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This research aims to design and develop a prototype wave power plant that utilizes the vertical motion of a buoy as a source of mechanical energy, which is then converted into electrical energy using a recoil starter mechanism. The system is designed to be installed at the stern of a prototype ship. The vertical movement of the buoy caused by ocean waves is transmitted to the recoil starter through a drive rope, producing a stable one-way rotational motion. This rotation is further transmitted to a gearbox to increase rotational speed before driving a DC generator. The electrical energy generated is stored in a 12 VDC battery, supported by a buck–booster converter to stabilize the output voltage. This study employs an experimental engineering approach to evaluate system performance based on empirical test data. The main components of the system include a buoy as a wave energy collector, a recoil starter as the initial rotating mechanism, a DC generator as the electrical energy producer, a buck–booster converter as a voltage regulator, a 12 VDC battery as an energy storage unit, and a monitoring system based on an ESP32 microcontroller integrated with a PZEM-017 sensor. Experimental results show that the recoil starter operates effectively in driving the generator under both no- load and buoy-loaded conditions. Increases in generator rotational speed are directly proportional to increases in output voltage and current. The PZEM-017 sensor demonstrates a high level of measurement accuracy, approaching 100% when compared with a multimeter. Overall, the proposed wave power generation system functions reliably and shows potential for further development as a small-scale alternative renewable energy source.

The increasing demand for electrical energy and the limited availability of fossil fuels have driven the development of renewable energy sources, including marine current energy, which remains underutilized in coastal and remote maritime regions. This study presents the design and realization of a small-scale marine current power generation prototype using a horizontal axis propeller turbine with a NACA S814 blade profile and analyzes the effect of turbine rotational speed on electrical power output. The system converts marine current kinetic energy into mechanical energy through turbine rotation and subsequently into DC electrical energy using a generator, which is stabilized by a Buck–Boost Converter and Maximum Power Point Tracking (MPPT) for charging a 12 VDC battery. Real-time monitoring of electrical and mechanical parameters is implemented using an Internet of Things (IoT)–based system comprising an ESP32 microcontroller, a PZEM-017 sensor, and an RPM sensor. Experimental results demonstrate a positive correlation between water flow rate, turbine rotational speed, and generator output voltage. The system begins operating at a minimum flow rate of 35.2 L/s at 56 RPM, producing 0.2 V, while optimal performance is achieved at 45.3 L/s and 516 RPM, generating up to 13.3 V. These results indicate that the proposed prototype is a viable alternative renewable energy source for marine applications.

Indonesia’s mineral downstreaming policy has become a strategic instrument to increase the added value of natural resources and strengthen the country’s position in the global mineral value chain. This study aims to analyze the effectiveness of the mineral downstreaming policy in encouraging regional economic transformation through the development of an integrated nickel processing industry in Obi Island, South Halmahera. The research employs a descriptive qualitative approach using secondary data obtained from government publications, corporate reports, policy documents, and environmental reports. Key data sources include regional economic statistics from the Central Bureau of Statistics, corporate publications from Harita Nickel, and regulatory frameworks such as Law No. 3 of 2020 concerning Mineral and Coal Mining. The findings show that the downstreaming policy has transformed Indonesia’s nickel industry by shifting export patterns from raw ore toward higher value-added products such as ferronickel and Mixed Hydroxide Precipitate (MHP), which are essential materials for electric vehicle battery production. The integration of Rotary Kiln Electric Furnace (RKEF) and High Pressure Acid Leach (HPAL) technologies in Obi Island has strengthened Indonesia’s role in the global battery supply chain while also stimulating regional economic growth in South Halmahera. However, the rapid expansion of the nickel industry also raises environmental governance challenges that require stronger regulatory oversight and sustainable mining practices. Therefore, future policy implementation should emphasize balanced economic development, environmental sustainability, and effective governance in mineral resource management.

Gununganyar Reservoir in Tuban Regency is one of the reservoirs used as a source of livelihood for the local community. However, further development and utilization of Gununganyar Reservoir have yet to be undertaken. The development of a small-scale floating Photovoltaic Solar Power Plant (floating solar panels) at Gununganyar Reservoir, aimed at providing an alternative and renewable energy source for operating raw water pumps and for supporting the Gununganyar Nature Tourism (WAG) initiative, constitutes an innovative and strategic effort to enhance energy efficiency and environmental sustainability in rural areas. This study focuses on the design and performance assessment of a floating solar panel system constructed with processed bamboo as an alternative floating material replacing HDPE, while integrating local wisdom and environmental conservation principles to minimize the reservoir’s carbon footprint. The methodology employs a simple quantitative approach combined with a literature review of relevant studies. Based on the analysis, the design of this small-scale floating solar panel system utilizes a 170 Wp off-grid solar module mounted at a tilt angle of approximately 7,1°, capable of generating a peak power output exceeding 2,962 kWp and supported by a battery capacity of  328,33 Ah. The implementation of these floating solar panels is expected to serve as a model for reservoir development by promoting energy self-sufficiency, stimulating local economic growth, and contributing to the achievement of net zero emissions by 2060.

