Dynamic Eco-Efficiency Projections for Construction and Demolition Waste Recycling Strategies at the City Level

In this article we have elaborated a consistent framework for the quantification and evaluation of eco‐efficiency for scenarios for waste treatment of construction and demolition (C&D) waste. Such waste systems will play an increasingly important role in the future, as there has been for many years, and still is, a significant net increase in stock in the built environment. Consequently, there is a need to discuss future waste management strategies, both in terms of growing waste volumes, stricter regulations, and sectorial recycling ambitions, as well as a trend for higher competition and a need for professional and optimized operations within the C&D waste industry. It is within this framework that we develop and analyze models that we believe will be meaningful to the actors in the C&D industry. Here we have outlined a way to quantify future C&D waste generation and have developed realistic scenarios for waste handling based on today's actual practices. We then demonstrate how each scenario is examined with respect to specific and aggregated cost and environmental impact from different end‐of‐life treatment alternatives for major C&D waste fractions. From these results, we have been able to suggest which fractions to prioritize, in order to minimize cost and total environmental impact, as the most eco‐efficient way to achieve an objective of overall system performance.     

The Sankey Diagram in Energy and Material Flow Management

The Sankey diagram is an important aid in identifying inefficiencies and potential for savings when dealing with resources. It was developed over 100 years ago by the Irish engineer Riall Sankey to analyze the thermal efficiency of steam engines and has since been applied to depict the energy and material balances of complex systems. The Sankey diagram is the main tool for visualizing industrial metabolism and hence is widely used in industrial ecology. In the history of the early 20th century, it played a major role when raw materials were scarce and expensive and engineers were making great efforts to improve technical systems. Sankey diagrams can also be used to map value flows in systems at the operational level or along global value chains. The article charts the historical development of the diagrams. After the First World War the diagrams were used to produce thermal balances of production plants for glass and cement and to optimize the energy input. In the 1930s, steel and iron ore played a strategic role in Nazi Germany. Their efficient use was highlighted with Sankey diagrams. Since the 1990s, these diagrams have become common for displaying data in life cycle assessments (LCAs) of products. Sankey diagrams can also be used to map value flows in systems at the operational level or along global value added chains. This article, the first of a pair, charts the historical development. The companion article discusses the methodology and the implicit assumptions of such Sankey diagrams.     

The Sankey Diagram in Energy and Material Flow Management

The Sankey diagram is an important aid in pointing up inefficiencies and potential for savings in connection with resource use. This article, the second of a pair, examines the use of Sankey diagrams in operational material flow management. The previous article described the development of the diagram and its use in the past.
Simple Sankey diagrams follow the requirement of conservation of energy or mass and allow a physical view of production systems. Advanced diagrams integrate stocks of materials beside the flows or show the different (ecological) quality of the materials. For the purpose of management, however, a further step is necessary: to illustrate the economic value of the energy and material flows and to use information from cost accounting. The use of flow charts showing added value or the costs of energy and material flows is particularly important for production systems. This article describes examples of each of these uses as well as assumptions that must be taken into account for Sankey diagrams to be used as an effective aid for decision-making in business and public policy.     

Energy Use and Environmental Impacts of the Swedish Building and Real Estate Management Sector

One of the key features of environmental policy integration in Sweden is sector responsibility. The National Board of Housing, Building and Planning is responsible for the building and real estate management sector and should, as a part of this responsibility, assess the environmental impacts of this sector. The aim of this study is to suggest and demonstrate a method for such an assessment. The suggested method is a life cycle assessment, based on an input‐output analysis. The method can be used for regular monitoring and for prioritization between different improving measures. For the assessment to sufficiently cover the Swedish Environmental Quality Objectives, complementary information is needed, in particular with respect to the indoor environment. According to the results, the real estate management sector contributes between 10% and 40% of Swedish energy use; use of hazardous chemical products; generation of solid waste; emissions of gases contributing to climate change; and human toxicological impacts, including nitrogen oxides (NOx) and particulates. Transport and production of nonrenewable building materials contribute significantly to several of the emissions. Heating of buildings contributes more to energy use than to climate change, due to the use of renewable energy sources. To reduce climate change, measures should therefore prioritize not only heating of buildings but also the important upstream processes.     

Exploring the Global Journey of Nickel with Markov Chain Models

Markov chain (MC) modeling is a versatile tool in policy analysis and has been applied in several forms to analyze resource flows. This article builds on previous discussions of the relationship among absorbing Markov chains (AMCs), material flow analysis (MFA), and input‐output (IO) analysis, and presents a full‐scale application of MC modeling for a particular globally relevant, nonrenewable resource, namely nickel. The MC model presented here is built on comprehensive, recently compiled nickel flow data for 52 geographic regions. Considering all possible cycles of recycling and reuse, nickel extracted in 2005 is estimated to have a technological lifetime of 73 ± 7 years. During its global journey, nickel enters use, for some application somewhere in the world, an average of three times, the largest share of which occurs in China. Nickel entering fabrication in 2005 is estimated to enter use approximately four times. Over time, nickel is lost to the environment and as a tramp element in carbon steel; the final distribution of nickel among these absorbing states is 78% and 22%, respectively. Of all the nickel in ore extracted in 2005, fully 28% will eventually end up in the tailings, slag, and landfills of China. MC results are also combined with geographically specific life cycle inventory data to determine the overall energy invested in nickel during its many cycles of use. MCs provide a powerful tool for tracking resources through the network of global production, use, and waste management, and opportunities for further integration with other modeling efforts are also discussed.     

