Analyzing the Environmental Benefits of Industrial Symbiosis

Studies of industrial symbiosis (IS) focus on the physical flows of materials and energy in local industrial systems. In an ideal IS, waste material and energy are shared or exchanged among the actors of the system, thereby reducing the consumption of virgin material and energy inputs, and likewise the generation of waste and emissions. In this study, the environmental impacts of an industrial ecosystem centered around a pulp and paper mill and operating as an IS are analyzed using life cycle assessment (LCA). The system is compared with two hypothetical reference systems in which the actors would operate in isolation. Moreover, the system is analyzed further in order to identify possibilities for additional links between the actors. The results show that of the total life cycle impacts of the system, upstream processes made the greatest overall contribution to the results. Comparison with stand‐alone production shows that in the case studied, the industrial symbiosis results in modest improvements, 5% to 20% in most impact categories, in the overall environmental impacts of the system. Most of the benefits occur upstream through heat and electricity production for the local town. All in all it is recommended that when the environmental impacts of industrial symbiosis are assessed, the impacts occurring upstream should also be studied, not only the impacts within the ecosystem.     

Understanding the Organization of Industrial Ecosystems

Industrial symbiosis (IS) has been used to describe the physical exchange and shared management of input and output materials by geographically proximate firms. Firms that engage in IS are said to belong to an industrial ecosystem. Symbiosis has been found to be motivated by economic considerations, such as lowering costs for waste disposal, as well as by environmental ones, such as accessing limited water supplies. Communication and trust among managers are thought to play important roles in exchanges; however, empirical studies have not been previously conducted. This study used social network analysis (SNA) to identify the prevalence of industrial symbiosis linkages in Barceloneta, Puerto Rico. The study quantified patterns in various relationships among firms and managers, including formal relations through supply chains, and informal ones through interpersonal interactions. SNA and statistical methods were used to explore how these ties correlate with observed industrial symbiosis activities. IS linkages were found to be less prevalent than product sales among firms and were concentrated among pharmaceutical firms at the core of the regional network. Trust among managers and position in the social hierarchy were found to be correlated with IS but not supply chain links. SNA was useful for examining the organization of different relationships in the industrial ecosystem, but contextual information is still needed to add meaning to its findings.     

Evaluation and Allocation of Greenhouse Gas Reductions in Industrial Symbiosis

Industrial symbiosis (IS) exchanges have been recognized to reduce greenhouse gas (GHG) emission, though methods for quantification of GHG emissions in IS exchanges are varied, and no standardized methods are available. This article proposes a practical approach to quantify total and allocated GHG emissions from IS exchanges by integrating the GHG protocol and life cycle assessment. The proposed method expands the system boundaries to include all IS companies, and the functional flow is set to be the sum of the main products. The total impact of a company is allocated to the main product. Three by‐product impact allocation methods of cutoff, avoidance, and 50/50 are proposed, and the total and distributed impacts of the IS systems in an industrial park are theoretically derived. The proposed method was tested to quantify GHG reduction in a real IS exchange developed between Korea Zinc (a zinc smelter) and Hankook Paper (a paper mill company) in the Ulsan Eco‐Industrial Park initiative. The total reduction of GHG emissions in this IS exchange, 60,522 tonnes of carbon dioxide per year, was the same in the GHG protocol, whereas GHG distribution between two companies depended on the allocation method. Given that the reduction of GHG emissions from IS exchanges is the product of the collaboration of giving companies and receiving companies, the 50/50 allocation method is best from an equivalent‐responsibility and benefit‐sharing perspective. However, this study suggests a more practical implementation approach based on a flexible and negotiable method of allocating the total GHG reduction between stakeholders.     

