The Impact of Scale,Recycling Boundary,and Type of Waste on Symbiosis and Recycling

Innovative waste recycling through industrial processes such as industrial and urban symbiosis has long been practiced and recently received much attention in the field of industrial ecology, with researchers making efforts to identify key contributing factors to successful industrial symbiosis. By analyzing 88 sample recycling projects in 23 eco‐towns in Japan, this article focuses on the factors of project scale, recycling boundary, and types of waste in relationship to environmental benefits and operational performance. The results showed that larger eco‐towns achieved more savings of virgin materials and higher stability in operation. Large‐scale projects tended to locate closer to the users of recycled products than did small‐scale projects. For treating similar types of waste, projects producing recycled products for special users (e.g., feedstock to a blast furnace for iron production) tended to locate closer to the users than those not producing for special users. The type of waste had a strong effect on the savings of virgin materials and recycling boundaries, while local factors had significant impacts on operational performance. The results also showed that agglomeration did not significantly contribute to the environmental benefits or operational performance of eco‐town projects. Another finding was that national agencies were helpful for facilitating cross‐prefecture transportation and long‐distance transaction of wastes. Implications of the findings are also discussed.     

Application of LCA as a decision-making tool for waste management systems

Aim, Scope and Background  When materials are recycled they are made available for use for several future life cycles and can therefore replace virgin material more than just once. In order to analyse the optimal waste management system for a given material, the authors have analysed the material flows in a life cycle perspective. It is important to distinguish this approach for material flow analysis for a given material from life cycle analysis of products. A product life cycle analysis analyses the product system from cradle to grave, but uses some form of allocation in order to separate the life cycle of one product from another in cases where component materials are recycled. This paper does not address allocation of burdens between different product systems, but rather focuses on methodology for decision making for waste management systems where the optimal waste management system for a given material is analysed. The focus here is the flow of the given material from cradle (raw material extraction) to grave (the material, or its inherent energy, is no longer available for use). The limitation on the number of times materials can be recycled is set by either the recycling rate, or the technical properties of the recycled material. Main Features  This article describes a mathematical geometric progression approach that can be used to expand the system boundaries and allow for recycling a given number of times. Case studies for polyethylene and paperboard are used to illustrate the importance of including these aspects when part of the Goal and Scope for the LCA study is to identify which waste management treatment options are best for a given material. The results and discussion examine the different conclusions that can be reached about which waste management option is most environmentally beneficial when the higher burdens and benefits of recycling several times are taken into account. Results  In order to assess the complete picture of the burdens and benefits arising from recycling the system boundaries must be expanded to allow for recycling many times. A mathematical geometric progression approach manages to take into account the higher burdens and benefits arising from recycling several times. If one compares different waste management systems, e.g. energy recovery with recycling, without expanding the system to include the complete effects of material recycling one can reach a different conclusion about which waste management option is preferred. Conclusions  When the purpose of the study is to compare different waste management options, it is important that the system boundaries are expanded in order to include several recycling loops where this is a physical reality. The equations given in this article can be used to include these recycling loops. The error introduced by not expanding the system boundaries can be significant. This error can be large enough to change the conclusions of a comparative study, such that material recycling followed by incineration is a much better option than waste incineration directly. Recommendations and Outlook  When comparing waste management solutions, where material recycling is a feasible option, it is important to include the relevant number of recycling loops to ensure that the benefits of material recycling are not underestimated. The methodology presented in this article should be used in future comparative studies for strategic decision-making for waste management. The approach should not be used for LCAs for product systems without due care, as this could lead to double counting of the benefits of recycling (depending on the goal and scope of the analysis). For materials where the material cycle is more of a closed loop and one cannot truly say that recycled materials replace virgin materials, a more sophisticated approach will be required, taking into account the fact that recycled materials will only replace a certain proportion of virgin materials.     

