LCA in architectural design—a parametric approach

Purpose

Life cycle assessment (LCA) has not been widely applied in the building design process because it is perceived to be complex and time-consuming. There is a high demand for simplified approaches that architects can use without detailed knowledge of LCA. This paper presents a parametric LCA approach, which allows architects to efficiently reduce the environmental impact of building designs.

Methods

First, the requirements for design-integrated LCA are analyzed. Then, assumptions to simplify the required data input are made and a parametric model is established. The model parametrizes all input, including building geometry, materials, and boundary conditions, and calculates the LCA in real time. The parametric approach possesses the advantage that input parameters can be adjusted easily and quickly. The architect has two options to improve the design: either through manually changing geometry, building materials, and building services, or through the use of an optimization solver. The parametric model was implemented in a parametric design software and applied using two cases: (a) the design of a new multi-residential building, and (b) retrofitting of a single-family house.

Results and discussion

We have successfully demonstrated the capability of the approach to find a solution with minimum environmental impact for both examples. In the first example, the parametric method is used to manually compare geometric design variants. The LCA is calculated based on assumptions for materials and building services. In the second example, evolutionary algorithms are employed to find the optimum combination of insulation material, heating system, and windows for retrofitting. We find that there is not one optimum insulation thickness, but many optima, depending on the individual boundary conditions and the chosen environmental indicator.

Conclusions

By incorporating a simplified LCA into the design process, the additional effort of performing LCA is minimized. The parametric approach allows the architect to focus on his main task of designing the building and finally makes LCA practically useful for design optimization. In the future, further performance analysis capabilities such as life cycle costing can also be integrated.

     

Normalization in LCA: how to ensure consistency?

The International Journal of Life Cycle Assessment -     

When Do Allocations and Constructs Respect Material,Energy, Financial,and Production Balances in LCA and EEIO?

Conservation of mass and energy are essential to physical accounting, just as price and market balances are essential to economic accounting. These principles guide data collection and inventory compilation in industrial ecology. The resulting balanced surveys, however, can rarely be used directly for life cycle assessment (LCA) or environmentally extended input‐output (EEIO) analysis; some modeling is necessary to recast coproductions by multifunctional activities as monofunctional unit processes (a.k.a. Leontief production functions or technical “recipes”). This modeling is done with allocations in LCA and constructs in input‐output. In this article, we ask how these models respect or perturb the balances of the original inventory. Which allocations or constructs, applied to what type of data set, have the potential to simultaneously respect its multiple physical, financial, and market balances? Our analysis builds upon the recent harmonization of allocations and constructs and the ongoing development of multilayered supply and use inventory tables. We derive the necessary and sufficient conditions for balanced models, investigate the role of data aggregation, and clarify these models' relation to system expansion. We find that none of the modeling families in LCA and EEIO are balanced in general, but special data characteristics can allow for the respect of multiple balances. An analysis of these special cases allows for clear guidance for data compilation and methods integration.     

LCA and decision making: when and how to use consequential LCA; 62nd LCA forum,Swiss Federal Institute of Technology,Zürich, 9 September 2016

The 62nd life cycle assessment (LCA) forum was held on 9 September 2016 to discuss the state of research and application with regard to consequential life cycle assessment. This conference report presents the highlights of the LCA forum. The state of the art of consequential LCA was presented from different viewpoints. It was pointed out that consequential LCA is more than marginal mixes and avoided burdens and involves causal modelling. It was also said that social responsibility calls for consequential LCA. Currently, different models are used to support decision making. It was suggested to make use of the variety of models to check the conclusiveness of their results and thus the reliability of the LCAs. Current and future implementations of consequential LCI models in background databases and linking algorithms were presented. Several speakers presented consequential LCA case studies covering the sectors energy, transport, housing and mining. Some of the LCA models used in the case studies are complemented with general and partial computable equilibrium models and agent-based models and use environmentally extended input-output data or process-based LCA data. Some of the presentations focused on elements such as constrained production, marginal market mixes and technologies or recycling and system expansion. In three parallel workshops, the needs, contents and methodology, and implementation of consequential LCA approaches were discussed. The participants seemed to generally agree on the basic goal that LCA should be able to reflect the consequences of decisions. The inquiry among the participants showed that the demand for consequential LCA studies is hardly existent. The appropriate implementation of consequential modelling in LCA databases and on the appropriate model to be used in consequential LCA case studies was debated. It revealed a need for further and extensive discussions to be able to reach (minimum) consensus.     

