Article
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Substitution between energy and CO2 intensive materials is a potentially important climate mitigation strategy. We compare buildings with concrete frames and wooden frames concerning their life-time carbon dioxide emissions as well as their total material, energy and carbon dioxide costs. By using consistent energy systems scenarios meeting stringent targets for atmospheric CO2 concentrations we investigate the impact of higher energy and carbon dioxide prices as well as of the availability of carbon capture and storage (CCS) technologies. We find that wooden frames cause lower carbon dioxide emissions given the prevailing energy system, but concrete frames obtain about the same emissions as the wood frame in a system where CCS is not used for wood incineration in the demolishing phase. The net present costs for the different buildings are also affected by the future energy supply system, even though the impact is small, especially compared to the total construction cost. We conclude that it is unclear whether wood framed buildings will be a cost-effective carbon mitigation option and that further analyses of costs should be performed before prescriptive materials policies are enforced in the buildings sector.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Most building-related analyses have used process-based LCA (Börjesson and Gustavsson, 2000;Cole and Kernan, 1996;John et al., 2008;Jonsson et al., 1998;Nässén et al., 2012;Bolin and Smith, 2011;Johnson, 2006;Kahhat et al., 2009;Upton et al., 2008;Diyamandoglu and Fortuna, 2015), as shown in Table 1. However, a few authors have recommended the hybrid approach since the process-based method could underestimate the environmental impacts from the extraction and manufacturing phases ( 2001; Lenzen and Treloar, 2002). ...
... Many authors have compared the environmental impacts caused by different external wall systems and materials (e.g. Cole and Kernan, 1996;John et al., 2008;Jonsson et al., 1998;Börjesson and Gustavsson, 2000;Nässén et al., 2012;Sandin et al., 2014;Lenzen and Treloar, 2002;Johnson, 2006;Upton et al., 2008;Kahhat et al., 2009;Bolin and Smith, 2011). Table 1 contains key facets of these studies. ...
... Besides, the construction phase was found to be accountable for less than 8% of total LCA impacts ( Kellenberger and Althaus, 2009). Other authors excluded the construction phase from the system boundaries in comparative LCA because the impacts were assumed to be independent of building frame materials (e.g., Nässén et al., 2012;Sandin et al., 2014). ...
Article
The construction industry consumes 40% of the global materials and produces one of the largest waste streams in the planet. In a circular economy, the reuse of building components in multiple life cycles aims at increasing resource efficiency and eliminating waste. But can reuse offset the environmental impacts of materials with high embodied energy (e.g. steel)? If so, in what conditions? In the study presented in this paper, the authors used two different life cycle assessment (LCA) methods to compare a single-use wood-framed wall against a reusable steel-framed wall in a tiny house in the U.S. The analyzed impact categories were global warming potential, embodied energy, and water use. One of the main goals of this study was to understand the benefits of reusing a material with high embodied energy when compared to a single-use alternative. Another equally important objective was to understand how different LCA methods can influence the results in a cradle-to-cradle (C2C) LCA. As results, reuse benefits depended on aggressive reuse rates (>70%) and multiple reuses of steel were needed to offset the embodied environmental impacts during steel production. Also, the analyses showed that process-based LCA and hybrid LCA can generate conflicting results in a C2C LCA.
... Because of that, it is also the building's component that can benefit the most from deconstruction and reuse. Many authors compared the environmental impacts caused by different external walls' systems and materials (e.g., Bolin & Smith, 2011;Börjesson & Gustavsson, 2000;Cole & Kernan, 1996;Diyamandoglu & Fortuna, 2015;John et al., 2008;Johnson, 2006;Jonsson et al., 1998;Kahhat et al., 2009;Lenzen & Treloar, 2002;Nässén et al., 2012;Sandin et al., 2014;Upton et al., 2008). Yet only a couple of these studies have considered the effects of reuse in the results (Börjesson & Gustavsson, 2000;Diyamandoglu & Fortuna, 2015). ...
... Most authors used the process-based LCA for other studies related to building materials (Börjesson & Gustavsson, 2000;Cole & Kernan, 1996;John et al., 2008;Jonsson et al., 1998;Nässén et al., 2012;Bolin & Smith, 2011;Johnson, 2006;Kahhat et al., 2009;Upton et al., 2008;Diyamandoglu & Fortuna, 2015). However, some authors recommended applying the hybrid approach to building-related LCAs, since the process-based method may underestimate the environmental impacts of the pre-use phases (Ochoa et al., 2002;Guggemos & Horvath, 2005;Nassen et al., 2007;Guan et al., 2016;Norman et al., 2006;Treloar et al., 2001). ...
... Construction and deconstruction of the external walls of a tiny house are manual processes that can be done by the house owner and do not necessarily demand contractors, skilled workers, or equipment. Previous studies also chose to exclude the construction phase from the system boundaries (e.g., Kellenberger & Althaus, 2009;Nässén et al., 2012;Sandin et al., 2014;Johnson, 2006). The use phase was excluded since the thermal resistance is the same for both external walls designs. ...
Thesis
Today, we use resources faster than they can be replaced. Construction consumes more resources than any other industry and has one of the largest waste streams. Resource consumption and waste generation are expected to grow as the global population increases. The circular economy (CE) is based on the concept of a closed-loop cycle (CLC) and proposes a solution that, in theory, can eliminate the environmental impacts caused by construction and demolition (C&D) waste and increase the efficiency of resources' use. In a CLC, building materials are reused, remanufactured, recycled, and reintegrated into other buildings (or into other sectors) without creating any waste. Designing out waste is the core principle of the CE. Design for disassembly or design for deconstruction (DfD) is the practice of planning the future deconstruction of a building and the reuse of its materials. Concepts like DfD, CE, and product-service systems (PSS) can work together to promote CLC in the built environment. PSS are business models based on stewardship instead of ownership. CE combines DfD, PSS, materials' durability, and materials' reuse in multiple life cycles to promote a low-carbon, regenerative economy. CE prioritizes reuse over recycling. Dealing with resource scarcity demands us to think beyond the incremental changes from recycling waste; it demands an urgent, systemic, and radical change in the way we design, build, and procure construction materials. This dissertation aims to answer three research questions: 1) How can researchers estimate the environmental benefits of reusing building components, 2) What variables are susceptible to affect the environmental impact assessment of reuse, and 3) What are the barriers and opportunities for DfD and materials' reuse in the current design practice in the United States. The first part of this study investigated how different life cycle assessment (LCA) methods (i.e., hybrid LCA and process-based LCA), assumptions (e.g., reuse rates, transportation ii distances, number of reuses), and LCA timelines can affect the results of a closed-loop LCA. The second part of this study built on interviews with architects in the United States to understand why DfD is not part of the current design practice in the country.
... They came to the conclusion that the timber building had a lower impact overall. Nässén et al. (2012) considered that the case for favouring timber over concrete as a construction material was more ambiguous. The methodology that they chose involved the evaluation of net present costs and carbon balances over the whole life of building structures with different material compositions. ...
... The energy costs for erecting and operating the buildings were not included since they were assumed to be independent of building type. In the study of Dodoo et al. (2009), recycling rates for timber and steel were assumed to be 90%, which was considered optimistic by Nässén et al. (2012) who assumed 80%. Building lifetimes were assumed to be 100 years and two scenarios were considered with construction years of 2010 and 2050. ...
... The associated GHG emissions (CO2 equivalents) of the concrete structure were 49% higher than those attributable to the wooden frame equivalent. Nässén et al. (2012) compared the whole life carbon emissions associated with buildings constructed using concrete or timber frames. The model assumed that the land used for providing timber for the timber framed house was replaced with new long-rotation forest for the future production of wood materials. ...
Technical Report
Full-text available
The Norwegian Government has set ambitious goals for the fossil carbon intensiveness of the Norwegian economy. The built environment can make an important contribution towards achievingthose goals by:  Building energy efficient buildings;  Using low embodied energy materials;  Using construction materials as stores of atmospheric carbon dioxide. An analysis of life cycle assessment (LCA) studies published in the scientific literature has been undertaken. The use of timber in construction has an important role to play as part of an energy reduction and carbon storage strategy for the built environment. In the majority of studies analysed there is agreement that there are environmental advantages associated with the use of timber in construction from a climate change mitigation perspective. At the time of writing this report there is no LCA-based tool that is sophisticated enough to be used at the whole building level to assist in decision-making processes for materials to minimise environmental impacts. This can only be determined on a case-by-case basis. However, LCA can be used to inform policy decisions regarding the use of materials to minimise the climate change impacts of the built environment in Norway, if the GWP (global warming potential) impact category is used in combination with the embodied energy data. But the methodology does have inherent uncertainties. The original terms of reference for the report, were as follows:  General considerations on the different methods of environmental impact analysis and evaluations (LCA, EPD, HWP, BREEAM….) and what the differences are between these systems;  Conduct an analysis on wood LCAs that have been done in Norway and comparable countries, anda compilation of these data. Which factors influence the analysis and how much do single factors affect the result?  Conduct a similar analysis on competing materials like concrete and steel;  Conduct an analysis comparing the environmental impacts of wood and other materials. What is actually being compared and what does it imply for the real climate footprint?  Summarise the results, evaluation of their importance and the use such findings can have for political decisions in the future. The report begins with a description of the Norwegian built environment and forest products’ sectors and then gives an overview of the methodologies used in LCA and the strengths and weaknesses of the technique. LCA is a complex subject and there is still debate about the methodologies and impact categories. LCA does not have the level of accuracy needed in many impact categories in order to make comparative assessments and only the impact categories global warming potential and ozone layer depletion potential are considered to be sufficiently robust to give accurate and reliable data. A review of building assessment schemes has also been undertaken. LCA comprises only a minor part of building assessment schemes, such as the Building Research Establishment Environmental Assessment Method (BREEAM) and Leadership in Energy and Environmental Design (LEED) and these have little to say about the choice of materials for construction. These schemes have some value in promoting more environmentally-conscious designs, but they are not sufficiently robust to be used as tools to inform policy-making, or building material choices. The report focuses on issues surrounding carbon sequestration in forests and how atmospheric carbon can be stored in long-life products in the built environment. One of the advantages of using timber in construction is the potential for the storage of biogenic carbon (derived from atmospheric carbon dioxide) in long-life structures. Although this does have a role to play in climate change mitigation, this literature review has revealed that most studies show that the effects of substitution for high embodied energy materials and for fossil fuels for energy production are much more significant. The overwhelming majority of LCAs of timber products have shown that the amount of atmospheric carbon stored in the wood (measured as CO2 equivalents) is always larger than the GHG (greenhouse gas) emissions associated with the processing of the material. Additional benefits arise when the wood is incinerated at the end of the life cycle, with substitution of fossil fuels. The highest fossil fuel substitution benefits arise when coal is replaced with timber wastes/by-products. In a Norwegian context, the highest benefits will arise if wood is used as a fuel for cement kilns, or as a carbon-source for aluminium anodes, followed by a replacement of oil for heating then natural gas for heating or electricity production. This report also reviews the scientific literature of published LCA studies of commonly-used building materials (timber, cement/concrete, aluminium, steel, poly(vinyl chloride)). It is shown that the outcomes of the LCAs are very heavily dependent upon the assumptions made and the system boundaries used. It is not possible to arrive at definitive a value of (for example, global warming potential, GWP) that is characteristic for a material, but there is a range of values. The methodology used to determine the environmental impacts is complex and many studies are not readily amenable to comparative studies. This is because of differences in functional unit, supporting databases, assumptions regarding material life, maintenance, end-of-life scenarios, etc. In addition, most studies lack sufficient transparency to allow for proper verification of the results obtained. LCAs also inevitably contain simplifications, which may affect the accuracy of the data. Most studies do not employ a sensitivity analysis to show how the assumptions and variabilities affect the results. It is necessary to consider the whole life cycle when making materials choices and the only way to do this is at the whole building level. However, this increases the degree of uncertainty in the calculations and involves assumptions and the introduction of scenarios which may not be realistic or reasonable. A variety of factors can affect the LCA of building materials over their lifetime, which can be divided into uncertainties and variabilities. Uncertainties arise from lack of precise knowledge regarding processes or the use of assumptions. Variabilities can arise due to different choices regarding the use of materials, such as frequency and type of maintenance, different disposal methods, transport distances, etc. Combinations of uncertainty and variability can be difficult to separate. There is considerable scope for uncertainty to affect the data, especially when the in-service and end-of-life stages of the life cycle are included. Consequently, there is considerable variability in the methodology applied for LCAs, which has a significant influence on the output and hence the task of making comparative assertions is extremely difficult. However, there has been some degree of consensus reached with the introduction of environmental product declarations (EPDs) and standardisation of procedures; known as product category rules (PCRs). Nonetheless, there is still concern that inter-product comparisons are not reliable, due to uncertainties and variations in the assumptions made, the use of different databases, etc. The main advantage with EPDs which are produced in conformity with the European standard EN 15804, is that the impacts have to be reported separately for different life cycle stages. Of these, the cradle to factory gate life cycle stage (modules A1-A3) is likely to be the most reliable, since this part of the life cycle involves the least assumptions and the most accurate data. This study has largely focussed on data concerned with the embodied energy associated with materials and the global warming potential (GWP) environmental impact category, because these have the lowest uncertainties. GWP data is strongly influenced by the time-frames of the study and by a range of different factors that have to be taken into account when making comparative studies:  Greenhouse gas (GHG) emissions associated with the manufacture of construction materials, maintenance, replacement and disposal;  GHG emissions associated with operational energy requirements, if these are relevant and realistic and have not been introduced to favour one material over another;  Carbon emissions and storage from forestry operations and sequestration by growing biomass;  Substitution effects associated with the use of timber in comparison to other building materials;  End-of-life scenarios, such as recycling, or incineration with energy recovery. The embodied energy used to produce construction materials is an important consideration when analysing the environmental impacts. This initial embodied energy is to be distinguished from the recurring embodied energy which arises due to maintenance of the materials and the operating energy, which is energy consumed due to the operational requirements (e.g., heating) of the building. As the operating efficiency of buildings improves, the embodied energy will be a larger proportion of the overall energy requirements. The embodied energy also represents a greater proportion of the overall energy consumption of the sector in a growing market. Sawn timber products are lower embodied energy materials when compared, on a functional unit basis, with non-renewable construction products. The increased use of timber in construction will result in more carbon storage in the harvested wood products carbon pool at a critical time. This can form part of a wider strategy to move to a low fossil carbon economy. Although timber is the dominant material used in single-family dwellings, it is little used in multipleoccupancy buildings. The Norwegian forests are currently absorbing levels of carbon dioxide which are equivalent to about 40% of the annual emissions, but this will fall as the age structure of the forests matures. In order to maintain these high levels of sequestration it is necessary to increase the harvesting intensity of Norwegian forests. The carbon in the HWPs produced should be stored in long life products in the built environment for the maximum climate change mitigation effect. The use of timber in high-rise non-residential and multiple-occupancy residential construction would give benefits from a climate change mitigation perspective. The Norwegian forest products sector should use the opportunity provided by the increased use of timber in multi-occupancy and multi-storey buildings to develop an export industry in pre-fabricated structures. Adding value to the forest products sector is essential. By encouraging a cross laminated timber industry in Norway, there will be potential for export of multi-occupancy buildings using modular construction methods to exterior markets, such as the UK.
