The outermost layer of the paddy grain is the rice husk, also called rice hull.
Burning rice husk producedrice husk ash (RHA), if the burning process is incomplete carbonized rice husk (CRH) is produced.
Rice husk is a difficult biomass fuel compared with wood and bagasse, due to high silica content of rice husk ash
The best estimate on costs for transporting rice husk was provided bythe faculty of Bogor Agricultural University as 200 Rp/M.T./kilometer in two-ton loads with a haul distance of five kilometers.
The annual production of rice husk is approximately 4.6 million tons.