Obsolescence in LCA–methodological challenges and solution approaches

Purpose

Obsolescence, as premature end of use, increases the overall number of products produced and consumed, and thereby can increase the environmental impact. Measures to decrease the effects of obsolescence by altering the product or service design have the potential to increase use time (defined as the realized active service life) of devices, but can themselves have (environmental) drawbacks, for example, because the amount of material required for production increases. As such, paying special attention to methodological choices when assessing such measures and strategies using life cycle assessment (LCA) needs is crucial.

Methods

Open questions and key aspects of obsolescence, including the analysis of its effects and preventative measures, are discussed against the backdrop of the principles and framework for LCA given in ISO 14040/44, which includes guidance on how to define a useful functional unit and reference flow in the context of real-life use time.

Results and discussion

The open and foundational requirements of ISO 14040/14044 already form an excellent basis for analysis of the phenomenon obsolescence and its environmental impact in product comparisons. However, any analysis presumes clear definition of the goal and scope phase with special attention paid to aspects relevant to obsolescence: the target product and user group needs to be placed into context with the analysed “anti-obsolescence” measures. The reference flow needs to reflect a realized use time (and not solely a technical lifetime when not relevant for the product under study). System boundaries and types of data need to be chosen also in context of the anti-obsolescence measure to include, for example, the production of spare parts to reflect repairable design and/or manufacturer-specific yields to reflect high-quality manufacturing.

Conclusions

Understanding the relevant obsolescence conditions for the product system under study and how these may differ across the market segment or user types is crucial for a fair and useful comparison and the evaluation of anti-obsolescence measures.

     

Improving odour assessment in LCA—the odour footprint

Purpose

Odour is an important aspect of systems for human and agricultural waste management and many technologies are developed with the sole purpose of reducing odour. Compared with greenhouse gas assessment and the assessment of toxicity, odour assessment has received little attention in the life cycle assessment (LCA) community. This article aims to redress this.

Methods

Firstly, a framework for the assessment of odour impacts in LCA was developed considering the classical LCA framework of emissions, midpoint and endpoint indicators. This suggested that an odour footprint midpoint indicator was worth striving for. An approach to calculating an areal indicator we call “odour footprint”, which considers the odour detection threshold, the diffusion rate and the kinetics of degradation of odourants, was implemented in MATLAB. We demonstrated the use of the characterisation factors we calculated in a case study based on odour removal technology applied to a pig barn.

Results and discussion

We produced a list of 33 linear characterisation factors based on hydrogen sulphide equivalents, analogous to the linear carbon dioxide equivalency factors in use in carbon footprinting, or the dichlorobenzene equivalency factors developed for assessment of toxic impacts in LCA. Like the latter, this odour footprint method does not take local populations and exposure pathway analysis into account—its intent is not to assess regulatory compliance or detailed design. The case study showed that despite the need for materials and energy, large factor reductions in odour footprint and eutrophication potential were achieved at the cost of a smaller factor increase in greenhouse emissions.

Conclusions

The odour footprint method is proposed as an improvement on the established midpoint method for odour assessment in LCA. Unlike it, the method presented here considers the persistence of odourants. Over time, we hope to increase the number of characterised odourants, enabling analysts to perform simple site-generic LCA on systems with odourant emissions.     

LCA as an element in environmental management systems—comparison of conditions in selected organisations in Poland, Sweden and Germany

Purpose

In this two-part paper (Background and Initial Assumptions (part 1) and Results of Survey Research (part 2)), we present surveys whose main objective is to determine whether, and to what extent, the life cycle assessment (LCA) technique is used for the identification and assessment of environmental aspects in environmental management systems (EMS) and whether there are any differences in this respect between the companies and countries analysed.

