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
Engelenburg, M. van; Deetman, S.P.; Fishman, T.; Behrens, P.A.; Voet, E. van der 2024
Construction materials are associated with significant environmental and resource impacts. The circular use of materials already in use as stocks may provide an opportunity to reduce these impacts.... Show moreConstruction materials are associated with significant environmental and resource impacts. The circular use of materials already in use as stocks may provide an opportunity to reduce these impacts. We provide a dataset describing the potential global urban mine consisting of transportation infrastructure in an open database based on geospatial data from OpenStreetMaps. We reveal the significant opportunities of the embedded materials in this huge stock. With this Total Resources in Physical Infrastructure, or TRIPI, the database we provide easy access to a global dataset covering 175 countries and sub-regions, allowing researchers to select an area of study, and find the location as well as the material composition of the physical infrastructure. Material stocks are reported on a national level and commonly used regional aggregations. Material stocks are reported per kg, kg per capita, and kg per area; and for the physical type of infrastructure that is available in kilometres and area (km2). This dataset can be used in various research applications such as Material Flow Analysis, Material stock inventories, Country-level comparisons of infrastructure density, and others, and inform policy on harnessing the opportunities of the urban mine. 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
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
Dong, D.; Tukker, A.; Steubing, B.R.P.; Oers, L.F.C.M. van; Rechberger, H.; Aguilar Hernandez, G.A.; ... ; Voet, E. van der 2022
To conserve resources and enhance the environmental performance, China has launched the "Zero waste" concept, focused on reutilization of solid waste and recovery of materials, including copper.... Show moreTo conserve resources and enhance the environmental performance, China has launched the "Zero waste" concept, focused on reutilization of solid waste and recovery of materials, including copper. Although several studies have assessed the copper demand and recycling, there is a lack of understanding on how different waste management options would potentially reduce primary copper demand and associated environmental impacts in China in the context of energy transition. This study addresses this gap in view of a transition to low-carbon energy system and the optimization of copper waste management combining MFA and LCA approaches. Six types of waste streams (C&DW, ELV, WEEE, IEW, MSW, ICW) are investigated in relation to various "Zero waste" strategies including reduction, reuse (repair, remanufacturing or refurbishment), recycling and transition from informal to formal waste management. Under present Chinese policies, reuse and recycling of copper containing products will lead to a somewhat lower dependency on primary copper in 2100 (11187Gg), as well as lower total GHG emissions (64869 Gg CO2-eq.) and cumulative energy demand (1.18x10 boolean AND 12 MJ). Maximizing such "Zero waste" options may lead to a further reduction, resulting in 65% potential reduction of primary copper demand, around 55% potential reduction of total GHG emissions and total cumulative energy demand in 2100. Several policy actions are proposed to provide insights into future waste management in China as well as some of the challenges involved. Show less
Verhagen, T.J.; Pieters, L.; Voet, E. van der; Straalen, V. van; Tunn, V. 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
Deetman, S.P.; Boer, H.S. de; Engelenburg, M. van; Voet, E. van der; Vuuren, D.P. van 2021
We analyse how the global material stocks and flows related to the electricity sector may develop towards 2050. We focus on three electricity sub-systems, being generation, transmission and storage... Show moreWe analyse how the global material stocks and flows related to the electricity sector may develop towards 2050. We focus on three electricity sub-systems, being generation, transmission and storage and present a model covering both bulk and critical materials such as steel, aluminium and neodymium. Results are based on the second Shared Socio-Economic Pathway scenario, with additional climate policy assumptions based on the IMAGE integrated assessment framework, in combination with dynamic stock modelling and an elaborate review of material intensities.Results show a rapid growth in the demand for most materials in the electricity sector, as a consequence of increased electricity demand and a shift towards renewable electricity technologies, which have higher material intensities and drive the expansion of transmission infrastructure and electricity storage capacity. Under climate policy assumptions, the annual demand for most materials is expected to grow further towards 2050. For neodymium, the annual demand grows by a factor 4.4. Global demand for steel and aluminium in the electricity sector grows by a factor 2 in the baseline or 2.6 in the 2-degree climate policy scenario.We show that the combination of rapid growth of capital stocks and long lifetimes of technologies leads to a mismatch between annual demand and the availability of secondary materials within the electricity sector. This may limit the sector to accomplish circular material flows, especially under climate policy assumptions. We also highlight the potential for electric vehicles to curb some of the material demand related to electricity storage through adoption of vehicle-to-grid services. Show less
Koning, A. de; Oorschot, J. van; Voet, E. van der 2021
Residential buildings and service sector buildings have an important contribution to climate change, directly via energy use in these buildings and indirectly through construction activities and... Show moreResidential buildings and service sector buildings have an important contribution to climate change, directly via energy use in these buildings and indirectly through construction activities and the production and disposal of buildings materials. In this paper, we introduce a model that looks at total global building stock for 26 regions between 1970 and 2050 and calculates the floor space and building materials both in new buildings and in demolished buildings. For residential buildings, we build upon the work of Marinova et al. (2019, this issue), who used a building material database to come up with scenarios for materials in the residential building stock. This paper adds two things. First, we introduce a new regression-based model for service building floor space, recognizing 4 different types of service-related buildings. Secondly, we use a dynamic stock model, based on lifetime distributions found in literature, to calculate the construction (inflow) and demolition (outflow) of building floor space for both residential and service-related purposes. We combine this with data from the building material database to come up with scenarios for the annual demand for construction materials worldwide as well as an estimation of the availability of waste materials after building demolition towards 2050. The model can thus be used to assess the potential for closing the material cycles in the construction sector, while distinguishing urban and rural areas explicitly. The results show that demand for construction materials will continue to increase in most regions, even in developed countries. Global demand for steel and cement for the building sector is estimated to be 769 Mt/yr and 11.9 Gt/yr respectively, by the end of the modelling period. This represents a respective growth of 31% and 14% compared to today. Drivers behind this are an expected growth of global residential building stock of about 50%, and a growth of about 150% in the building stock for services. Our model projects that by 2050, only 55% of construction-related demand for copper, wood and steel could potentially be covered by recycled building materials. For other materials the availability of scrap may be higher, reaching up to 71% of new demand in the case of aluminium. This means that in most regions urban mining cannot cover the growing demand for construction materials. (C) 2019 Published by Elsevier Ltd. Show less
In this paper, we develop a dynamic stock model and scenario analysis involving a bottom‐up approach to analyze copper demand in China from 2005 to 2050 based on government and related sectoral... Show moreIn this paper, we develop a dynamic stock model and scenario analysis involving a bottom‐up approach to analyze copper demand in China from 2005 to 2050 based on government and related sectoral policies. The results show that in the short‐term, China's copper industry cannot achieve a completely circular economy without additional measures. Aggregate and per capita copper demand are both set to increase substantially, especially in infrastructure, transportation, and buildings. Between 2016 and 2050, total copper demand will increase almost threefold. Copper use in buildings will stabilize before 2050, but the copper stock in infrastructure and transportation will not yet have reached saturation in 2050. The continuous growth of copper stock implies that secondary copper will be able to cover just over 50% of demand in 2050, at best, even with an assumed recycling rate of 90%. Finally, future copper demand depends largely on the lifetime of applications. There is therefore an urgent need to prolong the service life of end‐use products to reduce the amount of materials used, especially in large‐scale applications in buildings and infrastructure. Show less
Bleischwitz, R.; Spataru, C.; VanDeveer, S.D.; Obersteiner, M.; Voet, E. van der; Johnson, C.; ... ; Vuuren, D.P. van 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... 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
