Illustrating limitations of energy studies of buildings with LCA and actor analysis

Does passive housing really have better environmental performance than conventional housing? Three passive houses and four conventional houses were compared using a life cycle assessment (LCA) methodology. The comparison also provided an actor analysis for the building supply chain and building inhabitants. Results are presented for two scenarios: 'conventional choices' and 'green choices' by the actors. The comparison confirms that passive houses have lower energy use than conventional houses, but when the environmental impact of energy production is taken into consideration, the outcome is less clear. Conventional houses can be equally good environmentally in terms of global warming, acidification, or radioactive waste as typical passive houses with electrical heating depending on the actors' choices. Actor analysis shows that inhabitants' and material producers' electricity choice are very important, while other choices (e.g. green transport) are less important. The findings highlight the importance of environmentally responsible decisions throughout the whole life cycle and the need for appropriate behaviours and actions, along with implications for improved communication. Les logements passifs ont-ils un rendement environnemental vraiment meilleur que les logements classiques ? Trois maisons passives et quatre maisons classiques ont ete comparees en utilisant une methodologie faisant appel a l'analyse du cycle de vie (ACV). Cette comparaison a egalement fourni une analyse des acteurs concernant la chaine logistique dans le batiment et les habitants des immeubles. Les resultats sont presentes pour deux scenarios, les acteurs operant dans l'un des << choix classiques >> et dans l'autre des << choix verts >>. La comparaison confirme que les maisons passives ont une consommation energetique moindre que les maisons classiques, mais lorsque l'impact environnemental de la production d'energie est pris en compte, le resultat est moins clair. Selon les choix operes par les acteurs, les maisons classiques peuvent etre aussi bonnes en termes de rechauffement climatique, d'acidification ou de dechets radioactifs que les maisons passives types equipees de chauffage electrique. L'analyse des acteurs montre que les choix faits en matiere d'electricite par les habitants et les fabricants de materiaux ont beaucoup d'importance, tandis que les autres choix (par ex. transport vert) sont moins importants. Ces constatations mettent en evidence l'importance de la prise de decisions environnementalement responsables tout au long du cycle de vie, la necessite de comportements et de mesures adaptes, ainsi que les implications qui en decoulent en termes d'amelioration de la communication. Mots cles: analyse des acteurs, evaluation environnementale, logement, comportement des habitants, analyse du cycle de vie (ACV), batiment bas carbone, maison passive

A framework for integrating sustainability estimation with concepts of rules of building measurement

BIM promises improvement in project delivery efficiencies such as reduction in costs and errors and timely completion. Benefits are also expected in sustainable construction aspect with research efforts being extended to sustainable design and assessment. These efforts are still been explored for the purposes of unifying quantification methodologies, the standardisation of system boundaries, terms of references and sustainability measures. Embodied energy and CO2 are two common measures that have been widely used in the construction sector. Although a number calculation system exists, they are not useful to the iterations that occur at the early stages of the project life cycle. At the procurement stage, professionals often rely on schedules and bill of quantities with no reference to sustainability credentials. It is therefore important to integrate sustainability measure with concepts in standard measurement methods. As such, we propose a framework to integrate sustainability credential with the concepts in rule of building measurement. We conclude that this framework can be applicable to any rule of building measurement and it is implementable in a computer programmable environment

Urban Form Energy Use and Emissions in China: Preliminary Findings and Model Proof of Concept

