Wood in carbon efficient construction (€CO2)
Title of the research project: Wood in carbon efficient construction (€CO2)
Coordinator of the project Mr. Matti Kuittinen, Aalto University
Project period 01.12.2010 – 31.03.2013
URL of the project http://www.eco2wood.com
FUNDING
Total budget in EUR 2 119 931,50
PROJECT TEAM
Work Package 1
Leif Gustavsson, PhD M Linnaeus University Professor Sweden Ambrose Dodoo, PhD M Linnaeus University Senior Lecturer Sweden Roger Sathre, PhD M Linnaeus University Researcher Sweden Krushna Mahapatra, PhD M Linnaeus University Senior Lecturer Sweden Per-Erik Eriksson M SP Wood Technology Head of section Sweden Joakim Noren M SP Wood Technology Dr., LCA specialist Sweden Diego Peñaloza M SP Wood Technology Dr., LCA specialist Sweden
Work Package 2
Matti Kairi, Dr., M Aalto University Professor Finland Lauri Likosalmi, M.Sc. M Aalto University Researcher Finland Atsushi Takano, M.Sc. M Aalto University Researcher Finland Anna Fomkin, M.Sc. F Aalto University Researcher Finland
Work Package 3
Tarja Häkkinen, Dr. F VTT Senior principal scientist Finland Sirje Vares, M.Sc F VTT Senior scientist Finland Antti Ruuska, M.Sc M VTT Research scientist Finland Nusrat Jung, M.Sc F VTT Research scientist Finland Appu Haapio, Dr. F VTT Senior scientist Finland
Work Package 4
Winter, Stefan. Dr.-Ing M TU München Professor Germany Hafner, Annette. Dr.-Ing F TU München Researcher Germany Ott, Stephan. Dipl.-Ing. M TU München Researcher Germany Takano, Atsushi M Aalto University M.Eng. (Arch.), Researcher Finland Department of Forest Products Technology Kuittinen, Matti M Aalto University, M.Sc (Arch.) Researcher Finland Department of Architecture
Work Package 5
Tomi Toratti M VTT Dr., Senior researcher Finland Jesper Arfvidsson M Lund University Dr., Professor Sweden S Olof Mundt-Petersen M Lund University Researcher, PhD cand. Sweden Jorma Heikkinen M VTT M.Sc.(Eng), Senior Researcher Finland
Work Package 6 (also part of WP Austria)
Saana Tykkä F BOKU MA, Researcher Austria Gerhard Weiss M BOKU Dipl-Ing.Dr., Area leader Austria Alice Ludvig F BOKU Dr., Senior Researcher Austria
Work Package Austria
Franz Dolezal, Dr M Holzforschung Senior researcher Austria Alexander Deutsch, DI M Holzforschung Researcher Austria Christina Spitzbart F Holzforschung Mag. (FH) Austria Sylvia Polleres, DI F Holzforschung Senior researcher Austria Rupert Wolffhardt, Ing. M Holzforschung Senior researcher Austria Hildegund Mötzl, Mag. F IBO Key researcher Austria Philipp Boogman, DI M IBO Senior researcher Austria Robert Stanek, DI M IBO Researcher Austria Astrid Scharnhorst, DI(FH) F IBO Researcher Austria Susanne Geissler, Mag.Dr F Austrian Energy Agency Senior researcher Austria Silke Mader, Dr. F Austrian Energy Agency Senior researcher Austria Maria Amtmann, DI F Austrian Energy Agency Researcher Austria Oskar Mair am Tinkhof M Austrian Energy Agency Junior researcher Austria Michael Klinski, DI M Austrian Energy Agency Senior researcher Austria
SUMMARY AND CONCLUSIONS
Statements such as “wood is an environmentally friendly material” or “wooden houses can function as carbon storages” can sound very convincing but sometimes seem to lack concrete scientific proofs. The single chapters of this book have tried to bridge such gaps by applying concrete methods for defining carbon footprint of buildings during their full life cycles.
Therefore, chapter two (“Backgrounds”) has outlined two approaches towards Life Cycle Analysis (LCA)-measurements, namely attributional or consequential and has described the environmental policies, norms and standards that are currently framing such environmental assessments for the building sector.
There are several necessary parts and phases which must be included into such an analysis. Therefore the subsequent chapter three (“Greenhouse gas and primary energy balances”) presents definitions of the functional units, evaluation indicators as well as the system boundaries. Thus, LCA involves material and energy flows within and between different economic sectors including forestry, manufacturing construction, energy and waste management.
