• Energy Research

This paper presents the findings of an expert working group of researchers from East Asian countries. The group was tasked with developing a theoretically sound and practically implementable methodology for assessing the sustainability of biomass utilisation in East Asian countries based on the needs and potential of biomass resources in this region. Building on six years of research conducted between 2007 and 2013, the working group formulated a set of main and secondary indicators for biomass utilisation under three pillars of sustainability. For the environmental pillar, the main indicator was life cycle greenhouse gas emissions and secondary indicators were water consumption and soil quality. For the economic pillar, the main indicator was total value added and secondary indicators were net profit, productivity, and net energy balance. For the social pillar, the main indicators were employment generation and access to modern energy, and the secondary indicator was the human development index. The application of the working group methodology and indicators in sustainability assessments of biomass utilisation will enable decision makers in East Asian countries to compare the sustainability of biomass utilisation options and to make decisions on whether or not to launch or sustain biomass utilisation initiatives.

Indonesia, as the largest palm oil producer in the world, also produces palm oil mill effluent (POME). While the latter is a liquid waste that is hazardous for the environment, with proper processing, it can be a potential energy source. The objective of this study was to study the performance of biogas production from POME at various temperatures. The POME and sludge mixture was fermented, according to the treatment, at 27-28oC, 45oC, and 55oC, with the results showing that methane could thereby be produced by as much as 0,19 m3, 0,25 m3, and 0,28 m3 respectively. For each kilogram of chemical oxygen demand (COD) removal, with POME fermentation at room temperature, 45oC, and 55oC, biogas could be produced with methane content of 65.44%, 62.57%, and 59.15%, respectively.

Biodiesel derived from palm oil has been recognized as a high-productivity oil crop among the first generation of biofuels. This study evaluated and discussed the net energy balance for biodiesel in Indonesia by calculating the net energy ratio (NER) and net energy production (NEP) form the total energy input and output. The results of the calculation of energy input for the default scenario demonstrated that the primary energy inputs in the biodiesel production lifecycle were the methanol feedstock, energy input during the biodiesel production process, and urea production. These three items amounted to 85% of the total energy input. Next, we considered and evaluated ways to potentially improve the energy balance by utilizing by-products and biogas from wastewater treatment in the palm oil mill. This result emphasized the importance of utilizing the biomass residue and by-products. Finally, we discussed the need to be aware of energy balance issues between countries when biofuels are transported internationally.

The purpose of this study is to develop a family-size biogas-fueled electricity generating system consisting of anaerobic digester, bio-filter scrubber, and power generating engine. Biogas was produced from a pilot scale wet anaerobic digester (5-m3 capacity). The biogas was filtered using bio-scrubber column filled with locally made compost to reduce hydrogen sulfide (H2S) content. Biogas composition was analysed using a gas chromatograph and its H2S level was measured using a H2S detector. A 750-W four stroke power generating engine was used with 100% biogas. Biogas consumed by the generator engine was measured at different load from 100 to 700 W (13.3 to 93.3% of the rated power). Three replications for each load experiment were taken. Results showed that the total biogas yield was 1.91 m3/day with methane content of 56.48% by volume. Bio-filter successfully reduced H2S content in the biogas by 98% (from 400 ppm to 9 ppm). Generator engine showed good performance during the test with average biogas consumption of 415.3 L/h. Specific biogas consumption decreased from 5.05 L/Wh to 1.15 L/Wh at loads of 100 W to 700 W, respectively. Thermal efficiency increased with loads from 6.4% at 100 W to 28.1 at 700 W. The highest thermal efficiency of 30% was achieved at a load of 600 W (80% of the rated power) with specific biogas consumption of 1.07 L/Wh.Article History: Received Janury 16th 2017; Received in revised form 2nd June 2017; Accepted 18th June 2017; Available onlineHow to Cite This Article: Haryanto, A., Marotin, F., Triyono, S., Hasanudin, U. (2017), Developing A Family-Size Biogas-Fueled Electricity Generating System. International Journal of Renewable Energy Development, 6(2), 111-118.https://doi.org/10.14710/ijred.6.2.111-118

The present study investigates the quality changes of wood bio-briquette fuel after the addition of spent coffee ground (SCG) into the initial feedstock materials (sawdust, shavings) in different mass ratios (1:1, 1:3). Analysis of SCGs fuel parameter proved great potential for energy generation by a process of direct combustion. Namely, level of calorific value (GCV = 21.58 MJ∙kg−1), of ash content (Ac = 1.49%) and elementary composition (C = 55.49%, H = 7.07%, N = 2.38%, O = 33.41%) supports such statement. A comparison with results of initial feedstock materials exhibited better results of SCG in case of its calorific value and elementary composition. Bulk density ρ (kg·m−3) and mechanical durability DU (%) of bio-briquette samples from initial feedstock materials were following for sawdust: ρ = 1026.39 kg·m−3, DU = 98.44% and shavings: ρ = 1036.53 kg·m−3, DU = 96.70%. The level of such mechanical quality indicators changed after the addition of SCG. Specifically, SCG+sawdust mixtures achieved ρ = 1077.49 kg·m−3 and DU = 90.09%, while SCG + shavings mixtures achieved ρ = 899.44 kg·m−3 and DU = 46.50%. The addition of SCG increased wood bio-briquettes energy potential but decreased its mechanical quality. Consequently, the addition of SCG in wood bio-briquette has advantages, but its mass ratio plays an important key role.