Vineyard pruning residues pellets for use in domestic appliances: a quality assessment according to the EN ISO 17225

Nowadays many types of biomass are studied to satisfy the increased demand of renewable energy based on pellet combustion. However, only a few biomasses fulfil the high quality standard required for pellet used in domestic appliances. European and International standards in force define this quality of non-industrial use of pellets in term of the origin of biomass, physical, mechanical and chemical parameters. Vineyard residues are a worldwide potential source of energy but their compliance to be used in domestic pellet stoves has not been yet proven according to the new standards in force. In order to meet this need, this study makes an exhaustive characterisation of vineyard based pellets manufactured from residues of Prosecco (Glera variety) vineyards, assessing both the quality of biofuel and its behaviour during combustion in a domestic pellet stove. The quality of biofuel has been evaluated according to the in force standards for wood and non-woody pellets. The results show that vineyard pellets do not meet the type B quality standards required for non-industrial use of wood pellet mainly because of the high amount of ash content (> 2%) and the high amount of copper (> 10 ppm) but they fulfil the specifications of the type B non-woody pellets. Furthermore, during combustion test of vineyard-based pellet the high emission of CO indicates incomplete combustion; and vineyard-based pellet NOx emissions are more than double compared to those obtained during the control tests, confirming that the analysed vineyard-based pellets are unsuitable, as they are, for use in traditional pellet stoves.