Contents lists available at ScienceDirect Industrial Crops & Products journal homepage: www.elsevier.com/locate/indcrop Impact of storage on energy performance of laricio pine wood chips: A case study in Italy Cinzia Buratti a,b , Francesco Cristarella Orestano b , Franco Cotana a,b , Pietro Quaglietta c , Pamela Antonelli c , Marco Barbanera b,d, ⁎ a Department of Engineering, University of Perugia, Via G. Duranti 67, 06125, Perugia, Italy b Biomass Research Centre, University of Perugia, Via G. Duranti 67, 06125, Perugia, Italy c Enel Produzione Spa, Via Carlo Bini, 2, 50134, Firenze, Italy d Department of Economics, Engineering, Society and Business Organization, University of Tuscia, 01100, Viterbo, Italy ARTICLE INFO Keywords: Wood chips Storage Covering systems Losses Heating value ABSTRACT This study evaluated the influence of storage method on the physical and chemical properties of laricio pine wood chips for energy generation in the region of Basilicata, Italy. The storage of wood chips is a key factor in the wood fuel supply chain because it allows to compensate temporal differences between production and consumption stages. Experimental trials were performed analyzing three storage methods of wood chips: un- covered pile, under vapour-permeable and waterproof cover (PP sheet), and under waterproof PVC cover (PVC sheet). During six months of storage (from August 2016 to January 2017), only the wood chips pile covered under PP sheet registered a decrease in moisture content (about -19%). Use of cover made of vapour-permeable material was also found to improve the heating value of biomass (about +15%). However, the ash content was observed to increase throughout the storage period, reaching the maximum value for the uncovered wood chips pile (about +74%). No statistically significant differences between PP and PVC sheets were detected for dry matter losses, while significant energy losses were found in every kind of storage system. As a result of the analyzed weather conditions, open-air uncovered storage is suitable for short-term storage periods (less than 2 months), while for long-term period the use of permeable covers is more profitable. 1. Introduction In Europe bioenergy is currently the main contributor to primary energy supply between other renewable sources, accounting for 61 percent of all renewable energy consumed in 2014 (AEBIOM, 2016). Furthermore, solid biomass is the market driver for bioenergy, mostly including woody biomass. For instance, in Italy it is expected that the role of bioenergy in the electricity sector will be increased up to 1.63 Mtoe in 2020, mostly by growing use of solid biomass (Paiano and Lagioia, 2016). Among the different types of biofuels, wood chips are the most used feedstock in Italian power plants (about 1.8 Mton per year), mainly due to the availability of national forest (about 4.9 Mm 3 ), exploited with a short cutting cycle (Krzyzaniak et al., 2016). In par- ticular, the largest share of wood chips is obtained from forest biomass as a side product of harvesting and thinning operations. To enhance competitiveness of primary forest fuels, several parameters have to be evaluated because the supply chain is more challenging and complex than that for many other products. In particular, storage is one of the most important stages of the wood chips supply chain, since it allows to compensate for the temporal variations between production and con- sumption. However, freshly harvested wood chips have a moisture content of 40–60% (Boubaker et al., 2016), thus feedstock is subjected to microbial attacks during prolonged storage (from several months to a year), causing degradation of the material. In particular, when the moisture content of any chipped organic material is higher than 20%, fungi and bacteria can colonize piles of comminuted material, leading to increase of internal temperature of the piles (), loss of dry matter (Barontini et al., 2014), reduction of energy content (Pecenka et al., 2014), and risk of self-ignition (Civitarese et al., 2015). In fact, in these conditions biomass could be subjected to different alteration processes, starting from auto-oxidative and enzymatic reactions of the extractive components producing the build-up of water and other subproducts (Brand et al., 2011). Several studies (Brand et al., 2011; Nicolaci et al., 2014; Jirjis, 2005) have been carried out to evaluate the changes in fuel quality and dry matter losses, which occur during storage of wood chips showing that, even if the higher heating value (HHV) could in some https://doi.org/10.1016/j.indcrop.2019.01.066 Received 24 September 2018; Received in revised form 29 January 2019; Accepted 31 January 2019 ⁎ Corresponding author at: Department of Economics, Engineering, Society and Business Organization, University of Tuscia, 01100, Viterbo, Italy. E-mail address: m.barbanera@unitus.it (M. Barbanera). Industrial Crops & Products 131 (2019) 301–306 Available online 07 February 2019 0926-6690/ © 2019 Elsevier B.V. All rights reserved. T