EVALUATION OF THE COHERENCE OF WASTE WOOD MANAGEMENT IN SWITZERLAND

摘要

Wood is one of the most important material flows used in Switzerland in the context of sub-exploitation of the sustainable potential of its forest resource. Various studies underline the benefits of the waste wood energy recovery in Switzerland on climate change mitigation and renewable energy production. However, the Swiss government acknowledges the presence of possible tensions between the goals of different federal policies which encourage individually or jointly the cascade use of wood, the energy or material recovery of waste wood. The aim of the present research is to evaluate the coherence of waste wood management in Switzerland. The question of a conflict of use between waste wood treatments is also studied. The structure of the proof rests, first, on a modelling of the metabolism of wood and waste wood in Switzerland over the period 2010-2110 by a Material flux analysis. Two scenarios are defined comparing the current domestic thermal treatments to the prospective scenario of waste wood cascade recovery on Swiss territory. Variants on additional options for its management are added under the assumption of the full exploitation of the full exploitation of the sustainable potential of the Swiss forest. This gives 16 different scenarios running with STELLA who generate climate and energy data. Secondly, a qualitative analysis is realized to find the causes of the waste wood management now prevailing in Switzerland. The evaluation of its coherence and the study of conflicts of use result from linking the quantitative data and the qualitative analysis. The simulation results show that the impacts of immediate waste wood energy recovery are less significant on CO2eq emissions reduction, but more significant on energy production than its cascade recovery on Swiss territory. The results give two win-lose situations where one scenario cannot maximize both the climatic and energy impacts. In addition, the results show that the prohibition to export waste wood, the increase of the energy efficiency of heat treatment plants and the improving of the sorting between hazardous and non-hazardous waste wood can improve the impact of waste wood management. The waste wood energy recovery has a relatively marginal influence on the CO2eq emissions diminution and the domestic energy production except to meet the heat demand. The consumption of wood products and waste wood material recovery do not result in perennial reductions of CO2eq but rather in a postponement in the future of the present emissions. Various "determiners" explain the current waste wood management.