Methods

The survey research was carried out using the computer assisted self-administered interviewing method among selected Polish, German and Swedish organisations which implement EMS in accordance with the requirements of ISO 14001 and/or the EMAS regulation.

Results

The organisations investigated, regardless of their country, are dominated by qualitative and semi-quantitative techniques of assessment and identification of environmental aspects. LCA was used sporadically, although some differences can be observed between the countries analysed.

Conclusions

The environmental managers accustomed to traditional qualitative and semi-quantitative solutions have not been given preparation to enable them to understand and adopt different approaches such as LCA. On the other hand, representatives of the organisations investigated declared that they were ready to accept an even longer timescale for the identification and assessment processes relating to environmental aspects, which represents a potential opportunity for LCA. The more precise understanding and definition of environmental problems that are precisely defined in LCA would represent a novelty for environmental managers. In practice, environmental problems are defined in a general sense and rather ambiguously, as this level of detail is sufficient in the context of qualitative and semi-quantitative techniques commonly used for the identification and assessment of environmental aspects.     

45th Discussion forum on LCA—environmentally extended input–output analysis and LCA, September 15, 2011, Berne, Switzerland

The discussion forum on life cycle assessment (LCA) on September 15, 2011, aimed at summarizing recent environmentally extended input?Coutput analysis (EE-IOA) and the combination with LCA for the computation of environmental impact of imports. Input?Coutput tables (IOT) represent the financial flows in a country or economic regions. Extending IOT with information on emissions and resource uses allows for the analysis of environmental impacts due to production and consumption activities in a country. This instrument is called EE-IOA. It enables the analysis of total environmental impacts of countries or economic regions. The combination with trade statistics and LCA was presented as an alternative to multiregional input?Coutput models for determining environmental impacts of imports over the whole life cycle. The 45th LCA forum gathered several international speakers who provided a broad and qualified view on the topic. The theoretical background, results for different countries and regions, uncertainties, and possible improvement options for EE-IOA were discussed. The following main conclusions were drawn at the end of the discussion forum: EE-IOA is a useful instrument for analyzing the total environmental impacts of countries and the main drivers of environmental impacts. As a next important step, the participants would like to see an increase in user friendliness of EE-IOA combined with LCA, e.g., by harmonizing data, data formats, and classifications.     

Marine plastics in LCA: current status and MarILCA’s contributions

The International Journal of Life Cycle Assessment -     

Impacts from hydropower production on biodiversity in an LCA framework—review and recommendations

Purpose

Expanding renewable energy production is widely accepted as a promising strategy in climate change mitigation. However, even renewable energy production has some environmental impacts, some of which are not (yet) covered in life cycle impact assessment (LCIA). We aim to identify the most important cause-effect pathways related to hydropower production on biodiversity, as one of the most common renewable energy sources, and to provide recommendations for future characterization factor (CF) development.

Methods

We start with a comprehensive review of cause-effect chains related to hydropower production for both aquatic and terrestrial biodiversity. Next, we explore contemporary coverage of impacts on biodiversity from hydropower production in LCA. Further, we select cause-effect pathways displaying some degree of consistency with existing LCA frameworks for method development recommendations. For this, we compare and contrast different hydrologic models and discuss how existing LCIA methodologies might be modified or combined to improve the assessment of biodiversity impacts from hydropower production.

Results and discussion

Hydropower impacts were categorized into three overarching impact pathways: (1) freshwater habitat alteration, (2) water quality degradation, and (3) land use change. Impacts included within these pathways are flow alteration, geomorphological alteration to habitats, changes in water quality, habitat fragmentation, and land use transformation. For the majority of these impacts, no operational methodology exists currently. Furthermore, the seasonal nature of river dynamics requires a level of temporal resolution currently beyond LCIA modeling capabilities. State-of-the-art LCIA methods covering biodiversity impacts exist for land use and impacts from consumptive water use that can potentially be adapted to cases involving hydropower production, while other impact pathways need novel development.

