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Consequential Life Cycle Environmental Impact Assessment
Abstract
This chapter describes the life cycle approach to energy chain analysis
and the methodology of life cycle assessment (LCA). Consequential LCA (cLCA) is
discussed in comparison with attributional LCA (aLCA). The methodological
approach of environmental impact assessment (EIA) is also presented. The methods,
with emphasis on cLCA, are discussed in the context of improving the knowledge of
unintended consequences from various forms of renewable energy. The chapter
presents a series of examples where cLCA are used to predict in advance, unan-
ticipated impacts of different forms of renewable energy technologies throughout
their life cycle, with particularly focus on the impact of biofuels production.
... External fossil fuel inputs are required to produce and harvest the feedstock, processing and handling the biomass, bioenergy plant operation, and transportation of feedstock and biofuels [2]. This is a typical example of an unintended consequence of renewable energy [3]. ...
... To evaluate the environmental impacts associated with biofuels production and identify any opportunity for environmental improvement, Life Cycle Assessment (LCA) is a standardized methodology frequently applied [3][4][5][6][7]. Slade et al. [8] evaluated the GHG emissions performance of the cellulosic ethanol supply chains in Europe. ...
High dependence on imported oil has increased U.S. strategic vulnerability and prompted more research in the area of renewable energy production. Ethanol production from renewable woody biomass, which could be a substitute for gasoline, has seen increased interest. This study analysed energy use and greenhouse gas emission impacts on the forest biomass supply chain activities within the State of Michigan. A life-cycle assessment of harvesting and transportation stages was completed utilizing peer-reviewed literature. Results for forest-delivered ethanol were compared with those for petroleum gasoline using data specific to the U.S. The analysis from a woody biomass feedstock supply perspective uncovered that ethanol production is more environmentally friendly (about 62% less greenhouse gas emissions) compared with petroleum based fossil fuel production. Sensitivity analysis was conducted with key inputs associated with harvesting and transportation operations. The results showed that research focused on improving biomass recovery efficiency and truck fuel economy further reduced GHG emissions and energy consumption.
... Produktlebens, um reproduzierbare Aussagen hinsichtlich der ökologischen Auswirkungen eines Produktes auf Basis quantifizierbarer Daten formulieren zu können. Diese Quantifizierung erfolgt durch auswirkungsspezifische Kategorien, welche die für das Produkt notwendigen Stoffströme mit den resultierenden Umweltauswirkungen in ein Verhältnis setzt [14,15]. ...
When developing products, engineers face challenges in solving technical, economical, but also ecological conflicts of objectives. A common technical conflict is the contradictory behaviour between the stiffness and mass of components. A possibility to resolve this contradiction is offered by multi-material components, which are made possible by a load-optimised design. Taking the example of topology-optimised multi-material components, this article shows a method for taking the ecological impact of raw material extraction into account in selecting suitable designs by offsetting a performance index with the results of ecological impact assessment calculations. These results are analysed in order to identify a possible solution according to the technical-ecological conflict of objectives.
... The regulatory rule in the European Union market is Regulation (EC) No 66/2010 (Eco-label Regulation), and it has been adopted by the major large businesses. Most carbon footprint certification tools, whether by a third party or a company working on their own products, relies on a range of LCA approaches and data, for instance: The Carbon Reduction Institute offers carbon neutral certification schemes (Whittaker et al. 2013); the non-profit association, Climatop, provides labelling for climate-friendly products (Andersen 2013) The advantages of applying environmental product declarations include: first it avoids the necessity to perform new LCA studies for the specific products of focus (performing LCAs are time-consuming, data intensive). Also, as environmental declarations follow a set of strict and mature rules and standards, their results make them suitable for comparison across products. ...
In this chapter, a wide range of Life Cycle Assessment (LCA) methods, new initiative for reducing emissions and improving resource efficiency, and Product Environmental Footprint are examined, in order to introduce the research tendency in this filed and clarify the differences among these Life Cycle Impact Assessment (LCIA) methods. The LCIA methods are broadly categorized as resource based and emission based. Life Cycle Inventory (LCI) database are also investigated, and the features of the generic LCI database are presented. The data formats of the ecoinvent database are deeply examined, with the aim of clarifying the attributes, types of each data components to help users to understand the role of inventory database in the practices.
... Instead, the emissions in all impact categories are considered to replace or substitute the emissions of a hypothetical reference system that produces the same amount of comparable products (i.e., electricity as per the electricity mix in Yucatan, and fossil diesel). This is known as consequential LCA [45]. ...
This paper presents a unique sustainability analysis of one of the first attempts to establish a biodiesel industry in Mexico. From 2008, several companies established medium to large-sized Jatropha curcas plantations in Yucatan, hiring local peasants to carry out the agricultural work. After five years, the plantations were abandoned due to poor seed yields and a lack of key knowledge for large-scale cultivation. Based on a multidisciplinary approach, we performed a three-dimensional sustainability evaluation of the potential biodiesel production chain, which included household interviews, a socioeconomic survey, and a life-cycle assessment (LCA).We identified both negative and positive effects in the three dimensions analyzed. Socially and culturally, the local peasant families understood sustainability as their ability to preserve their traditional lifestyle, and associated environmental services with their sense of identity. They therefore considered the jatropha plantations to be positive for sustainability, since they brought income, even though some perceived damage to the natural resources of the surrounding areas. Economically, peasants' annual household income increased by approximately $1080 USD due to the increased salaries paid by the jatropha companies. The LCA predicted large savings of greenhouse gas emissions ( > 50% compared to fossil diesel), but also potential negative impacts in some categories (human/ecological toxicity and eutrophication potentials) associated with the use of mineral fertilizers, insecticides, and pesticides applied during the cultivation stage. Biodiesel production would be potentially energetically self-sufficient, in addition to producing a 40% energy surplus. Finally, even though the sustainability indicators suggested a positive overall assessment, the reality was that the jatropha projects failed because they were predicated on unrealistically optimistic projections and poor agronomic knowledge of the plant.
