biomass briquettes

a briquette may of compressed hay

Briquette made of compressed hay. Manufacturer: Ruf (Germany).

Biomass briquettes are a form of solid biofuel consisting of compressed, flammable biomass. Wood briquettes are a particular form of biomass briquettes produced from compressed sawdust. However, more generally, biomass briquettes may consist of a variety of different materials often derived from agricultural waste, including hay (see illustration), rice husks, bagasse, and groundnut shells.