The search for the most eco-efficient strategies for sustainable housing construction; Dutch lessons

Although sustainability plays anincreasingly important role in common buildingpractice, there is very little known about theenvironmental benefits of sustainable housingconstruction. This paper presents a frameworkfor the search for the most eco-efficientstrategies for sustainable housing constructionand discusses the environmental benefits ofDutch sustainable housing construction. Twoquestions are answered: which goals regardingthe environmental benefits of Dutch sustainablehousing construction are currently feasible andwhat are the most eco-efficient strategies tofurther improve the environmental performanceof housing? Environmental benefits arecalculated by means of sets of measurescomposed by confronting priorities forreduction of the environmental impacts ofhouses with seven strategies for sustainablehousing construction. For the calculationsEco-Quantum is used. A traditionally builtterraced house is used as a reference point. Itturns out that goals such as `Factor 4' or`Factor 20' are still far from being achievedand that the prolongation of life spans andimprovement of reusability are the mosteco-efficient strategies. However, otherstrategies also need to be applied, becausethese two strategies carry large uncertainties.Sustainable housing construction may not beenough in itself to meet very high targets.Reflection on our way of living is alsorequired.     

Energy efficiency and low-carbon technologies in urban renewal

Buildings belong to the most cost-effective sectors where carbon dioxide (CO₂) reductions can be achieved, and urban regeneration offers a good intervention point for switching to sustainable fuel sources, as changes in energy infrastructure can be coupled with other construction, thus decreasing the cost. However, the potential energy savings that are feasible do not match the more ambitious policy targets. Based on case studies in the Netherlands, obstacles are identified in the context of urban renewal that need to be overcome if energy efficiency measures are to be implemented and space heating replaced with low-carbon technologies. The current free-market public policy instruments have not managed to address the obstacles identified in the case studies due to poor market signals, costs and payback periods, risks, and a lack of leadership on environmental targets and policies on sustainable urban renewal. The potential for stronger government intervention is examined for the effectiveness in reducing both energy consumption and CO₂ generation. Legislation could produce a certain policy outcome in terms of CO₂ reduction in urban renewal in the Netherlands if compliance and legitimacy are ensured, but policy consideration is also required to account for the dilemma of low-income households and the rebound effects associated with occupant behaviours.

Les bâtiments appartiennent à l'un des secteurs les plus rentables où il est possible de réaliser des réductions de CO₂ et où la rénovation urbaine permet de passer à des sources de combustibles durables, les modifications apportées aux infrastructures énergétiques pouvant être couplées avec d'autres constructions, ce qui en diminue le coût. Toutefois, les économies qu'il est possible de réaliser au niveau de l'énergie ne correspondent pas aux objectifs politiques plus ambitieux. Des études de cas menées aux Pays-Bas ont permis d'identifier, dans le contexte du renouveau urbain, des obstacles qu'il faut surmonter si l'on veut mettre en ?uvre des mesures d'efficacité énergétique et si l'on veut remplacer le mode actuel de chauffage des locaux par des technologies à faible dégagement de CO₂. Jusqu'à présent, les instruments de la politique publique libérale n'ont pas permis de renverser ces obstacles pour les raisons suivantes: faibles signaux du marché, coûts et périodes de récupération, risques et manque de leadership en matière d'objectifs environnementaux et de politique concernant la rénovation urbaine durable. Cet article examine les possibilités d'un interventionnisme plus fort de la part des autorités pour améliorer la réduction à la fois de la consommation d'énergie et de la production de CO₂. La législation pourrait produire quelques résultats en termes de réduction du CO₂ dans la rénovation urbaine aux Pays-Bas si l'on garantit la compatibilité et la légitimité; mais il faut également prendre en considération les questions de politique et tenir compte de l'impasse que constituent les foyers à faibles revenus et les effets de rebond associés au comportement des occupants.

Mots clés: patrimoine immobilier, réduction de CO₂, efficacité énergétique, logements, politique publique, rénovation, rénovation urbaine, Pays-Bas     

Dynamic-MFA examination of Chilean housing stock: long-term changes and earthquake damage

The dynamics and metabolism of the built environment are important for understanding the construction, renovation and demolition activities that characterize its long-term physical development. Previous research on building stock development is limited, particularly for developing countries. As one of the most seismically active countries in the world, Chile's built environment is constantly subjected to losses. This study included earthquake vulnerability and damage in a dynamic material flow analysis (MFA) of the Chilean housing stock. Stock and flows of residential floor area were modelled using population and life style parameters. Demolition was modelled assuming a constant demolition rate. By characterizing the building stock according to vulnerability classes and establishing a mass balance per class, the effects of different typology distributions on the overall damage to the stock caused by earthquakes could be assessed. Scenarios with different trends in typology distribution for new construction and renovation suggest that significant potential exists for reducing future earthquake damage in the Chilean housing stock. This is best achieved by gradually reducing the vulnerability of buildings to earthquakes. Legislation, building standards and financial instruments could be used to ensure such reductions in earthquake damage and thereby provide socio-economic benefits in the future.     

