This guide has been developed to provide information about the solid biofuel Quality Assurance and presents a methodology that helps operators in the solid biofuels industry design an appropriate Quality Assurance system according to their demands. It acts as a supporting document for the application of the CEN/TS 15234 developed by CEN/TC 335.This guide is applicable for all operators dealing with solid biofuels within the scope of CEN/TC 335 from the following sources (CEN/TS 14961):- products from agriculture and forestry;- vegetable waste from agriculture and forestry;- vegetable waste from food processing industry;- wood waste, with the exception of wo