The Construction of Normal Expectations

The gradual upward changes of standards in normal everyday life have significant environmental implications, and it is therefore important to study how these changes come about. The intention of the article is to analyze the social construction of normal expectations through a case study. The case concerns the present boom in bathroom renovations in Denmark, which offers an excellent opportunity to study the interplay between a wide variety of consumption drivers and social changes pointing toward long-term changes of normal expectations regarding bathroom standards. The study is problem-oriented and transdisciplinary and draws on a wide range of sociological, anthropological, and economic theories. The empirical basis comprises a combination of statistics, a review of magazine and media coverage, visits to exhibitions, and qualitative interviews. A variety of consumption drivers are identified. Among the drivers are the increasing importance of the home as a core identity project and a symbol of the unity of the family, the opportunities for creative work, the convenience of more grooming capacity during the busy family's rush hours, the perceived need for retreat and indulgence in a hectic everyday life, and the increased focus on body care and fitness. The contours of the emerging normal expectations are outlined and discussed in an environmental perspective.     

Can Efficiency Improvements Reduce Resource Consumption?

This work explores the historical effectiveness of efficiency improvements in reducing humankind's consumption of energy resources. Ten activities are analyzed, including pig iron production, aluminum production, nitrogen fertilizer production, electricity generation from coal, electricity generation from oil, electricity generation from natural gas, freight rail travel, passenger air travel, motor vehicle travel, and residential refrigeration. The data and analyses presented here demonstrate the dynamic interplay between technological innovation, market forces, and government policy. They also show that, historically, over long time periods, incremental improvements in efficiency have not succeeded in outpacing increases in the quantity of goods and services provided. Thus, the end result over these time periods has been, not surprisingly, a sizeable increase in the consumption of energy resources across all ten activities. However, there do exist a few examples of shorter, decade‐long time periods in which improvements in efficiency were able to match or outpace increases in quantity. In these cases, efficiency mandates, price pressures, and industry upheaval led to periods of reduced resource consumption. These cases suggest that with appropriate incentives, including, for example, efficiency mandates and price mechanisms, future resource consumption, and its associated environmental impacts, could be stabilized and even reduced.     

User−Producer Interaction in Housing Energy Innovations

Von Hippel and colleagues have highlighted the crucial role of users in innovation in different industries and types of products. They describe the innovation process in terms of the distinct domains of knowledge that producers and users possess. Producers have knowledge about technical solutions and users about their needs, the context of use, and their own capabilities as users. Both sets of knowledge are characterized by stickiness: They move relatively freely within their own domain but are difficult to transfer outside of it.
In the case of radical innovations for sustainable consumption, the problem of sticky information is compounded. Both producers and consumers need to reach out of their conventional competencies and search for new solutions. Societal actors, such as government bodies or environmental experts, can show the way to such solutions, but this new knowledge needs to be integrated with the sticky knowledge about everyday practices in production and consumption.
In the present article we attempt to conceptualize the role and interaction of user and producer knowledge with the knowledge of environmental experts in housing energy innovations. We do so by applying the user−producer interaction framework to a case study on the introduction of low-energy housing concepts in Finland. On the basis of this analysis, we draw conclusions on the potential and limitations of today's practices in the field. For example, we suggest that user involvement can help to enhance the acceptance of low-energy solutions but that the methods for involving users need to be adapted to the particular circumstances in each industry.     

以材料“创造”土地？——中国城市化进程的一个重要特征

中国快速城市化进程的一个重要特征是以土地为载体,通过大量投入钢铁、水泥等建材大规模修建城市建筑和基础设施,创造出大量的城市生产和生活空间。利用1985—2010年中国省级行政单元城市建成区总面积、城市居住用地总面积、城市住宅总面积和城市住宅建筑材料总使用量等数据,识别城市扩张模式,揭示中国城市化进程中土地、建筑面积及其构筑材料三者间的关系。研究表明2000年是中国城市扩张的重要分界点,2000年之前中国各省份的城市建成区总面积、城市住宅总面积和城市住宅建筑材料总使用量均较小且省份间差异不大,2000年之后三者迅速增长且省份间差异逐渐扩大。在地区尺度上,三者均呈现东部地区最高、中部次之、西部最低的特点,地区内部差异则表现为东部地区最大、西部次之、中部最小的特征。大多数省份的城市住宅总面积及其构筑材料总量随着城市建成区的扩张而增长,表明城市在发展初期以扩大建成区和水平扩张为主。随着城市化水平的不断提高,城市内部空间重组和用地置换导致高层建筑逐步替代了原有的单层或低矮建筑,城市扩张的方向由依赖土地的水平扩张转向以大量使用建筑材料为基础的垂直扩张,使得许多省份的城市住宅总面积逐渐超过辖区内居住用地总面积。这种以建筑材料\"创造\"出更多\"土地\"的城市垂直扩张在满足人们对城市生产和生活空间需求的同时,有利于节约土地资源和保护生态空间,但需要以消耗更多的建筑材料并承担建筑材料在开采、制造、运输、使用和废弃过程中所造成的环境影响为代价。