Applying Industrial Symbiosis to Smallholder Farms

The study of industrial symbiosis (IS) has largely focused on the exchange of energy and materials among industrial processes in an effort to increase value and reduce environmental impact. Agricultural systems, particularly those located in developing countries, can benefit from the principles of IS. Relatively few studies have analyzed the potential benefits of integrated material and energy flows in smallholder farming, even though these systems are considered essential to the world's food supply and poverty reduction. Although the concepts can be applied to virtually any system, the study of industrial symbiosis has traditionally focused on industrialized systems in developed countries. The research presented here applies the principles of IS to smallholder farms using optimization techniques to maximize farm output while minimizing wastes. Our research links IS to the growing field of integrated farming research (IFR), which seeks to create new technologies that increase the production of farms by viewing the farm as a system. Bridging these fields enriches the potential for robust research outcomes in both areas and fills a current knowledge gap. IS benefits from exploring new applications and increasing its penetration into the developing world. IFR benefits from established IS tools to create alternate pathways for increased output based on symbiotic relationships. A small farming system in Liberia, West Africa, is used as a case study. System integration of individual unit processes shows increased productivity and decreased waste. The results of this analysis indicate that there are unrealized opportunities for IS in developing countries, and integration of IS techniques into smallholder farming operations has the potential for impacting sustainable development.     

Using an Industrial Waste Account to Facilitate National Level Industrial Symbioses by Uncovering the Waste Exchange Potential

The identification of potential by‐product exchanges is important for fostering industrial symbiosis. To discover these potential exchanges, this article extends the analysis of local industrial symbiosis to a national scale. A waste input‐output table, which is a material flow accounting tool, was compiled and used as a database to examine the existing exchanges of by‐products. The supplies and demands of industrial wastes or by‐products were compared to highlight their potential use for promoting higher exchange flows. The analysis of the linkages indicated that the majority of each of the by‐products were reused by the few industries that had the technology and operational capacity for reuse. This finding is useful for determining which industries are good candidates for promoting further industrial symbiosis (IS). Based on a nation‐wide analysis that considered the industrial characteristics of Taiwan comprehensively, 23 types of major by‐products with greater reuse flows and 216 potential exchange patterns were identified between the industries. In addition, three types of eco‐industrial networks were characterized as follows according to their dominant types: (1) fossil fuel, metal, and mineral‐dominated; (2) agricultural and synthetic material‐dominated; and (3) information and communications technology (ICT) and chemical industry‐dominated eco‐industrial networks. This analysis highlights the resource exchange potentials and provides information to new firms for networking with existing businesses.     

城市废弃物资源化共生网络:概念、特征及体系解析

挖掘城市废弃物中有价值的资源,已经成为世界各国开展废弃物开发与管理的共同选择。产业共生是推动经济绿色发展和提高资源效率的战略工具,已经成为探讨废弃物资源化利用问题的重要视角。将产业共生理论引入城市废弃物资源化利用领域,提出城市废弃物资源化共生网络的概念,并将其典型特征概括为"四个统一",即价值网络与责任网络的统一,集聚共生与虚拟共生的统一,稳健型与脆弱性的统一以及自组织性与主体建构性的统一。借鉴超网络理论构建城市废弃物资源化共生网络体系的结构模型,并从共生单元、共生模式、共生界面和共生环境4个层面对该模型进行详细解析。城市废弃物资源化共生网络可分为核心网络和外围网络,两者之间存在全方位、多层次的合作机制。在城市废弃物资源化共生网络中,共生单元具有多层次性和多样性特征,它们之间存在着不同类型、效率各异的共生关系,推动共生模式向对称互惠一体化共生进化是破解城市废弃物资源化利用难题的关键;共生界面具有物质交换、能量传递、信息共享、知识传播及利益协调等多样化功能,而共生关系的进化以及共生界面功能发挥又依赖于优越的共生环境。此外,城市废弃物资源化共生网络有依托型、平等型、嵌套型和虚拟型等4种运作模式,国内典型案例分析表明这4种运作模式将长期并存。     

Evaluating the environmental performance of producing soil and surfaces through industrial symbiosis

Industrial symbiosis (IS), where different entities collaborate in the management of energy, utilities, materials, or services, has been identified as an approach to improve resource efficiency and circularity in industry. This article assesses the environmental performance of an IS network with firms involved in waste management, soil, surfaces, paper, lumber, and energy. The aim is to highlight the environmental performance of an IS network and pay particular attention to the improved performance for products in the IS network. Life cycle assessment is used to compare the current IS network with a reference scenario and a potential future development. The results suggest that there are significant benefits from the IS network. Large reductions in greenhouse gas (GHG) emissions and abiotic resource depletion were identified. Furthermore, large reductions in local impacts, namely eutrophication and acidification impacts are illustrated. It was shown that all firms in the network benefit from the synergies involved, with a large share of the benefits stemming from the facilitated exchanges with the waste management company. The replacement of conventional products and energy streams with bio‐based counterparts from within the network is of significant importance. Finally, the results point to the importance of the facilitation of by‐product synergies, and the significant value this creates in the region, with large potential to improve the environmental performance of firms and their products.     