Carbon footprint and embodied energy assessment of a civil works program in a residential estate of Western Australia

Purpose

With building construction and demolition waste accounting for 50 % of land fill space, the diversion of reusable materials is essential for Perth”s environment. The reuse and recovery of embodied energy-intensive construction materials during civil engineering works programs can offer significant energy savings and assist in the mitigation of the carbon footprint.

Methods

A streamlined life cycle assessment, with limited focus, was carried out to determine the carbon footprint and embodied energy associated with a 100-m section of road base. A life cycle inventory of inputs (energy and materials) for all processes that occurred during the development of a 100-m road section was developed. Information regarding the energy and materials used for road construction work was obtained from the Perth-based firm, Cossill and Webley, Consulting Engineers. These inputs were inserted into Simapro LCA software to calculate the associated greenhouse gas emissions and embodied energy required for the construction and maintenance of a 100-m road section using. Two approaches were employed; a traditional approach that predominantly employed virgin materials, and a recycling approach.

Results and discussion

The GHG emissions and embodied energy associated with the construction of a 100-m road section using virgin materials are 180 tonnes of CO₂-e and 10.7 terajoules (TJ), respectively. The substitution of crushed rock with recycled brick road base does not appear to reduce the carbon footprint in the pre-construction stage (i.e. from mining to material construction, plus transportation of materials to the construction site). However, this replacement could potentially offer environmental benefits by reducing quarrying activities, which would not only conserve native bushland but also reduce the loss of biodiversity along with reducing the space and cost requirements associated with landfill. In terms of carbon footprint, it appears that GHG emissions are reduced significantly when using recycled asphalt, as opposed to other materials. About 22 to 30 % of greenhouse gas (GHG) emissions can be avoided by replacing 50 to 100 % of virgin asphalt with Reclaimed Asphalt Pavement (RAP) during the maintenance period.

Conclusions

The use of recycled building and road construction materials such as asphalt, concrete, and limestone can potentially reduce the embodied energy and greenhouse gas emissions associated with road construction. The recycling approach that uses 100 % reused crushed rock base and recycled concrete rubble, and 15 % RAP during the maintenance period could reduce the total carbon footprint by approximately 6 %. This large carbon saving in pavement construction is made possible by increasing the percentage of RAP in the wearing course.     

How Much Sorting Is Enough

One strategy for mitigating the effects of rapidly growing global materials consumption is intensified recycling. A key barrier to recycling is the ability to segment or sort constituents within end‐of‐life products. Various sorting technologies hold promise, but each must demonstrate added value to achieve wide‐scale deployment. Potential factors affecting such value include the mix of scrap supply, the nature and mix of finished goods demand, sorting technology performance, and costs. This article examines the use of optimization models to identify economically efficient sorting strategies and their impact on scrap usage. Using this method, this article attempts to identify the conditions that amplify and mute the value of sorting to facilitate recycling. When this method is applied to a case representative of European aluminum secondary production, it is clear that sorting methods can add value in a broad range of conditions. Although better sorting performance (in the form of segmentation efficiency, referred to as recovery rate) correlates positively with cost savings and scrap utilization, it does not always vary monotonically with optimal sorter utilization (i.e., the fraction of scrap sorted rather than unsorted). Furthermore, the case analysis indicates that the value of sorting is more strongly dependent on recovery rate for the more heterogeneous fraction, which, in the case of aluminum, is the cast‐like fraction. Ultimately, sorting increases production flexibility, making a recycler more economically resilient in the face of changing supply and production conditions.     

Recycling in buildings: an LCA case study of a thermal insulation panel made of polyester fiber,recycled from post-consumer PET bottles

Background, aim, and scope  

The interest in polyethylene terephthalate (PET) recycling is quite recent, but it has been growing steadily over the past few years. In this context, the aim of this paper is to assess the eco-profile, the energy savings and the environmental benefits of the use of recycled raw materials to manufacture products for thermal insulation of buildings in Italy (i.e., PET bottles post-consumer).     