... The spatial data are publicly available on the website of the Aerial Photography & GIS Data for the Professional & Novice (for counties) [31], and the Kansas Data Access & Support Center (DASC) (for railroads and highways) (Lawrence, KS, USA) [32,33]. We use an attributional LCA (aLCA) approach in this study to investigate the spatial variability in LCIA metrics; however, we note the limitations of this approach raised by Andersen [34], who discussed potentially negative environmental impacts resulting from agricultural residue diversion, in that case, bagasse, for biofuel production. ...
To meet Energy Independence and Security Act (EISA) cellulosic biofuel mandates, the United States will require an annual domestic supply of about 242 million Mg of biomass by 2022. To improve the feedstock logistics of lignocellulosic biofuels in order to access available biomass resources from areas with varying yields, commodity systems have been proposed and designed to deliver quality-controlled biomass feedstocks at preprocessing “depots”. Preprocessing depots densify and stabilize the biomass prior to long-distance transport and delivery to centralized biorefineries. The logistics of biomass commodity supply chains could introduce spatially variable environmental impacts into the biofuel life cycle due to needing to harvest, move, and preprocess biomass from multiple distances that have variable spatial density. This study examines the uncertainty in greenhouse gas (GHG) emissions of corn stover logistics within a bio-ethanol supply chain in the state of Kansas, where sustainable biomass supply varies spatially. Two scenarios were evaluated each having a different number of depots of varying capacity and location within Kansas relative to a central commodity-receiving biorefinery to test GHG emissions uncertainty. The first scenario sited four preprocessing depots evenly across the state of Kansas but within the vicinity of counties having high biomass supply density. The second scenario located five depots based on the shortest depot-to-biorefinery rail distance and biomass availability. The logistics supply chain consists of corn stover harvest, collection and storage, feedstock transport from field to biomass preprocessing depot, preprocessing depot operations, and commodity transport from the biomass preprocessing depot to the biorefinery. Monte Carlo simulation was used to estimate the spatial uncertainty in the feedstock logistics gate-to-gate sequence. Within the logistics supply chain GHG emissions are most sensitive to the transport of the densified biomass, which introduces the highest variability (0.2–13 g CO2e/MJ) to life cycle GHG emissions. Moreover, depending upon the biomass availability and its spatial density and surrounding transportation infrastructure (road and rail), logistics can increase the variability in life cycle environmental impacts for lignocellulosic biofuels. Within Kansas, life cycle GHG emissions could range from 24 g CO2e/MJ to 41 g CO2e/MJ depending upon the location, size and number of preprocessing depots constructed. However, this range can be minimized through optimizing the siting of preprocessing depots where ample rail infrastructure exists to supply biomass commodity to a regional biorefinery supply system.
... It aims at elucidating the consequences of a shift in a product or a technology, e.g. a shift from combustion based to electric vehicles. Thus, cLCA has the properties to function as a modeling tool for predicting the future environmental consequences of technology shifts [2]. ...
Life Cycle Assessment (LCA) is a methodology for assessing the environmental aspects and potential impacts throughout a product´s life cycle from raw materials and energy extraction, components manufacture, assembly, distribution and sale, use and final end-of-life treatment such as disposal, recycling and energy recovery (i.e. cradle-to-grave). The environmental and resource impacts include climate change, stratospheric ozone depletion, toxicological stress on human health and ecosystems, the depletion of resources, water use and many others. This paper presents and discusses cases where LCA is used for assessing the environmental impact of electronics products and processes. Included are consumer electronics products, interconnect technology in electronics micro-integration, photovoltaic (PV) solar cells, and electric vehicles.
Here we propose a method to quantitatively assess and examine Global No Net Loss (GNNL) of forest biodiversity on a global
scale. The method produces a GNNL index of existing forest and enables future predictions of forest loss under different assumptions.
The method tests the feasibility of the GNNL index and enables discussion of policy for future global scale sustainable forest
management up to 2050. The GNNL index was estimated from an equation including forest areas per country per forest type (primary
forest, secondary forest and plantation forest), diversity of forest ecosystem, and species density. Estimates derived from
historical data revealed an approximate 7% reduction in GNNL index between 1990 and 2005. Predictions of the GNNL index until
2050 emphasize the importance of regenerating large portions of forests felled for agricultural land (or other uses) with
secondary forests.
KeywordsGlobal No Net Loss–Biodiversity–Primary forest–Secondary forest–Plantation forest
In order to estimate the environmental impacts of first generation biofuels produced in France, a Life Cycle Assessment (LCA) was conducted in 2009 and published in the beginning of 2010. However, there have been discrepancies in the interpretation of the results of this study. The objective of the article was to present the results of this LCA and the uncertainties for rapeseed methyl ester (RME), in order to help people to understand the debates about the environmental impacts of biofuels. The four steps of the LCA (goal and scope definition, inventory analysis, impact assessment and interpretation) were presented in this article with a focus on the main uncertainties. This LCA confirmed the ability of RME to save non renewable energy (–65%) and greenhouse gas emissions (GHG, –59%). Hence according to these results, RME produced in France fulfils the GHG sustainable criterion of the European Directive on renewable energy (2009/28/EC). However, the sensitivity analyses of the LCA clearly showed that there were many uncertainties at the inventory analysis step of the LCA. The main uncertainty resulted from the effect of indirect Land Use Change (iLUC), which was not taken into account in this LCA, except in a sensitivity analysis in which a GHG emission due to deforestation (positive emission) or reforestation (negative emission) was added to the emissions of the LCA. This sensitivity analysis showed that the iLUC effect could not be neglected. This suggests that an accurate estimation of this effect is necessary. However, in order to properly take into account the iLUC effect on GHG, along with all the emissions due to biofuel production, a consequential approach is more relevant than the simple addition of an iLUC GHG emission as it was done in the sensitivity analysis.