Resilient housing: a new resource-oriented approach

The institutional regimes framework has previously been applied to the institutional conditions that support or hinder the sustainability of housing stocks. This resource-based approach identifies the actors across different sectors that have an interest in housing, how they use housing, the mechanisms affecting their use (public policy, use rights, contracts, etc.) and the effects of their uses on the sustainability of housing within the context of the built environment. The potential of the institutional regimes framework is explored for its suitability to the many considerations of housing resilience. By identifying all the goods and services offered by the resource ‘housing stock’, researchers and decision-makers could improve the resilience of housing by better accounting for the ecosystem services used by housing, decreasing the vulnerability of housing to disturbances, and maximizing recovery and reorganization following a disturbance. The institutional regimes framework is found to be a promising tool for addressing housing resilience. Further questions are raised for translating this conceptual framework into a practical application underpinned with empirical data.     

Towards modelling of construction,renovation and demolition activities: Norway's dwelling stock, 1900–2100

The activities of construction, renovation and demolition related to the dwelling (housing) stock have a strong impact on both material and energy demands. A deeper understanding of the dynamics driving these activities is a precondition for a more consistent way to address material and energy demands. The method presented herein is based on a dynamic material flow analysis and is applied to the Norwegian dwelling stock. Input data to the model are population and socio-economic lifestyle indicators such as the average number of persons per dwelling and the average size of dwellings; these determine the size of the floor area stock. Parameters such as the lifetime of dwellings and renovation intervals complete the input set. Outputs of the model are the stock and flows of floor area for the period 1900–2100. Analysis of the renovation activity is given particular attention. Several scenarios are considered in order to test the model's sensitivity to input's uncertainties. Results are compared with statistical data, where the latter are available. The main conclusion is that in the coming decades renovation is likely to overtake construction as the major activity in the Norwegian residential sector.

Les activités de construction, de rénovation et démolition relatives au parc de logements ont un fort impact sur la demande de matériaux et d'énergie. Une meilleure compréhension de la dynamique qui anime ces activités est une condition préalable à une méthode plus cohérente de traitement des demandes de matériaux et d'énergie. La méthode présentée ici repose sur une analyse dynamique des flux de matériaux telle qu'elle est appliquée au parc de logements en Norvège. Les données fournies au modèle sont des indicateurs du mode de vie de la population et des indicateurs socio-économiques comme le nombre moyen de personnes par logement et la taille moyenne des logements; ces indicateurs déterminent la superficie des logements. Des paramètres comme la durée de vie des logements et les intervalles de rénovation complètent les données d'entrée. Les résultats du modèle sont le parc de logements et sa superficie pour la période 1900–2100. L'analyse de l'activité de rénovation reçoit une attention particulière. Plusieurs scénarios sont envisagés afin de mettre à l'épreuve la sensibilité du modèle par rapport aux incertitudes des entrées. Les résultats sont comparés aux données statistiques lorsque ces dernières sont disponibles. La conclusion principale réside dans le fait que dans les prochaines décennies, le secteur de rénovation risque de dépasser celui de la construction en tant qu'activité majeure du secteur résidentiel norvégien.

Mots clés: parc de bâtiments, construction, démographie, démolition, prévisions, logement, analyse des flux de matériaux, rénovation, parc résidentiel, Norvège     

The link between operational efficiency and environmental impacts: A joint application of Life Cycle Assessment and Data Envelopment Analysis

Life Cycle Assessment (LCA) allows the estimation of the environmental impacts of a process or product. Those environmental impacts depend on the efficiency with which operations are carried out. In the case that LCA data are available for multiple similar installations, their respective operational performances can be benchmarked and links between operational efficiency and environmental impacts can be established. In this paper, this possibility is illustrated with a case study on LCA of mussel cultivation in rafts. For each site (raft) both its inputs consumption and mussel production are known. A separate LCA of each site has been performed and its corresponding environmental impacts have been estimated. Using Data Envelopment Analysis (DEA) on the input/output data allows computing the relative efficiency of each mussel raft and setting appropriate efficiency targets. The DEA targets represent virtual cultivation sites, which consume less input and/or produce more output. The performance of an LCA study for each of these virtual cultivation sites and the comparison between their environmental impacts are used to estimate the environmental impacts consequences of operational inefficiencies. This direct link can help to convince the managers and operators of the cultivation sites of the double dividend of reducing inputs consumption and achieve operational efficiency: lower costs and lower environmental impacts.     