Application of Markov Chain Model to Calculate the Average Number of Times of Use of a Material in Society. An Allocation Methodology for Open-Loop Recycling. Part 1: Methodology Development (7 pp)

- Preamble. In this series of two papers, a methodology to calculate the average number of times a material is used in a society from cradle to grave is presented and applied to allocation of environmental impact of virgin material. Part 1 focuses on methodology development and shows how the methodology works with hypothetical examples of material flows. Part 2 presents case studies for steel recycling in Japan, in which the methodology is applied and allocation of environmental impact of virgin steel is conducted. - Abstract Goal, Scope and Background. It has been recognized that LCA has a limitation in assessing open cycle recycling of materials because of inevitable subjective judgments in setting system boundary. According with the enforcement of recycling laws, there has been a rapid increase in recycling ratio of materials at the end-of-life of products in many industrialized countries. So, materials' life cycle is getting more complicated, which makes it difficult to quantify the environmental impacts of materials used in a product in an appropriate way. The purpose of this paper is to develop a methodology to calculate the average number of times a material is used in a society from cradle to grave. The method developed in this paper derives the average number of times material is used; this value could be used for allocation of environmental burdens of virgin material as well as an indicator for assessing the state of material use in a certain year, based on material flow of material in that year. Main Features Our methodology is based on Markov chain model using matrix-based numerical analysis. A major feature of this method is that it creates transition probability matrices for a material from the way in which the material is produced, consumed, and recycled, making it possible to simply elicit indicators that assess the status of material use in products in society. Our methodology could be an alternative method to derive the average number of times material is used, which could be used for allocation of environmental burdens of virgin material. Results and Discussions The methodology was applied to hypothetical examples of material flows, in which a virgin material was produced and used in products, recycled and finally landfilled. In some cases, closed loop and open loop recycling of materials existed. The transition probability matrix was created for each material flow, and how many times a virgin material is used in products until all of the elements are ultimately landfilled. Conclusions This methodology is applicable to a complicated material flow if the status of residence of a material and its flow in a society can be figured out. All the necessary data are the amount of virgin material production, amount of the material used in products, recycling rate of the material at the end of life of each product, the amount of scrap of the material that are used for products. In Part 2 of this paper, case studies for steel were conducted.     

Should high-cobalt EV batteries be repurposed? Using LCA to assess the impact of technological innovation on the waste hierarchy

Lithium-ion batteries (LIBs) are a key technology in decarbonizing the transportation and electricity sectors, yet the use of critical materials, such as cobalt, nickel, and lithium, lead to environmental and social impacts. Reusing, repurposing, and recycling mitigate battery impacts by extending their lifespan and reducing reliance on virgin materials. Innovation that reduces demand for these problematic materials and increases battery efficiency also reduces impacts. Two examples of this technological innovation include, (1) the development of energy dense cathode chemistry containing less cobalt, a material with high social and environmental impacts; and (2) the use of columnar silicon thin film anode, which results in increased energy density compared to the commonly used graphite anode. This research assesses whether these technological innovations change the currently understood waste hierarchy, which prioritizes reuse or repurposing prior to recycling. This is of interest because retired high-cobalt batteries could supply their constituent materials sooner if recycled immediately and be used in low-cobalt, higher-performing batteries. The assessment considers the life cycle environmental impacts of two end-of-life management routes for a high-cobalt LIB: first, recycling the battery immediately after the first use life to produce a new, and less material intensive battery, and second, repurposing the battery for a stationary storage application followed by recycling. Findings show that battery reuse reduces life cycle environmental impacts relative to immediate recycling. Thus, from an environmental perspective, the waste hierarchy holds, and steps to retain the batteries in their highest value use, such as through repurposing, should still be prioritized.     