Conclusions

In the short term, coverage of biodiversity impacts from hydropower could be significantly improved by adding a time step representing seasonal ecological water demands to existing LCIA methods. In the long term, LCIA should focus on ecological response curves based on multiple hydrologic indices to capture the spatiotemporal aspects of river flow, by using models based on the “ecological limits to hydrologic alteration” (ELOHA) approach. This approach is based on hydrologic alteration-ecological response curves, including site-specific environmental impact data. Though data-intensive, ELOHA represents the potential to build a global impact assessment framework covering multiple ecological indicators from local impacts. Further, we recommend LCIA methods based on degree of regulation for geomorphologic alteration and a fragmentation index based on dam density for “freshwater habitat alteration,” which our review identified as significant unquantified threats to aquatic biodiversity.

     

LCA mainstreaming conditions in Latin America—based on learnings from 2005 to 2014

Purpose

Based on the 2005–2014 developments in the Latin American and the Caribbean region (LAC), this paper aims to understand the conditions’ levels for mainstreaming life cycle assessment/life cycle management (LCA/LCM) and map key next actions.

Methods

Along the paper, four mainstreaming conditions are analyzed: expansion of LCM/LCA training activities, availability of LCA studies, national LCA database operating, and existence and activity of national life cycle network(s). Assuming that countries with better conditions are in a better position to develop national LCA based regulations, policies are also researched to complement this study.

Results and discussion

With nine life cycle (LC) networks in 2014, the LAC region has positively developed its networking capacities since 2005 but not the databases area (only one LCA database, Mexicaniuh, is fully operational). It was found that countries with no networks, lack all LCA trainings, studies, and databases.Local capacities are limited which in best case, Chile, does not exceed 18 practitioners per 10 million inhabitants. Based on the total score on mainstreaming conditions, Mexico and Brazil are the most advanced countries, but their markets for LCA professionals are still small (Valdivia et al. 2015), which suggests that tailored made strategies are needed for stronger uptake of LCA by industrial sectors.Argentina, Peru, Chile, and Colombia are in the second tier but still lack a critical mass of business cases and the political will to improve their mainstreaming conditions.

Conclusions

LCA development in the LAC region since 2005 is overall positive but still insufficient to serve the growth of prosperous LCA markets. Well-functioning LC networks are essential to leapfrog LCA. In 2014, about 27 % of LAC countries counted on a LC network. A common language in the region (except for Portuguese in Brazil) has been instrumental for expanding LCA through regional cooperation. LCA-based policies are boosted when local capacities and databases are available following the cases of Mexico, Chile, and Brazil. More data and research are needed to understand the women role in advancing LCA and the causalities and motivations of LAC companies to decide for LCA implementation. The application of the methodology was possible thanks to good quality data available and delivered key findings to develop national road maps for advancing LCA. No indicator used is specific for the LAC region and similar exercises are encouraged in other regions such as Africa and Asia.

     

What causes more LCA research—subjective values,objective problems,or scientific traditions?

Purpose

This paper aims to verify whether life cycle assessment (LCA) research can be mainly treated as a kind of pro-environmental behavior due to public environment concerns, or academic and research activities based on scientific traditions.

Methods

This paper uses the international comparisons method for modeling and SPSS 16.0 for data processing. The data in this study were obtained from the Human Development Report by the United Nations Development Programme and the Web of Science by the Institute for Scientific Information.

Results and discussion

Our empirical study shows that the two main factors influencing the outputs per capita of the research articles in LCA in a particular country are the value of Environmental Performance Index, which represents the overall environmental quality, as well as the outputs per capita of the research articles in environmental science and technology. The results of statistical analysis show two J-type curves: with the change of the independent variables, the dependent variable changes in the same direction, but at a rate that is first slow, then fast.

Conclusions

LCA research results from scientific traditions and can only develop based on fundamental research in environmental science and technology. Further, LCA research is a pro-environmental behavior due to actual and objective effects rather than subjective motives as more research on LCA can accompany, even in some degree may lead to better overall environmental qualities. However, although environmental concerns are likely to affect the number of LCA studies as an implicit variable, this has not been empirically confirmed in our optimization model.