... They provide quantitative data for a better comparison in the way of EC per functional unit of building materials or products [26]. Accordingly, suitable materials with lower EC impacts can be identified by analyzing the LCA information of alternative materials during material selection [22,27,28]. Table 1 summarizes EC reduction options associated with the selection of materials, followed by a brief description of each strategy. ...
... Previous studies have revealed that the use of natural and bio-based materials has a high EC reduction potential, mainly due to their simple and low energy production methods [27,28,30]. Natural products, such as wood, natural wool, bamboo, water-based paints, and hemp and straw-based products, have relatively low EC contents compared to other traditional materials [22]. ...
Article
Full-text available
The choice of materials is crucial in responding to the increasing embodied carbon (EC) impacts of buildings. Building professionals involved in material selection for construction projects have a vital role to play in this regard. This paper aimed to explore the extent to which building professionals in Sri Lanka considered EC as a material selection criterion. A questionnaire survey was conducted among a sample of building professionals in Sri Lanka. The results indicated that the consideration of EC as a material selection criterion remained low among key professionals, such as architects, engineers, and sustainability managers, despite their reasonable influencing powers and knowledge of EC. Those respondents who had considered EC as a selection criterion said they had been primarily driven by green building rating systems and previous experience. Those respondents who had not considered EC during material selection commonly reported that they had been prevented from doing so by the lack of regulations and the lack of alternative low carbon materials. Respondents believed that the involvement of actors, such as the government, professional bodies, environmental organizations, activist groups, and the public, may be significant in promoting the greater consideration of EC during material selection.
... The choice of construction materials affects the building's environmental impact within the whole life cycle [14]. Studies from several countries show that wood materials used in building frames usually release less CO2 than other materials throughout the life cycle [15][16][17]. This is due to the relatively small amount of energy needed to manufacture wood products compared to other materials and the opportunity to replace fossil fuels with wood byproducts during the manufacturing process. ...
... Several methods of specifying the environmental impact exist. Generally, GWP is the main impact category assessed by many authors [2,[14][15][16][17][18][19][20]25,[27][28][29]33,35,36,42,[44][45][46][47][48][49][50]. Other environmental impacts are rarely discussed [16,27,33,35,46]. ...
Article
Full-text available
The aim of the study is to point out the burden of passive wood-based buildings throughout the life cycle from the environmental point of view to better understand the consequences and importance of building design in Slovakia. The analysis was carried out according to the Life Cycle Assessment methodology. The results were calculated by the CML-IA baseline method. The impacts of the product stage and operational energy use were the highest throughout the considered life cycle. Substances contributing to eleven impact categories were identified. Foundations, especially foam glass, were found to bear the majority of the impact of the overall construction materials. The normalization category showed considerable impact on marine aquatic ecotoxicity mainly due to building energy consumption over the course of 50 years. Loads connected to the replacement stage were the third highest. The study also proved high demand on elements of photovoltaics.
... One strategy to decrease the climate impact is to use a material with less climate impact instead of the conventional concrete. Engineered wood products (EWPs) such as cross-laminated timber (CLT) and laminated veneer lumber (LVL) have proven to be a successful alternative (Börjesson and Gustavsson 2000, Nässén et al. 2012, Guo et al. 2017, Lu et al. 2017, Mantanis et al. 2018). The selection of insulation material has also proven important in order to reduce the climate impact (Liljenström et al. 2015) and in this application as well, replacing glass wool, polystyrene, polyurethane, or rock wool by wood-based insulation material has been shown to have the potential to decrease the climate impact (Schiavoni et al. 2016, Hill et al. 2018. ...
... Construction cost (Tykkä et al. 2010) or total life cycle costs (Riala and Illola 2014) tend to be a key determinant for the choice of building material and construction technology. LCC-studies indicate that, when constructing multi-storey residential buildings in the Nordic countries, there are small differences in price between buildings with wooden frames and buildings with concrete frames (Eriksson 1995, Gustafsson 1998, Nässén et al. 2012, Pal et al. 2017. Studies in other countries indicate that construction with timber could be up to three times cheaper (Hossaini et al. 2015, Lu et al. 2017. ...
Article
Full-text available
Many studies have shown that wooden buildings in general have a lower climate impact than buildings built of conventional materials such as concrete and steel. In Sweden, however, only about 10% of the multi-dwelling buildings are built with timber frames. The goal of this empirical study is to provide a broad picture of the views of Swedish actors regarding the use of wood products in multi-storey residential buildings and suggest measures for an increased use. A questionnaire concerning the use of wood products in construction was sent out to Swedish developers, main contractors, and architects and 100 answers were received. The study shows that the views of the groups of actors differ in some respects and factors that may either facilitate or be obstacles to an increased use of wood products were identified and discussed.
... This conclusion is in agreement with several authors about the use of wood construction material in colder regions which will, in general, result in lower energy and CO2 balances from cradle to grave than when concrete is used, although the precise values of the energy and CO2 balances of building materials depend upon many factors (24,25,26,27,28,29,30). However, this conclusion is nuanced by (31), who found that wooden frames cause lower CO2 emissions given the prevailing energy system. ...
... The first conclusion from Table 1 was the relatively high value of the embodied energy with respect to the total life cycle energy and even more with regard to the HVAC energy (13,31). It has to be noted that cooling and ventilation were included in HVAC energy. ...
Article
Full-text available
Se ha estudiado un edificio residencial con estructura de madera laminada en Granada (España) con la metodología de análisis del ciclo de vida, análisis energético del ciclo de vida y análisis de sensibilidad a cambios en la eficiencia energética durante el uso, bases de datos, distancia del transporte y diferentes escenarios para los residuos. Los impactos ambientales de las etapas de producción de materiales y construcción, así como la energía embebida fueron relativamente significantes. El valor del calentamiento global ha sido muy bajo debido al secuestro de CO2 por la madera. El análisis de sensibilidad ha revelado que la mayor reducción se consigue con la mejora de la eficiencia energética, la alta incertidumbre en los impactos de las declaraciones ambientales de producto, el escaso efecto del transporte de larga distancia sobre los impactos totales y la viabilidad de conseguir el objetivo de valorización de la Directiva Marco para el horizonte 2020 (mayor del 70%).
... Several studies have shown that timber-based buildings generally have lower carbon footprint and lower energy consumption during their life cycle (i.e. lower embodied energy) than concrete buildings with comparable heating and cooling requirements [23]. Research on cradle-to-gate environmental performance has also confirmed very low values of carbon footprint and embodied energy for prefabricated TCC wall element [3]. ...
... • Timber part of TCC element represents storage for carbon, which was captured there during tree growth. In order to avoid release of the captured carbon in the atmosphere and consequential increase of carbon footprint it is important to apply available carbon capture and storage (CCS) technologies for timber incineration at the end of its lifetime [23]. ...
Chapter
Full-text available
Timber-concrete composites are interesting engineered wood products usually used for structural elements, which are mainly subjected to bending load; from simple floor systems to long-span bridges. This way, the advantage can be taken of timber tensile strength and concrete compression strength. The chapter begins with an introduction of various types of timber-concrete composite structural elements regarding type of the element, connection type and types of timber and concrete. Next, specific characteristics and advantages of timber-concrete composite structural elements are thoroughly discussed from viewpoints of engineering, architecture, builders and ecology. Furthermore, basic mechanical principles of timber-concrete composite structural elements are presented and some design methods are briefly described. Finally, worldwide inclusion of timber-concrete composite structures in currently applicable standards is discussed.
... These limitations cause uncertainty about the embodied carbon results for the roofing. They also lead to uncertainty about the reliability of comparative assessments of the embodied carbon effects of different design options [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. ...
... This solution uses a dry technique to form composite cross-sections, which is preferred for timber floors of historical or cultural interest [2,4]. Furthermore, it is also recognized in the scientific community that structures constructed from renewable bio-based construction materials such as timber have lower GHG emissions compared to structures made of concrete, steel or bricks [5][6][7][8][9]. Renewable bio-based construction materials have the potential to act as carbon sinks in the renovation of existing buildings [10]. ...
Article
A common occurrence in building renovation is the modification in the usage category that can lead to higher imposed loads, and consequently the need for structural improvements to the existing structure or to a structural element, such as timber floors. Strengthening practices oftentimes affect the originality of the building or a structural element under consideration. However, the preservation of the originality of timber floors having historical, architectural and cultural interest can be of high importance. This article provides insight into the field of timber floor strengthening techniques with regards to the requirements for conservation of the wooden built heritage. Moreover, a new strengthening technique using structural glass as a strengthening element for timber floors is presented, as reinforcing the bottom side of timber floors without compromising the appearance of the floor is an important objective of a successful intervention. In order to evaluate the performance of the newly proposed strengthening technique from a structural and environmental point of view, structural analysis and a life cycle assessment on a timber floor strengthened with cross-laminated timber panels and structural glass strips are performed. The structural analysis shows the possibility to use structural glass and still achieve a significant increase in the load-carrying capacity of the timber floor. Furthermore, the proposed strengthening technique has a lower global warming potential (GWP) and non-renewable cumulative energy demand compared to renovation and replacement with a cross-laminated timber panel, and a lower GWP compared to replacement with a reinforced concrete slab. This study not only represents the first holistic approach to evaluate the structural and environmental performance of the proposed strengthening technique, but it also addresses the aesthetically-aware design and technical limitations in the utilization of glass for the renovation of timber floors and thoroughly presents the possibilities to overcome these limitations.
... The advantages of wood in construction are various [2,3]. Wood is a material characterized by good mechanical strength both in tension and in compression, so it can be used for the manufacturing of elements prone to bending such as beams, compressed like the pillars, stretched like tie rods, without the need to combine it with other materials, unlike for example concrete and masonry. ...
Book
The construction sector alone accounts for 40 percent of resource consumption and environmental pollution. In line with the current considerations on environmental sustainability, particular attention is paid to eco-sustainable building materials such as timber. Timber is able to perform both load-bearing and comfort constructive functions. It is also a natural, renewable and recyclable material. However, its use as an engineering material calls for constant development and research. This book provides insight into the spread of the use of timber in the construction industry, presenting some thoughts on important aspects related to production, design and responsible use.
