• Energy Research
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A small compression ignition (CI) engine with a rated power of 4.41 kW has been tested in dual-fuel (diesel-biogas) mode without any significant modification. The objectives are to explore the effects of biogas flow rate and methane concentration on the performance and emissions of the CI engine run in dual-fuel mode. The experiments have been carried out at engine load and speed vary from 1000 rpm to 1500 rpm and 600 W to 1500 W, respectively. The results show that the output power and specific fuel consumption of the CI engine run in dual-fuel mode are higher than the CI engine run in pure diesel mode. Brake thermal efficiency of the CI engine run in dual-fuel mode strongly affected by biogas flow rate and methane concentration. There exists an optimum biogas flow rate for a maximum brake thermal efficiency. The biogas can reduce the diesel fuel consumption significantly. In the present CI engine, diesel replacement ratio varies from 15.3% to 87.5%. At engine load and speed of 1500 W and 1500 rpm, to get maximum efficiency, the present CI engine should be operated at biogas energy ratios of 15% and 18% using biogas with 60% and 70% methane concentrations, respectively.

Here, we demonstrate the direct biodiesel production from wet SCG in mild reaction temperature and short reaction time using reactive extraction Soxhlet (RES) method.

The development and utilization of wood briquettes is one of the efforts to reduce dependence on fossil fuels, including to fulfill overseas market need. This study aimed to evaluate the properties of wood briquettes made of the branches of three mangrove species and to analyze the effect of different wood species of mangrove branches, and the types of starch adhesive, on the quality of wood briquettes. The wood briquettes made in this study were 3 cm × 4 cm in a cylindrical shape using three wood species of mangrove branches, namely mata buaya (Bruguiera sexangula), buta-buta (Excoecaria agallocha), and bakau minyak (Rhizophora apiculata), while the adhesives used were tapioca starch, maize starch, and potato starch. The results showed that the moisture, ash content, and calorific value of the wood briquettes mostly met the ISO 17225-3:2-2020 class A2 standard and the specification and quality standards of wood briquettes for Grade A2 issued by the Korea Forest Research Institute, except the density. Wood briquettes made of mata buaya by using the three types of starch adhesives generally had better properties than all other types of wood briquettes. The interaction of mangrove wood species and the types of starch adhesive had a significant effect on the properties of wood briquettes, except for volatile matter and calorific value for which they had no significant effect. The use of wood briquettes from mangrove wood branches contributes to sustainable forest management and maintains the ecological function of mangrove forests while providing environmentally friendly alternative energy for households as a source of fuel/energy. Furthermore, future research is needed, such as investigating the optimal pressing pressure needed to achieve higher density of the wood briquettes.

The purposes of this study were to analyze the structural poverty among rice farmers in East Aceh Regency and to analyze factors causing the structural poverty among rice farmers in East Aceh Regency, Indonesia. Data collection was performed by observation, questionnaire distribution and interview. The research objects were rice farmers in East Aceh Regency. The research locations were 14 (fourteen) sub-districts based on the biggest rice field areas in East Aceh Regency. The data collection technique was purposive sampling. The total sample was 1200 respondents. The model in the present study was descriptive quantitative statistical technique to describe the structural poverty among rice farmers in East Aceh Regency. The analysis and research were performed in 5 (five) stages, i.e. ; (1) distributing questionnaires to the research locations; (2) making data tabulation in the form of table (data coding); (3) performing validity test on data; (4) calculating poverty index score; (5) analyzing data. The research result showed that the structural poverty of rice farmers in East Aceh Regency was due to limited access to education, wage difference and low income of farm workers, limited land ownership (size and ownership status of agricultural land), and limited facilities and infrastructures to support agricultural activities. The indicators of poverty in East Aceh Regency were prosperity level, level of material wealth, education, income, environment, land area, service and politics. Based on the indicators, the score of poverty index among rice farmers in East Aceh Regency was medium, with the score of average poverty index of 57.73 percent. The factors causing structural poverty among rice farmers in East Aceh Regency are the rice farmers’ dependency to higher social classes, structural injustice and structural wealth of farmers, small opportunity to own and control production assets, especially land and capital, development disparity and lack of policy which sided with poor farmers. The implications of this research are that the government continues to implement price stability policies, subsidies and funds programs, and social assistance policies, and any poverty reduction policies will have political implications that have a short-term impact.

The long-term use of fossil energy has expected to be exhausted if there is no breakthrough for renewable energy. Energy source future will become extinct along with the increasing energy needs and population, which impacts on energy consumption. Electrical energy sources by industry, households, offices, and schools are needed. For this reason, the development of biomass produced from rice husk as organic waste with developed through the biobriquette method has expected to provide a solution to overcome future energy scarcity. Besides, it can also be utilized for the development of adequate electrical energy in rural areas of Indonesia. As an agrarian country, most of its population depends on livelihoods in the agricultural sector. The biobriquette has developed used rice husk as the main of raw material plus other components as an adhesive. Therefore, to create high-quality briquettes and produce charcoal as fuel in driving steam turbines within power plants, further analysis is needed. The advanced method is necessary to develop in Indonesia. The rice husk has easily obtained and able to supply raw materials for processing briquette biomass at a more economical and efficient cost compared to biomass using gasification, pyrolysis, liquefaction, and biochemical methods. So far, rice husk only turns into a waste of rice refinery production without any use as electrical energy.

