Prolonged Carbon Storage and CO2 Reduction by Circular Design with Wood

The benefits of circularity and biogenic carbon storage are often overseen. This study links the circular design of buildings with prolonged biogenic carbon storage. Circularity in architectural design can involve extending the service life of a building frame, whilst forests grow back and store more carbon. Following this approach, Stora Enso has developed a mixed-use building concept with flexible and adaptable structures. Static and dynamic life cycle assessment (LCA) has been carried out to assess different scenarios, modelling and quantifying its potential benefits regarding whole life carbon. While whole life carbon is lower in all timber scenarios compared to conventional concrete buildings, dynamic LCA makes clear the benefits of carbon storage and carbon sequestration. Total emissions, considering a reference service life of 50 years, are 2,84 kg CO2-eq./m² floor area/year, considering biogenic carbon storage and carbon sequestration in regrowing forests. An increase of the building lifetime to 80 years aligns with a longer rotation time of forest trees, resulting in whole life carbon of -0,09 kg CO2-eq./m² floor area/year. This demonstrates that the effective implementation of built-in flexibility and adaptability can extend the service life of a building, unlocking environmental benefits of biogenic carbon storage of wood products in buildings.