Potential Use of Various Biomass Sources for Operating Cost Reduction in a Power Plant in Southern Thailand

Abstract

Apart from rubberwood waste, there are abundant biomass resources from agricultural residues in southern Thailand for fuel utilization, such as rice straws, rice husks, oil palm empty fruit bunches, and other oil palm residues. These locally available agricultural residues may be used as mixed biomass fuel to reduce operating costs in power generation. The selection of biomass types used depends on their availability and cost. In this work, a cost optimization model considering biomass and transportation costs was applied to a case study of a 7.5 MWe Yala biomass power plant in southern Thailand. At present, the power plant uses rubber woodchips solely as fuel. The power plant was assumed to run 24 h a day, 330 days a year with an overall biomass-to-electricity conversion efficiency of 20%. Several other potential biomass sources which were locally available in south Thailand within a 120 km radius of the plant were considered. For transportation, it was assumed to be done by 25-ton-capacity, 10-wheel trucks. K-means clustering was applied to group a number of supplies to the demand at the power plant as a centroid in calculating transportation cost from supply points to the demand point. Each type of biomass was gathered to supply the power plant where availability of no more than 40% of the total supply from a single source was assumed. From the simulation, it was found that rather than just rubber woodchips, rice straws, rice husks, and oil palm empty fruit bunches may also be utilized. There were 19, 33, and 35 supply sources of rubber woodchips, rice residues, and oil palm empty fruit bunches, respectively, that were within reasonable transport distance from the power plant. Reduction of the total cost almost 38%, or more than 1.70 million USD a year could be achieved.