The declining reserves and fluctuating prices of fossil fuels led to intensive search for an alternative to replace or complement petroleum derivates as main fuel resource. In this context biomass appears as an attractive feedstock, because of that a comprehensive characterization is needed, focusing morphological study, using scanning electron microscope (SEM) and particle size distribution, composition with X-ray dispersive energy (EDX), thermal analyses, using thermogravimetry and combustion gas analysis, to select the best behavior as a fuel from six biomass samples (almond shell, rice husk, straw, vegetable coal, wine pomace and a randomly chosen commercial brand of wood pellets) trying to comb all the range of commercial fuels most commonly available in the Spanish solid biofuel market. (c) 2011 Elsevier B.V. All rights reserved.