Frontiers in Renewable Energy https://jurnal.ugm.ac.id/v3/FREE <p align="justify">FREE is a biannually published open-source journal by the Center for Energy Studies Universitas Gadjah Mada (E-ISSN 2961-7855), publishing cutting-edge research from basic science to emerging renewable energy technologies, policies, and economics through online submission with a peer review system allowing authors to submit articles online and track their progress via its web interface. All varieties of research within these fields are welcome, provided they are novel and can make significant scientific and social contributions.&nbsp;</p> Center for Energy Studies Universitas Gadjah Mada en-US Frontiers in Renewable Energy 2961-7855 <ul> <li>Authors automatically transfer the copyright to the FREE and grant the FREE right of first publication with the work simultaneously licensed under a Creative Commons&nbsp;<a href="https://creativecommons.org/licenses/by-nc/4.0/" target="_blank" rel="noopener">Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)</a> International License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.</li> <li>Authors are able to enter into separate permission for non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal. (<a href="http://opcit.eprints.org/oacitation-biblio.html" target="_blank" rel="noopener">The Effect of Open Access</a>)</li> <li>Copyright on articles is retained by the respective author(s), without restrictions. A non-exclusive license is granted to FREE to publish the article and identify itself as its original publisher, along with the commercial right to include the article in a hardcopy issue for sale to libraries and individuals.</li> </ul> Biomass to Biofuel: Optimization of Chlorella sp Harvesting by Using Poly Aluminium Chloride as Coagulant https://jurnal.ugm.ac.id/v3/FREE/article/view/6700 <p>Microalgae of Chlorella sp. is a type of microalgae that has the potential to be a raw material for biodiesel because of its high oil content. Utilization of microalgae Chlorella sp. requires an effective and efficient harvesting process, one of them is coagulation. Because that, in this study PAC use as a coagulan in the process of harvesting microalgae of Chlorella sp. The purpose of this study is looking for optimization of increasing the dose, Ph and deposition time on microalgae yield of Chlorella sp. The result of this study use Box – Bahnken method on Response Surface Method (RSM) shows the value of the optimal response to the yield of the microalgae Chlorella sp. of 4.95 grams with a combination of an additional dose of 0.75 g/l, a pH of 10, and a settling time of 10 minutes.</p> Revata Maggandari Copyright (c) 2023 Revata Maggandari https://creativecommons.org/licenses/by-nc-nd/4.0 2023-12-01 2023-12-01 2 1 1 5 Gasification GASIFICATION OF ORGANIC WASTE IN UPDRAFT GASIFIER https://jurnal.ugm.ac.id/v3/FREE/article/view/7006 <p>The majority of Indonesia's waste is organic and could potentially be converted to energy. The most effective method for converting waste into energy is gasification with updraft gasifier. Different types of waste are contained in organic waste, which has a high moisture content ranging from 16.95% to 53.74% collected from TPST Piyungan, Yogyakarta. The effect of moisture content which are categorized as low, medium, and high on operation time, fuel conversion rate and heating rate is the main thing observed in this study. The ideal value for the organic waste moisture content that can be obtained for a successful gasification operation is 15.68%. The operational time range of 61.57 to 193.69 minutes, with optimum value of 66.68 minutes, sehingga menghasilkan nilai FCR optimal sebesar 38,28 gram/menit dan nilai laju pemanasan dengan nilai berturut-turut untuk IH (Initial Heating Rate) 37,10 <sup>o</sup>C/menit dan MH (Maximum Heating Rate) 19,96 <sup>o</sup>C/menit. The desired product quantity in ideal conditions is 86% for gas, 8% for liquid, and 6% for solids. Based on the complete testing process, the quantity of gas products (55.31 to 88.65%), followed by liquid products (1.64 to 4.57%) and solids (9.71 to 40.12%).