Energy and climate impact assessment of waste wood recovery in Switzerland

Abstract

Waste wood represents as much a waste to dispose of as a secondary resource to exploit. Various studies have assessed the energy potential and/or climate impact of energy recovery from waste wood. This paper aims to assess the long-term potential of waste wood for energy production and greenhouse gas (GHG) emissions reduction in Switzerland. Material flow analysis (MFA) is applied for modelling the metabolism of wood and waste wood in the Swiss anthroposphere over one century. The energy and climate impacts are estimated for 32 scenarios which assume different forest harvesting variants and waste wood treatment options. The scenario analysis shows that waste wood treatment options are more beneficial in the long term in terms of energy production (by energy recovery from waste wood) and of GHG emission reduction than the increase in the quantities of waste wood generated in the future caused by the advocated strategies of increased forest harvesting. By using the Maximin criterion, the long-term optimal additional potential for energy recovery from waste wood is estimated at 2110 GWh/year of useful energy, which offers a reduction of 364 tonnes of CO2 equivalents per year. As prerequisites, the nominal installed capacity of the waste wood boilers needs to be raised and their efficiency and as well as those of incineration plants need to be increased. In addition, the sustainable potential of Swiss forests must be fully exploited. This study identifies various recommendations for the optimal exploitation of energy recovery from waste wood.