Life Cycle Assessment (LCA) :: "You'll only see it when you understand it"

Inaugural lecture by Prof. dr. ir. Jeroen B. Guinée On the acceptance of his position of professor of Life Cycle Assessment at the Universiteit Leiden on Friday November 3, 2023Inaugural lecture by Prof. dr. ir. Jeroen B. Guinée On the acceptance of his position of professor of Life Cycle Assessment at the Universiteit Leiden on Friday November 3, 2023Industrial Ecolog

Digesting the alphabet soup of LCA

Article / Letter to editorCentrum voor Milieuwetenschappen LeidenCML/Industriele Ecologi

Environmental life cycle assessment: history, method and application to packaging

Industrial Ecolog

Ex ante life cycle assessment of GaAs/Si nanowire-based tandem solar cells: a benchmark for industrialization

Purpose The goal of this study is to perform an ex-ante life cycle assessment (LCA) of the emerging gallium-arsenide nanowire tandem solar cells on silicon (GaAs/Si) and to provide a benchmark for the commercialization of the technology. The environmental impacts and energy payback time (EPBT) of the GaAs/Si modules are compared with those of the incumbent single-Si modules. Parameters and efficiencies most relevant to be optimized in order to commercialize the technology are identified and discussed. Methods Two production routes for GaAs/Si solar cells are being up-scaled: the growth of GaAs nanowires on a native substrate, peel-off, and transfer to a silicon substrate (transfer route) and the direct growth of GaAs nanowires on a silicon substrate with assistance of a silicon-dioxide (SiO2) nanotube template (direct growth route). Two ex-ante LCAs for the different manufacturing routes and an LCA for the incumbent single-Si technology were conducted. Environmental impacts of the GaAs/Si technology were assessed and compared with the incumbent. Various scenarios regarding sensitive parameters and processes were modeled-such as modeling several industrial scale tools, the energy consumption of sensitive processes, the number of substrate reuses, the frequency of re-polishing the wafer, and benchmarking the scale of improvement of major impact drivers. Results and discussion The analysis showed that, if expected process efficiencies are achieved, a 28% efficient GaAs/Si module performs 5 to 20% better (transfer route) and 20 to 30% better (direct growth route, except the ozone depletion impact) compared with an 18% efficient single-Si module, for all impact categories assessed-climate change, land use, acidification, ozone depletion, freshwater, marine, terrestrial ecotoxicity, eutrophication, human toxicity, and photochemical oxidation. Critical hotspots identified include the use of gold, trifluoromethane (CHF3), and a GaAs wafer. The EPBT of the GaAs/Si nanowire tandem module is in between 1.37 (expected process efficiencies achieved) and 1.9 years (worst case scenario), while the EPBT of the single-Si module is 1.84 years. Results can be considered as a benchmark for the successful commercialization of the technology. Conclusions If 28% efficient GaAs/Si nanowire tandem modules are developed, expected process efficiencies are achieved, and at least 100 reuses of the GaAs substrate (transfer route) are realized; then, the GaAs/Si modules perform better compared with an 18% efficient single-Si module for most impact categories assessed. Conclusions from the ex-ante LCA are conditional (if-then) and can be used as a benchmark, allowing to quantify the efficiencies that need to be achieved to commercialize the technology.Environmental Biolog

Characterizing antibiotics in LCA-a review of current practices and proposed novel approaches for including resistance

Purpose With antibiotic resistance (ABR) portrayed as an increasing burden to human health, this study reviews how and to what extent toxicological impacts from antibiotic use are included in LCAs and supplement this with two novel approaches to include ABR, a consequence of antibiotic use, into the LCA framework. Methods We review available LCA studies that deal with toxicological aspects of antibiotics to evaluate how these impacts from antibiotics have been characterized. Then, we present two novel approaches for including ABR-related impacts in life cycle impact assessments (LCIAs). The first approach characterizes the potential for ABR enrichment in the environmental compartment as a mid-point indicator, based on minimum selective concentrations for pathogenic bacteria. The second approach attributes human health impacts as an endpoint indictor, using quantitative relationships between the use of antibiotics and human well-being. Results and discussion Our findings show that no LCA study to date have accounted for impacts related to ABR. In response, we show that our novel mid-point indicator approach could address this by allowing ABR impacts to be characterized for environmental compartments. We also establish cause-effect pathways between antibiotic use, ABR, and human well-being that generate results which are comparable with USEtox and most endpoint impact assessment approaches for human toxicology. Conclusions Our proposed methods show that currently overlooked impacts from ABR enrichment in the environment could be captured within the LCA framework as a robust characterization methodology built around the established impact model USEtox. Substantial amounts of currently unavailable data are, however, needed to calculate emissions of antibiotics into the environment, to develop minimum selective concentrations for non-pathogenic bacteria, and to quantify potential human health impacts from AB use.Industrial Ecolog