</p> Mhd Faisal Ain Lubis Copyright (c) 2023 Mhd Faisal Ain Lubis https://creativecommons.org/licenses/by-nc-nd/4.0 2023-12-01 2023-12-01 2 1 6 15 10.22146/free.v2i1.7006 Preliminary Study on Feasibility of 1.8 Million Tons/Year Capacity of Bio-methanol from Biomass as Raw Material of A20 Biofuel in Indonesia https://jurnal.ugm.ac.id/v3/FREE/article/view/7722 <p>Pertamina has developed A20, a low-emission fuel combination of 80% gasoline, 15% methanol, and 5% ethanol, in response to the Regulation of the Minister of Energy and Minerals Resources regarding the obligation to use biofuels as a combination of vehicle fuels. However, since Indonesia only has one methanol producer with a capacity of 660,000 tons/year, alternative ways are needed to meet the demand for methanol in A20. Empty oil palm fruit bunches (EFB) are a widely generated waste that accounts for over 20% of the total fresh fruit bunches of oil palm processed by the industry. EFB is an organic material rich in carbon content and can be used as a raw material for making biomethanol for biofuels through a gasification process. Therefore, the aim of this study is to discuss the economic feasibility of establishing a biomethanol manufacturing plant from EFB, using NPV, PP, and IRR as indicators. Based on the study's findings, a biomethanol plant is deemed feasible with an NPV of Rp4,334,875,634,343.80,-, PP within 4.87 years, and an IRR of 15.90%.</p> Rizky Mutiarani Copyright (c) 2023 Rizky Mutiarani https://creativecommons.org/licenses/by-nc-nd/4.0 2023-12-01 2023-12-01 2 1 16 22 BIOSTABLE ADDITIVE FOR REDUCING FILTER BLOCKING TENDENCY (FBT) AND STABILITY IMPROVEMENT OF B30 BIODIESEL AT OFFSHORE STORAGE. CASE STUDY: WEST SENO BANGKA OIL & GAS FIELD AT MAKASSAR STREET OFFHSORE EAST KALIMANTAN https://jurnal.ugm.ac.id/v3/FREE/article/view/7729 <p>Implementation biodiesel B30 in West Seno Bangka oil and gas offshore field located in Makassar Street East Kalimantan for supporting operation has been raised some issue, i.e: engine failed to start, unplanned stop of crew boat and filter blocking. In order to rectify the problem, Filter Blocking Tendency (FBT) and Particle Size Distribution (PSD) of B30 need to be observed and analyzed during storage at offshore for operational. The method FBT analysis based on ASTMD D2068-20 and PSD analysis based on ASTMD 7619-17. The number FBT and PSD increased over the time, the precipitation indicated occurred in B30 and lead some operational issues. Additive commercial Biostable put into biodiesel to reduce FBT and to maintain the stability B30. According to laboratory test, the additive was able to improve FBT and PSD during storage in 60 days observation. The Author then implemented additive in West Seno Bangka Field. Post applying Biostable, the FBT significantly reduced about 78% from 8.49 to 1.83. The improvement also indicated on PSD and maintain in good filterability. Based on the result, stability improvement and biodiesel quality improvement were achieved and reduced fuel filter replacement and increased reliability of equipment in West Seno Bangka Operation</p> Aris Ariyanto Copyright (c) 2023 Aris Ariyanto https://creativecommons.org/licenses/by-nc-nd/4.0 2023-12-01 2023-12-01 2 1 23 30 Development of Algal Oil Yield Model from Tetraselmis sp. Extraction by Pulsed Electric Field (PEF) https://jurnal.ugm.ac.id/v3/FREE/article/view/6720 <p>An algal oil extracted from <em>Tetraselmis sp.</em> by a pulsed electric field (PEF) is evaluated by an extraction yield model. The yield model is developed based on the lipid mass transfer model during the extraction process approximation by PEF. In this study, the influence of three main variables of PEF, which are duty cycle , frequency , and treatment time &nbsp;on the yield obtained in the experiment were investigated. In the experiment, the microalgae samples were extracted in the PEF chamber which is constructed for a batch process for a maximum volume of 100 mL for each sample. The PEF chamber consists of 8 stainless-steel plates 100x120 mm in size with 1 mm thickness which is placed on a 165x145x42 mm acrylic base. Further, the results of the experiment are modelled to represent the effect of each of these variables. By determine the maximum yield (grams of extracted lipids per 100 grams of microalgae) &nbsp;= 60.7002, frequency efficiency constant&nbsp;= 9.4397, frequency efficiency constant &nbsp;= 0.4891, and time constant &nbsp;= 55.5239, the proposed model gives the lowest error at 10.03 %. in the case of different at fixed electric field =1.68 kV/cm, =1 Hz and =20 min.</p> Prima Sejati Yano Surya Pradana Ade Kurniawan Yosephus Ardean Kurnianto Prayitno Thoriq Teja Samudra Arief Budiman Copyright (c) 2023 Prima Sejati, Yano Surya Pradana, Ade Kurniawan, Yosephus Ardean Kurnianto Prayitno, Thoriq Teja Samudra, Arief Budiman https://creativecommons.org/licenses/by-nc-nd/4.0 2023-12-01 2023-12-01 2 1 31 41