Management-related energy, nutrient and worktime efficiencies of the wood fuel production and supply chain: modelling and assessment

Abstract

Key messageThe modelling approach presented and tested in the present study relates local management decisions with efficiency indicators of the whole wood fuel chain, based on decisions ranging from silviculture to transport to customer. Energy and worktime efficiencies were better under large-scale energy production associated with high wood fuel demand, whereas nutrient efficiency was better under small-scale production associated with a moderate demand. Local management decisions all along the wood fuel chain highly influenced efficiency indicators, and thus its relevance for energy-transition policies.ContextBioenergy from wood can contribute to reach the goals of energy-transition policies. Use of wood as fuel should focus on low-quality wood, e.g. by-products from timber production, which production and supply is related to various management decisions. Reaching the policy objectives efficiently remains an issue.AimsThe aims are (1) to develop a modelling approach that links local management decisions with indicators of the whole wood fuel production and supply chain and (2) to test the model in a case study. The study should further provide first insights on how indicators of energy, nutrient and worktime efficiency vary according to wood fuel chain characteristics and the related management decisions.MethodsThe model depicts the flow of wood (biomass, nutrients, moisture content, heating value) from the forest stand to the heating plant for each silvicultural intervention simulated with a growth and yield model. It further quantifies the energy and worktime spent on different wood fuel chain tasks (e.g. felling, forwarding) set by the user. We defined four scenarios according to the scale of energy production (large vs. small) and the demand for wood fuel (high vs. moderate).ResultsThe case study revealed that the model outputs were plausible. Energy efficiency largely varied depending on the type of silvicultural intervention. Large-scale production associated with high demand was most favourable for energy and worktime efficiencies. In contrast, nutrient efficiency was best for small-scale production associated with moderate demand.ConclusionsLocal management decisions all along the wood fuel chain highly influenced efficiency indicators, and thus its relevance for energy-transition policies. Our model may contribute to strategic decision making in different forestry and energy production contexts.