PurposeOver the past two decades, consequential life cycle assessment (CLCA) has emerged as a modeling approach for capturing environmental
impacts of product systems beyond physical relationships accounted for in attributional LCA (ALCA). Put simply, CLCA represents
the convergence of LCA and economic modeling approaches.
MethodIn this study, a systematic literature review of CLCA is performed.
ResultsWhile initial efforts to integrate the two modeling methods relied on simple partial equilibrium (PE) modeling and a heuristic
approach to determining affected technologies, more recent techniques incorporate sophisticated economic models for this purpose.
In the last 3years, Multi-Market, Multi-Regional PE Models and Computable General Equilibrium models have been used. Moreover,
the incorporation of other economic notions into CLCA, such as rebound effects and experience curves, has been the focus of
later research. Since economic modeling can play a prominent role in national policy-making and strategic/corporate environmental
planning, developing the capacity to operate LCA concurrent to, or integrated with, these models is of growing importance.
ConclusionsThis paper outlines the historical development of such efforts in CLCA, discusses key methodological advancements, and characterizes
previous literature on the topic. Based on this review, we provide an outlook for further research in CLCA.
KeywordsExperience curves–CLCA–Partial equilibrium modeling–Computable general equilibrium modeling–Consequential life cycle assessment–Rebound effects
Goal, Scope and BackgroundA consequential life cycle assessment (LCA) is designed to generate information on the consequences of decisions. This paper
includes a comprehensive presentation of the consequential approach to system boundaries, allocation and data selection. It
is based on a text produced within the SETAC-Europe working group on scenarios in LCA. For most of the methodological problems,
we describe ideal methodological solutions as well as simplifications intended to make the method feasible in practice.
MethodWe compile, summarize and refine descriptions of consequential methodology elements that have been presented in separate papers,
in addition to methodological elements and general conclusions that have not previously been published.
Results and ConclusionsA consequential LCA ideally includes activities within and outside the life cycle that are affected by a change within the
life cycle of the product under investigation. In many cases this implies the use of marginal data and that allocation is
typically avoided through system expansion. The model resulting from a consequential life cycle inventory (LCI) also includes
the alternative use of constrained production factors as well as the marginal supply and demand on affected markets. As a
result, the consequential LCI model does not resemble the traditional LCI model, where the main material flows are described
from raw material extraction to waste management. Instead, it is a model of causal relationships originating at the decision
at hand or the decision-maker that the LCI is intended to inform.
Life-cycle assessment, or LCA, is an environmental accounting and management approach that considers all the aspects of resource use and environmental releases associated with an industrial system from cradle to grave. Specifically, it is a holistic view of environmental interactions that covers a range of activities, from the extraction of raw materials from the Earth and the production and distribution of energy, through the use, and reuse, and final disposal of a product. LCA is a relative tool intended for comparison and not absolute evaluation, thereby helping decision makers compare all major environmental impacts when choosing between alternative courses of action. This article presents a brief history of the development of LCA methodology and describes the basic components of conducting an LCA, that is, selecting a functional unit; defining the goal and scope of the study; compiling an inventory of relevant energy and material inputs and environmental releases; evaluating the potential environmental impacts; and interpreting the results to help decision makers make a more informed decision. Key issues associated with data collection, impact assessment modeling, and interpretation of the results are also outlined. The article concludes with the movement toward developing life cycle sustainability assessment (LCSA) which integrates LCA, life cycle costing (LCC) and social life cycle assessment (SLCA), to encompass the three pillars of sustainability, and a summary of the limitations of LCA.
A new approach to the allocation problem in open-loop recycling is introduced. The approach models the indirect effects of a change in the supply of, or demand for, the recycled material. This approach can be used for system expansion as well as for allocation.
In order to estimate the environmental impacts of first generation biofuels produced in France, a Life Cycle Assessment (LCA) was conducted in 2009 and published in the beginning of 2010. However, there have been discrepancies in the interpretation of the results of this study. The objective of the article was to present the results of this LCA and the uncertainties for rapeseed methyl ester (RME), in order to help people to understand the debates about the environmental impacts of biofuels. The four steps of the LCA (goal and scope definition, inventory analysis, impact assessment and interpretation) were presented in this article with a focus on the main uncertainties. This LCA confirmed the ability of RME to save non renewable energy (-65%) and greenhouse gas emissions (GHG, -59%). Hence according to these results, RME produced in France fulfils the GHG sustainable criterion of the European Directive on renewable energy (2009/28/EC). However, the sensitivity analyses of the LCA clearly showed that there were many uncertainties at the inventory analysis step of the LCA. The main uncertainty resulted from the effect of indirect Land Use Change (iLUC), which was not taken into account in this LCA, except in a sensitivity analysis in which a GHG emission due to deforestation (positive emission) or reforestation (negative emission) was added to the emissions of the LCA. This sensitivity analysis showed that the iLUC effect could not be neglected. This suggests that an accurate estimation of this effect is necessary. However, in order to properly take into account the iLUC effect on GHG, along with all the emissions due to biofuel production, a consequential approach is more relevant than the simple addition of an iLUC GHG emission as it was done in the sensitivity analysis.
The groundbreaking Encyclopedia of Ecology provides an authoritative and comprehensive coverage of the complete field of ecology, from general to applied. It includes over 500 detailed entries, structured to provide the user with complete coverage of the core knowledge, accessed as intuitively as possible, and heavily cross-referenced. Written by an international team of leading experts, this revolutionary encyclopedia will serve as a one-stop-shop to concise, stand-alone articles to be used as a point of entry for undergraduate students, or as a tool for active researchers looking for the latest information in the field.
