The constant increase in the use of biomass fuels has raised prices of the most common commercial products and consequently seeking for new alternative biomass resources for thermal conversion, like some industrial and agricultural wastes, becomes an interesting issue. To this aim, thirteen alternative raw biomass samples were analyzed and compared with briquette, wood pellets, and charcoal. Their proximate, ultimate and calorimetric analysis and physical properties data have been considered. In the same way gaseous-emissions, ash composition, deposition and corrosion tendencies were evaluated. In addition to these intrinsic and environmental parameters, a general economic study, based on our previously obtained data, has been developed. Some of the selected samples, like almond shell and especially olive stone, seem to be optimum biomass resources to use instead of wood pellets, charcoal or briquettes in grate boilers, while some others require pretreatment to improve their characteristics and make them suitable alternatives to be considered in a short term future. (C) 2017 Elsevier Ltd. All rights reserved.