René Kleijn

Dynamic substance flow analysis: the delaying mechanism of stocks, with the case of PVC in Sweden

Abstract Today’s stocks are tomorrow’s emissions and waste flows. As a result of the time lag introduced by the buffering function of the stock of materials and products in society environmental problem flows which seem to be under control can easily rebound. In this paper an example is given of how signal processing can be used in dynamic Substance Flow Analysis for estimating the future generation of waste and emissions from present societal stocks. An approach is outlined to estimate the outflow of waste products from stocks on the basis of assumptions on the shape of the distribution describing the inflow of new products, the average life span of the products, and the life-span distribution. To exemplify the approach we used a theoretical case of PVC in Sweden. It was found that the delaying mechanisms of the stocks can make the outcome counterintuitive. Furthermore, the chosen shape of the input-distribution function has the most influence on the predicted outflows, especially in the case of possible fashion-type (exponentially increasing) markets. The choice of the shape of the inflow distribution could, therefore, be based on qualitative knowledge of the market of the different products. The life-span distribution appears to have a more subtle influence on the height of the peaks and the time that they occur. So far only a normal distribution has been considered; more research is recommended into other types of distribution.

Recycling as a Strategy against Rare Earth Element Criticality: A Systemic Evaluation of the Potential Yield of NdFeB Magnet Recycling

End-of-life recycling is promoted by OECD countries as a promising strategy in the current global supply crisis surrounding rare earth elements (REEs) so that dependence on China, the dominant supplier, can be decreased. So far the feasibility and potential yield of REE recycling has not been systematically evaluated. This paper estimates the annual waste flows of neodymium and dysprosium from permanent magnets, the main deployment of these critical REEs, during the 2011-2030 period. The estimates focus on three key permanent magnet waste flows: wind turbines, hybrid and electric vehicles, and hard disk drives (HDDs) in personal computers (PCs). This is a good indication of the end-of-life recycling of neodymium and dysprosium maximum potential yield. Results show that for some time to come, waste flows from permanent magnets will remain small relative to the rapidly growing global REE demand. Policymakers therefore need to be aware that during the next decade recycling is unlikely to substantially contribute to global REE supply security. In the long term, waste flows will increase sharply and will meet a substantial part of the total demand for these metals. Future REE recycling efforts should, therefore, focus on the development of recycling technology and infrastructure.

Predicting future emissions based on characteristics of stocks

Abstract Future flows of emissions and waste from society to the environment can be estimated either as a percentage of the future stock or as a delayed input. The first approach is based on a static model where concentration is the driving force and is generally preferable for ease of calculation. The second approach is based on a dynamic model, where ageing is the driving force and knowledge of the life span is needed. We present the conditions under which the calculations based on a static model will produce acceptable approximations for a dynamic system.

Life Cycle Inventory of the Production of Rare Earths and the Subsequent Production of NdFeB Rare Earth Permanent Magnets

Neodymium is one of the more critical rare earth elements with respect to current availability and is most often used in high performance magnets. In this paper, we compare the virgin production route of these magnets with two hypothetical recycling processes in terms of environmental impact. The first recycling process looks at manual dismantling of computer hard disk drives (HDDs) combined with a novel hydrogen based recycling process. The second process assumes HDDs are shredded. Our life cycle assessment is based both on up to date literature and on our own experimental data. Because the production process of neodymium oxide is generic to all rare earths, we also report the life cycle inventory data for the production of rare earth oxides separately. We conclude that recycling of neodymium, especially via manual dismantling, is preferable to primary production, with some environmental indicators showing an order of magnitude improvement. The choice of recycling technology is also important with respect to resource recovery. While manual disassembly allows in principle for all magnetic material to be recovered, shredding leads to very low recovery rates (<10%).

Life cycle assessment of aquaculture systems—a review of methodologies

PurposeAs capture fishery production has reached its limits and global demand for aquatic products is still increasing, aquaculture has become the world’s fastest growing animal production sector. In attempts to evaluate the environmental consequences of this rapid expansion, life cycle assessment (LCA) has become a frequently used method. The present review of current peer-reviewed literature focusing on LCA of aquaculture systems is intended to clarify the methodological choices made, identify possible data gaps, and provide recommendations for future development within this field of research. The results of this review will also serve as a start-up activity of the EU FP7 SEAT (Sustaining Ethical Aquaculture Trade) project, which aims to perform several LCA studies on aquaculture systems in Asia over the next few years.MethodsFrom a full analysis of methodology in LCA, six phases were identified to differ the most amongst ten peer-reviewed articles and two PhD theses (functional unit, system boundaries, data and data quality, allocation, impact assessment methods, interpretation methods). Each phase is discussed with regards to differences amongst the studies, current LCA literature followed by recommendations where appropriate. The conclusions and recommendations section reflects on aquaculture-specific scenarios as well as on some more general issues in LCA.ResultsAquaculture LCAs often require large system boundaries, including fisheries, agriculture, and livestock production systems from around the globe. The reviewed studies offered limited coverage of production in developing countries, low-intensity farming practices, and non-finfish species, although most farmed aquatic products originate from a wide range of farming practices in Asia. Apart from different choices of functional unit, system boundaries and impact assessment methods, the studies also differed in their choice of allocation factors and data sourcing. Interpretation of results also differed amongst the studies, and a number of methodological choices were identified influencing the outcomes.Conclusions and recommendationsEfforts should be made to increase transparency to allow the results to be reproduced, and to construct aquaculture related database(s). More extensive data reporting, including environmental flows, within the greater field of LCA could be achieved, without compromising the focus of studies, by providing supporting information to articles and/or reporting only ID numbers from background databases. More research is needed into aquaculture in Asia based on the latest progress made by the LCA community.

