Waste heat potential assessment of the engine based power plant in Thai palm oil mills

Renewable energy (RE) and energy efficiency will be key to achieving sustainability. Biogas from palm oil mill effluent (POME) is an important RE resource. Thailand is the third-ranked in the world leading palm oil producers after Malaysia and Indonesia. In the last decade, Thai palm oil mills (POMs) have produced biogas which is used as fueled in engine power plants supporting the country's RE program. The spark-ignition (SI) engines are typically used as the prime movers for the power generation, and their thermal fuel efficiency may range 28-42% of the energy input, whereas the remaining 58- 72% converted to waste heat and dumped into the environment as thermal pollution. The aim of this study was to assess the waste heat potential of the engine power plants in Thai POMs by using a case study approach. The secondary data are collected from the mill and used as a baseline for the assessment. The results show that the electrical efficiency of the engine and actual capability of the engine power generation in Thai POMs are 38.48% and 333.57 GWh. The recoverable or usable thermal energy is 326.49 GWh or 37.67% of the fuel energy or equivalent saving 136,440 tons a year of biomass-fueled in Thai POMs. It has resulted from waste heat potential 384.11 GWh, with assumption effectiveness in 0.85.