Progress in the technology of energy conversion from woody biomass in Indonesia

Sustainable and renewable natural resources as biomass that contains carbon and hydrogen elements can be a potential raw materials for energy conversion. In Indonesia, they comprise variable-sized wood from forests (i.e. natural forests, plantations and community forests that commonly produce small-diameter logs used as firewood by local people), woody residues from logging and wood industries, oil-palm shell waste from crude palm oil factories, coconut shell wastes from coconut plantations, traditional markets as well as skimmed coconut oil and straws from rice cultivation. Four kinds of energy-conversion technologies have been empirically tested in Indonesia. First, gasification of rubber wood from unproductive rubber trees to generate heat energy for the drying of fermented chocolate seeds. Secondly, energy conversion from organic vegetable waste by implementing thermophylic fermentation methods that produce biogas as a fuel and for generating electricity and also concurrently generate organic by-products called hygen compost. Thirdly, gasification of charcoal and wood sawdust for electricity generation. Finally, environment-friendly energy conversion by carbonizing small-diameter logs, sawdust, wood slabs and coconut shells into charcoal. This yielded charcoal integrated with wood vinegar production through condensation of smoke/vapors emitted during carbonization, thereby mitigating the impact of air pollution. Among the four experimental technologies that of integrated charcoal and wood vinegar production had been spectacularly developed and favored by rural communities. This technology brought added value to the process and product due to the wood vinegar, useful as bio-pesticide, plant-growth hormone and organic fertilizer. Such integrated and environment-friendly production, therefore, should be sustained, because Indonesia occupies a significant and worldwide position as charcoal-producing and marketing country. The technology of integrated wood vinegar-charcoal production hence deserves its dissemination throughout Indonesia, particularly to the charcoal industry that still produces charcoal without condensing the generated vapor/smoke, hence polluting the air.