Proton exchange membrane (PEM) water electrolyzers are a promising technology for high-purity, efficient green hydrogen production, with expanding installations. This has increased demand for... Show moreProton exchange membrane (PEM) water electrolyzers are a promising technology for high-purity, efficient green hydrogen production, with expanding installations. This has increased demand for materials like platinum (Pt) used in PEM manufacturing. Conversely, Pt, which currently serves primarily as catalysts for internal combustion engine vehicles (ICEVs), would become available as ICEVs are phased out. Here, we simulate the Pt requirements for rapid scale-up PEM electrolyzers and quantitatively compare these requirements with the availability of Pt from scraped autocatalysts under the IEA-NZE scenario. Our results show that demand for Pt in PEM electrolyzers is expected to increase by an order of magnitude by 2050, while ICEVs are expected to cumulatively scrap ∼2500 tons of Pt. The Pt surplus from ICEVs would meet the increasing Pt demand for PEM eletrolyzers from 2030 onwards. These findings offer fresh insights into using the potential of urban mines to meet the energy transition challenges. Show less
Gervais, E.; Kleijn, E.G.M.; Nold, S.; Voet, E. van der 2023
Supply concentration and environmental, social, governance (ESG) issues constitute important supply risks. With strategic autonomy and responsible sourcing high on the political agenda these risks... Show moreSupply concentration and environmental, social, governance (ESG) issues constitute important supply risks. With strategic autonomy and responsible sourcing high on the political agenda these risks are especially relevant for the EU. This paper proposes an approach to conduct risk-based due diligence. Using a trade-linked material flow analysis, ESG and dependency hotspots along supply chains can be identified. Silver supply chains for photovoltaics (PV) are taken as case-study. The model traces silver from mining to PV module manufacturing, from 1995 to 2021. The supply of silver powder, paste, PV cells, and modules is found to be highly concentrated. These supply chains are linked to substantial ESG risks, mostly nested in fabrication and manufacturing, some of which have worsened over time. Over 87% of the silver used in PV transits through at least one country with a very high risk factor. Reshoring the PV industry to the EU can partially de-risk supply. Show less
Oorschot, J. van; Sprecher, B.; Rijken, B.; Witteveen, P.; Blok, M.; Schouten, N.; Voet, E. van der 2023
Buildings are an important part of society's environmental impacts, both in the construction and in the use phase. As the energy performance of buildings improve, construction materials become more... Show moreBuildings are an important part of society's environmental impacts, both in the construction and in the use phase. As the energy performance of buildings improve, construction materials become more important as a cause of environmental impact. Less attention has been given to those materials. We explore, as an alternative for conventional buildings, the use of biobased materials and circular building practices. In addition to building design, we analyze the effect of urbanization. We assess the potential to close material cycles together with the material related impact, between 2018 and 2050 in the Netherlands. Our results show a limited potential to close material cycles until 2050, as a result of slow stock turnover and growth of the building stock. At present, end-of-life recycling rates are low, further limiting circularity. Primary material demand can be lowered when shifting toward biobased or circular construction. This shift also reduces material related carbon emissions. Large-scale implementation of biobased construction, however, drastically increases land area required for wood production. Material demand differs strongly spatially and depends on the degree of urbanization. Urbanization results in higher building replacement rates, but constructed dwellings are generally small compared to scenarios with more rural developments. The approach presented in this work can be used to analyze strategies aimed at closing material cycles in the building sector and lowering buildings' embodied environmental impact, at different spatial scales. Show less
Deployment of clean energy technologies will require a considerable amount of materials. The surge in demand for metals related to emerging energy technologies may hinder the energy transition. In... Show moreDeployment of clean energy technologies will require a considerable amount of materials. The surge in demand for metals related to emerging energy technologies may hinder the energy transition. In this study we provide a comprehensive overview and analysis of existing work in this field, a solid quantitative baseline for material requirements of different energy technologies and quantitative information that can be used to generate learning curves for the material requirements of different energy technologies. We conducted a quantitative review of the material requirements of low-carbon energy technologies in 132 scientific publications, and provided a comparative analysis of detailed data including material intensity and lifetime data. Besides providing a large amount of structured quantitative data, the results of our work indicate that: (1) research on the demand for low carbon technology related metals has received much attention since the 2010s; (2) around 80% of the publications focus on the global level while national level studies are underrepresented; (3) science-based future scenarios are the main means of estimating total future material requirements; (4) most studies foresee material constraints of large-scale implementation of low-carbon technologies and the secure and responsible supply of these materials is still the subject of discussion; (5) changes in metal intensity caused by technological development and material requirements for non-critical components are important though often overlooked. Show less
