSB can replace the traditional particle board due to its better environmental performance. The analysis of the economic allocation criterion was relevant only for the EP category, being important to reduce diesel and N-based fertilizers use during sugarcane cultivation. Regarding the influence of the sugarcane bagasse consumption, it is suggested that the sugarcane bagasse be mixed up to 75 % during particle board manufacturing so that good quality properties and environmental performance of panels can be provided.