... In 1996, the IPCC declared that wood products require less energy than other alternative products. This statement has been confirmed by the construction industry in several examples of concrete versus timber buildings [12,55,62,87,96]. Generally, timber is less carbonintensive to transform and manufacture, even if each case should be evaluated considering key parameters such as the end-of-life planning of the structure [61,63]. ...
Thesis
Full-text available
Traditional wood-wood connections, widely used in the past, have been progressively replaced by steel fasteners and bonding processes in modern timber constructions. However, the emergence of digital fabrication and innovative engineered timber products have offered new design possibilities for wood-wood connections. The design-to-production workflow has evolved considerably over the last few decades, such that a large number of connections with various geometries can now be easily produced. These connections have become a cost-competitive alternative for the edgewise connection of thin timber panels. Several challenges remain in order to broaden the use of this specific joining technique into common timber construction practice: (1) prove the applicability at the building scale, (2) propose a standardized construction system, (3) develop a convenient calculation model for practice, and (4) investigate the mechanical behavior of wood-wood connections. The first building implementation of digitally produced through-tenon connections for a folded-plate structure is presented in this work. Specific computational tools for the design and manufacture of more than 300 different plates were efficiently applied in a multi-stakeholder project environment. Cross-laminated timber panels were investigated for the first time, and the potential of such connections was demonstrated for different engineered timber products. Moreover, this work demonstrated the feasibility of this construction system at the building scale. For a more resilient and locally distributed construction process, a standardized system using through-tenon connections and commonly available small panels was developed to reconstitute basic housing components. Based on a case-study with industry partners, the fabrication and assembly processes were validated with prototypes made of oriented strand board. Their structural performance was investigated by means of a numerical model and a comparison with glued and nailed assemblies. The results showed that through-tenon connections are a viable alternative to commonly used mechanical fasteners. So far, the structural analysis of such construction systems has been mainly achieved with complex finite element models, not in line with the simplicity of basic housing elements. A convenient calculation model for practice, which can capture the semi-rigid behavior of the connections and predict the effective bending stiffness, was thus introduced and subjected to large-scale bending tests. The proposed model was in good agreement with the experimental results, highlighting the importance of the connection behavior. The in-plane behavior of through-tenon connections for several timber panel materials was characterized through an experimental campaign to determine the load-carrying capacity and slip modulus required for calculation models. Based on the test results, existing guidelines were evaluated to safely apply these connections in structural elements while a finite element model was developed to approximate their performance. This work constitutes a firm basis for the optimization of design guidelines and the creation of an extensive database on digitally produced wood-wood connections. Finally, this thesis provides a convenient design framework for the newly developed standardized timber construction system and a solid foundation for research into digitally produced wood-wood connections.
... By retaining the atmospheric carbon in a sequestered form for their functional lifetimes, wood products play an important role in the global warming mitigation potential of the forestry sector [3][4][5][6]. Products made out of sustainably sourced wood displace other fossil intensive substitute products, such as concrete and steel [7][8][9][10][11][12][13][14]. Assessing the biogenic carbon stored in the form of biomass in the standing forests and wood products and estimating the resultant net carbon sequestration, on a temporal scale, in both pools combined, is essential to quantify the global warming mitigation potential of the forestry sector. ...
Article
Full-text available
Similar to standing trees in the forests, wood products play an important role in enhancing the global sequestered carbon pool, by retaining the atmospheric carbon in a sequestered form for the duration of the functional life of the wood products. This study uses a temporal radiative forcing analysis along with the functional half-life of different wood products to evaluate the impacts of wood products on global warming, including carbon storage and life cycle greenhouse gas production/extraction emissions. The methodology is applied to Washington State’s aboveground biomass and timber harvest data, and to the State’s comprehensive wood products mix. A moderate harvest rate simulation within Washington Biomass Calculator is used to estimate state harvest level, and statewide wood products manufacturing data is used for developing wood product mix estimates. Using this method, we estimate that the temporal carbon storage leads to a global warming mitigation benefit equivalent to 4.3 million tCO2eq. Even after factoring in the greenhouse gas emissions associated with the harvest operations and wood products manufacturing processes, within the temporal model, the results show a net beneficial impact of approximately 1.7 million tCO2eq, on an annual basis. It can further be noted that Washington State’s annual biomass growth in its private forests exceeds its annual harvest, by a significant margin. This net yearly accumulation of biomass in the State’s private forests leads to additional global warming mitigation benefits equivalent to 7.4 million tCO2eq. Based on these results, we conclude that Washington’s private forestry industry is a net global warming mitigator for the State, equivalent to 12% of the State’s greenhouse gas emissions in 2015.
... One way of reducing initial embodied emissions is to use building materials that can be produced with less energy and fewer emissions. Compared to buildings constructed from concrete, steel, or masonry, wooden buildings seem to expel the least GHG emissions over their life cycle [25][26][27][28][29][30][31][32][33][34]. Thus, while wooden buildings are beneficial for the planet insofar as they generate fewer emissions during manufacturing, the carbon storage of wooden buildings is an additional mitigation option in both the short and the long term. ...
Article
Full-text available
Although buildings produce a third of greenhouse gas emissions, it has been suggested that they might be one of the most cost-effective climate change mitigation solutions. Among building materials, wood not only produces fewer emissions according to life-cycle assessment but can also store carbon. This study aims to estimate the carbon storage potential of new European buildings between 2020 and 2040. While studies on this issue exist, they mainly present rough estimations or are based on a small number of case studies. To ensure a reliable estimation, 50 different case buildings were selected and reviewed. The carbon storage per m ² of each case building was calculated and three types of wooden buildings were identified based on their carbon storage capacity. Finally, four European construction scenarios were generated based on the percentage of buildings constructed from wood and the type of wooden buildings. The annual captured CO 2 varied between 1 and 55 Mt, which is equivalent to between 1% and 47% of CO 2 emissions from the cement industry in Europe. This study finds that the carbon storage capacity of buildings is not significantly influenced by the type of building, the type of wood or the size of the building but rather by the number and the volume of wooden elements used in the structural and non-structural components of the building. It is recommended that policymakers aiming for carbon-neutral construction focus on the number of wooden elements in buildings rather than more general indicators, such as the amount of wood construction, or even detailed indirect indicators, such as building type, wood type or building size. A practical scenario is proposed for use by European decision-makers, and the role of wood in green building certification is discussed.
... In the production phase of buildings, the selection of materials has a key role in CO 2-eq emission. Studies from several countries have shown that wood materials used in building frames usually release less CO 2 than other materials throughout the life cycle [25][26][27][28][29][30]. This is due to the relatively small amount of energy needed to manufacture wood products compared to other materials and the opportunity of replacing fossil fuels with wood byproducts during the manufacturing process. ...
Article
Full-text available
The building sector is one of the major contributors to global CO2 emission. The energy retrofit of existing buildings reduces CO2 emission in the operation phase but entails new emissions to produce, maintain and dispose the materials used for retrofitting (non-operation CO2 emission). This study analyses the life cycle carbon balance of a building retrofitted to passive house level, considering two alternative standards applicable in Sweden. The study considers the implications of using different building materials for thermal insulation, building façade and windows of the retrofitted building. It also considers different electricity production scenarios, assuming standalone production with fossil coal, fossil gas, and a mix of wind and biomass. Our results show that the operation CO2 emission decreases by between 50-82% in the retrofitted building depending on the passive house standard, with minor deviations between electricity scenarios. The non-operation CO2 emission accounts for between 4-25% of the operation CO2 savings depending on the passive house standard and material option. Deviations between material options are increasingly reduced when assuming fossil gas and wind/biomass for electricity production instead of fossil coal. A careful selection of materials can reduce the net CO2 savings by up to 68%, especially when using wood material.
... Greater losses of carbohydrates were observed with birch than with pine even at a slightly lower temperature during thermal modification in open systems (Zaman et al., 2000). The formation of soluble xylose-rich carbohydrates during thermal modification was greater in closed systems saturated with steam than in an open system (Karlsson et al., 2012). The degradation of wood polymers leads to shrinkage of the wood cell wall and, thus, to the dimensions of the wood and a small reduction in wood density occurs when degraded materials are removed during the heating. ...
... The advantages of wood in construction are various [2,3]. Wood is a material characterized by good mechanical strength both in tension and in compression, so it can be used for the manufacturing of elements prone to bending such as beams, compressed like the pillars, stretched like tie rods, without the need to combine it with other materials, unlike for example concrete and masonry. ...
... Concurrently, researchers are investigating the use of wood as an alternative to traditional building materials in larger commercial buildings. It has been demonstrated that timber structures often result in a lower cradle-to-gate CO 2 emissions compared to concrete, steel, or brick-based structures [7][8][9][10][11][12][13][14][15][16][17]. ...
Article
In this study, the cradle-to-gate environmental impact of a hybrid, mid-rise, cross-laminated timber (CLT) commercial building is evaluated and compared to that of a reinforced concrete building with similar functional characteristics. This study evaluates the embodied emissions and energy associated with building materials, manufacturing, and construction. Two alternative designs are considered for fire protection in the hybrid CLT building: 1) a ‘fireproofing design’, where gypsum wallboard is applied to the structural wood; and 2) a ‘charring design’, where two extra layers of CLT are added to the panel. The life cycle environmental impacts are assessed using TRACI 2.1 and the total primary energy is evaluated using the Cumulative Energy Demand impact method. Results show that an average of 26.5% reduction in the global warming potential is achieved in the hybrid CLT building compared to the concrete building, excluding biogenic carbon emissions. Except ozone depletion, where the difference in impact between scenarios is <1%, replacing fireproofing with charring is beneficial for all impact categories. The embodied energy assessment of the building types reveals that, on average, the total primary energy in the hybrid CLT buildings and concrete building are similar. However, the non-renewable energy (fossil-based) use in the hybrid CLT building is 8% lower compared to that of the concrete building. As compared to the concrete building, additional 1,556 tCO2e and 2,567 tCO2e are stored in the wood components of the building (long-term storage of biogenic carbon) in the scenario with fireproofing and with charring, respectively.
... Wood is one of the most important building materials worldwide. In recent years, the use of wood in above-ground applica-tions, particularly in Use Class 2 (outside, not in ground contact, covered) and Use Class 3 (outside, not in ground contact, not covered) applications [10] has increased considerably [23,26]. Modern trends stimulate the use of wood even in applications for which wood has not been traditionally used (bathrooms and multistory buildings). ...
Article
After the durability of wood against wood decay fungi, its water performance is the next most important factor that influences the performance of wood in outdoor, above-ground applications. It is therefore of major importance to optimize methods that are able to predict the moisture behaviour of wood in outdoor applications. In order to elucidate these questions, samples were prepared from European oak (Quercus robur/Q. petraea), sweet chestnut (Castanea sativa), European larch (Larix decidua), Scots pine heartwood and sapwood (Pinus sylvestris), Norway spruce (Picea abies) and beech (Fagus sylvatica). The moisture performance of the samples was altered by thermal modification, wax, oil and biocide treatment. Two types of specimens were prepared; smaller specimens (1.5 × 2.5 × 5.0 cm) were exposed to natural weathering for three periods (9, 18 and 27 months) and subsequently analyzed in the laboratory with various methods (contact angle, short- and long-term water uptake and water vapor uptake). In parallel, bigger specimens (2.5 × 5.0 × 50 cm) were exposed outdoors in a monolayer exposure and equipped with moisture monitoring sensors for 18 months. Water performance of wood could change as a result of weathering, being the most evident at thermally modified wood, where the decrease of the moisture performance was the most evident. The results of the study clearly showed that the water performance of the majority of the materials decreased with natural weathering. These results indicate that in order to elucidate the moisture performance of wood fully, a variety of laboratory tests needs to be applied, relating to both liquid water performance and water vapour interactions with wood.
... High greenhouse gas emission and non-renewable natural resource consumption led to some important environmental problems such as; forest destruction, waste accumulation and global warming. Prevention of these problems is very important in order to ensure sustainability and to protect the ecological balance (Joseph, Tretsiakova, 2010;Nässén et al. 2012). The solutions recommended are; increasing the number of green buildings that consume less natural resource and energy, emitting less carbon, using waste materials and renewable energy sources. ...