This article examines the Sarawak Corridor of Renewable Energy in Malaysia, or SCORE, a US $105 billion infrastructure development plan in Sarawak on the island of Borneo, from a sustainability standpoint. SCORE aims to build 20,000 megawatts of hydroelectric dams along a 320 km corridor comprising more than 70,000 km2 by 2030. The article begins by explaining social science methods utilized for its research interviews and site visits. It then argues that sustainability consists of seven principles articulated in international law: prudence, equity, responsibility, precaution, justice, governance, and compatibility. Next, the paper introduces readers to SCORE before assessing it according to these seven sustainability criteria. The paper finds that SCORE erodes environmental prudence by emitting millions of tons of carbon dioxide and feeding industries that will pollute the land and water. It worsens intergenerational equity by exacerbating poverty and consolidating wealth for corporations and politicians. It degrades responsibility by intensifying tropical deforestation and flaunts precaution by downplaying and ignoring risks to water quality and availability. It is unjust, imposing dams on communities and forcibly relocating thousands of indigenous people, mitigates good governance by condoning bribes and kickbacks along with the violent suppression of dissent, and is incompatible with Malaysia’s own energy policy targets and international standards.
Purpose
To construct future visions of how innovative technologies should be used in the envisioned sustainable society while being aware of system-wide environmental impacts, consequential life cycle assessment (c-LCA) is useful. To systematically evaluate the technologies being aware of uncertainties in choice of technologies made in the future, in this article, we propose a novel graphical representation for theoretical range of impacts that contain results from c-LCA studies. This approach allows analyses of the consequences of the technology introduction without conducting detailed modeling of consequences.
Methods
We stand on an assumption that the future environmental impacts reduced by a new technology depends on (1) how much the efficiency of the technology is improved, (2) how much of less-efficient technology is directly and indirectly replaced by the new technology, and (3) how much product is needed in the envisioned future. The difficulty in c-LCA is that items 2 and 3 are uncertain from various socioeconomic reasons that are often difficult to predict. By organizing the results from product LCAs in a systematic way, the proposed methodology allows exhibiting the range of consequential changes in environmental impact associated with a technology innovation, taking into account of those uncertainties on a plain coordinated by the amount of product needed in the future and environmental impact on horizontal and vertical axes, respectively.
Results
Part 1 describes the methodological framework in detail, whereas part 2 elaborates on the applications of the methodology. By taking transportation technologies assuming various energy sources in Taiwan, choices of technologies and evaluation of technology improvements serve as the case studies to demonstrate the application of the methodological framework.
Conclusions
By using the proposed method to organize the assumptions in c-LCA, discussions on different choices of technologies are made more systematic. In this way, stakeholders can focus on visions of the future society, which lead to different choices of technologies.
Purpose
To construct future visions of how innovative technologies should be used in the envisioned sustainable society while being aware of system-wide environmental impacts, consequential life cycle assessment (c-LCA) is useful. To systematically evaluate the technologies being aware of uncertainties in the choice of technologies made in the future, in this article, we propose a novel graphical representation for theoretical range of impacts that contain results from c-LCA studies. This approach allows analyses of the consequences of technology introduction without conducting a detailed modeling of consequences.
Methods
We stand on an assumption that the future environmental impacts reduced by a new technology depends on (1) how much the efficiency of the technology is improved, (2) how much of the less efficient technology is directly and indirectly replaced by the new technology, and (3) how much product is needed in the envisioned future. The difficulty in c-LCA is that (2) and (3) are uncertain from various socioeconomic reasons that are often difficult to predict. By organizing the results from product life cycle assessments in a systematic way, the proposed methodology allows exhibiting the range of consequential changes in environmental impact associated with a technology innovation, taking into account those uncertainties on a plain coordinated by the amount of product needed in the future and environmental impact on the horizontal and vertical axes, respectively.
Results
Part 1 describes the methodological framework in detail, whereas Part 2 elaborates on the applications of the methodology. By taking transportation technologies assuming various energy sources in Taiwan, the choices of technologies and the evaluation of technology improvements serve as the case studies to demonstrate the application of the methodological framework.
Conclusions
By using the proposed method to organize the assumptions in c-LCA, discussions on different choices of technologies are made more systematic. In this way, stakeholders can focus on visions of future society, which lead to different choices of technologies.
An imlementation of life-cycle analysis (LCA) for energy systems is presented and applied to two renewable energy systems (wind turbines and building-integrated photovoltaic modules) and compared with coal plants.
This paper describes a new tool to assess the medium- and long-term economic and environmental impacts of large-scale policies. The approach – macro life cycle assessment (M-LCA) – is based on life cycle assessment methodology and includes additional elements to model economic externalities and the temporal evolution of background parameters. The general equilibrium model GTAP was therefore used to simulate the economic consequences of policies in a dynamic framework representing the temporal evolution of macroeconomic and technological parameters. Environmental impacts, expressed via four indicators (human health, ecosystems, global warming and natural resources), are computed according to policy life cycle and its indirect economic consequences. In order to illustrate the approach, two 2005–2025 European Union (EU) energy policies were compared using M-LCA. The first policy, the bioenergy policy, aims to significantly increase energy generation from biomass and reduce EU energy demand for coal. The second policy, the baseline policy, is a business as usual policy where year 2000 energy policies are extended to 2025. Results show that, compared to the baseline policy, the bioenergy policy generates fewer impacts on three of the four environmental indicators (human health, global warming and natural resources) at the world and EU scales, though the results may differ significantly at a regional level. The results also highlight the key contribution of economic growth to the total environmental impacts computed for the 2005–2025 period. A comparison of the results with a more conventional consequential LCA approach illustrates the benefits of M-LCA when modeling the indirect environmental impacts of large-scale policies. The sensitivity and uncertainty analysis indicates that the method is quite robust. However, its robustness must still be evaluated based on the sensitivity and uncertainty of additional parameters, including the evolution of economic growth.
