An assessment of greenhouse gas emissions from CLT and glulam in two residential nearly zero energy buildings

ABSTRACT

This paper analyses and compares the embodied and operational greenhouse gas (GHG) emissions of two nearly Zero Energy Buildings, a student housing building in Trondheim, Norway, and a residential building in Växjö, Sweden. The student housing in Trondheim, Moholt Allmenning Tower B, is a 9-storey tower composed of cross laminated timber (CLT) panels and concrete floor slabs with a total heated floor area of 3801 m². The apartment building in Växjö, House A, consists of 8 floors composed of glued laminated timber (glulam) beams with a wood-cassette floor, and concrete slabs with a total heated floor area of 3483 m². The results show that the use of CLT has the largest reduction of total GHG emissions due to substituting concrete elements in the structural frame. The comparative assessment of the external wall and the internal floor constructions shows that the use of CLT adds marginal GHG emissions per unit of area of component. The calculation of operational GHG emissions shows that the use of the Nordic electricity mix disfavours the full-electric energy system of Moholt Allmenning Tower B, in contrast to the district heating used in Norra Vallen Building A.

KEYWORDS:

• Cross laminated timber
• environmental product declaration
• glue laminated timber
• greenhouse gas emission
• life cycle assessment
• nearly zero energy building

Acknowledgments

This work was supported by the EU Horizon 2020 NERO – Nearly Zero Energy Wooden Buildings in Nordic Countries under grant agreement 754177. Special thanks to Jan Johansson and Johan Thorsell of the Växjö Municipality, and Carina Herbertsson of the Växjö Bostader for helping on finding data and information.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by EU Horizon 2020 [grant number 754177].