Chapter
Full-text available
Wood is a preferred building material from the earliest known years of man’s existence, due to its workability, versatility and aesthetical properties. The earliest known use of wooden constructions is tent-like shelters obtained from little branches. The large diameter tree trunks started to be used after the improvement of tools such as stone axes and animal teeth. Wood has been used as one of the most preferred structural materials until the Industrial Revolution. The technological developments following the Industrial Revolution have increased the use of modern building materials. However, the manufacturing processes of modern building materials are hazardous to the environment. A significant amount of greenhouse gas is emitted, non-renewable natural resources are consumed and waste is produced during the manufacture of commonly used modern building materials such as; concrete, steel, polymers, etc. Even though some environmental problems arise at the beginning of the Industrial Revolution because of the modern materials production process, no precautions have been taken. Hence, the environmental problems increased and deepened. High greenhouse gas emission and non-renewable natural resource consumption led to some important environmental problems such as; forest destruction, waste accumulation and global warming. Prevention of these problems is very important in order to ensure sustainability and to protect the ecological balance. The solutions recommended are; increasing the number of green buildings that consume less natural resource and energy, emitting less carbon, using waste materials and renewable energy sources.
... Further, at the end of their lifetime, wood building products generally need to be used to create bioenergy that displaces fossil-fuel energy sources, which provides a further impetus to their displacement benefit [45]. A study by Nässén et al. [46] even suggested that wood-based buildings would only be of benefit when the bioenergy produced from the endof-life products was generated with carbon capture and storage technology capabilities. ...
Article
Full-text available
Background There are high estimates of the potential climate change mitigation opportunity of using wood products. A significant part of those estimates depends on long-lived wood products in the construction sector replacing concrete, steel, and other non-renewable goods. Often the climate change mitigation benefits of this substitution are presented and quantified in the form of displacement factors. A displacement factor is numerically quantified as the reduction in emissions achieved per unit of wood used, representing the efficiency of biomass in decreasing greenhouse gas emissions. The substitution benefit for a given wood use scenario is then represented as the estimated change in emissions from baseline in a study’s modelling framework. The purpose of this review is to identify and assess the central economic and technical assumptions underlying forest carbon accounting and life cycle assessments that use displacement factors or similar simple methods. Main text Four assumptions in the way displacement factors are employed are analyzed: (1) changes in harvest or production rates will lead to a corresponding change in consumption of wood products, (2) wood building products are substitutable for concrete and steel, (3) the same mix of products could be produced from increased harvest rates, and (4) there are no market responses to increased wood use. Conclusions After outlining these assumptions, we conclude suggesting that many studies assessing forest management or products for climate change mitigation depend on a suite of assumptions that the literature either does not support or only partially supports. Therefore, we encourage the research community to develop a more sophisticated model of the building sectors and their products. In the meantime, recognizing these assumptions has allowed us to identify some structural, production, and policy-based changes to the construction industry that could help realize the climate change mitigation potential of wood products.
... This reinforced concrete material is one of a large share of global emissions [1]. The process of wood processing from raw materials to production or the cradle-to-gate process produces lower CO2 emissions compared to concrete, steel, or brick constructions [2][3][4][5]. Therefore, building structural materials with wood materials should be introduced in Indonesia to overcome these CO2 emission issue. ...
Article
Full-text available
Laminated Veneer Lumber (LVL) is one of the engineered wood products consisting of wood veneers that are glued and pressed together. In this study, the behavior of LVL Sengon slender beam is numerically investigated by means of nonlinear finite element analysis (FEA), where only half of the experimental beam was modeled due to symmetry of the load configuration. The LVL Sengon wood material used Hill failure criterion with isotropic hardening rules, and its mechanical properties in both tension and compression are modelled according to its mechanical properties in tension obtained from the clear specimen test. The contact analysis is defined for each contacting and contacted elements. The FEA results well agreed with the experimental results in term of the load-deflection curve and failure mode of the beam. It is found that the lateral support has no effect on the stiffness of the beam. The beam stiffness and ultimate load increase by the increase of beam height-to-width ratio (𝑑/𝑏).
... Dimoudia and Tompa [88] stated that the highest EE values belong to concrete and reinforcing steel, representing about 59% to 66% of the total EE of a studied building. Wood-based materials have much lower EE values compared to conventional materials, such as concrete and steel, making them a more sustainable and low-carbon construction alternative [89][90][91]. According to Buchanan and Levine, this is due to the fact that the manufacturing process for wood-based materials is much less energy-intensive than that for other construction materials. ...
Article
Full-text available
The main goal of this study was to review current studies on the state of the art of wood constructions with a particular focus on energy efficiency, which could serve as a valuable source of information for both industry and scholars. This review begins with an overview of the role of materials in wood buildings to improve energy performance, covering structural and insulation materials that have already been successfully used in the market for general applications over the years. Subsequently, studies of different wood building systems (i.e., wood-frame, post-and-beam, mass timber and hybrid constructions) and energy efficiency are discussed. This is followed by a brief introduction to strategies to increase the energy efficiency of constructions. Finally, remarks and future research opportunities for wood buildings are highlighted. Some general recommendations for developing more energy-efficient wood buildings are identified in the literature and discussed. There is a lack of emerging construction concepts for wood-frame and post-and-beam buildings and a lack of design codes and specifications for mass timber and hybrid buildings. From the perspective of the potential environmental benefits of these systems as a whole, and their effects on energy efficiency and embodied energy in constructions, there are barriers that need to be considered in the future.
... Buildings using steel and concrete contain and consume 12-and 20% more energy, respectively than wooden buildings [27]. Moreover, products made from sustainably sourced wood replace other fossil-intensive substitutes, like concrete and steel [54][55][56][57][58][59]. ...
Chapter
Full-text available
This chapter examined the various stages and benefits of wooden extra stories from the perspective of Finnish housing and real estate companies through interviews with professionals involved in these projects. Key findings highlighted are as follows: (1) in the feasibility study, project planning primarily focuses on property condition and potential improvement targets as well as other considerations, for example, compliance with current regulations and parking arrangements; (2) in the project planning, application of extra stories is thoroughly examined, and construction costs, profits, and the sale of building rights are discussed; (3) in implementation planning, issues related to building rights, city plan change, and conditions of the company that manages the property play an important role; and (4) during construction, frequent information updates are made to residents regarding the site arrangements and the construction program. Wooden extra floor construction, which requires commitment, investment, and cooperation among the interested parties, has great potential in construction technology, contracting mechanisms, and ecological engineering solutions. It is believed that this chapter will increase the dissemination of wooden extra stories, thus contributing to the greater use of more sustainable materials in renovation projects and the ecologically sensitive engineering approaches to meet the challenges arising from climate change.
... Considerable previous research indicates that wood is an ideal choice for building construction compared to steel or concrete. This is because of its lower carbon and environmental emissions (Glover et al. 2002;Hill and Dibdiakova 2016;Nässén et al. 2012b). Some research emphasizes the importance of increasing the quota of wood in a building. ...
Article
Full-text available
Purpose The construction sector is interested in considering environmental implications as necessary criteria for sustainability. In this regard, wood materials, especially engineering wood, are a promising choice for sustainable buildings. In some countries such as Malaysia, timber is rarely considered in the construction sector despite there being abundant access to wood. This is because of the scarcity of timber structures and the dominance of alternative materials such as steel and concrete. The cross-laminated timber-steel composite introduced in this research benefits both the wood and the steel markets leading to standardization and a more extensive market. At the same time, it contributes to environmentally friendly requirements. The main objective was to investigate timber applications in local construction and make proposals for its promotion. The new specimen described here could potentially enhance the strength of timber beams using steel plates. Four current structural methods have been chosen based on environmental and economic comparisons with a new composite structure. Methods The life cycle assessment (LCA) and life cycle cost (LCC) have been used to compare the performance of four current conventional structures. Results and discussion The results showed that the new proposed structure has lower emissions in all environmental categories, namely, Global Warming Potential (GWP), Human Carcinogenic Toxicity (HCT), Fossil Depletion Potential (FDP), Ozone Layer Depletion (OLD), Terrestrial Acidification (TA) and embodied energy. The results of the LCC are consistent with the environmental issue as the new composite has a lower cost over its entire life span. Conclusions The new structure provides a novel and sustainable alternative for the construction industry.
... Furthermore, CO 2 emissions can be significantly reduced by replacing Portland cement with geopolymers such as slag and fly ash [7,20]. The production of traditional concrete and particularly Portland cement is a significant contributor to global greenhouse gas emissions [59,60]. Considering current global climate debates and continuing population growth related to an inevitable increase in demand for concrete [20,61], it is of global significance to find a more sustainable alternative to replace traditional concrete in the building and construction sector. ...
Article
Full-text available
Using fibre-reinforced polymers (FRP) in construction avoids corrosion issues associated with the use of traditional steel reinforcement, while seawater and sea sand concrete (SWSSC) reduces environmental issues and resource shortages caused by the production of traditional concrete. The paper gives an overview of the current research on the bond performance between FRP tube and concrete with particular focus on SWSSC. The review follows a thematic broad-to-narrow approach. It reflects on the current research around the significance and application of FRP and SWSSC and discusses important issues around the bond strength and cyclic behaviour of tubular composites. A review of recent studies of bond strength between FRP and concrete and steel and concrete under static or cyclic loading using pushout tests is presented. In addition, the influence of different parameters on the pushout test results are summarised. Finally, recommendations for future studies are proposed.
... Therefore, a life cycle approach is important to assess the environmental performance of buildings. Studies from several countries have shown that wood materials used in building frames usually use less energy and release less CO2 than other materials throughout the life cycle (Gustavsson, et al., 2006;Gerilla, et al., 2007;Upton, et al., 2008;Dodoo, et al., 2009;Blengini and Di Carlo, 2010;Bribián, et al., 2011;Nässén, et al., 2012;Tettey, et al., 2014;Peñaloza, et al., 2016;Kovacic, et al., 2018;Pittau, et al., 2018). This is due to the relatively small amount of energy needed to manufacture wood products compared to other materials and the opportunity to replace fossil fuels with wood by-products during the manufacturing process. ...
Article
The building sector has a significant impact on the environment, accounting for 36% of CO2 emissions and about half of material consumption in Europe. Residential buildings dominate the European building stock. In Finland, residential buildings account for up to 80% of the existing buildings and the rate of construction is higher compared to other building types. Therefore, residential buildings play an important role in the transition to a sustainable built environment. A number of studies show that increasing the use of wood can lower the life cycle environmental impacts of buildings. In Scandinavia, the use of wood in small houses is well established, used in 90% of cases. Furthermore, the increasing number of high-rise wooden buildings suggests a growing interest in the potential of wood in large-scale buildings. Green building certification provides criteria to assess the sustainability level of buildings and is expected to influence the building sector in the near future, by promoting the use of sustainable technologies. The aim of this study was to investigate how green building certification schemes assess wood materials and how wood materials can help fulfil sustainability criteria for green buildings. We analyse the sustainability criteria adopted by the most common certification schemes in Finland, BREEAM, LEED and the Nordic Swan Ecolabel, as well as the upcoming Level(s) certification promoted by the European Commission. The analysis shows that the contribution of wood materials to the overall score of green building certifications accounts for between 10 and 36%. Wood is advantageous as a renewable and low-carbon material. Furthermore, wood can offer indirect benefits due to its recycling potential and to water saving in the construction stage. However, wood materials have to comply with some requirements, such as sustainable forest management and low volatile organic compound content. The new European certification suggests a comprehensive assessment including circular material life cycles.
... The unintended dynamic under-performance of timber floors has often led to the use of concrete topping as a means of reducing the perception of vibrations 15 due to dynamic excitations [4,9,10]. These upgrading measures contravene the lightness and sustainability advantages of timber and can diminish the poten- tial benefits underpinning the use of wood in construction [11]. It is therefore imperative to find new solutions that would mitigate the undesirable vibration discomfort associated with timber floors while upholding the advantages of tim- 20 ber as a building construction material. ...
Article
Full-text available
The low modal mass and stiffness of timber floors impose a number of motion-control challenges to the structural designer. These difficulties can often led to the implementation of sub-optimal solutions, such as the addition of supplemental mass and stiffness in the form of concrete slabs, that conflict with the claimed sustainability and lightweight advantages of wood. In this paper, we present a novel beam configuration that enhances the vibration comfort response of timber flooring systems while retaining the original environmental benefits of wood in construction. By taking advantage of modern digital-fabrication tools, we devise, test and analyse new beam configurations that incorporate flexural resonators tuned to key structural frequencies of the system. These resonators are integrated into the body of the beam and the structure is sized to satisfy typical strength and stiffness demands. A series of numerical, experimental and parametric studies demonstrate the vibration absorbing capabilities of the new designs and the feasibility of their implementation to satisfy current occupant comfort criteria.
... 46). This suggestion is supported by findings in the literature [13][14][15][16]. ...