Verhagen, T.J.; Cetinay, H.; Voet, E. van der; Sprecher, B. 2022
To achieve climate neutrality, future urban heating systems will need to use a variety of low-carbon heating technologies. The transition toward low-carbon heating technologies necessitates a... Show moreTo achieve climate neutrality, future urban heating systems will need to use a variety of low-carbon heating technologies. The transition toward low-carbon heating technologies necessitates a complete restructuring of the heating system, with significant associated material requirements. However, little research has been done into the quantity and environmental impact of the required materials for this system change. We analyzed the material demand and the environmental impact of the transition toward low-carbon heating in the Netherlands across three scenarios based on the local availability and capacity for sources of low-carbon heat. A wide range of materials are included, covering aggregates, construction materials, metals, plastics, and critical materials. We find that while the Dutch policy goal of reducing GHG emissions by 90% before 2050 can be achieved if only direct emissions from the heating system are considered, this is no longer the case when the cradle-to-gate emissions from the additional materials, especially insulation materials, are taken into account. The implementation of these technologies will require 59–63 megatons of materials in the period of 2021–2050, leading to a maximum reduction of 62%. Show less
Inaugural Lecture by Prof.Dr. Ester van der Voet on the acceptance of her position as Associate Professor at the chair of Sustainable Resource Use at Leiden University on Monday 2 Mei 2022
Oorschot, J. van; Voet, E. van der; Blok, M.; Schouten, N.; Witteveen, P.; Rijken, B.; Hoorn, A. van 2022
Raw Materials are crucial in the development, production, and improvement of modern-day technology. Reliable access to critical, scarce, and valuable materials used in electronics is becoming a... Show moreRaw Materials are crucial in the development, production, and improvement of modern-day technology. Reliable access to critical, scarce, and valuable materials used in electronics is becoming a worldwide concern. Therefore, the quantification of material recovery from the urban mine is currently pursued worldwide. Commonly, data on (Waste) Electrical and Electronic Equipment is scattered, not harmo-nized, and uses different types of classifications and terminology. This provides a big challenge of a structured mapping of secondary raw materials in the urban mine. To address these issues, a state-of -the-art methodology has been developed and is presented by analyzing and tracking printed circuit boards in different key Electrical and Electronic Equipment over time. A total of 4051 composition data records where analyzed to extract the concentration of 19 elements in printed circuit boards between 1990 until 2020. The methodology harmonizes urban mine data, provides structured information that can be used to analyze and monitor the impact of product trends on their components and concentration of the elements in electronics. The resulting database and harmonization protocols are made freely available at the urban mine platform. (c) 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Show less
Koning, A. de; Oorschot, J. van; Voet, E. van der 2021
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... Show moreForty 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. Show less
Schipper, B.W.; Lin, H.C.; Meloni, M.A.; Wansleeben, K.; Heijungs, R.; Voet, E. van der 2018
Future global copper demand is expected to keep rising due to copper's indispensable role in modem technologies. Unfortunately, increasing copper extraction and decreasing ore grades intensify... Show moreFuture global copper demand is expected to keep rising due to copper's indispensable role in modem technologies. Unfortunately, increasing copper extraction and decreasing ore grades intensify energy use and generate higher environmental impact. A potential solution would be reaching a circular economy of copper, in which secondary production provides a large part of the demand. A necessary first step in this direction is to understand future copper demand. In this study, we estimated the copper demand until 2100 under different scenarios with regression and stock dynamics methods. For the stock dynamics method, a strong growth of copper demand is found in the scenarios with a high share of renewable energy, in which a much higher copper intensity for the electricity system and the transport sector is seen. The regression predicts a wider range of copper demand depending on the scenario. The regression method requires less data but lacks the ability to incorporate the expected decoupling of material use and GDP when the stock saturates, limiting its applicability for long-term estimations. Under all considered scenarios, the projected increase in demand for copper results in the exhaustion of the identified copper resources, unless high end-of-life recovery rates are achieved. These results highlight the urgency for a transition towards the circular economy of copper. Show less
Kuipers, K.J.J.; Oers, L.F.C.M. van; Verboon, M.; Voet, E. van der 2018
