Biodiesel is an alternative fuel for diesel engines produced by transesterification and esterification of vegetable oils or animal fats with short-chain alcohols such as methanol. The reaction requires a catalyst, which is generally a strong base, thus producing a new chemical compound called methyl ester. One of the most common sources of biodiesel feedstock is CPO (Crude Palm Oil). CPO production in Indonesia is very high at 30.2 million tons in 2016, but CPO prices are low. Biodiesel can be produced using conventional methods, this method is less efficient because of its very slow and inefficient heating resulting from the transfer of energy to materials that depend on the convection currents and the thermal conductivity of the reaction mixture) which causes researchers to use new methods of producing Biodiesel, that is by using induction heating method. An induction heater is a technology that has been applied both in industry and households. The weight of the catalyst used uses variations of 0.6; 0.8; 1.0; 1.2; 1.4 %. The analysis showed that for optimal catalyst weight of 1.4%, yield biodiesel of 83.94%, density of 0.875 gr/cm3, the viscosity of 5.78 cSt, and flash point >100 oC. The use of 1.4% catalyst concentration produced biodiesel product that has a high yield and according to SNI 7128: 2015

The purpose of this research was to review the power output generated during the operation of the solar panels. Data that used to be taken of the Solar Power Plant or PLTS that operate PT. Pertamina (Persero) RU III Plaju observed data starting from January 2017 until December 2017 PLTS system installed in PT. Pertamina (Persero) RU III Plaju is a kind of photovoltaic grid connected (on grid). The results obtained that in manual calculations obtained fill factor of 0.7594 and output power of 250.884 Watts. Whereas the data in real time in the field fluctuating occurs at any time. This is because the weather was overcast, the lack of sunlight and shadow position (shading) that occurs due to the PLTS clouded by trees or buildings around also affects the results of the output voltage of the PLTS.

Abstract. Palm oil mill effluents (POMEs) can contaminate soil, groundwater, and also the water environment. The increasing production of crude palm oil in Indonesia produces an enormous amount of POME waste. Therefore, a method is needed that can be used to purify POMEs. In this paper, an electrocoagulation (EC) method for purification of wastewater and a design to optimize this method are presented. An optimization experiment was performed by varying voltage and process time. The applied voltages were 6, 9, and 12 V and the process time was varied between 30 and 150 minutes. The measured parameters were: COD, BOD 5 , pH, TSS, lipids, and NH 3 -N. The result shows that optimum conditions were achieved at a voltage of 12 V and a process time of 150 minutes with COD at 8000 mg/L, BOD 5 at 12000 mg/L, pH at 7.46, TSS at 324 mg/L, lipids at 17.8 mg/L, and NH 3 -N at 0.65 mg/L. The results are in accordance with environmental quality standards for pure water. This study proves that the proposed EC method is effective in purifying POMEs from pollutants.

Solar energy can be utilize to power a system located far from the electricity sources such a mobile tower applied in open-pit mining in PT Bukit Asam Tbk. However, the tropical weather in an open-pit mining can increase the surface temperature of a Photovoltaic (PV) panel, lead to overheating and the reduction of the efficiency and the reduced electricity power. This condition requires a cooling system to reduce the temperature. This paper presents the application of Phase Change Material (PCM) and heatsink as the cooling system for a PV panels. The PCM installed are in two sizes aluminum hollows, a 0.0025 m3 and 0.00625 m3. The experiment was conducted in 2 batches, 14-29 February 2020 for the installed 0.0025 m3 aluminum hollow, and 1-14 March 2020 for 0.00625 m3. The application of a 0.00625 m3 can reduce the PV panel’s surface temperature up to 3-5°C. The generated current using PCM 0.00625 m3 is 0.034 A for Isc and 0.014 A Iload higher than without cooling system. The application of a aluminum hallow with the size of 0.00625 m3 gives 9-20% efficiency, and the efficiency gives 8-15%. The experimental results show that the use of a hollow aluminum with a size of 0.00625 m3 can reduce the surface temperature of the PV panel and increase the power and efficiency of the PV panels.