Analysis of static and dynamic modelling approaches for temporal carbon sequestration in Life Cycle Assessment of harvested wood products

The use of bio-based materials such as wood is increasing in different industries due to the association of lower environmental impacts with bio-based materials. One advantage of bio-based materials is the conversion of atmospheric carbon dioxide into organic carbon during the biomass growth and the temporal carbon sequestration during the use stage. The quantification of this temporal carbon sequestration in the use stage and the time taken by the subsequent biomass generation to sequester carbon is not accounted for in state-of-the-art Life Cycle Assessment with static indicators such as Global Warming Potential 100, therefore neglecting temporal gaps between the release and sequestration of biogenic carbon. To account for this, the methodology of dynamic LCA is applied for a beechwood-based product. For this, different emission times of the product as well as emissions from a beech forest, derived from an implemented forest carbon model, are included in a dynamic Life Cycle Inventory. These emissions are then characterized dynamically with respect to the climate change impact category. Furthermore, different product lifetimes and by-product modelling approaches are applied to show the potential variability of the results due to modelling decisions. To enable a comparison, the two most common static LCA approaches for biogenic carbon are applied to the same product system, showing large differences between the static and dynamic approaches. The dynamic results showed, that no climate neutrality for the analyzed beech-wood material was reached within a timeframe of 100 years, when the product is being incinerated. Finally, the application of dynamic LCA for a second material lifetime is discussed.