生活垃圾焚烧炉渣制备免烧墙体砖对环境负荷的影响

运用生命周期评价法,以试验和生产数据为基础,参考有关统计数据及资料,对利用生活垃圾焚烧炉渣制备免烧墙体砖、灰砂砖及烧结砖进行比较分析,探讨功能单位墙体砖制备过程及与其相关的原料开采、原油生产、电力生产和煤炭生产过程对环境负荷的影响.结果表明,功能单位焚烧炉渣免烧墙体砖、灰砂砖和烧结砖的环境负荷分别为3.51x10-12/a.3.58x10-12/a和6.60x10-12/a;生活垃圾焚烧炉渣免烧墙体砖与烧结砖相比,可减少不可再生资源消耗54%,与灰砂砖和烧结砖相比,可分别减少不可再生能源消耗43%和62%.     

Comparison of environmental impacts of building structures with in situ cast floors and with precast concrete floors

In this paper, the environmental impacts of two types of slab systems are studied. The first type, a concrete-based one-way spanning slab, is the most common solution in residential buildings in Spain. The second type, a hollow core slab floor, is increasingly becoming more used in buildings, but is not being broadly used in residential buildings as yet. The study is undertaken through the Life Cycle Analysis methodology, applying the EPS 2000 method. The assessment shows that the environmental impact of a building structure with precast concrete floors is 12.2% lower than that with in situ cast floors for the defined functional unit.     

Environmental assessment of anaerobically digested sludge reuse in agriculture: Potential impacts of emerging micropollutants

Agricultural application of sewage sludge has been emotionally discussed in the last decades, because the latter contains organic micropollutants with unknown fate and risk potential. In this work, the reuse of anaerobically digested sludge in agriculture is evaluated from an environmental point of view by using Life Cycle Assessment methodology. More specifically, the potential impacts of emerging micropollutants, such as pharmaceuticals and personal care products, present in the sludge have been quantified. Four scenarios were considered according to the temperature of the anaerobic digestion (mesophilic or thermophilic) and the sludge retention time (20 or 10 d), and they have been compared with the non-treated sludge.From an environmental point of view, the disposal of undigested sludge is not the most suitable alternative, except for global warming due to the dominance (65-85%) of the indirect emissions associated to the electricity use. Nutrient-related direct emissions dominate the eutrophication category impact in all the scenarios (>71.4%), although a beneficial impact related to the avoidance of industrial fertilisers production is also quantified (up to 6.7%). In terms of human and terrestrial toxicity, the direct emissions of heavy metals to soil dominate these two impact categories (>70%), and the contribution of other micropollutants is minimal. Moreover, only six (Galaxolide, Tonalide, Diazepam, Ibuprofen, Sulfamethoxazole and 17α-ethinyloestradiol) out of the 13 substances considered are really significant since they account for more than 95% of the overall micropollutants impact.     

公路建设应与环境保护协调发展

针对我国公路存在的问题,阐明了修建公路的重要性,分析了公路建设对环境的影响,提出公路建设环境保护的一般原则,对公路景观设计方法进行了探讨,强调公路建设与环境保护应和谐发展。     

城乡规划指导下的新农村村庄整治与建设

以铜陵市五洲村建设为例,结合目前村庄建设现状,以环境整治为切入点,对村庄规划与整治建设进行了论述,以期使农村在城乡规划的指导下有序建设。     

A generic model of Exergy Assessment for the Environmental Impact of Building Lifecycle

A generic model of Exergy Assessment is proposed for the Environmental Impact of the Building Lifecycle, with a special focus on the natural environment. Three environmental impacts: energy consumption, resource consumption and pollutant discharge have been analyzed with reference to energy-embodied exergy, resource chemical exergy and abatement exergy, respectively. The generic model of Exergy Assessment of the Environmental Impact of the Building Lifecycle thus formulated contains two sub-models, one from the aspect of building energy utilization and the other from building materials use. Combined with theories by ecologists such as Odum, the paper evaluates a building's environmental sustainability through its exergy footprint and environmental impacts. A case study from Chongqing, China illustrates the application of this method. From the case study, it was found that energy consumption constitutes 70-80% of the total environmental impact during a 50-year building lifecycle, in which the operation phase accounts for 80% of the total environmental impact, the building material production phase 15% and 5% for the other phases.