The transition from fossil fuels to renewable energy is vital for addressing climate change and ensuring energy security. Hybrid renewable energy systems (HRES), particularly those integrating solar photovoltaic (PV) and wind power, have emerged as a promising solution to overcome the intermittency and variability of individual sources. This study develops a comprehensive simulation and optimization framework for hybrid PV–wind systems, incorporating advanced energy storage options such as lithium-ion batteries and ultracapacitors. Using high-resolution meteorological and load data, both grid-connected and off-grid configurations are analyzed to evaluate system reliability, cost-effectiveness, and adaptability across different climates. A special focus is given to Kuwait, where high solar irradiance and moderate wind resources align with national energy diversification goals under Kuwait Vision 2035. The results highlight the technical and economic feasibility of hybrid systems, showing significant improvements in energy yield, load matching, and levelized cost of energy (LCOE) compared to standalone technologies. Furthermore, the study underscores the importance of intelligent control strategies, advanced component technologies, region-specific optimization, and explicit planning and performance evaluation insights in ensuring sustainable and resilient deployment of hybrid renewable systems.

Cross-flow heat exchangers are widely used in thermal and energy systems for their compactness and structural simplicity; however, their thermal–hydraulic performance remains strongly constrained by geometric configuration, flow regime, and pressure-drop penalties. This review systematically examines more than four decades of research on cross-flow and compact heat exchangers, covering theoretical, numerical, and experimental investigations. The effects of geometric modifications—such as fin and tube shape, pitch, orientation, and surface interruption—are critically analyzed, revealing that non-uniform, flow-disturbing geometries can enhance heat transfer by 15–50%, albeit often at the cost of increased hydraulic resistance. Studies of mechanical vibration and flow oscillation demonstrate notable enhancements in heat transfer in low-Reynolds-number and buoyancy-dominated regimes when vibration parameters are optimally tuned. The integration of porous media, including metal foams and packed spheres, has shown substantial performance gains, often exceeding 40–90%, though significant pressure-drop challenges accompany this approach. More recently, artificial intelligence and data-driven optimization techniques have emerged as powerful tools for balancing thermal enhancement and hydraulic penalties. Despite these advances, key gaps persist in condensation-dominated applications, low-Reynolds-number regimes, long-term reliability, and experimentally validated coupled thermal–hydraulic optimization. This review consolidates existing knowledge, identifies unresolved challenges, and outlines future research directions towards high-efficiency, application-specific cross-flow heat exchanger design.

The power shortage and dependence on fossil fuels are the two key challenges facing the electricity sector in Iraq. Employing renewable energy sources may provide a promising solution for the electric power industry issues across the country. This necessitates extensive research efforts from multiple perspectives to establish their region-specific feasibility and viability. This study introduces an optimal sizing of a hybrid renewable energy system (HRES) under multiple solar tracking strategies for a residential community in Iraq. The proposed HRES integrates solar photovoltaic (PV), wind turbines, diesel generator, battery bank, and power converter. The solar tracking configurations employed in this work are horizontal-axis continuous adjustment (HACA) tracker, vertical-axis continuous adjustment (VACA) tracker, and two-axis (TA) tracker. The focus is on quantifying the viability of the solar tracking systems and their impacts on the overall system optimality and performance, considering the load demand, renewable resources, and cost data in the region. The results show that the optimal design of the HRES with the VACA solar tracking provides the best economic performance, yielding the lowest total net present cost and cost of energy, \$2.99 million and 0.134 \$/kWh respectively, the highest return on investment and internal rate of return values, 15.5% and 19.8%, respectively, and the shortest simple payback period at 4.7 years. Furthermore, the results revealed that the HACA solar tracking and the TA solar tracking do not lead to a lower overall system cost compared to the no solar tracking configuration. From the technical standpoint, the results demonstrate that an enhancement in solar capturing results in a reduction in solar PV array size within the hybrid system and simultaneously increases its efficiency in electricity generation. Environmentally, it was found that advanced solar tracking systems may not necessarily provide meaningful environmental benefits. The findings and the conducted analyses presented in this paper highlight the significance of assessing solar tracking technologies at the hybrid system level to carefully determine their viability from economic, technical, and environmental perspectives.

Indonesia is an archipelagic country with 17,001 islands spread across 34 provinces, in remote, outermost, and farthest islands that are very possible to meet the needs of New and Renewable Energy-based energy. Hydroelectric power plants depend on environmental sustainability conditions and water catchment areas so that the flow of water will continue to be maintained to turn turbines to produce electricity. In rural areas that are not reached by the National Power Plant, you can build micro-scale hydroelectric power plants, and if constrained by very minimal costs, you can build pico-hydro scale power plants. This research method utilizes rooftop area identification using Google Earth (GE) and Unmanned Aerial Vehicle (UAV). The results of this study found the potential of pico-micro-hydro power of 18 kW and solar power plants (Pembangkit Listrik Tenaga Surya, PLTS) Rooftop offgrid 596.83 kWh. This research shows that new renewable energy can sup Dimension Stationport the development of micro-enterprises based on green energy for community welfare.

Access to modern energy services is crucial for reducing energy poverty, which involves lowering costs, increasing access to energy appliances, ensuring safety and efficiency, and providing renewable energy sources for household needs like cooking, heating, and lighting. Marginalised communities often use fire-prone energy sources, leading to fire accidents and incidents. Off-grid renewable energy systems are gaining popularity in these communities, but energy stacking remains a common practice. This study aims to understand the uptake and acceptability of solar power in underprivileged areas by analysing home energy consumption trends, identifying energy-related problems, and proposing solutions considering the needs and circumstances of the impacted communities. The study involved 40 households and found that paraffin, firewood, and liquefied petroleum gas (LPG) were used for cooking, while solar energy was mainly used for lighting. However, households believed solar energy was not affordable and insufficient, and 98% of participants believed the availability of renewable energy sources was the main reason for using it. Implementing renewable energy technologies for cooking and heating and financial investment in solar energy is necessary to ensure affordability and sustainability.

This study investigates the technical and financial viability of a proposed 40 MW solar photovoltaic (PV) power plant in two Iraqi regions: Al Sulaymaniyah and Al Muthana. The study encompassed technical aspects, economic assessment, cost analysis, and estimation of net annual greenhouse gas (GHG) reduction. Emphasis was placed on optimization of energy production and cost-effectiveness. The analysis utilizes the RETScreen software to assess the feasibility of installing PV systems at the selected sites. The research parameters considered in the study included the horizontal and tilted daily solar radiation, the annual electricity production, capacity factor, and GHG reduction. The financial analysis and feasibility included simple payback (SPB), net present value (NPV), and annual life cycle savings. These projects can be best achieved when supported by grants and a reasonable tariff starting from \$0.035/kWh or more, resulting in a NPV of \$5,209,217 and \$4,819,530 in the Al Sulaymaniyah and Al Muthana projects, respectively.