Life cycle assessment of composite materials made of recycled thermoplastics combined with rice husks and cotton linters

Background, aim, and scope  The goal of this study is to analyze the environmental impact of new composite materials obtained from the combination of recycled thermoplastics (polypropylene [PP] and high-density polyethylene [HDPE]) and biodegradable waste of little economic value, namely, rice husks and recycled cotton. The environmental impact of these materials is compared to the impact of virgin PP and HDPE using life cycle assessment. Materials and methods  From-cradle-to-grave life cycle inventory studies were performed for 1 kg of each of the three new composites: PP+cotton linters, PP+rice husks, and HDPE+cotton linters. Inventory data for the recycling of thermoplastics and cotton were obtained from a number of recycling firms in Spain, while environmental data concerning rice husks were obtained mainly from one rice-processing company located in Spain. Life cycle inventory data for virgin thermoplastics were acquired from PlasticsEurope. Two different scenarios—incineration and landfilling—were considered for the assessment of disposal phase. A quantitative impact assessment was performed for four impact categories: global warming over a hundred years, nonrenewable energy depletion, acidification, and eutrophication. Results  The composites subject to analysis exhibited a significantly reduced environmental impact during the materials acquisition and processing phases compared to conventional virgin thermoplastics in all of the impact categories considered. The use of fertilizers for rice cultivation, however, impaired the results of the rice husk composite in the eutrophication category where it nevertheless outperformed its conventional counterparts. The compounding phase fundamentally implies an electric consumption. The disposal phase was analyzed with regard to emissions in the global warming category. Discussion  Composites obtained from renewable sources are still in an incipient state of development in comparison with petroleum-derived plastics. In the future, as mass production of these plastics becomes more widespread, their environmental impact can be expected to reach lower levels than those obtained in our study. The new materials exhibited adequate mechanical performance for the application analyzed (structures used in aquaculture). Conclusions  The composites subject to analysis exhibited a significantly reduced environmental impact compared to conventional virgin thermoplastics using 1 kg of material as a functional unit. Recommendations and perspectives  In accordance with the International Organization for Standardization 14044:2006 standard, it would be advisable to avoid impact allocation. This posed some difficulties, since rice husks are a coproduct of rice. Thus, some impact allocation was done in our study on the basis of economic value. It would also be advisable to take the land use impact category into consideration when performing comparative studies between composites and conventional plastics, albeit the definition of this category is currently the subject of scientific debate.     

Evaluation of Life Cycle Assessment Recycling Allocation Methods

Life cycle assessment practitioners struggle to accurately allocate environmental burdens of metals recycling, including the temporal dimension of environmental impacts. We analyze four approaches for calculating aluminum greenhouse gas emissions: the recycled content (RC) or cut‐off approach, which assumes that demand for recycled content displaces primary production; end‐of‐life recycling (EOLR), which assumes that postuse recycling displaces primary production; market‐based (MB) approaches, which estimate changes in supply and demand using price elasticities; and value‐corrected substitution (VCS), which allocates impact based on price differences between primary and recycled material. Our analysis suggests that applications of the VCS approach do not adequately account for the changing scrap to virgin material price ratio over time, whereas MB approaches do not address stock accumulation and depletion. The EOLR and RC approaches were analyzed using two case studies: U.S. aluminum beverage cans and vehicle engine blocks. These approaches produced similar results for beverage cans, which have a closed material loop system and a short product life. With longer product lifetimes, as noted with the engine blocks, the magnitude and timing of the emissions differs greatly between the RC and EOLR approaches. The EOLR approach indicates increased impacts at the time of production, offset by negative impacts in future years, whereas the RC approach assumes benefits to increased recycled content at the time of production. For vehicle engine blocks, emissions using EOLR are 140% higher than with RC. Results are highly sensitive to recycled content and future recycling rates, and the choice of allocation methods can have significant implications for life cycle studies.     

