Eco-efficiency analysis of recycling recovered solid wood from construction into laminated timber products

To establish a bioeconomy, the demand for renewable resources like wood is likely to increase. To satisfy the demand, cascading, i.e. the sequential use of one unit of a resource in multiple applications with energy recovery as the final step, is a key concept to improve the efficiency of wood utilization. Today, the systematic wood cascading is still in its infancies and limited to the downcycling of wood, i.e. the degradation of material quality. New recycling technologies are needed, which maintain the material quality at the beginning of the cascade chain and mobilize yet unused resources. Therefore, a new recycling technology for recovered solid wood from construction into glued laminated timber products was developed.¹ To identify the environmental and economic performance of the process, the eco-efficiency was assessed by the joint application of life cycle assessment (LCA) and life cycle costing (LCC). As reference system, the incineration of the recovered wood was analyzed, representing the common treatment for recovered wood from construction in Germany. System expansion was applied to solve multifunctionality. The results indicate that the recycling of recovered wood into glued laminated timber products is environmentally and economically viable and offers possibility for the production of value added products. The recycling further shows up to 29% of lower environmental impacts and 32% of lower costs compared to the incineration, if system expansion is based on wood energy. The operational processes required for the solid wood cascading are of minor relevance for the economic and environmental performance. Instead, primary technologies like glue lamination and the incineration are key drivers. In all considered scenarios, the material recycling has a 15-150% higher eco-efficiency compared to the incineration. In conclusion, the further development for the practical implementation of the recycling process is recommended to enhance the implementation of the cascading concept.