Article
Full-text available
The concept of the bioeconomy is associated with sustainable development changes and involves transitions in both production and consumption within systems. Many of these transitions relate to using renewable resources, like forest biomass, to meet basic needs, such as food, energy and housing. However, consumers must become aware of the forest-based bioeconomy so that they can contribute to the transition. This study aims to contribute to an understanding of this matter that may lead to social acceptance of the forest-based bioeconomy and, in particular, to Swedish consumer awareness of the concept and of a particular product (wooden multi-story buildings) representing the forest-based bioeconomy. The results show consumer awareness of forest sequestration capacity but less awareness of the connection to the forest-based bioeconomy and the role of wooden multi-story buildings. The results indicate a slow transition that is hindered by path dependence and limited comprehension among consumers of the effects of their choices for a forest-based bioeconomy. This study provides valuable insights for future studies of how consumer awareness and social acceptance of the forest-based bioeconomy are interconnected.
Conference Paper
Full-text available
با افزایش نگرانی ها درباره تاثیرات محیط زیستی صنعت ساختمان، انرژی نهفته و نشر کربن در مصالح مورد توجه قرار گرفتند. انرژی نهفته مجموع انرژی هایی است که در بازه عمر یک محصول از مرحله استخراج تا مرحله بازیافت مصرف می شود همچنین انرژی نهفته کمتر گویای این است که کربن دی اکسید کمتری در فرآیندهای تولید حمل و نقل و استفاده از آن مصالح تولید شده است و به اصطلاح ردپای کربن آن کوچک است در عصر حاضر که توسعه پایدار در دستور کار صنایع مختلف از جمله صنعت ساختمان است، انرژی نهفته به عنوان شاخص پایداری مصالح در نظر گرفته می شود با توجه به اینکه صنعت ساختمان بخش قابل توجه ای از انرژی را در جهان مصرف می کند انرژی نهفته در مصالح مختلفی مانند بتن، سیمان، فولاد، آجر، چوب، شیشه و آلومینیوم که در ساختمان سازی ایران متداول هستند در این مقاله بررسی می شود
Thesis
This study presents the correlation between laboratory and field tests in assessing the functional and aesthetic service life of the wood. The results obtained in the laboratory experiments were combined and compared with the results obtained in field trials. Thus, we evaluated the potential of various laboratory tests for the purpose of predicting the dynamics of moistening of wood in external conditions of use. To determine the correlation between laboratory and field tests, we calculated the Pearson coefficient of correlation, which determines the linear connection of two numeric variables. The results showed that it could be inferred that some faster laboratory tests can be used to predict the interaction of water with wood in external use, but a good knowledge of the conditions of use is needed. The importance of the aesthetic service life of wood is increasing and because colour is one of the most important parameters of aesthetics, we have determined and evaluated the differences in the colour changes with respect to the direction of exposure. It turned out that photo-degradation covers the signs of blue staining, and in wet months, blue staining may reappear. The results of the comparison of colour changes obtained with laboratory and field tests showed the positive Pearson correlation coefficients between natural aging of the wood and the combination of wood colouring with blue-staining fungi and artificial aging of wood. Therefore, it would be sensible to assemble a two-step laboratory test (staining with fungi and artificially accelerated aging) in order to simulate the colour changes in the best way compared to the wood tested in field trials.
Conference Paper
The aim of our work was to study the mechanical characteristics in conditions of flat stress state and widen the current knowledge of construction plywood appliance. It was decided that the best method for this investigation was to examine randomly selected plywood batches and analyse the results with the use of mathematical methods of statistics. The specimens were made up of plywood that was typified by different veneer grades. The main two groups of the specimens were manufactured with PF and UF resin. The conducted tests under the main types of flat stress in material (linear tension, compression and transverse bending) showed the strengths and their correlation between theoretical and obtained values. Based on the carried on plywood research the linear correlation dependence of veneer thickness on strength limit was obtained along and across fibres of external layers under compressive stress. Our experiments prove that veneer grade does not affect the tensile strength independent of the applied load direction regarding the fibre of external layers. This means that veneer grade defines only the quality of appearance. The mentioned above accessed results could be used for practical calculations during the design and manufacturing.
Article
The increasing interest in bio-based construction materials has resulted in the emergence of the concept of “buildings as a carbon sink”. Quantifying and comparing the effects of carbon sequestration and storage in buildings from a life cycle perspective involves the evaluation of flows and processes taking place at different timescales and across ecological, technological, and economic domains. This scoping review sheds light on the heterogeneous body of approaches and results from relevant scientific literature of the past decade: 180 articles were reviewed following a systematic search and relevance-checking process. Contributions are evaluated based on the scale of interest (material, building, building stock), the sequestration mechanism (photosynthesis, carbonation) and the accounting methodology adopted to quantify global warming. The majority of works taking a life cycle perspective adopt static methods, with only a few accounting for dynamic effects over time, although more recent studies do tend to recognise the need for dynamic life cycle assessment. A characterisation of current and future carbon storage in the global building stock is still needed, and substantial work remains to be done to validate the theory of buildings as a carbon sink to mitigate the effects of climate change. Reports on carbon stored in durable construction products and buildings mostly find cumulative effects that are less than emissions from fossil fuel use in a single year (ranging from negligible to 175%). Furthermore, net gains in storage in the built environment can be offset by net losses in forest carbon, and the benefits of substitution with wood are sometimes overstated. Further adoption of bio-based construction materials can – at best – only make a substantial contribution to climate change mitigation in the context of rapid global progress in decarbonisation.
Article
This research uses uncertainty analysis to determine and compare the range of embodied carbon outcomes of mid-rise mass timber and concrete buildings in Australia. In doing so, it measures the variability in inventory databases, transportation distance, lifetime of building components, biogenic carbon emissions, carbonation of concrete materials and end-of-life scenarios. Through the use of Monte Carlo analysis, the research found that the embodied carbon of a mass timber building ranged from 196 kgCO2-e/m² to 590 kgCO2-e/m² with a mean of 417 kgCO2-e/m². For a post-tensioned concrete building the range was 307 kgCO2-e/m² to 618 kgCO2-e/m² with a mean of 465 kgCO2-e/m². This equates to a 48 kgCO2-e/m² reduction in mean embodied carbon for the mass timber building. Using deterministic analysis, previous research suggested a more substantive 129 kgCO2-e/m² reduction. These results demonstrate that mass timber buildings do typically have a lower embodied carbon, compared to concrete buildings, however the significance of this depends on the assumptions made, and the input data used. For the concrete building, the variation in embodied carbon is primarily influenced by the inventory data and building products' lifetime. The greater range of embodied carbon in the mass timber building is due to variations associated with the inventory data, allocation of biogenic carbon emissions (sequestration, and forest management losses) and, different end-of-life scenarios associated with timber products. Despite this, the research suggests that with a carefully planned end-of-life strategy, mass timber mid-rise buildings have the potential to benefit from lower embodied carbon emissions, as compared to concrete buildings, across their full lifecycle.
Article
Full-text available
The existing building stock is estimated to need major renovations in the near future. At the same time, the EU energy-efficiency strategy entails upgrading the energy performance of renovated buildings to meet the nearly-zero energy standard. To upgrade existing buildings, two main groups of measures can be adopted: thermally-improved building envelope and energy-efficient technical devices. The first measure usually involves additional building materials for thermal insulation and new building cladding, as well as new windows and doors. A number of commercially-available materials can be used to renovate thermal building envelopes. This study compares the life-cycle primary energy use and CO2 emission when renovating an existing building using different materials, commonly used in renovated buildings. A Swedish building constructed in 1972 is used as a case-study building. The building's envelope is assumed to be renovated to meet the Swedish passive house standard. The entire life cycle of the building envelope renovation is taken into account. The results show that the selection of building materials can significantly reduce the production primary energy and associated CO2 emissions by up to 62% and 77%, respectively. The results suggest that a careful material choice can significantly contribute to reduce primary energy use and CO2 emissions associated with energy renovation of buildings, especially when renewable-based materials are used.
Article
In this paper, it is attempted to study possible sustainability solutions for building structures. In this context, comparisons are made between two load-bearing columns with different building materials – glued laminated timber and concrete – with regard to structural design, economic consequences and the emission of greenhouse gases. In terms of structural design, the results show that with small axial forces, glulam columns will result in smaller cross-sectional areas compared to concrete columns. However, at larger axial forces, concrete columns will result in smaller cross-sectional areas than glulam columns. An increased column length also means larger dimensions for glulam columns, but this does not always apply to concrete columns. With respect to environmental impact, it is shown that using glulam columns is the more environmentally friendly option. From an economic point of view, the cost estimates for glulam and concrete columns may vary depending on the country and the abundance of the construction material. In Sweden, a forest-rich country, it is shown that the costs for both column types are quite similar considering small axial loads. At higher axial loading, concrete is generally the cheaper alternative.
Article
The recent energy and environmental crises and corresponding regulations have increased interest in replacing conventional materials with sustainable materials in construction. Due to the outstanding properties of wood, such as recyclability, reusability and natural renewability, it is considered a sustainable material. In addition, wood has a high strength-to-weight ratio and outstanding acoustic and thermal insulation properties, which make it an appropriate construction material in numerous applications, including in main structural members such as beams, columns and flooring systems as well as in non-structural members, such as windows, doorframes and insulating envelopes. Recent advancements in the production of engineering wood and efficient adhesives have made the fabrication of structural members with large cross sections, long spans and structural properties comparable to steel and reinforced concrete feasible and cost-effective. As a result, interest in long-span timber buildings has increased greatly. In this paper, a comprehensive review of research studies investigating various aspects of long-span timber structures, including material properties, structural performance and sustainability, are presented. In particular, over 100 research papers were systematically reviewed to study the constructability of long-span flooring systems. The techniques and methodologies available for the fabrication, analysis and experimental investigations of structural flooring systems are also reviewed in detail. Overall, this comprehensive review helps to achieve a greater understanding of structural static and dynamic responses of long-span timber flooring systems, and undertaking the challenges and opportunities presented in this paper could significantly contribute to the improvement of the structural design to reach optimised, sustainable, and constructible systems.
Article
Full-text available
Buildings play a vital role in reaching the targets stated by the Intergovernmental Panel on Climate Change to limit global warming to 1.5 degrees. Increasing the use of wood in construction is a proposed upcoming strategy to reduce the embodied greenhouse gas emissions of buildings. This study examines existing life cycle assessments of wooden buildings. The aim is to investigate embodied greenhouse gas emission results reported, as well as methodological approaches applied in existing literature. The study applies the protocol for Systematic Literature Reviews and finds 79 relevant papers. From the final sample, the study analyses 226 different scenarios in-depth in terms of embodied emissions, life cycle assessment method, life cycle inventory modelling and biogenic carbon approach. The analysis shows that the average reported values of embodied greenhouse gas emissions of wooden buildings are one-third to half of the embodied emissions reported from buildings in general. Additionally, from the analysis of the final sample we find that the majority of wooden building life cycle assessments apply similar methods and often leave out biogenic carbon from the assessment or simply do not declare it. This implies that the focus on variability in the different methods applied in wooden building life cycle assessments needs to be increased to establish the relationship between methodological choices and embodied emissions of wooden buildings. Further, transparency and conformity in biogenic carbon accounting in life cycle assessments is essential to enhance comparability between life cycle assessment studies and to avoid distortions in embodied GHG emission results.
Conference Paper
Full-text available
In the last few years Circular Economy (CE) is receiving increasing attention worldwide as a way to overcome the current production and consumption model based on continuous growth and increasing resource throughput. The concept of the CE is increasingly seen as a major policy agenda item and a testing challenge, for the construction sector. Nowadays, an omnipresent problem of resource scarcity and a need for reduction of waste generation make a discussion about eco-friendly production models more serious than ever before. Construction sector is one of the world's largest waste generators. Fortunately, the Circular Economy can help to diminish an environmental impact of the construction sector. The paper provides an overview of the literature on Circular Economy theoretical approaches, strategies and implementation cases, in construction sector. Finally, the suggestions for future development are also discussed in this paper.