发展菜籽油制备生物柴油产业的一种有效对策

菜籽油是生产生物柴油的主要原料之一,目前用菜籽油生产生物柴油的主要瓶颈是原料成本较高,一般占到总生产成本的75%左右。在介绍国内外菜籽油制备生物柴油产业发展现状和存在的主要问题的基础上,提出了利用现有冬闲田生产高芥酸油菜籽,以高芥酸菜籽油为原料联产制备生物柴油、芥酸及其系列衍生产品和甘油、甾醇类化合物等高值副产品的对策,并从产品用途与市场需求潜力、企业经济效益、生产技术和条件、原料来源等几方面分析了这一发展对策的可行性。该对策的实施,将实现我国菜籽油制备生物柴油产业的兴起和可持续发展,提高生物柴油产品品质,带动我国生物化工和其它诸多行业的共同发展,为我国社会主义新农村建设作出贡献。     

Plastics recycling: challenges and opportunities

Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. As a consequence, the production of plastics has increased markedly over the last 60 years. However, current levels of their usage and disposal generate several environmental problems. Around 4 per cent of world oil and gas production, a non-renewable resource, is used as feedstock for plastics and a further 3–4% is expended to provide energy for their manufacture. A major portion of plastic produced each year is used to make disposable items of packaging or other short-lived products that are discarded within a year of manufacture. These two observations alone indicate that our current use of plastics is not sustainable. In addition, because of the durability of the polymers involved, substantial quantities of discarded end-of-life plastics are accumulating as debris in landfills and in natural habitats worldwide.Recycling is one of the most important actions currently available to reduce these impacts and represents one of the most dynamic areas in the plastics industry today. Recycling provides opportunities to reduce oil usage, carbon dioxide emissions and the quantities of waste requiring disposal. Here, we briefly set recycling into context against other waste-reduction strategies, namely reduction in material use through downgauging or product reuse, the use of alternative biodegradable materials and energy recovery as fuel.While plastics have been recycled since the 1970s, the quantities that are recycled vary geographically, according to plastic type and application. Recycling of packaging materials has seen rapid expansion over the last decades in a number of countries. Advances in technologies and systems for the collection, sorting and reprocessing of recyclable plastics are creating new opportunities for recycling, and with the combined actions of the public, industry and governments it may be possible to divert the majority of plastic waste from landfills to recycling over the next decades.     

Comparative LCAs for Curbside Recycling Versus Either Landfilling or Incineration with Energy Recovery (12 pp)

