Heat and cold production for winemaking using pruning residues: Environmental impact assessment

In grape production, managing the pruning residues is an issue due to economic (low value and poor market demand) and phytosanitary reasons. Energetic valorisation is an option but up to now, no attention has been paid on the possibility of valorising this biomass for the contextual generation of heat and cold to supply the requirement of winemaking. In this study, three scenarios are compared using the Life Cycle Assessment approach. In the Baseline Scenario, the pruning residues are left on the soil, in the Alternative Scenario 1 they are collected and used to produced heat and cold, while in the Alternative Scenario 2 only pruning residues needed to supply heat to the winery are collected. The environmental results are not univocal and the identification of the best scenario depends on the considered impact category. Alternative Scenario 1 involves environmental benefits for impact categories such as climate change, ozone depletion, acidification and freshwater eutrophication due to the avoided heat production from natural gas and to the avoided electricity consumption for cooling. The energetic valorisation of residues reduces (from 1.6 to 9.5 times) the environmental impact for the impact categories not affected by the emissions from wood combustion; for these impact categories, the impact increases from 4% to 38 times. Pollutants control devices should be considered in new installations while specific subsidies for this kind of investment should be foreseen by policymakers.