Biofuels are heavily debated as to their potential to reduce transport-related greenhouse gas emissions. Life cycle thinking gave rise to formal evaluations of the energy balance of such fuels, which led to the vigorously conducted “corn to ethanol” debates. Just as consensus was building on such evaluations came the “carbon debt” insights, a result of applying consequential Life Cycle Assessment (LCA) backed by advanced economic modeling. Increasingly, hopes have shifted to the 2nd generation biofuels, viewed as a “technological home run”. Could this also backfire? We investigate a simple South African case in which there might not be improvements in environmental performance: a sugar mill sells its bagasse, currently used at low efficiency to provide process heat, to an advanced biofuels producer, and buys an equivalent amount of coal without investing in efficiency improvements. Seven scenarios are generated, ranging from the status quo, where no bagasse is diverted, to 100% bagasse diversion, with one scenario including an energy efficiency improvement in the sugar mill. A consequential LCA is applied to the seven scenarios, covering global warming potential (GWP), non-renewable energy use, aquatic eutrophication and terrestrial acidification. A basic financial analysis of the proposed scenarios shows that they are realistic, with potentially lucrative returns. Results show that diverting bagasse without efficiency improvements from its current use to an ethanol bio-refinery would indeed backfire for all environmental impacts studied. The base case outperforms all the other scenarios, with the 100% bagasse diversion scenario emerging the worst. Investments into energy efficiency are therefore a precondition for diverting cellulosic residues into biofuel production.
Purpose
Consequential LCA (CLCA) is becoming widely used in the scientific community as a modelling technique which describes the consequences of a decision. However, despite the increasing number of case studies published, a proper systematization of the approach has not yet been achieved. This paper investigates the methodological implications of CLCA and the extent to which the applications are in line with the theoretical dictates. Moreover, the predictive and explorative nature of CLCA is discussed, highlighting the role of scenario modelling in further structuring the methodology.
Methods
An extensive literature review was performed, involving around 60 articles published over a period of approximately 18 years, and addressing both methodological issues and applications. The information was elaborated according to two main aspects: what for (questions and modes of LCA) and what (methodological implications of CLCA), with focus on the nature of modelling and on the identification of the affected processes.
Results and discussion
The analysis points out that since the modelling principles of attributional LCA (ALCA) and CLCA are the same, what distinguishes the two modes of LCA is the choice of the processes to be included in the system (i.e. in CLCA, those that are affected by the market dynamics). However, the identification of those processes is often done inconsistently, using different arguments, which leads to different results. We suggest the use of scenario modelling as a way to support CLCA in providing a scientifically sound basis to model specific product-related futures with respect to technology development, market shift, and other variables.
Conclusions
The CLCA is a sophisticated modelling technique that provides a way to assess the environmental consequences of an action/decision by including market mechanisms into the analysis. There is still room for improvements of the method and for further research, especially in relation to the following aspects: clarifying when and which market information is important and necessary; understanding the role of scenario modelling within CLCA; and developing a procedure to support the framing of questions to better link questions to models. Moreover, we suggest that the logic of mechanisms could be the reading guide for overcoming the dispute between ALCA and CLCA. Going further, this logic could also be extended, considering CLCA as an approach—rather than as a modelling principle with defined rules—to deepen LCA, providing the conceptual basis for including more mechanisms than just the market ones.
A point of view is suggested from which the Hierarchical Holographic Modeling (HHM) method can be seen as one more method within the Theory of Scenario Structuring (TSS), which is that part of Quantitative Risk Assessment having to do with the task of identifying the set of risk scenarios. Seen in this way, HHM brings strongly to our attention the fact that different methods within TSS can result in different sets of risk scenarios for the same underlying problem. Although this is not a problem practically, it is a bit awkward conceptually from the standpoint of the “set of triplets” definition of risk, in which the scenario set is part of the definition. Accordingly, the present article suggests a refinement to the set of triplets definition, which removes the specific set of scenarios, found by any of the TSS methods, from the definition of risk and casts it, instead, as an approximation to the “true” set of scenarios that is native to the problem at hand and not affected by the TSS method used.
Many policies are being designed to mitigate impacts of human activities on the environment. An environmental evaluation of these policies should include assessments of their impacts according to all known environmental impacts. Moreover, because policies may indirectly affect regions or economic sectors not initially targeted by these policies, indirect environmental consequences should be included in environmental balances. Life cycle analysis (LCA) is a holistic method made to assess environmental impacts caused by products or services according to various environmental damage categories. However, the ability of LCA to model environmental consequences due to a change is restricted to marginal changes occurring in small life cycles. New methodological developments are needed to study major changes and their environmental consequences as they may happen when a policy is applied at large scale. For that purpose, the economic general equilibrium model GTAP has been used to predict global economic perturbation that would be caused by two different European energy policies (bioenergy policy and business as usual policy). LCA was then used to assess environmental impacts due to European energy generation and perturbation of world economy. Despite the bioenergy policy involves more energy from renewable technologies which are expected to be less polluting, results show that due to rebound effects, bioenergy policy results in more environmental impacts. Combining both GTAP and LCA improves environmental assessment made with GTAP because it allows computing environmental impacts according to products life cycles instead of using economic sector emission factors and because emissions and extractions from environment are related to impacts on environment. Regarding LCA method, this new approach allows studying significant changes affecting large systems with a global modeling of economy in a time dependent environment. However, more work is needed to evaluate this new approach, especially uncertainty should be studied.