Background This article describes two projects conducted recently by Sound Resource Management (SRMG) – one for the San Luis Obispo County Integrated Waste Management Authority (SLO IWMA) and the other for the Washington State Department of Ecology (WA Ecology). For both projects we used life cycle assessment (LCA) techniques to evaluate the environmental burdens associated with collection and management of municipal solid waste. Both projects compared environmental burdens from curbside collection for recycling, processing, and market shipment of recyclable materials picked up from households and/or businesses against environmental burdens from curbside collection and disposal of mixed solid waste. Method logy. The SLO IWMA project compared curbside recycling for households and businesses against curbside collection of mixed refuse for deposition in a landfill where landfill gas is collected and used for energy generation. The WA Ecology project compared residential curbside recycling in three regions of Washington State against the collection and deposition of those same materials in landfills where landfill gas is collected and flared. In the fourth Washington region (the urban east encompassing Spokane) the WA Ecology project compared curbside recycling against collection and deposition in a wasteto- energy (WTE) combustion facility used to generate electricity for sale on the regional energy grid. During the time period covered by the SLO study, households and businesses used either one or two containers, depending on the collection company, to separate and set out materials for recycling in San Luis Obispo County. During the time of the WA study households used either two or three containers for the residential curbside recycling programs surveyed for that study. Typically participants in collection programs requiring separation of materials into more than one container used one of the containers to separate at least glass bottles and jars from other recyclable materials. For the WA Ecology project SRMG used life cycle inventory (LCI) techniques to estimate atmospheric emissions of ten pollutants, waterborne emissions of seventeen pollutants, and emissions of industrial solid waste, as well as total energy consumption, associated with curbside recycling and disposal methods for managing municipal solid waste. Emissions estimates came from the Decision Support Tool (DST) developed for assessing the cost and environmental burdens of integrated solid waste management strategies by North Carolina State University (NCSU) in conjunction with Research Triangle Institute (RTI) and the US Environmental Protection Agency (US EPA)1. RTI used the DST to estimate environmental emissions during the life cycle of products. RTI provided those estimates to SRMG for analysis in the WA Ecology project2. For the SLO IWMA project SRMG also used LCI techniques and data from the Municipal Solid Waste Life- Cycle Database (Database), prepared by RTI with the support of US EPA during DST model development, to estimate environmental emissions from solid waste management practices3. Once we developed the LCI data for each project, SRMG then prepared a life cycle environmental impacts assessment of the environmental burdens associated with these emissions using the Environmental Problems approach discussed in the methodology section of this article. Finally, for the WA study we also developed estimates of the economic costs of certain environmental impacts in order to assess whether recycling was cost effective from a societal point of view. Conclusions Recycling of newspaper, cardboard, mixed paper, glass bottles and jars, aluminum cans, tin-plated steel cans, plastic bottles, and other conventionally recoverable materials found in household and business municipal solid wastes consumes less energy and imposes lower environmental burdens than disposal of solid waste materials via landfilling or incineration, even after accounting for energy that may be recovered from waste materials at either type disposal facility. This result holds for a variety of environmental impacts, including global warming, acidification, eutrophication, disability adjusted life year (DALY) losses from emission of criteria air pollutants, human toxicity and ecological toxicity. The basic reason for this conclusion is that energy conservation and pollution prevention engendered by using recycled rather than virgin materials as feedstocks for manufacturing new products tends to be an order of magnitude greater than the additional energy and environmental burdens imposed by curbside collection trucks, recycled material processing facilities, and transportation of processed recyclables to end-use markets. Furthermore, the energy grid offsets and associated reductions in environmental burdens yielded by generation of energy from landfill gas or from waste combustion are substantially smaller then the upstream energy and pollution offsets attained by manufacturing products with processed recyclables, even after accounting for energy usage and pollutant emissions during collection, processing and transportation to end-use markets for recycled materials. The analysis that leads to this conclusion included a direct comparison of the collection for recycling versus collection for disposal of the same quantity and composition of materials handled through existing curbside recycling programs in Washington State. This comparison provides a better approximation to marginal energy usage and environmental burdens of recycling versus disposal for recyclable materials in solid waste than does a comparison of the energy and environmental impacts of recycling versus management methods for handling typical mixed refuse, where that refuse includes organics and non-recyclables in addition to whatever recyclable materials may remain in the garbage. Finally, the analysis also suggests that, under reasonable assumptions regarding the economic cost of impacts from pollutant emissions, the societal benefits of recycling outweigh its costs.     

Design for the Next Generation: Incorporating Cradle-to-Cradle Design into Herman Miller Products

In the late 1990s, office furniture manufacturer Herman Miller, Inc., entered into a collaboration with architect William McDonough to create a system for designing cradle-to-cradle products. This collaboration led to the creation of a tool—the Design for Environment (DfE) product assessment tool—that evaluates progress towards cradle-to-cradle products. The first product Herman Miller designed using the DfE product assessment tool was the Mirra chair. Over the course of the chair's development, the DfE process generated a number of design changes, including selecting a completely different material for the chair's spine, increasing recycled content in chair components, eliminating all PVC (polyvinyl chloride) components, and designing the chair for rapid disassembly using common tools.
The areas of greatest success in designing the Mirra chair for the environment were the increased use of recyclable parts and increased ease of disassembly, whereas the areas of greatest challenge were increasing recycled content and using materials with a green chemistry composition. The success in recyclability reflects the use of metals, materials that have a well-established recycling infrastructure. The success in disassembly reflects the high degree of control that Herman Miller has over product assembly. The challenge to increasing recycled content is the use of plastics in chairs. Unlike the metals, which all contain some recycled content, most plastics are made from virgin polymers. The challenge to improving materials chemistry is the limited range of green chemicals and materials on the market.
The Mirra chair exemplifies the value of incorporating the environment into design and the need for tools to benchmark progress, as well as the challenges of creating a truly cradle-to-cradle product. Herman Miller recognizes that working toward cradle-to-cradle products is a journey that will involve continuous improvement of its products.     