Article
High levels of GHG emissions are the result of the activities of the construction industry; for example, cement and steel production alone are responsible for 10–12% of global Green House Gas (GHG) emissions. In order to control climate change, while complying with the levels set by the Paris agreement and the IPCC 2018 report (a maximum of +1.5 °C above pre-industrial levels), serious measures need to be adopted so that GHG emissions can be reduced. Indeed, it is only through the adoption of the Circular Economy (CE) principles that the construction sector will be able to play a strategic role in the achievement of such reductions. Despite the importance of the topic, there are few comprehensive reviews of possible strategies to produce low-carbon materials; this paper analyses literature reviews on low-carbon material, starting from international policies on GHG emission reduction and CE principles, providing a critical summary of current knowledge. On the basis of a thorough literature review whose references have been made in accordance with the relevance of the topic of study, the approaches adopted in order to produce low-carbon materials, the materials investigated and the related issues and challenges, the work identifies in an original way eight approaches (known as Low-carbon Emission Approaches - LEAs) related to the production process that could help reduce the GHG emissions of construction materials. Comparing the results of the literature review analysis with the material life cycle by means of a matrix that relates LCA and LEAs, the paper underlines LEA's capability to reduce GHG levels. In particular, focusing on the 8 LEAs identified, it emerges that, in order to create low-carbon products for construction, it is possible to use alternative materials (up to −40% of GHG emission) and natural materials (up to −90%), to introduce secondary raw materials (up to −40/50%), to implement CCS and CCU systems in the production process (up to −70%), to increase the use of energy from renewable sources (up to −60%), and to increase product performance. The work also highlights some limitations linked to several factors, such as: the costs for initial investments, some changes in the cultural paradigm, the impossibility for the market to receive innovative products, and the lack of skills of technicians and companies, and so on; these problems need to be solved in the shortest time possible in order to achieve the goal set by the Intergovernmental Panel on Climate Change.
Article
In recent years, several comparative life cycle analyses have shown that increasing the use of wood in buildings can reduce the life cycle primary energy use and carbon emission of buildings. This study reviews the life cycle inventory methodology of primary energy use and carbon emissions, based on ecoinvent database, considering different modelling choices for (i) materials heating values; (ii) biogenic carbon; (iii) calcination and carbonation processes; (iv) electricity production scenarios; (v) impact distribution of multi-functional processes; (vi) post-use benefits. The analysis relates to the standards while the implication of different modelling choice is shown by comparing the primary energy use and carbon emission in the production and end-of-life stages of a multi-storey residential building with concrete, cross laminated timber and modular timber structures, respectively. The results highlight the displacement between different modelling choices in terms of primary energy use and carbon emissions. Such modelling options especially influence the LCA results in the product stage and beyond the end of life stage, and especially wood- and/or cement-based materials.
Article
Pleasant interior space is essential for modern people who spend considerably more time in the buildings than they did in the past. To achieve this, one aspect includes an ambient temperature that maintains the thermal equilibrium of the human body. The construction of wood framed buildings is becoming increasingly popular worldwide, and there have been recent trends toward constructing high-rise wooden houses. In this respect, heating methods appropriate for use in wooden buildings are being studied. Dry floor heating systems are predominantly used in wooden houses, but they provide a poor heat storage performance, which is not conducive to saving energy. In this study, the effects of thermal comfort and energy savings were analyzed after applying a phase change material (PCM) to floor heating, which can be used to reduce the peak temperature and contribute to energy savings. To enable shape stabilization, this study used Macro-Packed PCM (MPPCM), as shape stabilization is necessary when applying PCM. The heat storage performance was improved by applying MPPCM to a dry floor heating system. Paraffin-based PCMs, such as n-octadecane, n-eicosane, and n-docosane, were used to obtain a comfortable floor temperature range. Experimental temperatures ranged from 28 °C to 35 °C, with an entire temperature range of 7 °C. Experimental results showed that the heat storage performance of MPPCM reduced the amount of energy used for heating by 43%, and n-eicosane was the most effective PCM for use in floor heating with respect to obtaining a comfortable floor temperature.
Article
Full-text available
From the environmental perspective, wooden structures are favorable insulators that are suitable for carbon fixation and wooden-related products are considered the most sustainable material. Research has indicated that wooden structures have superior energy-saving performance compared to reinforced concrete (RC) structures. In this study, a CLT-based hybrid structure system that potentially improves the efficiency of energy consumption is proposed. The proposed hybrid structure system, which preserved original RC beams, columns and replaced CLT floors and walls, has less building weight compared to the original RC building. Additionally, less energy required for the manufacturing of building materials in the renovation of the aged building is achieved, compared to building a new CLT building. The energy consumptions for buildings with heights of 10 stories were compared. CLT and RC were selected as benchmark building materials to compare the energy-saving efficiencies with the proposed hybrid structure system. In addition, to examine the energy consumption differences at different latitudes, the energy consumptions in Taipei, Tokyo, Harbin, and Singapore were compared as well. The simulation results indicate the proposed hybrid structure system, which comprises RC beams and columns and CLT floors and walls, and has an energy-saving efficiency close to that of a CLT structure, by approximately 3–5% higher, however, had a superior energy consumption performance to the RC structure. In general, the proposed hybrid structure system can be effectively used for old building renewal in the selected Asian cities.
Article
Purpose Over the last eight years, the Middle East has experienced a series of high profile conflicts which have resulted in over 5.6 million Syrians forced to migrate to neighbouring countries within the MENA (Middle East and North Africa) region or to Europe. That have exerted huge pressure on hosting countries trying to accommodate refugees in decent shelters and in quick manner. Temporary shelters normally carry a high environmental burden due to their short lifespan, and the majority are fabricated from industrialised materials. This study assesses the carbon impact for a minus carbon experimental refugee house in Sweden using life cycle assessment (LCA) as tool. SimaPro and GaBi software were used for the calculations and the ReCiPe midpoint method for impact assessment. The results show that using local plant-based materials such as straw, reeds and wood, together with clay dug from close to the construction site, can drastically reduce the carbon footprint of temporary shelters and even attain a negative carbon impact of 226.2 kg CO2 eq/m2. Based on the results of the uncertainty importance analysis, the overall global warming potential impact without and with sequestration potential are mostly sensitive to the variability of the GWP impact of wood fibre insulation. Design/methodology/approach The methodology is designed to calculate the GWP impact of the refugee house over its entire life cycle (production, operation and maintenance and end of life). Then, the sensitivity analysis was performed to explore the impact of input uncertainties (selection of material from the database and the method) on the total GWP impact of the refugee house with and without sequestration. The ISO standards (International Standard 14040 2006; International Standard 14044 2006) divide the LCA framework into four steps of Goal and scope, inventory analysis, impact assessment, and interpretation. Findings This study has shown an example for proof of concept for a low impact refugee house prototype using straw, reeds, clay, lime and wood as the principle raw materials for building construction. Using natural materials, especially plant-based fibres, as the main construction materials, proved to achieve a minus carbon outcome over the life cycle of the building. The GWP of the shelter house without and with sequestration are found to be 254.7 kg CO 2 eq/m ² and -226.2 kg CO2 eq/m2, respectively. Originality/value As there are still very few studies concerned with the environmental impact of temporary refugee housing, this study contributes to the pool of knowledge by introducing a complete LCA calculation for a physical house prototype as a proof of concept on how using low impact raw materials for construction combined with passive solutions for heating and cooling can reach a minus carbon outcome. The GWP of the shelter house without and with sequestration are found to be 254.7 kg CO2 eq/m2 and -226.2 kg CO2 eq/m2.
Article
Full-text available
As one of the most prominent industries in developed and developing countries, the construction industry has had substantial impacts on different aspects of the environment, society, and economy. In recent years, sustainable construction has been introduced as an approach to evaluate the various construction phases based on environmental, economic, and social dimensions, also known as the triple bottom line (TBL). To conduct a sustainability analysis of the buildings in Tehran, the capital city of Iran, two conventional construction frames were selected, namely steel frame and concrete frame. In this research, three conventional approaches for the evaluation of the TBL, namely the life cycle assessment (LCA), life cycle cost (LCC), and social life cycle assessment (SLCA), were, respectively, used for the study of environmental, economic, and social impacts. The main results of the study are summarized as the following: Overall, based on the LCA results, the concrete frame led to almost 38% more environmental pollution than steel frame. In terms of the total prices of the buildings, considering their LCC and with respect to the present value (PV) method, the steel frame was almost 152,000 USD more expensive than the concrete frame. The quantified results of the social dimension by the SLCA method showed that concrete and steel buildings had a score of 0.199 and 0.189, respectively, which indicates that concrete had a slightly better social performance based on expert opinions. A multi-criteria assessment and sensitivity analysis of the results were conducted by a graphical tool, namely the mixing triangle, and showed that the overall preference of each alternative depends mainly on the importance weights given to each aspect of the assessment. However, one of the main findings of the research was that overall, giving a high importance weight to environmental dimension leads to sustainability preference of steel over concrete frame, while giving high importance weights to economic or social dimensions leads to sustainability preference of concrete over steel frame. Findings of the study are beneficial to decision-makers in the construction industry since they can decide on the best alternative among concrete and steel frames based on their strategies.
Article
Full-text available
Natural frequency of any natural or artificial material play a role in selection it for industrial and manufacturing applications. Natural frequency for material meaning its ability to absorb external vibration for avoiding resonance. In the presented paper wood and steel will used as a type of natural materials, concrete also will used but as an artificial material. Calculation of natural frequency for each material will done with same volume of structure. Natural properties of wood show superiority for many mechanical applications. The aim of this study is to investigate the effects of various factors including characteristics of wood, steel and concrete on their natural frequencies with the aim of producing recommendations to promote sustainability. Fuzzy logic control system also implemented for optimizing the impacts of these characteristics on the structure' vibration. In addition, the natural frequencies of structures have been assessed against the wind, earthquakes, and traffic vibrations. The results reveal that for the same dimensions of the structure, wood shows the highest natural frequency, steel followed by concrete. Results indicate that wood can complement natural properties of a range of industrial manufacturing materials to promote sustainability and improve performance. This can have implications for heavy machines laboratories (like foundation for that machines) and other engineering applications.
Article
Full-text available
Purpose – The aim of this study is to assess the role of CO2 capture and storage (CCS) technologies in the reduction of CO2 emissions from European industries. Design/methodology/approach – A database covering all industrial installations included in the EU ETS has been created. Potential capture sources have been identified and the potential for CO2 capture has been estimated based on branch- and plant-specific conditions. Emphasis is placed here on three branches of industry with promising prospects for CCS: mineral oil refineries, iron and steel, and cement manufacturers. Findings – A relatively small number (∼270) of large installations (>500,000 tCO2/year) dominates emissions from the three branches investigated in this study. Together these installations emit 432 MtCO2/year, 8 percent of EU's total greenhouse gas emissions. If the full potential of emerging CO2 capture technologies was realized, some 270-330 MtCO2 emissions could be avoided annually. Further, several regions have been singled out as particularly suitable to facilitate integrated CO2 transport networks. The most promising prospects for an early deployment of CCS are found in the regions bordering the North Sea. Research limitations/implications – Replacement/retrofitting of the existing plant stock will involve large investments and deployment will take time. It is thus important to consider how the current industry structure influences the potential to reduce CO2 in the short- medium and long term. It is concluded that the age structure of the existing industry plant stock and its implications for the timing and deployment rate of CO2 capture and other mitigation measures are important and should therefore be further investigated. Practical implications – CCS has been recognized as a key option for reducing CO2 emissions within the EU. This assessment shows that considerable emission reductions could be achieved by targeting large point sources in some of the most emission-intensive industries. Yet, a number of challenges need to be resolved in all parts of the CCS chain. Efforts need to be intensified from all stakeholders to gain more experience with the technological, economical and social aspects of CCS. Originality/value – This study provides a first estimate of the potential role for CO2 capture technologies in lowering CO2 emissions from European heavy industry. By considering wider system aspects as well as plant-specific conditions the assessment made in this study gives a realistic overview of the prospects and practical limitations of CCS in EU industry.
Article
Full-text available
The objective of this study was to calculate indicative ranges of production costs and assess the main sources of cost for a number of energy crops, both annual and perennial, on a regional level in Europe. The production costs were calculated in terms of the economic compensation required by the farmer in order to grow the crop, and therefore include not only the cost of cultivation, but also the costs of land and risk, which are often omitted in production cost calculations. The cost of land was calculated as the opportunity cost based on the production of cereals. Thus, higher food prices lead to higher land costs, which in turn lead to higher energy crop production costs. The analysis was performed for three cases with different assumptions concerning yields and production cost reductions resulting from scale (total cultivation area in the region), and learning effects. The calculated energy crop production costs were found to be consistently lowest for short-rotation coppice (SRC) crops and highest for annual straw crops. The production costs of SRC crops were calculated to be about 4-5 € GJ -1 under present conditions and 3-4 € GJ -1 under improved future conditions. The production costs for perennial grasses were calculated to be about 6-7 € GJ -1 and 5-6 € GJ -1 under present and improved future conditions, respectively. The production costs for annual straw crops were estimated to be 6-8 € GJ -1 under present conditions with small potential for cost reductions in the future.
