Fuel quality of stored wood chips Influence of semi-permeable covering material

Storage is an important component in securing the supply chain for forest fuels, but can result in substantial dry matter and energy losses that reduce the economic value of the material. This study examined fuel quality and amount of recovered energy during storage of forest-residue chips stored in a full-scale pile and the effect of covering the pile with a water-resistant, vapour-permeable fabric. Moisture content in the covered part declined continuously during the trial, while mean moisture content in the uncovered part did not change, due to rewetting at the surface. Average dry matter losses after seven months were 5.8% in the covered part and 7.3% in the uncovered part. Combined changes in fuel quality and dry matter decreased the amount of assessable energy (expressed as net calorific value as-received from an initial kg of dry base) by 5.3% in the uncovered part and 0.6% in the covered part. Thus covering the pile with a semi-permeable fabric provides opportunities to store wood chips at lower cost.