Sustainable development of global supply chains—part 1: sustainability optimization framework

In global industry supply chains, environmental sustainability optimization addresses the overall consumption of resources and energy, the reduction of carbon emissions and generated waste to name a few. In this paper, we propose a holistic sustainability optimization framework for strategic network design of industry supply chains under consideration of economic, social as well as ecologic objectives. The framework is flexible to incorporate multiple sustainability indicators, alternative sustainability optimization strategies as well as a variety of internal and external industry-specific factors which impact the sustainability of the entire industry supply chain in the long-term. The core of the framework is an end-to-end closed-loop value chain model consisting of process, transport and product-in-use modules. For the first time, the product-in-use impact (“use” vs. “make”) is integrated in one network design approach. In addition, the model fully closes the loop from sourcing of raw materials via manufacturing towards reverse value chain steps such as disposal and recycling. Finally, we propose the minimize-time-to-sustainability approach as new optimization strategy for long-term network design problems focusing on minimizing the time, industry supply chain structures need to transform into sustainability steady states for all defined sustainability indicators such as CO₂e emissions, costs or social indicators based on defined target values. In part 2 of this paper the application of the optimization framework to the European automotive industry is shown.     

Renewable resources in the chemical industry – Breaking away from oil?

Rising prices for fossil-based raw materials suggest that sooner or later renewable raw materials will, in principle, become economically viable. This paper examines this widespread paradigm. Price linkages like those seen for decades particularly in connection with petrochemical raw materials are now increasingly affecting renewable raw materials. The main driving force is the competing utilisation as an energy source because both fossil-based and renewable raw materials are used primarily for heat, electrical power and mobility. As a result, prices are determined by energy utilisation. Simple observations show how prices for renewable carbon sources are becoming linked to the crude oil price. Whether the application calls for sugar, starch, virgin oils or lignocellulose, the price for the raw material rises with the oil price. Consequently, expectations regarding price trends for fossil-based energy sources can also be utilised for the valuation of alternative processes. However, this seriously calls into question the assumption that a rising crude oil price will favour the economic viability of alternative products and processes based on renewable raw materials. Conversely, it follows that these products and processes must demonstrate economic viability today. Especially in connection with new approaches in white biotechnology, it is evident that, under realistic assumptions, particularly in terms of achievable yields and the optimisation potential of the underlying processes, the route to utilisation is economically viable. This makes the paradigm mentioned at the outset at least very questionable.     

Biodiesel production from waste cooking oil: 2. Economic assessment and sensitivity analysis

The economic feasibilities of four continuous processes to produce biodiesel, including both alkali- and acid-catalyzed processes, using waste cooking oil and the ‘standard’ process using virgin vegetable oil as the raw material, were assessed. Although the alkali-catalyzed process using virgin vegetable oil had the lowest fixed capital cost, the acid-catalyzed process using waste cooking oil was more economically feasible overall, providing a lower total manufacturing cost, a more attractive after-tax rate of return and a lower biodiesel break-even price. On the basis of these economic calculations, sensitivity analyses for these processes were carried out. Plant capacity and prices of feedstock oils and biodiesel were found to be the most significant factors affecting the economic viability of biodiesel manufacture.     

