Environmental Assessment of Electricity Production from Rice Husk: A Case Study in Thailand

Abstract

The energy demand of Thailand has been steadily increasing at about 4% per year. A largeportion of the fossil fuels is imported thus causing concern for energy security. In addition, utilizationof fossil fuels is associated with emissions of CO2, SO2 and NOX leading to environmental impacts. To approach the reduction of these problems, alternative (renewable) energy sources are proposed.Rice husk is a potential source of energy for an agricultural country like Thailand with high riceproduction. Rice mills can use the rice husk generated by them as a fuel to produce energy. However,the environmental profile of the energy production must be assessed to ensure reduced environmentaldamage. This study has been carried out at the Roi Et Green Project which is a pilot project ofcapacity 9.8 MW using rice husk as the feedstock. The power plant uses 290 tons of rice husk and1,400 tons of water in one day, and has a power requirement of 1 MW. Net power output is 8.8 MW,which will be sold to Electricity Generation Authority of Thailand (EGAT) for 21 years under thesmall power producer (SPP) scheme. The raw materials consumed and environmental emissions ofenergy production from rice husk are determined. The study shows that the emissions of SO2 and NOXare lesser in case of coal and oil-fired power generation, but higher than for natural gas. Theemission of CO2 from combustion of rice husk are considered zero since they do not contribute toglobal warming. CO and dust emissions are slightly higher than conventional power productionpointing to need for improving the combustion efficiency of the rice husk power plant. Overall, thestudy indicates that rice husk is a viable feedstock for electricity production and performs betterthan fossil fuels (especially coal and oil) from the point of view of environmental emissions.