Numerical approaches towards life cycle interpretation five examples

The ISO-standard for LCA distinguishes four phases, of which the last one, the interpretation, is the least elaborated. It can be regarded as containing procedural steps (like a completeness check) as well as numerical steps (like a sensitivity check). This paper provides five examples of techniques that can be used for the numerical steps. These are the contribution analysis, the perturbation analysis, the uncertainty analysis, the comparative analysis, and the discernibility analysis. All five techniques are described at a non-technical level with respect to basic concept, possibilities, tabular and graphical representation, restriction and warnings, and all are illustrated with a simple example.

Recycling Potential of Neodymium: The Case of Computer Hard Disk Drives

Neodymium, one of the more critically scarce rare earth metals, is often used in sustainable technologies. In this study, we investigate the potential contribution of neodymium recycling to reducing scarcity in supply, with a case study on computer hard disk drives (HDDs). We first review the literature on neodymium production and recycling potential. From this review, we find that recycling of computer HDDs is currently the most feasible pathway toward large-scale recycling of neodymium, even though HDDs do not represent the largest application of neodymium. We then use a combination of dynamic modeling and empirical experiments to conclude that within the application of NdFeB magnets for HDDs, the potential for loop-closing is significant: up to 57% in 2017. However, compared to the total NdFeB production capacity, the recovery potential from HDDs is relatively small (in the 1-3% range). The distributed nature of neodymium poses a significant challenge for recycling of neodymium.

Energy and climate impacts of producing synthetic hydrocarbon fuels from CO(2).

Within the context of carbon dioxide (CO2) utilization there is an increasing interest in using CO2 as a resource to produce sustainable liquid hydrocarbon fuels. When these fuels are produced by solely using solar energy they are labeled as solar fuels. In the recent discourse on solar fuels intuitive arguments are used to support the prospects of these fuels. This paper takes a quantitative approach to investigate some of the claims made in this discussion. We analyze the life cycle performance of various classes of solar fuel processes using different primary energy and CO2 sources. We compare their efficacy with respect to carbon mitigation with ubiquitous fossil-based fuels and conclude that producing liquid hydrocarbon fuels starting from CO2 by using existing technologies requires much more energy than existing fuels. An improvement in life cycle CO2 emissions is only found when solar energy and atmospheric CO2 are used. Producing fuels from CO2 is a very long-term niche at best, not the panacea suggested in the recent public discourse.

Substance flows through the economy and environment of a region : Part II: Modelling.

In the tradition of the study of materials flows through society, the Substance Flow Analysis (SFA) method and its software tool SFINX are presented. SFA aims at providing the relevant information for a country’s overall management strategy regarding single substances or coherent groups of substances. Three modelling techniques and their possibilities and limitations are discussed: Bookkeeping, static modelling, and dynamic modelling. The computer program SFINX can be used for varoius purposes: (1) to obtain an overview of stocks and flows of a substance in, out and through a nation’s economy and environment for a specific year, (2) to trace the origins of specific pollution problems, and (3) to estimate the effectiveness of certain abatement measures. Each application has its own requirements with regard to data and modelling.

Environmental Impacts of Diet Changes in the EU

The report is a scientific contribution to the European Commissions Integrated Product Policy framework, which seeks to minimise the environmental degradation caused throughout the life cycle of products. This report first presents an overview of the environmental impact cause by current dietary habits in EU27. It then develops three alternative diets on the basis of health recommendations from EFSA, WHO and other organisations, and calculates the changes in environmental impacts achievable through a shift towards these diets. Finally the report analyses policy measures which stimulate the uptake of healthy diets by consumers. The report shows that current dietary habits in Europe are responsible for 27% of all environmental impacts in Europe. A shift to healthier diets shows that the contribution to overall environmental impacts in Europe can be reduced to 25% in case of reduced consumption of red meat. The contribution reduces to just 26% if indirect effects such as household budget re-distribution and price and substitution effects in the agricultural sector are taken into account. Because food and nutrition are strongly rooted in traditions and habits, policy measures aiming at stimulating a change towards healthy diets need to include a combination of different instruments, ranging from consumer awareness raising to public procurement activities.