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This paper is to study the drying method to reduce the moisture content (MC) of the woodchip. The methods used are to utilize the heat from solar and waste heat from the Biomass Power Plant (BioPP). By using a 250 °C heat waste from the BioPP, and stirring on the woodchip inside the drying equipment, the results obtained to reduce the MC from more than 40 % to MC around 20 % will take 2 h and 4 h faster than that which was not done on woodchips. Reducing MC from 40 % to 20 % will save 25.44 % on the woodchip consumption for combustion in the boiler of the BioPP. An analysis related to MC, CV, and woodchip consumption in generating electricity is also carried out. When MC is 26.70 %, the CV is 13.5 GJ T-1, and the woodchip consumption becomes 4.62 T h-1 and 1.31 T MWh-1, the energy produced is 764.7 kWh T-1. When the MC is higher, 47.68 %, causing the CV to become 9.8 GJ T-1, it is found that the consumption of the woodchips becomes 6.41 T h-1 and 1.81 T MWh-1, the energy produced is 551.3 kWh T-1.

Many countries are currently making efforts to obtain alternative energy to reduce dependence on fossil energy resources. “Uwi” plant is a carbohydrate source that has many types and is tolerant of being planted on the upland, so it has the potential to be used as a food crop and as bioenergy. This research aims to study the potential of varieties of “uwi” (Dioscorea sp.) as raw material for ethanol production. The eight varieties of “uwi” were studied to assess their ethanol potential. The selected raw materials are Dioscorea alata L. (white yam, purple yam, and yellow yam); Dioscorea esculenta (Lour.) Burkill (“uwi gembili” and “uwi gembolo"); Dioscorea bulbifera L. ("uwi gandul"); Dioscorea pentaphylla L. ("uwi katak") and Dioscorea hispida Dennst. (“uwi gadung"). A field experiment with Randomized Block Design was used to obtain homogenous tuber raw material, followed by laboratory methods on the assessment of ethanol production potential through fermentation. The research showed that the variety, D. hispida had the highest ethanol content (4.94 %), followed by D. esculenta (4.16 %) and D. alata (white yam) (3.89 %). The lowest ethanol production was obtained from D. pentaphylla (0.36 %) and D. bulbifera (1.53 %). However, in terms of productivity, D. alata (white-yam) is the most prospective considering its high production, ease of cultivation and tolerance of forest stands. [ABSTRACT FROM AUTHOR]

This paper aims to analyse the healthy-smart concept as a standard design of kitchen waste biogas for urban people. The anaerobic digester (AD) is designed for family size. The planned vertical digester is a one-stage- semi-continuous type because this AD type is easy to operate in urban areas. Kitchen waste or food waste can be generalized as all bio-materials produced from kitchen activities (including vegetables, fruits, bread, rice, coffee ground, tea leaves, etc). The biggest problem with household waste is the non-uniformity of feedstock entering the digester biogas. Five steps will be carried out: to establish technical standards in designing kitchen waste; to calculate the biogas potential from kitchen waste; to simulate the methane demand and generation profile; to calculate the geometry of the biogas digester; and to analyse the operation parameter for gas production into the healthy-smart concept. With a simple simulation of two people in the household for 1 d, the results show that biogas produced from kitchen waste is sufficient for cooking purposes. For the healthy-smart concept of biogas production, some operation parameters must be considered, such as; pH, alkalinity, temperature, volatile fatty acid concentration, volatile solids, and C/N ratio. The results can be used in overcoming the urban household waste and also as a reference in sustainable urban planning. [ABSTRACT FROM AUTHOR]