Engr. Alexis T. Belonio, in a lecture given at PhilRice Los Banos on July 15, said rice husks and straws, found in the rice farming environment have so much potential as energy sources.
For an average harvest of 4.5 t/ha, there are around 900 kg of rice husks and 4,500 kg of rice straws.
“At 3,000 kcal/kg of rice husks and 4,000 kcal/kg of rice straws, there are about 20, 700, 000 kcal of energy available per hectare of rice farms. When gasified, it can provide 600 to 1,200 kcal/m3 of gas per kg of rice biomass,” Belonio explained.
Annually, around 2-3 M metric tons of rice husk and 15-17 M metric tons of rice straw are produced in the country.
Rice biomass does not only provide energy but also help in the restoration of the soil. It also contributes to carbon sequestration for GHG mitigation.
Belonio shared that there are many technologies developed using biomass energy to provide farmers alternative ways to improve rice farming operations.
Among these technologies are the rice husk conical grate, gasifier stoves, combustors for paddy drying, crude and hydrous bioethanol distillers, and retrofitted spark-ignition engines.
The conical grate rice husk stove is a direct combustion device for household cooking and small-scale industries using rice husks as fuel. The typical household-size stove requires 1-2 kg/hr and boils 2 L of water in 14-18 min. Price ranges from P500-2,000 per unit.
The rice husk gas stove requires a small fan (either AC or DC) to supply the air required in gasifying rice husks. 1 kg of rice husk can supply heat for boiling 2 L of water in 8-14 min. Price ranges from P2,000-5,000 per unit.
Gasifiers provide clean energy for domestic and cottage industry.
Belonio hopes that with the growing demand for energy and declining supply of fossil fuel, research and academic institutions will work together to develop and improve further energy technologies.