Exploring the emergence of waste recovery and exchange in industrial clusters

Self-organized industrial symbiosis (IS) starts with one actor's decision to invest in a waste recovery plant and the other actors' decision to buy the recovered flow. Technical and institutional conditions of the cluster influence actors' decisions. This paper explores the emergence of IS collaborations in industrial clusters under different techno-economic conditions in the long term. We propose a mixed-integer linear programming model that incorporates costs and constraints associated with waste recovery and exchange to study actors' investment decisions and investigate shaped symbiotic exchanges under rising energy prices and limited electricity supply. The approach is implemented in Iran's Persian Gulf Mining and Metals Special Economic Zone as a case study. The results revealed that changes in internal or external condition simultaneously influence the industrial and waste recovery plants. For instance, increasing energy prices without raising product prices significantly decreased the production level of industrial plants and, consequently, heat recovery potential. Furthermore, the waste heat recovery plants' contribution to improving the cluster's economic and environmental performance was not the same. Electricity recovery from a power plant's waste heat can result in 55 PJ grid electricity intake reduction and 720 M€ cluster cash flow increase. Recovered cooling or electricity from the steelmaking plant waste heat was consumed internally rather than shaping IS. These model outcomes show its capability to study IS within the socio-technical structure of the cluster, not a standalone phenomenon. Implemented conceptualization offers a novel system-level approach, which could be adjusted to assess other industrial development strategies.     

Assessing the “Short Mental Distance” in Eco‐Industrial Networks

Like many economic exchanges, industrial symbiosis (IS) is thought to be influenced by social relationships and shared norms among actors in a network. While many implicit references to social characteristics exist throughout the literature, there have been few explicit attempts to operationalize and measure the concepts. The “short mental distance,”“trust,”“openness,” and “communication” recorded among managers in Kalundborg, Denmark, set a precedent for examining and encouraging social interactions among key personnel in the dozens of eco‐industrial networks around the world. In this article we explore the relationships among various aspects of social embeddedness, social capital, and IS. We develop a conceptual framework and an approach using quantitative and qualitative methods to identify and measure these social characteristics, including social network structure, communication, and similarities in norms and conceptions of waste, and apply them in an industrial network in Nanjangud, South India. The findings suggest that there is a fairly high level of shared norms about dealing with waste—the “short mental distance”—in this network, but by‐product transactions are only weakly correlated with the structure and content of communication among managers. Replication of this approach can increase the understanding and comparability of the role of social characteristics in eco‐industrial activities around the world.     

国内外产业共生网络研究比较述评

产业共生网络是指基于物质及能量交换以及知识及基础设施共享而形成的在不同产业主体之间的合作共赢网络,是产业转型升级的重要保障。作为产业共生的运作方式,产业共生网络的研究国外从20世纪90年代开始从概念到实例就展开了一系列探讨,国内自2002年也开始在网络结构等方面开展相关研究。尤其在2008年以后,产业共生网络的研究方向不断拓宽,研究成果丰富多样。为明晰国内外产业共生网络研究的发展态势,促进产业共生网络理论体系的发展并使其得到有效应用。本文从共生网络内涵、结构、功能及评价、演化、管理调控等方面比较分析了国内外产业共生网络的研究进展,并对产业共生网络的发展前景做了展望。未来产业共生网络研究在不同尺度的比较及推演、数据信息平台的搭建以及产业共生网络演化模拟及管理调控的耦合等方面需重点关注。     

Material Flow Optimization in By‐product Synergy Networks

By‐product synergy (BPS) is an industrial ecology practice that involves utilization of industrial by‐products as feedstocks for other industrial processes. A novel decision support tool is developed to analyze BPS networks that involve material processing and transport among regional clusters of companies. Mathematical programming techniques are used to determine the optimal network design and the material flows that minimize total cost or environmental impacts. This methodology is incorporated into a graphical software package called Eco‐Flow?. The tool has been applied to model and analyze available synergies in an existing BPS network centered in Kansas City, Missouri. A base case, which assumes no synergies, is compared with the optimal BPS solution found by Eco‐Flow?. The results for Kansas City suggest that when companies in the network cooperate to optimize the system profitability, up to $15 million per year of savings are possible. The findings also indicate that the BPS approach would result in 29% reduction in total cost, 25.8% reduction in average company cost, 30% reduction in carbon dioxide (CO₂) emissions, and 37% reduction in waste to landfill. The modeling approach is being extended to better represent the dynamics of industrial and ecological processes.     