Goal, Scope and Background
Traditionally, comparative life cycle assessments (LCA) have not considered rebound effects, for instance in case of significant price differences among the compared products. No justifications have been made for this delimitation in scope. This article shows that price differences and the consequent effects of marginal consumer expenditure may influence the conclusions of comparative LCA significantly. We also show that considerations about rebound effects of price differences can be included in LCAs. Methods
The direct rebound effect of a price difference is marginal consumption. Based on statistical data on private consumption in different income groups (Statistics Denmark 2005a, 2005b), the present article provides an estimate of how an average Danish household will spend an additional 1 DKK for further consumer goods, when the household has gained money from choosing a cheaper product alternative. The approach is to use marginal income changes and the following changes in consumption patterns as an expression for marginal consumption. Secondly, the environmental impact potentials related to this marginal consumption are estimated by the use of environmental impact intensity data from an IO-LCA database (Weidema et al. 2005). Finally, it is discussed whether, and in which ways the conclusions of comparative LCAs can be affected by including the price difference between product alternatives. This is elucidated in a case study of a comparative LCA screening of two different kinds of Danish cheese products (Fricke et al. 2004). ResultsCar purchase and driving, use and maintenance of dwelling, clothing purchase and insurance constitutes the largest percentages of the marginal consumption. In a case study of two cheeses, the including the impact potentials related to the price difference results in significant changes in the total impact potentials. Considering the relatively small price difference of the two products, it is likely also to have a significant influence on the results of comparative LCAs more generally. DiscussionThe influence of marginal consumption in comparative LCAs is relevant to consider in situations with large differences in the price of the product alternatives being compared, and in situations with minor differences in the impact potentials related to the alternatives. However, different uncertainties are linked to determining the pattern for marginal consumption and the environmental impact potential related to this. These are first of all related to the method used, but also include inaccurate data of consumption in households, aggregation and weighting of income groups, aggregation of product groups, estimation and size of the price difference, and the general applicability of the results. Conclusion
Incorporating marginal consumption in consequential LCAs is possible in practice. In the case study used, including the rebound effects of the price difference has a significant influence on the result of the comparative LCA, as the result for the impact categories acidification and nutrient enrichment changes in favour of the expensive product. Recommendations and PerspectivesIt is recommended that the rebound effects of price differences should be included more frequently in LCAs. In order to ensure this, further research in marginal consumption and investment patterns and IO data for different countries or regions is required. Furthermore, this study does not consider the economic distributional consequences of buying an expensive product instead of a cheaper product (e.g. related to how the profit is spent by those who provided the product). It should also be noted, that more expensive products not necessarily result in less consumption, as those who provided the product also will spend the money they have earned from the sale. Ideally, these consequences should also be further investigated. Likewise, the development of databases to include marginal consumption in PC-tools is needed. In general, considerations of marginal consumption would favour expensive product alternatives, depending, however, on the type of consumer.
Preface. Foreword. Part 1: LCA in Perspective. 1. Why a new Guide to LCA? 2. Main characteristics of LCA. 3. International developments. 4. Guiding principles for the present Guide. 5. Reading guide. Part 2a: Guide. Reading guidance. 1. Management of LCA projects: procedures. 2. Goal and scope definition. 3. Inventory analysis. 4. Impact assessment. 5. Interpretation. Appendix A: Terms, definitions and abbreviations. Part 2b: Operational annex. List of tables. Reading guidance. 1. Management of LCA projects: procedures. 2. Goal and scope definition. 3. Inventory analysis. 4. Impact assessment. 5. Interpretation. 6. References. Part 3: Scientific background. Reading guidance. 1. General introduction. 2. Goal and scope definition. 3. Inventory analysis. 4. Impact assessment. 5. Interpretation. 6. References. Annex A: Contributors. Appendix B: Areas of application of LCA. Appendix C: Partitioning economic inputs and outputs to product systems.
Background, Aims and ScopeThe 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. ResultsThe 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). DiscussionThe 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 PerspectivesThe 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.
Background, aim and scopeThe environmental effect of globalisation has been debated intensively in the last decades. Only few well-documented analyses
of global versus local product alternatives exist, whilst recommendations on buying local are vast. At the same time, the
European Environmental Agency’s Third Assessment concludes that the resource use within the EU is stabilising at the expense
of increased resource use for import of products to the EU. Taking its point of departure in vegetable oils, this article
compares rapeseed oil and palm oil as a local and a global alternative for meeting the increasing demand for these products
in the EU. By using detailed life cycle assessment (LCA), this study compares the environmental impacts and identifies alternative
ways of producing rapeseed oil and palm oil to the EU market in order to reduce environmental impacts.
Materials and methodsThe consequential approach for system delimitation is applied (Ekvall and Weidema 2004; Weidema 2003; Schmidt 2008a; Schmidt and Weidema 2008). This approach differs from the attributional approach in a way that the actual affected suppliers and technologies are
modelled instead of averages. In addition, co-product allocation is avoided by system expansion. The method for life cycle
impact assessment (LCIA) is EDIP97 updated (LCA-Center 2007). In addition, land use and the associated impacts on biodiversity are assessed using the LCIA method described in Schmidt
(2008b).
ResultsThe characterised results of the LCA show that palm oil is environmentally preferable to rapeseed oil within ozone depletion,
acidification, eutrophication, photochemical smog and land use, whilst the differences within global warming and biodiversity
are less clear. The most significant process contributing to global warming from rapeseed oil is the cultivation of rapeseed,
whilst the oil palm cultivation and the palm oil mill (effluent treatment) are equally important. Regarding land use and biodiversity
for rapeseed oil, the avoided production caused by system expansion has a major role, whilst system expansion has only limited
effect on the results of palm oil.
DiscussionAlternative cultivation practices and technologies are assessed. The findings for rapeseed oil are that local expansions of
the cultivated area on set-aside area is preferable to displacement of crops which are compensated for by increased agricultural
production abroad and that the full press technology in the oil mill is preferable to solvent extraction. Concerning palm
oil, cultivation on peat increases the contribution to global warming significantly with a factor of 4–5 compared to cultivation
on the current mix of soils types. The other hotspot related to global warming (effluent treatment) can be markedly reduced
by installation of digester tanks and subsequent utilisation of biogas.
ConclusionsThe results of the scenarios show that the approach to system delimitation matters. When the consequential approach to system
delimitation is applied in the agricultural stage, uncertainties show to be significant. These uncertainties are mainly related
to the determination of how increased production is achieved, increased cultivated area and/or increased intensification.