Article
Full-text available
The capture and storage of CO2 from combustion of fossil fuels is gaining attraction as a means to deal with climate change. CO2 emissions from biomass conversion processes can also be captured. If that is done, biomass energy with CO2 capture and storage (BECS) would become a technology that removes CO2 from the atmosphere and at the same time deliver CO2-neutral energy carriers (heat, electricity or hydrogen) to society. Here we present estimates of the costs and conversion efficiency of electricity, hydrogen and heat generation from fossil fuels and biomass with CO2 capture and storage. We then insert these technology characteristics into a global energy and transportation model (GET 5.0), and calculate costs of stabilizing atmospheric CO2 concentration at 350 and 450 ppm. We find that carbon capture and storage technologies applied to fossil fuels have the potential to reduce the cost of meeting the 350 ppm stabilisation targets by 50% compared to a case where these technologies are not available and by 80% when BECS is allowed. For the 450 ppm scenario, the reduction in costs is 40 and 42%, respectively. Thus, the difference in costs between cases where BECS technologies are allowed and where they are not is marginal for the 450 ppm stabilization target. It is for very low stabilization targets that negative emissions become warranted, and this makes BECS more valuable than in cases with higher stabilization targets. Systematic and stochastic sensitivity analysis is performed. Finally, BECS opens up the possibility to remove CO2 from the atmosphere. But this option should not be seen as an argument in favour of doing nothing about the climate problem now and then switching on this technology if climate change turns out to be a significant problem. It is not likely that BECS can be initiated sufficiently rapidly at a sufficient scale to follow this path to avoiding abrupt and serious climate changes if that would happen.
Article
Full-text available
The aim of this study is to examine how the options for producing electricity, fuels, and heat in a carbon-constrained world affect the cost-effectiveness of a range of fuels and propulsion technologies in the transportation sector. GET 7.0, a global energy system model with five end-use sectors, is used for the analysis. We find that an energy system dominated either by solar or by nuclear tends to make biofuels in plug-in hybrids cost-effective. If coal with carbon capture and storage (CCS) dominates the energy system, hydrogen cars, rather than plug-in hybrids tend to become cost-effective. Performing a Monte Carlo simulation, we then show that the general features of our results hold for a wide range of assumptions for the costs of vehicle propulsion technologies (e.g., batteries and fuel cells). However, sufficiently large changes in say the battery costs may overturn the impact of changes in the energy supply system, so that plug-in hybrid vehicles become cost-effective even if coal with CCS dominate the energy supply. We conclude that analyses of future energy carriers and propulsion technologies need to consider developments in the energy supply system.
Article
Full-text available
The capture of carbon dioxide at the point of emission from coal- or gas-burning power plants is an attractive route to reducing carbon dioxide emissions into the atmosphere. To commercialize carbon capture, as well as transport of liquified carbon dioxide and its storage in exploited oil fields or saline formations, many technological, commercial, and political hurdles remain to be overcome. Urgent action is required if carbon capture and storage is to play a large role in limiting climate change.
Article
Full-text available
Steel is used as a case study to decompose the links between primary and secondary markets, in order to examine how prices in the one market influence the prices in the other, and how volatility can be transmitted between them.
Article
To supply biomass from production areas to energy importing regions, long-distance international transport is necessary, implying additional logistics, costs, energy consumption and material losses compared to local utilisation. A broad variety of bioenergy chains can be envisioned, comprising different biomass feedstock production systems, pre-treatment and conversion operations, and transport of raw and refined solid biomass and liquid bio-derived fuels. A tool was developed to consistently compare the possible bioenergy supply chains and assess the influence of key parameters, such as distance, timing and scale on performance. Chains of European and Latin American bioenergy carriers delivered to Western Europe were analysed using generic data. European biomass residues and crops can be delivered at 90 and 70 €/tonnedry (4.7 and 3.7 €/GJHHV) when shipped as pellets. South American crops are produced against much lower costs. Despite the long shipping distance, the costs in the receiving harbour can be as low as 40 €/tonnedry or 2.1 €/GJHHV; the crop's costs account for 25–40% of the delivered costs. The relatively expensive truck transport from production site to gathering point restricts the size of the production area; therefore, a high biomass yield per hectare is vital to enable large-scale systems. In all, 300 MWHHV Latin American biomass in biomass integrated gasification/combined cycle plants may result in cost of electricity as little as 3.5 €cent/kWh, competitive with fossil electricity. Methanol produced in Latin America and delivered to Europe may cost 8–10 €/GJHHV, when the pellets to methanol conversion is done in Europe the delivered methanol costs are higher. The energy requirement to deliver solid biomass from both crops and residues from the different production countries is 1.2–1.3 MJprimary/MJdelivered (coal ∼1.1 MJ/MJ). International bioenergy trade is possible against low costs and modest energy loss.
Article
Sawmill residue is an important component of biomass resources for California; however, factors allowing for projections of future resources are not well established. Differences exist relative to timber diameter class, species type, and milling technology used in other western states for which residue factors have been developed. In this study, sawmill residue production was estimated by two methods. The first utilized lumber production and a sawmill residue volume factor, while the second used total log consumption by sawmills and a sawmill residue weight factor. These two factors were developed based on literature, historic data, and experiences from timber specialists, which can be used to predict sawmill residue production in recent years in California. Estimated sawmill residue generation in California ranged from 2.2 to 2.6 Mt, dry weight basis, in 2002 and 2.2–2.5 Mt in 2003. Residues were also estimated for 1988, 1994, and 2000 for comparison to other reported estimates for sawmill residues in these years. Coarse and fine residues and bark accounted for approximately 45%, 32%, and 23% of total sawmill residues generated. Potentially, more than two million metric tons of sawmill residues are available for bioenergy production and could contribute to California's Renewable Portfolio Standard (RPS) for increasing amounts of electricity from renewable resources and to other policy objectives for increasing amounts of renewable biofuels and bio-based products.
Article
Techniques for the reduction of the specific energy consumption for iron and steel making are identified and characterized to assess the potential for future energy-efficiency improvement and research and development priorities. World-wide average specific energy consumption for steel making is estimated to be 24 GJ/tonne. The most energy-efficient process requires 19 GJ/tonne for primary steel and 7 GJ/tonne for secondary steel. Seven specific smelting reduction pro-cesses and four groups of near-net-shape casting techniques are described and evaluated. In the longer term, the specific energy consumption for making steel from iron ore can be reduced to 12.5 GJ of primary steel per tonne. A further reduction of up to 2.5 GJ of crude steel per tonne may be achieved when tech-niques are developed that can recover and apply heat from the hot steel at a high temperature. The specific energy consumption for secondary steel making can be reduced to 3.5 GJ/tonne by energy-efficient melting and shaping techniques.
Article
A preliminary bottom-up analysis of the energy use in the chemical industry has been performed, using a model containing datasets on production processes for 52 of the most important bulk chemicals as well as production volumes for these chemicals. The processes analysed are shown to cover between 70% and 100% of the total energy use in the chemical sector. Energy use and the heat effects of the reactions taking place are separately quantified. The processes are also compared with energetically-ideal processes following the stoichometric reactions. The comparison shows that there is significant room for process improvements, both in the direction of more selective processes and in the direction of further energy-savings.
Article
In this study a method is suggested to compare the net carbon dioxide (CO2) emission from the construction of concrete- and wood-framed buildings. The method is then applied to two buildings in Sweden and Finland constructed with wood frames, compared with functionally equivalent buildings constructed with concrete frames. Carbon accounting includes: emissions due to fossil fuel use in the production of building materials; the replacement of fossil fuels by biomass residues from logging, wood processing, construction and demolition; carbon stock changes in forests and buildings; and cement process reactions. The results show that wood-framed construction requires less energy, and emits less CO2 to the atmosphere, than concrete-framed construction. The lifecycle emission difference between the wood- and concrete-framed buildings ranges from 30 to 130 kg C per m2 of floor area. Hence, a net reduction of CO2 emission can be obtained by increasing the proportion of wood-based building materials, relative to concrete materials. The benefits would be greatest if the biomass residues resulting from the production of the wood building materials were fully used in energy supply systems. The carbon mitigation efficiency, expressed in terms of biomass used per unit of reduced carbon emission, is considerably better if the wood is used to replace concrete building material than if the wood is used directly as biofuel.
Article
The relations between building material competitiveness and economic instruments for mitigating climate change are explored in this bottom-up study. The effects of carbon and energy taxes on building material manufacturing cost and total building construction cost are modelled, analysing individual materials as well as comparing a wood-framed building to a reinforced concrete-framed building. The energy balances of producing construction materials made of wood, concrete, steel, and gypsum are described and quantified. For wood lumber, more usable energy is available as biomass residues than is consumed in the processing steps. The quantities of biofuels made available during the production of wood materials are calculated, and the cost differences between using these biofuels and using fossil fuels are shown under various tax regimes. The results indicate that higher energy and carbon taxation rates increase the economic competitiveness of wood construction materials. This is due to both the lower energy cost for material manufacture, and the increased economic value of biomass by-products used to replace fossil fuel.
Article
There is a considerable disagreement in the literature on the magnitude of primary energy use and CO2 emissions linked to the production of buildings. In this paper we assess the Swedish building sector using top-down input–output analysis. These top-down results are then disaggregated into sectors and activities, which are compared to results from 18 previous bottom-up studies using process-LCA methodology. The analysis shows almost 90% higher specific energy use (GJ/m2) for the top-down methodology. The differences are only around 20% for the share coupled to production and processing of building materials, while for other involved sectors such as transport, construction activities, production of machines and service sectors, the input–output analysis gives much higher values. Some of these differences can be explained by truncation errors due to the definition of system boundaries in the bottom-up studies. The apparent underestimation of energy use for transport, services etc. in bottom-up studies is only of marginal importance when comparing for example materials choices, but when comparing the production phase to the use phase of buildings such errors are likely to result in an underestimation of the relative importance of the production phase since the use phase is dominated by more easily estimated direct energy use.
Article
More than 50% of the CO2 emitted during cement production originates from the calcination of limestone. This CO2 is reabsorbed during the life cycle of cement based product such as concrete and mortars in a process called carbonation.The impact that concrete carbonation has in the assessment of CO2 emissions from cement production has not been fully documented. Specifically, there is a lack of knowledge about the carbonation of demolished and crushed concrete. The existing models for calculating carbonation do not take into account what takes place after the concrete has been demolished. Consequently, the contribution of the cement and concrete industry to net CO2 emissions may be significantly overestimated.This paper encompasses theoretical work, laboratory studies, surveys and calculations based on the concrete production in the Nordic countries of Denmark, Iceland, Norway and Sweden. The estimated CO2-uptake through carbonation of the concrete produced in the year 2003 seems during a 100 year period to amount to a significant proportion of the CO2 emitted by calcination of the raw mix used to produce the Portland cement used in the concrete.
Article
In this study we investigate the effects of post-use material management on the life cycle carbon balance of buildings, and compare the carbon balance of a concrete-frame building to that of a wood-frame building. The demolished concrete is either landfilled, or is crushed into aggregate followed by exposure to air for periods ranging from 4 months to 30 years to increase carbonation uptake of CO2. The demolished wood is assumed to be used for energy to replace fossil fuels. We calculate the carbon flows associated with fossil fuel used for material production, calcination emission from cement manufacture, carbonation of concrete during and after its service life, substitution of fossil fuels by recovered wood residues, recycling of steel, and fossil fuel used for post-use material management. We find that carbonation of crushed concrete results in significant uptake of CO2. However, the CO2 emission from fossil fuel used to crush the concrete significantly reduces the carbon benefits obtained from the increased carbonation due to crushing. Stockpiling crushed concrete for a longer time will increase the carbonation uptake, but may not be practical due to space constraints. Overall, the effect of carbonation of post-use concrete is small. The post-use energy recovery of wood and the recycling of reinforcing steel both give higher carbon benefit than the post-use carbonation. We conclude that carbonation of concrete in the post-use phase does not affect the validity of earlier studies reporting that wood-frame buildings have substantially lower carbon emission than concrete-frame buildings.
Article
The purpose of this paper is to assess fuel choices in the transportation sector under stringent global carbon constraints. Three key questions are asked: (i) when is it cost-effective to carry out the transition away from gasoline/diesel; (ii) to which fuel is it cost-effective to shift; and (iii) in which sector is biomass most cost-effectively used? These questions are analyzed using a global energy systems model (GET 1.0), with a transportation module, where vehicle costs (fuel cell, reformer and storage tank), infrastructure and primary energy availability are treated explicitly. The model is run under the assumption that atmospheric concentrations of CO2 should be stabilized at 400 ppm. Three main results emerge: (i) despite the stringent CO2 constraints, oil-based fuels remain dominant in the transportation sector over the next 50 years; and (ii) once a transition towards alternative fuels takes place, the preferred choice of fuel is hydrogen, even if we assume that hydrogen fuel cell vehicles are substantially more costly than methanol fuel cell vehicles. There may, under some circumstances, be a transient period of several decades with a significant share of methanol in the transportation sector. (iii) Biomass is most cost-effectively used in the heat and process heat sectors. If carbon sequestration from biomass is allowed, biomass is primarily used for hydrogen generation since small-scale heat applications are not suitable for carbon sequestration. Detailed sensitivity analyses show that these results are robust with respect to several parameters. Some policy conclusions are drawn.