Urbanization is reshaping China's economy, society, and energy system. Between 1990 and 2008 China added more than 300 million new urban residents, bringing the total urbanization rate to 46%. The ongoing population shift is spurring energy demand for new construction, as well as additional residential use with the replacement of rural biomass by urban commercial energy services. This project developed a modeling tool to quantify the full energy consequences of a particular form of urban residential development in order to identify energy- and carbon-efficient modes of neighborhood-level development and help mitigate resource and environmental implications of swelling cities. LBNL developed an integrated modeling tool that combines process-based lifecycle assessment with agent-based building operational energy use, personal transport, and consumption modeling. The lifecycle assessment approach was used to quantify energy and carbon emissions embodied in building materials production, construction, maintenance, and demolition. To provide more comprehensive analysis, LBNL developed an agent-based model as described below. The model was applied to LuJing, a residential development in Jinan, Shandong Province, to provide a case study and model proof of concept. This study produced results data that are unique by virtue of their scale, scope and type. Whereas most existing literature focuses on building-, city-, or national-level analysis, this study covers multi-building neighborhood-scale development. Likewise, while most existing studies focus exclusively on building operational energy use, this study also includes embodied energy related to personal consumption and buildings. Within the boundaries of this analysis, food is the single largest category of the building energy footprint, accounting for 23% of the total. On a policy level, the LCA approach can be useful for quantifying the energy and environmental benefits of longer average building lifespans. In addition to prospective analysis for standards and certification, urban form modeling can also be useful in calculating or verifying ex post facto, bottom-up carbon emissions inventories. Emissions inventories provide a benchmark for evaluating future outcomes and scenarios as well as an empirical basis for valuing low-carbon technologies. By highlighting the embodied energy and emissions of building materials, the LCA approach can also be used to identify the most intensive aspects of industrial production and the supply chain. The agent based modeling aspect of the model can be useful for understanding how policy incentives can impact individual behavior and the aggregate effects thereof. The most useful elaboration of the urban form assessment model would be to further generalize it for comparative analysis. Scenario analysis could be used for benchmarking and identification of policy priorities. If the model is to be used for inventories, it is important to disaggregate the energy use data for more accurate emissions modeling. Depending on the policy integration of the model, it may be useful to incorporate occupancy data for per-capita results. On the question of density and efficiency, it may also be useful to integrate a more explicit spatial scaling mechanism for modeling neighborhood and city-level energy use and emissions, i.e. to account for scaling effects in public infrastructure and transportation

Energy saving policies and low energy residential buildings: a LCA case study to support decision-makers in Piedmont (Italy)

Background, aim and scope A low-energy family house recently built in Northern Italy was selected by Regione Piemonte as an outstanding example of resource efficient building. An economic incentive was awarded to cover the extra costs of the thermal insulation, windows and equipment in order to decrease the yearly winter heat requirement from the legal standard of 109 to 10 kW h/m2, while existing buildings in the study area typically require 200 kW h/m2. As the building was claimed to be sustainable on the basis of its outstanding energy-saving performance, an ex post life cycle assessment (LCA) was set up to understand whether, and to what extent, the positive judgement could be confirmed in a life cycle perspective. Materials and methods After an analysis of the literature on LCA of whole buildings, a detailed life cycle assessment has been conducted by encompassing all the life cycle phases. Emphasis was given on the end-of-life stage, too often disregarded due to lack of data or heavily simplified. Virtually all the materials used in the building structure, finishes and equipment were considered, paying attention to their expected service duration and the recycling potential. In order to increase transparency and therefore credibility and acceptance of LCA in the building sector, an uncertainty analysis was carried out. Results and discussion The dramatic contribution of material-related impacts emerged. Structure and finishes materials represented the highest relative contribution, but maintenance operations also played a major role. The contributions of equipment, construction stage and transportation were minor. The important role of the recycling potential also emerged. Unlike standard buildings, where heating-related impacts overshadow the rest of the life cycle, there is no single dominating item or aspect. Rather, several of them play equally important roles. Conclusions The study confirmed that the initial goal of resource and environmental efficiency was reached, but to a much lower extent than previously thought. In comparison to a standard house, while the winter heat requirement was reduced from 109 to 10 kW h/m2 (10:1 ratio), the life cycle energy was only reduced by 2.1:1 and the carbon footprint by 2.2:1. Recommendations and perspectives The findings emphasise the need for incorporating the life cycle approach in energy-saving policies and economic incentives schemes in the building sector, in Italy and elsewhere, as single-step improvements might not be effective in a life cycle perspective and could even disappoint expectation