Understanding the Evolution of Industrial Symbiosis Research

This study analyzes the evolution of the research field of industrial symbiosis (IS). We elucidate its embedding in industrial ecology (IE), trace the development of research themes, and reveal the evolution of the research network through analysis of the core literature and journals that appeared from 1997 to 2012 by citation analysis, cocitation analysis, and network analysis. In the first period (1997–2005), IS research held a minority share in the IE literature. The research revolved around the concept of IS, the assessment of eco‐industrial park projects, and the establishment of waste treatment and recycling networks. In the second period (2006–2012), diverse research approaches and theories enriched the field, which has led to a maturation in theory building. Our findings clearly illustrate that IS evolved from practice‐oriented research toward coherent theory building through a systematic underpinning and linking of diverse topics. As scientific attention shifted from exploring a phenomenon to elucidating underlying mechanisms, IS knowledge found worldwide practical implementation. The coauthorship network shows that the academic communities of IS are distributed worldwide and that international collaboration is widespread. Through bibliometric and network analysis of IS, we have created a systemic, quantitative image of the evolution of the IS research field and community, which gives IS researchers an underpinned overview of the IS research and may help them to identify new directions and synergy in worldwide research.     

Redefining Industrial Symbiosis

The most commonly cited definition of industrial symbiosis (IS), by Chertow (2000) , has served well to foster discussion and research for more than a decade. The definition reflected the state of research and practice at the time; as both have advanced, some terms have been interpreted in substantially different ways. In this article we analyze those generally used terms for their connection to the ecological metaphor that is the root of industrial ecology, and their varied interpretations in IS research and practice over time. We then propose an updated definition intended to communicate the essence of IS as a tool for innovative green growth: IS engages diverse organizations in a network to foster eco‐innovation and long‐term culture change. Creating and sharing knowledge through the network yields mutually profitable transactions for novel sourcing of required inputs and value‐added destinations for non‐product outputs, as well as improved business and technical processes. We posit that, although geographic proximity is often associated with IS, it is neither necessary nor sufficient—nor is a singular focus on physical resource exchange.     

Revealing the Environmental Advantages of Industrial Symbiosis in Wood‐Based Bioeconomy Networks: An Assessment From a Life Cycle Perspective

The German government has recently initiated funding schemes that incentivize strategies for wood‐based bioeconomy regions. Regional wood and chemical industries have been encouraged to act symbiotically, that is, share pilot plant facilities, couple processes where feasible, and cascade woody feedstock throughout their process networks. However, during the planning stages of these bioeconomy regions, options need to be assessed for sustainably integrating processes and energy integration between the various industries that produce bio‐based polymers and engineered wood products. The aim of this paper is to identify the environmental sustainability of industrial symbiosis for producing high‐value‐added, bio‐based products in the wood‐based bioeconomy region of Central Germany. An analysis was conducted of three possible future scenarios with varying degrees of symbiosis in the bioeconomy network. A life cycle assessment (LCA) approach was used to compare these three scenarios to a traditional fossil‐based production system. Eleven environmental impact categories were considered. The results show that, in most cases, the bioeconomy network outperformed the fossil‐based production system, mitigating environmental impacts by 25% to 130%.     

Barriers to Industrial Symbiosis: Insights from the Use of a Maturity Grid

The concept of industrial symbiosis (IS) over the last 20 years has become a well‐recognized approach for environmental improvements at the regional level. Many technical solutions for waste and by‐product material, water, and energy reuse between neighboring industries (so‐called synergies) have been discovered and applied in the IS examples from all over the world. However, the potential for uptake of new synergies in the regions is often limited by a range of nontechnical barriers. These barriers include environmental regulation, lack of cooperation and trust between industries in the area, economic barriers, and lack of information sharing. Although several approaches to help identify and overcome some of the nontechnical barriers were examined, no methodology was found that systematically assessed and tracked the barriers to guide the progress of IS development. This article presents a new tool—IS maturity grid—to tackle this issue in the regional IS studies. The tool helps monitor and assess the level of regional industrial collaboration and also indicates a potential path for further improvements and development in an industrial region, depending on where that region currently lies in the grid. The application of the developed tool to the Gladstone industrial region of Queensland, Australia, is presented in the article. It showed that Gladstone is at the third (active) stage of five stages of maturity, with cooperation and trust among industries the strongest characteristic and information barriers the characteristic for greatest improvement.     

