Materials of organic-vegetable origin such as plants, seaweed, organic plant waste, wood, branches, wood chips, pellets, sawdust and all processing waste from the food industry or wood. They are the so-called biomass, a renewable source from which energy has long been produced. Biological residues are the fuel for efficient and high-performance boilers. Some of these, the polycombustibles, can use different types of biomass in order to make the utmost use of the material available at any given time. Biomass-type boilers can be used for the production of electrical and thermal energy, whether in residential units or for commercial and industrial activities.