Life cycle primary energy use and carbon footprint of wood-frame conventional and passive houses with biomass-based energy supply

• In this study the primary energy use and carbon footprint over the life cycle of a wood-frame apartmentbuilding designed either conventionally or to the passive house standard are analyzed. Scenarioswhere the building is heated with electric resistance heaters, bedrock heat pump or cogeneration-baseddistrict heat, all with biomass-based energy supply, are compared. The analysis covers all life cyclephases of the buildings, including extraction of raw materials, processing of raw materials into buildingmaterials, fabrication and assembly of materials into a ready building, operation and use of the buildings,and the demolition of the buildings and the post-use management of the building materials. Theprimary energy analysis encompasses the entire energy chains from the extraction of natural resourcesto the delivered energy services. The carbon footprint accounting includes fossil fuel emissions, cementprocess reaction emissions, potential avoided fossil fuel emissions due to biomass residues substitutionand end-of-life benefit of post-use materials. The results show that the operation of the buildingaccounts for the largest share of life cycle primary energy use. The passive house design reduces theprimary energy use and CO2 emission for heating, and the significance of this reduction depends onthe type of heating and energy supply systems. The choice of end-use heating system strongly influencesthe life cycle impacts. A biomass-based system with cogeneration of district heat and electricitygives low primary energy use and low carbon footprint, even with a conventional design. The amountof biomass residues from the wood products chain is large and can be used to substitute fossil fuels.This significantly reduces the net carbon footprint for both the conventional and passive house designs.This study shows the importance of adopting a life cycle perspective involving production, construction,operation, end-of-life, and energy supply when evaluating the primary energy use and climaticimpacts of both passive and conventional buildings.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Samhällsbyggnadsteknik -- Husbyggnad (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Civil Engineering -- Building Technologies (hsv//eng)

Nyckelord

Byggteknik

Civil engineering

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