Issue Journal of Engineering and Science Vol. 2 No. 1 (Jan–Jun 2023) contains five articles focused on electric power quality, renewable/hybrid energy efficiency, power factor improvement in large installations, and environmentally friendly material and process innovations. The first article discusses improving the voltage profile at the Banda Aceh Substation through the installation of a 25 MVAR capacitor bank—likely evaluating increases in bus voltage levels, power factor improvement, reduction of network losses, and voltage profile stability during peak load. The second article assesses the influence of adding/configuring a porous plate on panels made from cat tail (Typha latifolia) plant fibers on the sound absorption coefficient, pointing toward low‑cost acoustic applications and green materials. The third article offers an innovation in coil heater technology for the brick firing process with the aim of reducing emissions (e.g., fossil fuel consumption, particulate smoke) and improving temperature uniformity so that brick quality becomes more consistent. The fourth article again addresses optimization of voltage system performance—this time at the Nagan Raya steam power plant—through the design/control of a capacitor bank to improve power factor, keep voltage within standard limits, and potentially reduce reactive power penalty costs. The fifth article investigates the effects of using a grid‑tie inverter in a hybrid solar panel–diesel system, including grid synchronization, load management, reduction of generator operating hours, conversion efficiency, and potential reductions in fuel consumption and emissions. Overall, this issue highlights integrated technical approaches for: (1) enhancing the quality and efficiency of power systems, (2) substituting and optimizing renewable energy in hybrid configurations, and (3) utilizing natural materials and more sustainable process technologies.