The power plant research has studied the biomass power plant is using rice husk as fuel. At present, there are higher rates of rice husk prices make the cost of electricity increases. This power plant electricity sold to the provincial electricity authority 8 MW with 210 tons of daily consumption of fuel per day, 1000-1400 THB husk price per ton. As a result, the cost of electricity rising with external factors, according to the second law of thermodynamics, which affect the energy efficiency of heat and electricity, so we see how to use the fuel quantity of biomass electric plant also lacked analysis.Use the appropriate fuel quantities, whether to use the current fuel consumption at appropriate or not. Can be adjusted to appropriate or not to do a study, it is interesting to study the appropriate fuel quantities used to produce electricity, biomass power plant? To guide the analysis of finding the suitability of fuel supply and economic evaluation for power plant.