The objectives of this study are to perform the exergy analysis and ambient temperature optimization of the Kamojang geothermal power plant by employing Engineering Equation Solver (EES). The geothermal capacity is 55 MW and the field is vapor-dominated reservoir with temperature 245 °C. In the initial state temperature, pressure and mass flow data are collected from the plant operation. The study results show that system has overall efficiency of 35.86% which means that only 111,138.92 kW electrical power can be extracted from 309,000 kW thermal power being produced by 10 production wells of Kamojang. This low efficiency is due to irreversibility associated with different processes and components in the system. The largest irreversibility occurs in condenser due to which 53% of total energy is disposed into the environment. Ambient temperature at Kamojang varies from 17 to 20 °C. The effect of this variation in temperature is also investigated and it is observed that higher temperature does not have any significant impact on system efficiency

Organic Rankine Cycle is a technology that convert low-temperature heat sources into a mechanical energy, and it can be used to produce electrical energy in a closed system. The heat sources can be received from renewable energy such as geothermal, solar, and biomass. Furthermore, the ORC system can also be used to increase energy efficiency in the industry by utilizing the waste heat produced. Therefore, there are two classification of the ORC system, namely a heat recovery system and binary power plant. Recently, the ORC system has made a thrive in the geothermal power plant. The ORC system can be applied to resources with low to medium temperature characteristics (<90°C - 150°C). This paper will present an overview of the implementation, model, and innovation of ORC system technology in geothermal resources.

Energy is one of the essential human needs that plays a crucial role in achieving sustainable development. Indonesia is among the countries that are highly focused on developing renewable energy to reduce greenhouse gas emissions and achieve net-zero emissions. In addition, the government has launched various policies and programs to promote the use of renewable energy, such as increased investment in biomass, geothermal, and solar power generation. Wind energy stands out as a sufficient, widely available, and an environmentally friendly alternative in renewable energy. In 2021, the Indonesian Energy Outlook highlights that Indonesia has an energy potential of 154.9 gigawatts (GWs). It is associated with minimal emissions of greenhouse gases during its operation and does not demand vast tracts of land. However, the actual installed capacity of wind power plants is at a modest 157.41 megawatts (MWs). Meanwhile, the targeted capacity is 255 MWs for 2025. One significant factor contributing to this lower-than-expected capacity is a lack of in-depth research into the potential of wind energy. Consequently, the primary aim of this paper is to conduct a thorough examination of the wind energy potential in Indonesia. This includes an analysis of the current state of both existing and upcoming power plants, as well as a review of recent studies conducted by Indonesian researchers on wind turbines. Furthermore, this paper explores the government program to encourage the sustainable development of wind power plants. It also explains various aspects including the untapped wind energy potential, the interference in developing wind power plants, and the strategy to harness the full potential of abundant renewable resources in Indonesia. Through an in-depth investigation of the potential of wind energy, this review aims to provide a more comprehensive understanding of the current conditions and prospects of wind power plants in Indonesia as well as contribute to a more accurate mapping of wind energy potential and more targeted development, specifically in remote areas, outer islands, and borders. The results obtained are expected to support Indonesia’s energy transition toward more environmentally friendly and sustainable renewable energy sources, thereby reducing dependence on fossil fuels.

Coconut shells and waste cassava peels could be used as the main raw material for biomass briquettes for alternative energy sources in Indonesia. This study aims to analyze the quality of briquettes based on a coconut shell and cassava peel adhesive through proximate analysis with three treatment ratio variations. The ratio of coconut shell to cassava peel used varied from V1 (75%:25%), V2 (70%:30%), and V3 (65%:35%). Based on the result, the charcoal briquettes produced have a density of 0.61 gram/cm³-0.66 gram/cm³, water content of 5.51%-7.85%, ash content of 1.50%-2.86%, combustion rate of 0.021 gram/s-0.026 gram/s, and the calorific value of 6,161 cal/gram-6,266 cal/gram. However, all the treatment variations appropriate the SNI 01-6235-2000, the national standard of Indonesia for the quality of charcoal briquette, which includes the calorific value (>5,000 cal/gram), moisture content (<8%), and ash content (<8%). Briquettes with the best quality were generated by V1 with a density of 0.66 gram/cm³, water content of 5.51%, ash content of 1.50%, combustion rate of 0.026 gram/s, and calorific value of 6,266 cal/gram. Furthermore, briquette material from the coconut shell waste with natural cassava peel adhesive can be feasible as an alternative fuel.

Information security, especially cryptography still seems becoming an interested topic of researches in the recent years since it will be responsible to secure a system and data for misusing of attackers. With spreading of internet of things (IoT) applications in many fields whereas many devices will be connected to internet, security issues become one of three common issues related to IoT applications such as innovations, security and interoperability. As a new application of IoT is implemented, a new security system will be needed as well. This paper discusses on designing a quantum random number generator (QRNG) which has a potential for security solution of IoT ecosystem applications.