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The experiment determined the technical and financial efficiency of five storage techniques, specifically designed for SRF poplar chips stored at the farm site in small (20 m3) piles. The treatments on test were: uncovered storage, storage under a temporary roof structure, cover under a semi-permeable fleece sheet, cover under two types of plastic sheet (i.e. white and black). Each treatment was replicated 3 times. Researchers monitored temperature and moisture content trends inside the piles, and determined dry matter losses at the end of the 170 days storage period. In general, piles under plastic cover presented opposite trends compared to all other piles. They acquired moisture rather than losing it, and showed gradual temperature trends instead of a typical peak-and-drop behaviour. Dry matter losses varied from 5.1% to 9.8%, and were highest for the uncovered treatment, and lowest for the plastic cover treatment. Under the conditions of north-western Italy, uncovered storage was a cost-effective option. Protecting the piles with some cover incurred more cost than it saved, resulting in a higher storage cost per unit energy. Although more expensive, sheltering the piles under a simple roof structure offered the benefit of a higher reduction of moisture content, which may turn the chips into a higher quality fuel. Of course, these results were closely related to the Southern European climate, and the specific year of the test. Occasional wetter years may overturn these results. © 2013 Elsevier Ltd. All rights reserved.

The experiment determined the technical and financial efficiency of five storage techniques, specifically designed for SRF poplar chips stored at the farm site in small (20 m3) piles. The treatments on test were: uncovered storage, storage under a temporary roof structure, cover under a semi-permeable fleece sheet, cover under two types of plastic sheet (i.e. white and black). Each treatment was replicated 3 times. Researchers monitored temperature and moisture content trends inside the piles, and determined dry matter losses at the end of the 170 days storage period. In general, piles under plastic cover presented opposite trends compared to all other piles. They acquired moisture rather than losing it, and showed gradual temperature trends instead of a typical peak-and-drop behaviour. Dry matter losses varied from 5.1% to 9.8%, and were highest for the uncovered treatment, and lowest for the plastic cover treatment. Under the conditions of north-western Italy, uncovered storage was a cost-effective option. Protecting the piles with some cover incurred more cost than it saved, resulting in a higher storage cost per unit energy. Although more expensive, sheltering the piles under a simple roof structure offered the benefit of a higher reduction of moisture content, which may turn the chips into a higher quality fuel. Of course, these results were closely related to the Southern European climate, and the specific year of the test. Occasional wetter years may overturn these results. © 2013 Elsevier Ltd. All rights reserved.

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We conducted a comparative study of chipping logging residues at the roadside landing or at the yarder pad, the latter inaccessible to heavy road vehicles. Field data was collected from real operations in the Italian mountain, and it was used for building a simulation model that could generalize the results of the study. The model was built with Arena 14 and carefully reflected interaction delays between individual units along the chain. Chipping at the pad with a chipper and two shuttles was the best compromise solution of low supply cost and fuel consumption. At a mean cost of Euro22.7 per fresh tonne, this solution was 10% cheaper than chipping at the landing. Using three chip shuttles did not allow a meaningful reduction of supply cost over a two-shuttle chain, but resulted in a 7% increase of fuel consumption. The distance between the pad and the roadside landing was by far the most important factor in determining supply cost, and accounted for 80% of the variability in the data, for both systems. Under these circumstances, the higher speed and payload of the chip shuttles made it preferable to chip at the pad, provided enough shuttles are available.

We conducted a comparative study of chipping logging residues at the roadside landing or at the yarder pad, the latter inaccessible to heavy road vehicles. Field data was collected from real operations in the Italian mountain, and it was used for building a simulation model that could generalize the results of the study. The model was built with Arena 14 and carefully reflected interaction delays between individual units along the chain. Chipping at the pad with a chipper and two shuttles was the best compromise solution of low supply cost and fuel consumption. At a mean cost of Euro22.7 per fresh tonne, this solution was 10% cheaper than chipping at the landing. Using three chip shuttles did not allow a meaningful reduction of supply cost over a two-shuttle chain, but resulted in a 7% increase of fuel consumption. The distance between the pad and the roadside landing was by far the most important factor in determining supply cost, and accounted for 80% of the variability in the data, for both systems. Under these circumstances, the higher speed and payload of the chip shuttles made it preferable to chip at the pad, provided enough shuttles are available.

Vineyards cover about eight millions of hectares worldwide and their annual pruning generates a large amount of ligno-cellulosic biomass, potentially available for industrial and energy use. Commercial pruning residue harvesters are now available, which may allow cost-effective recovery. The study aimed at determining the quantity and the quality of pruning residues potentially derived from vineyard management. Data were obtained from 17 fields in Northern and Central Italy. Fields were harvested with seven different machines. The experimental design adapted to the necessities of field trials, but was adequate for testing the main sources of variability. Net residue yield varies around 1 oven dry tonne per hectare, with minor differences between grape varietals and harvesting technologies. Losses are still high, and are generally related to ineffective management techniques. Moisture content at harvest varies between 40% and 45%, whereas the higher heating value is slightly lower than that of forest fuels. Comminuted vineyard residues are unsuitable for firing residential boilers, due to the frequent presence of oversize and/or undersize particles. The application of pesticides does not result in any significant contamination with noxious chemicals, because these products are almost completely weathered before residues are recovered. In wine-producing regions, the recovery of vineyard pruning residue may represent a substantial source of industrial bio-fuel. © 2011 Elsevier Ltd.