Overall, palm oil tends to be environmentally preferable to rapeseed oil within all impact categories except global warming,
biodiversity and ecotoxicity where the difference is less pronounced and where it is highly dependent on the assumptions regarding
system delimitation in the agricultural stage.
Recommendations and perspectivesSince the environmental performance of rapeseed oil and palm oil is a result of the current applied technologies and since
improvement options exist in both product systems, it may be more relevant for decision makers to focus on requirements on
the applied technologies in the product systems rather than preferring the one oil over the other.
Life Cycle Assessment (LCA) has matured over the past decades and become part of the broader field of sustainability assessment. To strengthen LCA as a tool and eventually increase its usefulness for sustainability decision-making, it is argued that there is a need to expand the ISO LCA framework by integration and connection with other concepts and methods. This paper explores the potential options for deepening and broadening the LCA methodologies beyond the current ISO framework for improved sustainability analysis. By investigating several environmental, economic and social assessment methods, the paper suggests some options for incorporating (parts of) other methods or combining with other methods for broadening and deepening the LCA.
The use of renewable energy is a possible solution to reduce the contribution to climate change of human activities. Nevertheless, there is much controversy about the non-climate related environmental impacts of renewable energy as compared to fossil energy. The aim of this study is to assess a new technology of biomethane production by monofermentation of cultivated crops. Based on the results of an attributional Life Cycle Assessment (LCA), the contribution to climate change of biomethane production and injection into the grid is 30–40% (500a time horizon) or 10–20% (100a) lower than the contribution of natural gas importation. The reduction depends mainly on the biogas yield, the amount of readily available nitrogen in the digestate and the type of agricultural practices. Nevertheless, the natural gas definitively generates far lower ecosystem quality and human health damages than the biomethane production. Farming activities have the most important contribution to the damages mainly because of land occupation and the use of fertilizer. The main improvement opportunities highlighted are: the increase of biogas yield, the choice of good agricultural practices and the cultivation of winter or summer crops exclusively. Future research should include the emission and sequestration of CO2 from soil. The ripple effects related to the total increase of farming area and the consequences of farming activities on the food production chain should be addressed as well. To this aim, the switch to consequential LCA is a critical challenge, from both the methodological and application point of view, to support decision-making.
This study assesses the direct and indirect environmental impacts to be expected if Switzerland should replace one percent of its current diesel consumption with imports of A) soybean methyl ester (SME) from Brazil, or B) palm methyl ester (PME) from Malaysia. In order to take into account possible future consequences, what-if scenarios were developed and assessed by means of a consequential LCA. In contrast to attributional LCA, the consequential approach uses system enlargement to include the marginal products affected by a change of the physical flows in the central life cycle. This means that the LCA considers all inputs and outputs which are linked to biodiesel production and that the product system is subsequently expanded to include the marginal products affected. Both future systems are assessed in comparison with the environmental scores of the fossil equivalent to biodiesel, i.e. diesel low in sulphur. The environmental burdens are measured by means of greenhouse gas emissions (GHG), land occupation and various non-aggregated and aggregated environmental impact indicators.
In this paper we develop a typology of consequences that can be used for environmental assessments of investment in technologies. As an illustration we estimate how the inclusion of different cause–effect chains could affect the estimated greenhouse gas emissions resulting from buying and using a fuel cell bus today. In contrast to earlier studies, we include cause–effect chains containing positive feedback from adoption (e.g. economies of scale and learning). We discuss how our findings affect the usefulness and limitations of consequential life-cycle assessment (LCA) and how LCA methodology in more general can be used to support strategic technology choice. A major conclusion is that environmental assessments of investment in emerging technologies should not only include effects resulting from marginal change of the current system but also marginal contributions to radical system change.
Decision-making is central to life cycle assessment (LCA), both in the sense that LCA may be used as decision support and in the sense that different methodological choices in LCA are relevant to different applications. This latter issue is pursued in this paper: i.e., how the decision-making context, and thus goal definition, may be used to guide methodological choices in LCA. A distinction is made between a retrospective or accounting perspective and a prospective perspective, where the consequences of alternative actions are investigated. This has significant implications for LCA guidelines, including the standard on LCA compiled by the International Standardization Organization (ISO).
The growing demand for biofuels has led to an increased demand for feedstocks which in turn is anticipated to induce changes in the cropping systems or land requirement for agriculture use. This study used consequential life cycle assessment (LCA) to evaluate the environmental consequences of possible (future) changes in agricultural production systems and determine their effects on land use change (LUC) and greenhouse gas (GHG) implications when cassava demand in Thailand increases. Six different cropping systems to increase cassava production including converting unoccupied land to cropland, yield improvement, displacement of area currently under sugarcane cultivation and the other potential changes in cropping systems in Viet Nam and Australia are modeled and assessed. The comparative results show that LUC is an important factor in overall GHG emissions of the first generation biofuels especially change in soil carbon stock contributing about 58–60% of the net GHG emissions. Increased cassava production by expanding cultivation area has a significantly larger effect on GHG emissions than increased productivity. The analysis shows that increasing productivity of both sugarcane and cassava are important ways to maximize benefits in using of certain area of Thailand to serve both the food and fuel industries.
Various authors have stated that Environmental Impact Assessment (EIA) differs fundamentally from product Life Cycle Assessment (LCA). This paper shows the contrary. LCA is a specific elaboration of a generic environmental evaluation framework. EIA is a procedure rather than a tool, in which LCA certainly may be useful. Particularly in strategic and project EIAs, environmental comparisons of process and abatement alternatives may be relevant. Although these alternatives may lead to different emissions and effects at the location of the process itself (which is usually the focus in project EIAs), they can also influence the demand for activities upstream and downstream in the production chain. Including such secondary effects in an EIA, which may be crucial for a proper comparison of alternatives, requires a system approach that takes into account all relevant effects. This is, in fact, LCA. A review of five case studies shows that it is quite feasible to use elements of LCA in EIA.