The lack of street lighting infrastructure on the connecting roads between hamlets in Tepansari Village hinders community mobility and increases security risks at night. This community service program aims to implement Solar Power Street Lighting (PJUTS) technology as a renewable energy solution while building infrastructure independence through community empowerment. The implementation method uses the Asset-Based Community Development (ABCD) approach which includes five stages: discovery, design, define, delivery, and destiny. The program involved a collaboration between 7 KPM students, 2 village officials, and 10 local residents. The results of the service show that two PJUTS units have been successfully installed at strategic points and are functioning optimally independently without the burden of village electricity costs. In addition to physical outputs, this activity succeeded in increasing the technical capacity of residents in preventive maintenance of solar panel and battery components through a learning-by-doing process. The immediate impact felt by the community is an increased sense of security and mobility comfort, which supports social-religious and economic activities at night. This program proves that the integration of appropriate technology and participatory empowerment is an effective strategy in realizing sustainable rural infrastructure independence in accordance with SDGs point 7 targets.

Nickel has become a strategic mineral in the global industrial value chain, particularly for stainless steel production and electric vehicle battery manufacturing. As one of the world’s largest nickel producers, Indonesia has implemented a downstream industrialization policy aimed at increasing value added and strengthening export performance. This study analyzes the effects of international nickel prices, destination countries’ GDP per capita, exchange rates, and the downstreaming policy on the value of Indonesia’s nickel exports (HS 75) over the period 2010–2023. The study employs a quantitative approach using panel data regression with secondary data covering five major export destination countries, namely China, Japan, South Korea, Thailand, and Singapore. Based on the Chow and Hausman tests, the Fixed Effects Model is selected as the most appropriate estimation technique, indicating the presence of country-specific heterogeneity among importing countries. The results show that destination countries’ GDP per capita and international nickel prices have a positive and statistically significant effect on Indonesia’s nickel export value. The downstreaming policy dummy variable also exhibits a positive and significant impact, suggesting that the nickel ore export ban implemented since 2020 has effectively shifted export composition toward higher value-added processed nickel products. In contrast, exchange rates are found to have no significant effect on export performance. Overall, the findings provide empirical evidence supporting the effectiveness of Indonesia’s downstream industrialization policy and highlight the importance of global demand conditions in driving the performance of processed nickel exports.

The integration of Digital Signal Processing (DSP) algorithms in low power microcontroller based embedded systems has emerged as a promising solution to optimize energy efficiency without compromising signal accuracy and performance. This study focuses on the design and optimization of DSP algorithms specifically for microcontrollers, aimed at achieving real-time, reliable monitoring for applications such as healthcare, environmental sensing, and IoT devices. The research highlights the system's ability to handle complex signal processing tasks while maintaining low power consumption, ensuring long-term, continuous operation in remote or battery-powered environments. The system employs various techniques, including advanced power management strategies such as dynamic voltage scaling (DVS) and adaptive voltage scaling (AVS), along with lightweight AI algorithms and model pruning, to minimize energy use. The results show significant reductions in power consumption compared to traditional systems, particularly during continuous monitoring tasks. Despite this, the optimized DSP algorithms maintain or even enhance signal accuracy, ensuring that critical monitoring data remains reliable. Furthermore, the system demonstrates robust performance and reliability over extended periods, making it suitable for long-term deployment in critical applications such as wearable medical devices and industrial sensors. This research provides a foundation for the development of future low power embedded systems, emphasizing the importance of DSP-aware optimization in achieving energy-efficient and high-performance monitoring. Future improvements may include advanced AI-driven power optimization techniques, enhanced scalability, and cross-domain interoperability, ensuring that these systems can be effectively deployed across diverse applications, from healthcare to environmental monitoring.

The advancement of automotive technology has accelerated the adoption of renewable‑energy‑based electric vehicles, including the integration of solar panels on electric scooters. Indonesia’s tropical climate provides abundant solar energy potential; however, the limited surface area of scooters often restricts panel placement to the footrest section. This study aims to evaluate the impact of using a 10 mm clear acrylic cover on the performance of a 50 Wp monocrystalline solar panel in an electric scooter battery‑charging system. An experimental method was employed by comparing the panel’s performance under two conditions: without a cover and with the acrylic cover installed. Key parameters observed included voltage, current, and charging power, recorded using a data logger. Tests were conducted for 30 minutes under varying solar radiation intensities. The results indicate that the acrylic cover reduces the panel’s output power, from 55 W to 45 W at a solar radiation intensity of approximately 1100 W/m². These findings suggest that the use of an acrylic cover must be carefully considered to maintain optimal charging system performance.

The advancement of automotive technology has accelerated the adoption of renewable‑energy‑based electric vehicles, including the integration of solar panels on electric scooters. Indonesia’s tropical climate provides abundant solar energy potential; however, the limited surface area of scooters often restricts panel placement to the footrest section. This study aims to evaluate the impact of using a 10 mm clear acrylic cover on the performance of a 50 Wp monocrystalline solar panel in an electric scooter battery‑charging system. An experimental method was employed by comparing the panel’s performance under two conditions: without a cover and with the acrylic cover installed. Key parameters observed included voltage, current, and charging power, recorded using a data logger. Tests were conducted for 30 minutes under varying solar radiation intensities. The results indicate that the acrylic cover reduces the panel’s output power, from 55 W to 45 W at a solar radiation intensity of approximately 1100 W/m². These findings suggest that the use of an acrylic cover must be carefully considered to maintain optimal charging system performance.