The meaning of life … cycles: lessons from and for safe by design studies

The concepts of Safe by Design (SbD) and Safe and Sustainable by Design (SSbD) are receiving increasing attention. The definitions of both concepts include the term ‘life cycle’ in combination with the terms ‘chemical’, ‘material’ and ‘product’, but their meanings are not further elaborated and defined in scholarly publications on SbD/SSbD. Here, we address two research questions: (1) How are the terms chemical, material and product used and defined in the scholarly literature on SbD and SSbD; (2) How are life cycles defined and which are considered in the scholarly literature on SbD/SSbD? We found largely consistent, though still confusing, uses of the terms product, material and chemical and we found four types of life cycles in the reviewed papers. Using consistent definitions of the terms product, material and chemical, we reduce the four types of life cycles found to three types of distinctive life cycles: (1) the life cycle of a product; (2) the life cycle of a chemical in a specific product; (3) the life cycle of a chemical in all its product applications. We discuss the different trade-offs that each of these life cycle approaches canidentify and argue that they are complementary and should preferably all be applied in SbD/SSbD studies.Environmental Biolog

Abiotic resource use in life cycle impact assessment: part II - Linking perspectives and modelling concepts

Starting from a lack of consensus on how to consistently assess abiotic resource use in life cycle assessment, a structured approach was developed to enable a classification of perspectives on resource use, based on the so-called role of resources. Using this classification, this paper focusses on analysing links between perspectives and modelling concepts, i.e. the conceptual implementation. To analyse the modelling concepts for a selection of existing LCIA methods and other modelling approaches, the concept of the system model is introduced. It defines the relevant inventory flows to be assessed by the LCIA method, and, at the same time, to be considered in the characterization model, and how the flows and stocks of resources used to calculate the characterization factors are positioned in relation to environment (nature) and economy (technosphere). For consistency, they should be aligned with the position of inventory flows and, at the same time, reflect the perspective on resources taken by the method. Using this concept, we critically review a selection of methods and other modelling approaches for consistency with the perspectives on resource use, as well as for their internal consistency. As a result of the analysis, we highlight inconsistencies and discuss ways to improve links between perspectives and modelling concepts. To achieve this, the new framework can be used for the development or improvement of LCIA methods on resource use.Horizon 2020(H2020)KIC EIT Raw Materials project number 16121Industrial Ecolog

Quantified Uncertainties in Comparative Life Cycle Assessment: What Can Be Concluded?

Industrial Ecolog

Top-down characterization of resource use in LCA: from problem definition of resource use to operational characterization factors for dissipation of elements to the environment

Purpose The methods for assessing the impact of using abiotic resources in life cycle assessment (LCA) have always been heavily debated. One of the main reasons for this is the lack of a common understanding of the problem related to resource use. This article reports the results of an effort to reach such common understanding between different stakeholder groups and the LCA community. For this, a top-down approach was applied. Methods To guide the process, a four-level top-down framework was used to (1) demarcate the problem that needs to be assessed, (2) translate this into a modeling concept, (3) derive mathematical equations and fill these with data necessary to calculate the characterization factors, and (4) align the system boundaries and assumptions that are made in the life cycle impact assessment (LCIA) model and the life cycle inventory (LCI) model. Results We started from the followingdefinition of the problemof using resources: the decrease of accessibility on a global level of primary and/or secondary elements over the very long term or short term due to thenetresult of compromising actions. Thesystem modeldistinguishes accessible and inaccessible stocks in both the environment and the technosphere. Human actions can compromise the accessible stock through environmental dissipation, technosphere hibernation, and occupation in use or through exploration. As abasis for impact assessment, we propose two parameters: the global change in accessible stock as a net result of the compromising actions and the global amount of the accessible stock. We propose three impact categories for the use of elements: environmental dissipation, technosphere hibernation, and occupation in use, with associated characterization equations for two different time horizons. Finally, preliminary characterization factors are derived and applied in a simple illustrative case study for environmental dissipation. Conclusions Due to data constraints, at this moment, only characterization factors for "dissipation to the environment" over a very-long-term time horizon could be elaborated. The case study shows that the calculation of impact scores might be hampered by insufficient LCI data. Most presently available LCI databases are far from complete in registering the flows necessary to assess the impacts on the accessibility of elements. While applying the framework, various choices are made that could plausibly be made differently. We invite our peers to also use this top-down framework when challenging our choices and elaborate that into a consistent set of choices and assumptions when developing LCIA methods.Industrial Ecolog

Forty years of Leiden environmental science: the history of the Leiden Institute of Environmental Sciences (CML) 1978-2018

Forty years of Leiden environmental sciences relates the story of CML, today one of the Faculty of Science’s eight institutes but with its roots in a more or less in dependent group of ex-activists within the university. Back in the day, many of those at the top of the university would probably have had trouble accepting that ‘those upstarts’ would still be around forty years on – not locked away in some cubbyhole with their stencil duplicator, but as a professor, assistant professor or even a dean. Today they are professors emeritus or have retired: Helias Udo de Haes, Wouter de Groot, Gerard Barendse, Gjalt Huppes, Gerard Persoon, Hans de Iongh and Jan Boersema – which doesn’t stop most of them just carrying on working. And a new generation of environmental scientists is now leading CML’s research and teaching: Geert de Snoo, Arnold Tukker, Martina Vijver, Peter van Bodegom, Jeroen Guinée, Ester van der Voet and René Kleijn.Industrial EcologyConservation Biolog