Article
This paper investigates the amount of energy required to construct buildings, and the resulting carbon dioxide emissions to the atmosphere from the fossil fuel components of that energy. Energy requirements and carbon dioxide emissions are compared for typical commercial, industrial and residential buildings, using New Zealand as an example. A modest change from concrete and steel to more wood construction could lead to a substantial reduction in energy requirements and carbon dioxide emissions, but the sustainability of such a change has significant forestry implications.
Article
In this study we examine the use of wood products as a means to mitigate climate change. We describe the life cycle of wood products including forest growth, wood harvest and processing, and product use and disposal, focusing on the multiple roles of wood as both material and fuel. We present a comparative case study of a building constructed with either a wood or a reinforced concrete frame. We find that the production of wood building material uses less energy and emits less carbon than the production of reinforced concrete material. We compare the relative cost of the two building methods without environmental taxation, under the current Swedish industrial energy taxation regime, and in scenarios that incorporate estimates of the full social cost of carbon emission. We find that the inclusion of climate-related external costs improves the economic standing of wood construction vis-à-vis concrete construction. We conclude that policy instruments that internalise the external costs of carbon emission should encourage a structural change toward the increased use of sustainably produced wood products.
Article
Total energy use during the life cycle of a building is a growing research field. The embodied energy makes up a considerable part of the total energy use in low energy buildings. Recycling provides the opportunity to reduce the embodied energy by using recycled materials and reusable/recyclable materials/components. This paper presents values on embodied energy, energy needed for operation and the recycling potential of the most energy efficient apartment housing in Sweden (). In a life span of 50 years, embodied energy accounted for 45% of the total energy need. The recycling potential was between 35% and 40% of the embodied energy.
Article
A variety of factors affect the energy and CO2 balances of building materials over their lifecycle. Previous studies have shown that the use of wood for construction generally results in lower energy use and CO2 emission than does the use of concrete. To determine the uncertainties of this generality, we studied the changes in energy and CO2 balances caused by variation of key parameters in the manufacture and use of the materials comprising a wood- and a concrete-framed building. Parameters considered were clinker production efficiency, blending of cement, crushing of aggregate, recycling of steel, lumber drying efficiency, material transportation distance, carbon intensity of fossil fuel, recovery of logging, sawmill, construction and demolition residues for biofuel, and growth and exploitation of surplus forest not needed for wood material production. We found the materials of the wood-framed building had lower energy and CO2 balances than those of the concrete-framed building in all cases but one. Recovery of demolition and wood processing residues for use in place of fossil fuels contributed most significantly to the lower energy and CO2 balances of wood-framed building materials. We conclude that the use of wood building material instead of concrete, coupled with greater integration of wood by-products into energy systems, would be an effective means of reducing fossil fuel use and net CO2 emission to the atmosphere.
Article
This paper assesses a construction and demonstration (C&D) waste recycling program in relation to technical, institutional, and economic considerations. The focus is primarily placed on a feasibility study for a new mechanical sorting process that was installed with several unit operations, including bar screening, trommel screening, air classifier, disk screening, and final manual sorting. Lab analyses, consisting of sieve analysis, LA abrasion test, friability test, organic content test, and fineness test, with respect to three types of product streams (A, B, and C) were conducted in accordance with selected physical and chemical properties. Findings clearly indicate that the reuse of fine particle generated in product stream A as construction materials in roadbed is highly recommended if the impurities can be removed beforehand. The product stream B could be suitable for reusing as the covering materials in daily operation of sanitary landfills. Yet it could also be used as backfill materials in the construction projects if the impurities can be removed in advance. Only does the LA abrasion test support the reuse of product stream C as coarse aggregate or pavement subbase for those new structures. Once the secondary materials market is stable and the institution settings are sufficient, it is worthwhile addressing that the associated cost-benefit analysis does confirm the economic potential for such a management practice.
Article
In this paper, primary energy use and carbon dioxide (CO2) and methane (CH4) emissions from the construction of a multi-storey building, with either a wood or a concrete frame, were calculated from life-cycle and forest land-use perspectives. The primary energy input (mainly fossil fuels) in the production of building materials was found to be about 60–80% higher when concrete frames were considered instead of wood frames. The net greenhouse gas (GHG) balance for wood materials will depend strongly on how the wood is handled after demolition of the building. The nrt GHG balance will be slightly positive if all the demolition wood is used to replace fossil fuels, slightly negative if part of the demolition wood is re-used, and clearly positive if all wood is deposited in landfills, due to the production of CH4. However, if the biogas produced is collected and used to replace fossil fuels, the net GHG emissions will be insignificant. If concrete frames are used, the net GHG emissions will be about those when demolition wood from the wood-framed building is deposited in landfills and no biogas is collected. We have considered that the CO2 released from the chemical processes in the production of cement will be re-bound to the concrete by the carbonisation process. Otherwise, the net GHG emission would be more than twice as high when concrete frames are used. If forest biomass is used instead of fossil fuels, the net area of forest land required to supply both raw material and energy for the production of building materials, will be about twice as high when wood frames are used instead of concrete frames. However, the GHG mitigation efficiency, expressed as CO2 equivalents per unit area of forest land, will be 2–3 times higher when wood frames are used if excess wood waste and logging residues are used to replace fossil fuels. The excess forest in the concrete frame alternative is used to replace fossil fuels, but if this forest is used for carbon storage, the mitigation efficiency will be higher for the first forest rotation period (100 yr), but lower for the following rotation periods. Some of the data used in the analyses are uncertain, but an understanding of the complexity in comparing different alternatives for utilising forest for GHG mitigation, and of the fact that the time perspective applied affects the results markedly, is more important for the results than the precise figures in the input data.
Article
Data developed by the Consortium for Research on Renewable Industrial Materials were used to estimate savings of greenhouse gas emissions and energy consumption associated with use of wood-based building materials in residential construction in the United States. Results indicate that houses with wood-based wall systems require 15–16% less total energy for non-heating/cooling purposes than thermally comparable houses employing alternative steel- or concrete-based building systems. Results for non-renewable energy consumption are essentially the same as those for total energy, reflecting the fact that most of the displaced energy is in fossil fuels. Over a 100-year period, net greenhouse gas emissions associated with wood-based houses are 20–50% lower than emissions associated with thermally comparable houses employing steel- or concrete-based building systems. Assuming 1.5 million single-family housing starts per year, the difference between wood and non-wood building systems represents about 9.6 Mt of CO2 equivalents per year. The corresponding energy benefit associated with wood-based building materials is approximately 132 PJ year−1. These estimates represent about 22% of embodied energy and 27% of embodied greenhouse gas emissions in the residential sector of the US economy. The results of the analysis are very sensitive to assumptions and uncertainties regarding the fate of forestland that is taken out of wood production due to reduced demand for wood, the continued production of co-products where demand for wood products is reduced, and the rate at which carbon accumulates in forests.
Article
This study investigates the global impact of wood as a building material by considering emissions of carbon dioxide to the atmosphere. Wood is compared with other materials in terms of stored carbon and emissions of carbon dioxide from fossil fuel energy used in manufacturing. An analysis of typical forms of building construction shows that wood buildings require much lower process energy and result in lower carbon emissions than buildings of other materials such as brick, aluminium, steel and concrete. If a shift is made towards greater use of wood in buildings, the low fossil fuel requirement for manufacturing wood compared with other materials is much more significant in the long term than the carbon stored in the wood building products.As a corollary, a shift from wood to non-wood materials would result in an increase in energy requirements and carbon emissions.The results presented in this paper show that a 17% increase in wood usage in the New Zealand building industry could result in a 20% reduction in carbon emissions from the manufacture of all building materials, being a reduction of about 1.5% of New Zealand’s total emissions. The reduction in emissions is mainly a result of using wood in place of brick and aluminium, and to a lesser extent steel and concrete, all of which require much more process energy than wood. There would be a corresponding decrease of about 1.5% in total national fossil fuel consumption. These figures have implications for the global forestry and building industries. Any increases in wood use must be accompanied by corresponding increases in areas of forest being managed for long term sustained yield production.
Article
Establishing a successful construction/demolition (C&D) waste recyling operation in the USA is a challenge today, especially because secondary materials markets have not yet matured. Increasingly, municipal solid waste (MSW) landfill operations refuse to accept C&D waste. Skyrocketing tipping fees due to the scarcity of landfill sites, and growing concerns from regulatory agencies and the public, have placed C&D waste recycling operations under intense scrutiny. The experiences of regional C&D recyclers indicate that successful recycling operations require a minimum of 0.8 ha of clear space for processing equipment, incoming waste stockpiles, recycled materials, and manoeuvring room for mobile equipment and operations. Reasonable quality, reliable equipment suitable for these operations generally costs between $300 000 and $750 000 for a 400-500 tonne/day operation. At present, operators of these facilities make a profit almost solely on tipping fees, with the recycling operation functioning mainly to maintain materials throughput. Different categories of C&D recycling machinery and waste processing strategies are presented. Strategies for converting C&D landfills into successful C&D recycling operations are also examined. C&D waste recycling economics are presented to demonstrate the essential ingredients for successful operations.
Environmental impacts of the New Zealand building industry, Research Rep. 92-2
  • Honey Bg Buchanan
Honey BG, Buchanan AH. Environmental impacts of the New Zealand building industry, Research Rep. 92-2. New Zealand: Department of Civil Engineering, University of Canterbury; 1992.
Energy use and environmental impact of new residential buildings
  • K Adalberth
Adalberth K. Energy use and environmental impact of new residential buildings. PhD dissertation. Department of Building Physics, Lund University, Sweden; 2000.
Wâlludden trâhus i fem våningar e Erfarenheter och lârdomar. Rapport TVBK-3032. Lund: Tekniska Hàgskolan i Lund
  • S Persson
Persson S. Wâlludden trâhus i fem våningar e Erfarenheter och lârdomar. Rapport TVBK-3032. Lund: Tekniska Hàgskolan i Lund; 1998.
LCA of building frame structures: environmental impact over the life cycle of wooden and concrete frames
  • T Björklund
  • A M Tillman
Björklund T, Tillman AM. LCA of building frame structures: environmental impact over the life cycle of wooden and concrete frames. Technical Environmental Planning Report 1997:2. Gothenburg, Sweden: Chalmers University of Technology; 1997.
Energi-och miljøanalyser af bygninger. SBI-meddelelse 108. Denmark: Statens Byggeforskningsinstitut
  • P Nielsen
Nielsen P. Energi-och miljøanalyser af bygninger. SBI-meddelelse 108. Denmark: Statens Byggeforskningsinstitut; 1995.
Emerging scarcities Scarcity and growth revisited. Natural resources and the environment in the new millennium
  • C Azar
  • Simpson Rd
  • Ma Toman
  • Ayres
Azar C. Emerging scarcities. In: Simpson RD, Toman MA, Ayres RU, editors. Scarcity and growth revisited. Natural resources and the environment in the new millennium; 2005.
Opportunities of using sawmill residues in Australia. Forest and Wood Products in Australia Limited
  • D Goble
  • C Jarvis
Goble D, Jarvis C. Opportunities of using sawmill residues in Australia. Forest and Wood Products in Australia Limited; 2007.
Building materials and CO 2 . Western European emission reduction strategies. ECN-C-97e065
  • D J Gielen
Gielen DJ. Building materials and CO 2. Western European emission reduction strategies. ECN-C-97e065. Petten, The Netherlands: Energy research Centre of the Netherlands (ECN); 1997.
Energy and communications. Mer trä i byggandet e Underlag för en nationell strategi att främja användningen av trä i byggandet
  • Ministry
  • Enterprise
Ministry of Enterprise. Energy and communications. Mer trä i byggandet e Underlag för en nationell strategi att främja användningen av trä i byggandet, vol. 1. Stockholm: Regeringskansliet, Näringsdepartementet; 2004.
Construction: construction costs for new residential buildings
Statistics Sweden. Construction: construction costs for new residential buildings 2007, BO 26 SM 00802; 2009.
Environmental impacts of the New Zealand building industry
  • B G Honey
  • A H Buchanan
Honey BG, Buchanan AH. Environmental impacts of the New Zealand building industry, Research Rep. 92-2. New Zealand: Department of Civil Engineering, University of Canterbury; 1992.
Scarcity and growth revisited. Natural resources and the environment in the new millennium
  • C Azar
Azar C. Emerging scarcities. In: Simpson RD, Toman MA, Ayres RU, editors. Scarcity and growth revisited. Natural resources and the environment in the new millennium; 2005.