The need for a practical, economic and environmentally sound solution for old timber and used wood-based products arises by the requirements for resource conservation and by recent regulations. Co-firing coal with waste wood is the most promising option to contribute to the thermal recycling of solid wastes.

The overall environmental impact caused by the co-utilisation of waste wood with coal was evaluated by using Life Cycle Assessment (LCA) as established by SETAC. This provide opportunities to evaluate direct environmental impact of various processes, to identify interventions for improvement, and to apply those results to reduce energy resource consumption and environmental emissions from the beginning to the end of the life of a product.

In this work the environmental impact of co-utilising lignite and waste wood in an industrial steam boiler was evaluated. Results obtained showed, that co-utilisation is technically feasible provided that agglomeration problems could be confronted. Moreover, it can meet strict environmental standards in relation to toxic gas and heavy metals emissions. A net decrease of CO2 emissions can be achieved by the thermal use of waste wood. Furthermore, co-firing offers a number of technical, economical and environmental benefits in addition to reduced net CO2 emissions, such as conservation of fossil fuel resources, minimisation of waste disposal and reduction of the dependence on fuel imports.

Keywords : LCA, coal, waste wood, co-utilisation