Biodiesel is a renewable energy source in Indonesia of which the use is regulated by the government in the form of mandatory policy of biodiesel and diesel fuel blending. The production of biodiesel in Indonesia is not developed (the need is 3.4 million kiloliters but the total national production is only 1,703 kiloliters). It is because the selling price (referring to Mean of Platts Singapore) is always lower than the production cost. Biodiesel production is influenced by raw materials and process technology, so it needs to be conducted biodiesel production modeling as a basis in determining the supporting policies of biodiesel selling price. The purpose of this study is to identify the raw materials, process technology, and modeling the production cost structure of palm oil-based biodiesel. Identification of raw materials was conducted by literature study and field survey to biodiesel producers. Identification of process technology was conducted by field survey and mass balance calculation using Grand Inizio technology to get the number of yield of each raw material. Then, production cost study was based on the specifications of raw materials and process technology with heuristic approach. Types and specifications of palm oil widely used by Indonesian producers are Crude Palm Oil (CPO) FFA<5%, Refined Palm Oil (RPO) FFA<5%, Refined Oil FFA<1%, Palm Fatty Acid Distillated (PFAD) FFA 90%. The technology process used was transesterification for FFA level <1% and esterification-transesterification for FFA level <5%. The resulting yield for 1000 kg of raw material is 1051.75 kg CPO, 975.94 kg RPO and PFAD, 973.81 kg Refined Oil with Grand Inizio technology approach. The production cost model represents the total production cost influenced by the costs of Inside Battery Limit, Outside Battery Limit, general cost and glycerol value-added.ABSTRAKBiodiesel adalah sumber energi terbarukan di Indonesia yang diatur penggunaannya oleh pemerintah dalam bentuk kebijakan mandatori pencampuran biodiesel dengan solar (biosolar). Produksi biodiesel di Indonesia tidak berkembang (kebutuhan 3.4 juta kiloliter namun total produksi nasional hanya 1.703 kiloliter). Hal tersebut disebabkan harga jual (mengacu Mean of Platts Singapore) yang selalu lebih rendah dibandingkan biaya pokok produksi. Produksi biodiesel dipengaruhi oleh bahan baku dan teknologi proses, sehingga perlu dilakukan pemodelan produksi biodiesel sebagai landasan dalam menentukan kebijakan pendukung harga jual biodiesel. Tujuan penelitian ini adalah mengidentifikasi bahan baku, teknologi proses, dan memodelkan struktur biaya produksi biodiesel berbasis minyak sawit. Identifikasi bahan baku dilakukan dengan studi literatur dan survei lapangan ke produsen biodiesel. Identifikasi teknologi proses dilakukan dengan survei lapangan dan perhitungan neraca massa dengan teknologi Grand Inizio untuk mendapatkan jumlah rendemen dari masing-masing bahan baku. Selanjutnya kajian biaya produksi dilakukan berdasarkan spesifikasi bahan baku dan teknologi proses dengan pendekatan heuristik. Jenis dan spesifikasi minyak sawit yang banyak digunakan produsen di Indonesia adalah Crude Palm Oil (CPO) ALB<5%, Refined Palm Oil (RPO) ALB<5%, Refined Oil ALB<1%, Palm Fatty Acid Distillated (PFAD) ALB 90%. Teknologi proses yang digunakan adalah transesterifikasi untuk kadar ALB<1% dan esterifikasi-transesterifikasi untuk kadar ALB<5%. Rendemen yang dihasilkan untuk 1000 kg bahan baku adalah CPO 1051.75 kg, RPO dan PFAD 975.94 kg, Refined Oil 973.81 kg dengan pendekatan teknologi Grand Inizio. Model biaya produksi merepresentasikan total biaya produksi yang dipengaruhi oleh biaya Inside Battery Limit, Outside Battery Limit, biaya umum dan nilai tambah gliserol.

Oil palm plantations have expanded rapidly in Southeast Asia, particularly in Indonesia and Malaysia. A lot of products, including food and other edible products, oleo-chemicals, cosmetics, personal and household care, pharmaceutical products, and biodiesels are derived from palm oil, thus making them one of the most economically important plants. After 25–30 years of age, the palms are felled and replaced due to declining oil production. Oil palm trunks (OPT) are considered significant waste products. The trunks remain on the plantation site for nutrient recycling or burning. This increases insect and fungi populations causing environmental problems for the new palm generation or air pollution due to the fire. Up till now, OPT has received less attention in research studies. Therefore, this review summarizes the utilization of OPT into products made of oil palm fibers mainly derived from OPT and its application as the substitution of wood panel products. Some research works have been carried out on oil palm fibers that are derived from OPT for exploiting their potential as raw material of composite panel products, which is the objective of this review. Areas of development are processed into various conventional composite panel products such as plywood and laminated board which are usually predominantly made of wood and bonded by synthetic resins, particleboard with binder, or binderless and cement board which is arranged with wood as a minor component. All of the products have been presented and described technically according to best knowledge of the authors and literature review.