     

Enabling optimization in LCA: from “ad hoc” to “structural” LCA approach—based on a biodiesel well-to-wheel case study

Purpose

Applied life cycle assessment (LCA) studies often lead to a comparison of rather few alternatives; we call this the “ad hoc LCA approach.” This can seem surprising since applied LCAs normally cover countless options for variations and derived potentials for improvements in a product life cycle. In this paper, we will suggest an alternative approach to the ad hoc approach, which more systematically addresses the many possible variations to identify the most promising. We call it the “structural LCA approach.” The goals of this paper are (1) to provide basic guidelines for the structural approach, including an easy expansion of the LCA space; (2) to show that the structural LCA approach can be used for different types of optimization in LCA; and (3) to improve the transparency of the LCA work.

Methods

The structural approach is based on the methodology “design of experiments” (Montgomery 2005). Through a biodiesel well-to-wheel study, we demonstrate a generic approach of applying explanatory variables and corresponding impact categories within the LCA methodology. Explanatory variables are product system variables that can influence the environmental impacts from the system. Furthermore, using the structural approach enables two different possibilities for optimization: (1) single-objective optimization (SO) based on response surface methodology (Montgomery 2005) and (2) multiobjective optimization (MO) by the hypervolume estimation taboo search (HETS) method. HETS enables MO for more than two or three objectives.

Results and discussion

Using SO, the explanatory variable “use of residual straw from fields” is, by far, the explanatory variable that can contribute with the highest decrease of climate change potential. For the respiratory inorganics impact category, the most influencing explanatory variable is found to be the use of different alcohol types (bioethanol or petrochemical methanol) in biodiesel production. Using MO, we found the Pareto front based on 5 different life cycle pathways which are nondominated solutions out of 66 different analyzed solutions. Given that there is a fixed amount of resources available for the LCA practitioner, it becomes a prioritizing problem whether to apply the structural LCA approach or not. If the decision maker only has power to change a single explanatory variable, it might not be beneficial to apply the structural LCA approach. However, if the decision maker (such as decision makers at the societal level) has power to change more explanatory variables, then the structural LCA approach seems beneficial for quantifying and comparing the potentials for environmental improvement between the different explanatory variables in an LCA system and identifying the overall most promising product system configurations among the chosen PWs.

Conclusions

The implementation of the structural LCA approach and the derived use of SO and MO have been successfully achieved and demonstrated in the present paper. In addition, it is demonstrated that the structural LCA approach can lead to more transparent LCAs since the potentially most important explanatory variables which are used to model the LCAs are explicitly presented through the structural LCA approach. The suggested structural approach is a new approach to LCA and it seems to be a promising approach for searching or screening product systems for environmental optimization potentials. In the presented case, the design has been a rather simple full factorial design. More complicated problems or designs, such as fractional designs, nested designs, split plot designs, and/or unbalanced data, in the context of LCA could be investigated further using the structural approach.     

Are there infinitely many trucks in the technosphere,or exactly one? How independent sampling of instances of unit processes affects uncertainty analysis in LCA

Purpose

Product systems use the same unit process models to represent distinct but similar activities. This notably applies to activities in cyclic dependency relationships (or “feedback loops”) that are required an infinite number of times in a product system. The study aims to test the sensitivity of uncertainty results on the assumption made concerning these different instances of the same activities. The default assumption assumes homogeneous production, and the same parameter values are sampled for all instances (e.g., there is one truck). The alternative assumption is that every instance is distinct, and parameter values are independently sampled for different instances of unit processes (e.g., there are infinitely many trucks). Intuitively, sampling the same values for each instance of a unit process should result in more uncertain results.

Methods

The results of uncertainty analyses carried out under either assumption are compared. To simulate models where each instance of a unit process is independent, we convert network models to acyclic LCI models (tree models). This is done three times: (1) for a very simple product system, to explain the methodology; (2) for a sample product system from the ecoinvent database, for illustrative purposes; and (3) for thousands of product systems from ecoinvent databases.

Results and discussion

The uncertainty of network models is indeed greater than that of corresponding tree models. This is shown mathematically for the analytical approximation method to uncertainty propagation and is observed for Monte Carlo simulations with very large numbers of iterations. However, the magnitude of the difference in indicators of dispersion is, for the ecoinvent product systems, often less than a factor of 1.5. In few extreme cases, indicators of dispersion are different by a factor of 4. Monte Carlo simulations with smaller numbers of iterations sometimes give the opposite result.