Industrial Symbiosis in Kalundborg, Denmark: A Quantitative Assessment of Economic and Environmental Aspects

As a subdiscipline of industrial ecology, industrial symbiosis is concerned with resource optimization among colocated companies. The industrial symbiosis complex in Kalundborg, Denmark is the seminal example of industrial symbiosis in the industrial ecology literature. In spite of this, there has been no in-depth quantitative analysis enabling more comprehensive understanding of economic and environmental performances connected to this case. In this article some of the central industrial symbiotic exchanges, involving water and steam, in Kalundborg are analyzed, using detailed economic and environmental data. It is found that both substantial and minor environmental benefits accrue from these industrial symbiosis exchanges and that economic motivation often is connected to upstream or downstream operational performance and not directly associated with the value of the exchanged byproduct or waste itself. It is concluded that industrial symbiosis, as viewed from a company perspective, has to be understood both in terms of individual economic and environmental performance, and as a more collective approach to industrial sustainability.     

Industrial Waste Reuse and By‐product Synergy Optimization

By‐product synergy is a growing practice worldwide. It consists in the maximization of resources utilization with the replacement of raw materials by by‐products as inputs for industrial processes. In order to support decision making in such strategic projects, appropriate tools must be developed. This article presents the results of a research project, which includes the development of a multiobjective mathematical programming model for the optimization of by‐product flows, synergy configurations, and investment decisions in eco‐industrial networks. This model is evaluated using data related to the Kalundborg industrial symbiosis (IS) in order to illustrate its utilization, as well as to assess, in a retrospective manner, the behavior of the companies involved with respect to both economic and environmental benefits of synergies. The experiments also illustrate the influence of the municipality on synergy implementation and how a scenario‐based approach can be used to anticipate raw material price increase. The results are generally coherent with the actual timing of synergy initializations. Further, the considerable effect of water price on the length of investments’ payback period illustrates the impact of policies and regulations on IS.     

Industrial Recycling Networks as Starting Points for Broader Sustainability‐Oriented Cooperation?

Closing loops by intercompany recycling of by‐products is a core theme of industrial ecology (IE). This article considers whether industrial recycling networks or industrial symbiosis projects can be used as a starting point for much broader intercompany cooperation for sustainable development. Evidence presented is based on the results of an empirical investigation of the recycling network Styria in Austria, the recycling network Oldenburger Münsterland in Germany, and the manufacturing sector in Austria. Statistical analysis shows that the percentage of by‐products that are passed on to other companies for recycling purposes is not higher in member companies of the recycling networks than in the other companies of the manufacturing sector in Austria. In terms of cooperation, the relationships with the respective recycling partners are found to be very similar to regular customer relations. Furthermore, the companies of the recycling networks remain unaware of the network to which they belong. Instead, one of the main findings of this study is that intercompany recycling activities are regarded by the company representatives as bilateral market transactions, not as collaborative network activities. This has potentially significant implications for the use of industrial symbiosis networks as starting points for sustainability networks with broader cooperation toward sustainability. The findings raise interesting questions as to whether such broader cooperation might result from a conscious planning process or might emerge largely spontaneously as part of normal market coordination. In any case, intercompany recycling is clearly considered to be a very important field of collaborative action for sustainability in industry.     

The Evolution of Facilitated Industrial Symbiosis

While much work has been done on the conditions surrounding the emergence and establishment of industrial symbiosis (IS), new attention is being paid to understanding the evolution of IS over time. We demonstrate empirically how a new, facilitated IS initiative developed and evolved over an 8‐year period. We explore its network evolution by considering how the facilitator's actions enabled and precluded two fundamental network processes—serendipitous and goal‐directed processes. We discuss implications for a more generalized theory of IS development by exploring why and how different evolutionary trajectories may unfold.