The way in which GHG (greenhouse gas) emissions associated with grid electricity consumption is handled in different LCA (life cycle assessment) studies, varies significantly. Apart from differences in actual research questions, methodological choices and data set selection have a significant impact on the outcomes. These inconsistencies result in difficulties to compare the findings of various LCA studies. This review paper explores the issue from a methodological point of view. The perspectives of ALCA (attributional life cycle assessment) and CLCA (consequential life cycle assessment) are reflected. Finally, the paper summarizes the key issues and provides suggestions on the way forward. The major challenge related to both of the LCA categories is to determine the GHG emissions of the power production technologies under consideration. Furthermore, the specific challenge in ALCA is to determine the appropriate electricity production mix, and in CLCA, to identify the marginal technologies affected and related consequences. Significant uncertainties are involved, particularly in future-related LCAs, and these should not be ignored. Harmonization of the methods and data sets for various purposes is suggested, acknowledging that selections might be subjective.
The environmental impact of energy systems has a diverse origin. The combustion of fuels leads directly to emissions and potential environmental harm, whereas the use of electricity does not lead directly to environmental impacts. However, the production of electricity from fuels leads to emissions of, for example, carbon dioxide and nitrogen oxides, which can lead to climate change and acidification respectively. If wind turbines or photovoltaic cells produce the electricity, these emissions are avoided. However, the material-intensive production of wind turbines and photovoltaic cells is associated with environmental releases. Therefore, assessing the environmental impacts of energy carriers involves not only the process of using the energy carrier but also all related processes: from extracting primary energy from nature, its conversion into secondary energy carriers, its use, and any processing of waste flows at the end. Environmental life cycle assessment is the "cradle-to-grave" approach for assessing the environmental impacts of products such as electricity and petroleum. The cradle-to-grave approach involves all steps between extracting materials and fuels from the environment until the point where all materials are returned to the environment. The methodology of life cycle assessment and its application to energy systems are the subject of this article.
Environmental life cycle assessment (LCA) has developed fast over the last three decades. Whereas LCA developed from merely energy analysis to a comprehensive environmental burden analysis in the 1970s, full-fledged life cycle impact assessment and life cycle costing models were introduced in the 1980s and 1990 s, and social-LCA and particularly consequential LCA gained ground in the first decade of the 21st century. Many of the more recent developments were initiated to broaden traditional environmental LCA to a more comprehensive Life Cycle Sustainability Analysis (LCSA). Recently, a framework for LCSA was suggested linking life cycle sustainability questions to knowledge needed for addressing them, identifying available knowledge and related models, knowledge gaps, and defining research programs to fill these gaps. LCA is evolving into LCSA, which is a transdisciplinary integration framework of models rather than a model in itself. LCSA works with a plethora of disciplinary models and guides selecting the proper ones, given a specific sustainability question. Structuring, selecting, and making the plethora of disciplinary models practically available in relation to different types of life cycle sustainability questions is the main challenge.
Life Cycle Assessment is a tool to assess the environmental impacts and resources used throughout a product's life cycle, i.e., from raw material acquisition, via production and use phases, to waste management. The methodological development in LCA has been strong, and LCA is broadly applied in practice. The aim of this paper is to provide a review of recent developments of LCA methods. The focus is on some areas where there has been an intense methodological development during the last years. We also highlight some of the emerging issues. In relation to the Goal and Scope definition we especially discuss the distinction between attributional and consequential LCA. For the Inventory Analysis, this distinction is relevant when discussing system boundaries, data collection, and allocation. Also highlighted are developments concerning databases and Input-Output and hybrid LCA. In the sections on Life Cycle Impact Assessment we discuss the characteristics of the modelling as well as some recent developments for specific impact categories and weighting. In relation to the Interpretation the focus is on uncertainty analysis. Finally, we discuss recent developments in relation to some of the strengths and weaknesses of LCA.
Greenhouse gas release from land use change (the so-called "carbon debt") has been identified as a potentially significant contributor to the environmental profile of biofuels. The time required for biofuels to overcome this carbon debt due to land use change and begin providing cumulative greenhouse gas benefits is referred to as the "payback period" and has been estimated to be 100-1000 years depending on the specific ecosystem involved in the land use change event. Two mechanisms for land use change exist: "direct" land use change, in which the land use change occurs as part of a specific supply chain for a specific biofuel production facility, and "indirect" land use change, in which market forces act to produce land use change in land that is not part of a specific biofuel supply chain, including, for example, hypothetical land use change on another continent. Existing land use change studies did not consider many of the potentially important variables that might affect the greenhouse gas emissions of biofuels. We examine here several variables that have not yet been addressed in land use change studies. Our analysis shows that cropping management is a key factor in estimating greenhouse gas emissions associated with land use change. Sustainable cropping management practices (no-till and no-till plus cover crops) reduce the payback period to 3 years for the grassland conversion case and to 14 years for the forest conversion case. It is significant that no-till and cover crop practices also yield higher soil organic carbon (SOC) levels in corn fields derived from former grasslands or forests than the SOC levels that result if these grasslands or forests are allowed to continue undisturbed. The United States currently does not hold any of its domestic industries responsible for its greenhouse gas emissions. Thus the greenhouse gas standards established for renewable fuels such as corn ethanol in the Energy Independence and Security Act (EISA) of 2007 set a higher standard for that industry than for any other domestic industry. Holding domestic industries responsible for the environmental performance of their own supply chain, over which they may exert some control, is perhaps desirable (direct land use change in this case). However, holding domestic industries responsible for greenhouse gas emissions by their competitors worldwide through market forces (via indirect land use change in this case) is fraught with a host of ethical and pragmatic difficulties. Greenhouse gas emissions associated with indirect land use change depend strongly on assumptions regarding social and environmental responsibilities for actions taken, cropping management approaches, and time frames involved, among other issues.
Climatop includes sustainability criteria
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