Biomass-based pellet fuels (“pellets” or “briquettes”) are solid bio-fuels that are prepared by compressing biomass materials, mostly in the form of lignocellulosic/woody biomass

Pellets can be prepared from any type of biomass, both fresh, e.g. energy crops and virgin lumber, as well as waste, for e.g. industrial waste and co-products, food waste, and agricultural residues. Among these, wood pellets are the most common one, which are generally prepared by compacting sawdust from industrial wood wastes from the milling of lumber, manufacturing of wood products and furniture, as well as construction. Other agricultural waste sources may include empty fruit bunches, palm kernel shells, coconut shells, and tree tops and branches, which are normally discarded during logging operations.

Biomass pellets are categorised by four factors, i.e. heating value, moisture and ash content, and dimensions. They are very dense and normally produced with a very low moisture content (below 10%), allowing for a high combustion efficiency. Traditionally, biomass pellets are used for home industry as an alternative fuel for cooking. Their use in commercial or residential heating may also applicable to a limited extent, especially in remote areas. Nowadays, due to environmental concerns and replacement of coal- and nuclear-based power plants, their use for power generation, for example in a combined heat and power (CHP) facilities, is recently increasing.