At the building level, chapter four (“Carbon footprint calculation methodology”) introduces in detail the following necessary information that is required for practical assessment of the environmental impact of whole buildings: Quantities and qualities of building materials, environmental impacts of products, energy demand of the building and energy supply systems. According to the situation, service life of building components and elements also has to be taken into account. Calculations of wooden-based building-systems are rather complex and sometimes practical simplifications may be required and are also proposed when they shall include only direct environmental effects from a building. The chapter suggest therefore a simple but accurate system-approach as the best starting point.
In order to cover the full value chain chapter five (“Environmental aspects of raw material supply and manufacturing”) complements these findings with the life cycle aspects at the wooden product level. It is most often the information on the single products that has to be compared when designing, planning and building a house. Here the assessment considered the extraction of raw materials, transportation and manufacturing stages of the products and discusses the impacts of different factors on the carbon footprint of sawn timbers. It suggests improvements for new eco-efficient solutions such as needs for different seasoning of timber but also a consideration of variations in saw mill-specific results.
Building up on the fundamentals of system boundaries for practical LCAs of whole buildings from chapter four, chapter six (“Good practices for carbon efficient wood construction”) demonstrates applied good practices for carbon efficient wood constructions. It outlines the design phase for low carbon wooden houses and evaluates the influence of the construction phase as well as different production phases (on-site versus off-site). Furthermore it demonstrates the influences of transportation and waste management, the influences of use and maintenance phase as well as the influences of end-of-life, deconstruction and recycling phases for wooden materials.
Subsequent chapter seven (“Service life and moisture safety”) outlines in detail possibilities for risk reduction of risks commonly attributed with wooden buildings. For a wooden building sufficiently long service life phases are necessary in order to compete with other buildings. Heat, moisture and air are interrelated and influence the service life of wooden buildings and therefore they have to be considered already in the planning phase. The chapter shows how moisture control and indoor environment shall be assessed and predicted and outlines five factors that unconditionally have to be considered for wooden buildings.
The final chapter six on case studies applies all findings with calculating the energy efficiency and carbon efficiency for eight wood-framed buildings from Austria, Finland, Germany, Italy and Sweden. It shows how the use of wood affects to carbon footprint and primary energy demand of wood-framed buildings.
Overall, our findings indicate that there are convincing advantages and potentials of using wood in construction for mitigating climate change, however, the current normative political framework in these emerging matters is still under development. The scientifically proven methods and measures for assessing the benefits of wood are extensively outlined and discussed in this book. The lifecycles of buildings involve a number of material and energy flows in different phases of the construction. These flows include forestry, transportation, manufacturing of products, construction, energy use, waste management and recycling. Especially for wooden buildings there is a considerable amount of information required and carbon footprint analysis is more complex than that of many other products. When the assessment focuses on the building itself, this book suggests practical system simplifications. It also outlines the changes that can be caused when different building designs are applied. The system boundaries and principles used for calculation can significantly influence the assessment results, therefore clear descriptions of all assessment assumptions and results are most fundamental requirements in all calculations. All case studies include the production phases and most include construction and end-of-life phases as well. For demonstration, use phases have been set to both 50 and 100 years. When case specific data was not available, Ecoinvent database was used.
From our findings we can conclude a number of insights for the use of wood in carbon efficient construction:
Full life cycle and energy chains should be considered with broad enough system boundaries to include all significant parts.
Simplified system boundaries are proposed for practical calculations of the direct environmental effects resulting from buildings.
Geographical and country specific differences have significant effects on carbon footprint of wood based products. Climatic differences have an impact on forest species and ways of logging and country specific energy mixes have an impact on CO2 emissions.
The book has demonstrated that country specific data should be made available and results should be presented separately for the different ways of accounting.
There should be optimal use of renewable energy sources in all phases of production and use phase.
Long-term and resource efficient use of wood for premium qualities, such as plywood, laminated wood and timber frame constructions are necessary for ensuring sustainable construction with wood.
Maintenance and material replacement have significant effects on durability of wooden buildings. The book lists out concrete moisture safety measures for an appropriate service life; these shall be already included in the design phase.
In the planning and design phase also the deconstruction, reuse and recycling of all products shall be considered.
Due to progressive technical developments, buildings might require less and less energy in the future. Thus, we foresee a shift in life cycle calculations from the use phase to the production phase. This is why efforts for reduction of carbon footprint and energy efficiency will become even more important for the construction phases of buildings. The present book is one step into this direction.