Thermodynamic rarity of electrical and electronic waste: Assessment and policy implications for critical materials

The strategic relevance of extracting raw materials from waste from electrical and electronic equipment (WEEE) in the EU is increasing due to value chain risks caused by geopolitical instability, accessibility of specific minerals, and decreasing reserves due to growing extraction rates. This article examines the quantities of so-called critical raw materials (CRMs) originating within WEEE streams from a depletion perspective. Presently, current recycling targets are based solely on mass collection and recycling rates. We examine the potential limitations of this approach using an exergy-based indicator named thermodynamic rarity. This indicator represents the exergy costs needed for producing materials from the bare rock to market. The case of Italy is used to explore the application of the indicator at the macro (national) and micro (company) level for the product categories “small electronics” and “screens and monitors.” Our estimations show significant differences between the mass and rarity of materials within Italian WEEE streams. While iron accounts for more than 70% of the weight of the product categories analyzed, it accounts for less than 15% of the rarity. Similarly, several CRMs with a small mass have a higher rarity value, for example, tungsten with less than 0.1% of the mass and over 6% of the rarity. The policy context is reflected upon, where it is argued that thermodynamic rarity can provide novel insights to support end-of-life WEEE decision-making processes, for example, target development and recycling standards setting to help prioritize material monitoring and recovery options.     

Adapting Stand‐Alone Renewable Energy Technologies for the Circular Economy through Eco‐Design and Recycling

Renewable energy (RE) technologies are looked upon favorably to provide for future energy demands and reduce greenhouse gas (GHG) emissions. However, the installation of these technologies requires large quantities of finite material resources. We apply life cycle assessment to 100 years of electricity generation from three stand‐alone RE technologies—solar photovoltaics, run‐of‐river hydro, and wind—to evaluate environmental burden profiles against baseline electricity generation from fossil fuels. We then devised scenarios to incorporate circular economy (CE) improvements targeting hotspots in systems’ life cycle, specifically (1) improved recycling rates for raw materials and (ii) the application of eco‐design. Hydro presented the lowest environmental burdens per kilowatt‐hour of electricity generation compared with other RE technologies, owing to its higher efficiency and longer life spans for main components. Distinct results were observed in the environmental performance of each system based on the consideration of improved recycling rates and eco‐design. CE measures produced similar modest savings in already low GHG emissions burdens for each technology, while eco‐design specifically had the potential to provide significant savings in abiotic resource depletion. Further research to explore the full potential of CE measures for RE technologies will curtail the resource intensity of RE technologies required to mitigate climate change.     

Estimation of Waste Battery Generation and Analysis of the Waste Battery Recycling System in China

China produces and consumes a large amount of batteries annually, which leads to many waste batteries needing to be recycled. The collection and recycling system of primary, alkaline secondary, and lithium‐ion secondary batteries in China is particularly poor, and waste battery recycling enterprises generally sustain economic losses if they solely use waste batteries as raw materials. Increasing the profits of waste battery recycling systems is a key problem that needs to be considered. This article quantitatively analyzes waste battery generation in China by using annual sales data and probable lifetime distribution of various batteries. The results show that the rapid growth of battery usage has led to an increased generation of waste batteries and the percentage of different types of waste batteries is changing over time. In 2013, the total quantity of all waste batteries in the medium lifetime scenario reached 570 kilotons, of which primary, alkaline secondary, and lithium‐ion secondary waste batteries accounted for approximately 36%, 28%, and 35%, respectively. Based on a real‐world case study of a typical domestic waste battery recycling enterprise in China, material flow analysis and cost‐benefit analysis were conducted to study the development of the recycling process of comingled waste batteries. Through scenario analysis, we conclude that increasing the use of waste batteries as raw materials and the recycling of other materials that are less valuable reduces the profits of the waste battery recycling enterprise. Higher profits can be achieved by adding the production of high value‐added downstream products and government support. At the same time, the essential role of the government in developing a waste battery recycling system was identified. Finally, relevant suggestions are made for improvements in both the government and enterprise sectors.