Conclusions

Given the small magnitude of the difference, we believe that breaking away from the default approach is generally not warranted. Indeed, (1) the alternative approach is not more robust, (2) the current default approach is conservative, and (3) there are more pressing challenges for the LCA community to meet. This being said, the study focused on ecoinvent, which should normally be used as a background database. The difference in dispersion between the two approaches may be important in some contexts, and calculating the uncertainty of tree models as a sensitivity analysis could be useful.

     

49th Discussion forum on LCA—sustainable consumption patterns—September 18, 2012, Zurich, Switzerland

There are different ways and strategies to reduce the environmental impacts caused today. One starting point for reducing the environmental impacts of today is the private consumption. Finally, all goods and services provided in a country contribute to fulfil the needs and demands of consumers. Several national and international initiatives therefore aim for a considerable reduction of the environmental impacts of consumption patterns. The 49th LCA Discussion Forum analysed the present consumption patterns of households and their consequent environmental impacts. Based on this, potentials for a reduction of the environmental impacts were identified and discussed. In this context, the possible applications, advantages and drawbacks of the life cycle assessment (LCA) methodology were analysed. National and international speakers provided qualified insights on the topic. The 49th Discussion Forum concentrated on different aspects of sustainable consumption patterns. The focus lay on private households and the environmental impacts caused by their consumption patterns. In the first session, the idea of the “2000-Watt society” was introduced as an example of a concept of a “sustainable lifestyle”. Another way of analysing the total impacts is the consumption perspective introduced in a second presentation. Based on an analysis of environmental impacts due to final demand of Swiss households, different measures for a reduction of environmental impacts were proposed and analysed. The second session examined similar activities in Germany. The short presentations covered the communication of LCA results. The third session focused on web-based eco-calculators. In the last session, two scientific inputs were given on the modelling of household consumption patterns and on the impact of rebound effects on the environmental impact of private consumption. The most important consumption domains are nutrition, mobility and energy use in households. Apart from different modelling approaches and boundary conditions, the majority of the presentations showed that today’s consumption patterns in Switzerland and Germany are far away from a sustainable level. Considerable reduction measures are needed in order to reach this goal. Eco-calculators and similar tools provide an effective way to raise customer awareness. In general, it is very important to communicate LCA results in a simple, clear and transparent way.     

Functional unit and product functionality—addressing increase in consumption and demand for functionality in sustainability assessment with LCA

Purpose

The static functional unit definition in the current LCA framework has limitations in addressing the changing product functionality and associated environmental impact of constantly evolving product technologies. As a result, it overlooks the changes in consumer behaviour of increased consumption of products in provided services as well as in growing volumes. This article aims to present a new framework in defining a dynamic functional unit of product technologies that caters for changes in consumer behaviour and growing market.

Methods

A new approach to defining the functional unit is proposed that caters for changes in consumer behaviour and the use of technology from a technical performance perspective. A dynamic approach to definition of the functional unit is proposed that is based on Kano’s model of product function and satisfaction.

Results and discussion

The new approach is demonstrated on a case study in which the analysis of historical data for two TV product technologies—CRT and LCD—is used to show how the total environmental impact is increasing due to the increased functionality which triggers an increase in the volume of the market. Despite the efforts of improving product life cycle design, the society is still faced with increasing environmental impact from the product type overall.

Conclusions

This article presents the challenges of using a static, single functional unit definition in an industrial culture with constant evolution of products that influences usage behaviour and demonstrates the vicious circle of improving product efficiency that leads to further consumption and environmental impact. To address this problem, a new framework of dynamic functional unit definition is put forward for performing comparative LCA to manage the development of product life cycle design that helps keep the total environmental impact of the company’s product portfolio within absolute boundaries.

     

The common understanding of simplification approaches in published LCA studies—a review and mapping

The International Journal of Life Cycle Assessment - This paper aims to investigate the common understanding of the variety of simplifications in LCA, by reviewing what simplification approaches...     

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

Introduction

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

Summary of the topics presented in DF 47

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

Conclusions

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