Utilization of Renewable Energy for Power Sector in Yemen: Current Status and Potential Capabilities

A severe energy crisis has plagued Yemen for decades, and most of the population lack access to electricity. This has harmed the country’s economic, social, and industrial growth. Yemen generates electricity mainly from fossil fuels, despite having a high potential for renewable energy. Unfortunately, the situation has recently been compounded by the country’s continuing war, which has been ongoing since early 2015. It has impacted the country’s energy infrastructure negatively, resulting in power outages. Therefore, this paper aims to provide an updated perspective on Yemen’s current energy crisis and explain its key issues and potential solutions. Besides, it examines the potential, development, and current state of renewable energy sources, such as solar, wind, geothermal, and biomass. Based on the findings, Yemen is one of the world’s wealthiest countries in terms of sunlight and wind speed, and these two resources are abundant in all regions of the country. In addition, this paper sheds light on the solar energy revolution that has arisen since the war started due to the complete outage of the national electricity. Within a few years, solar energy in Yemen has increased its capacity by 50 times and has recently become the primary source of electricity for most Yemenis. Furthermore, the paper discusses the difficulties and challenges that face the implementation of renewable energy investment projects. Numerous recommendations for potential improvements in Yemen’s widespread use of renewable energy are also provided in this paper. All of the ideas presented in this paper are hoped to increase the efforts to grow renewable energy production in Yemen, thereby solving the issues of energy poverty and reducing environmental effects. The presented analysis can be used as a scientific reference for researchers and industrial companies looking for suitable solutions to advance Yemen’s renewable energy

Performance analysis of photovoltaic and wind turbine grid-connected systems under LVRT conditions

The integration of grid-connected renewable energy systems has gained significant attention and introduces several challenges and considerations. One of these challenges is ensuring the reliable and stable operation of these systems under various grid conditions. For example, faults at the grid could lead problems such as DC-link over-voltage and AC over-current that may cause disconnection or damage to inverter. This paper presents a comprehensive analysis of the performance of photovoltaic (PV) and doubly-fed induction generator (DFIG) wind turbine grid-connected systems under low voltage ride-through (LVRT) conditions. The study aims to investigate their behavior, and stability during LVRT events and provide insights for enhancing their grid integration capabilities. The PV and DFIG systems are modelled and simulated using MATLAB Simulink under three difference conditions, with and without using reactive current injection and DC chopper circuit. Various performance parameters, including grid voltage, grid current, DC-link voltage, active power, and reactive power, are analyzed to assess the system's behavior and compare their responses. The principal results reveal distinct performance characteristics of the PV and DFIG systems. The PV system shows higher overshoot currents, over-voltage, and significant drops in active power during fault occurrences, while the DFIG system exhibits lower overshoot currents and better stability in the DC-link voltage. Reactive power responses differ between the systems, with the PV system demonstrating a higher capability for support. The implementation of DC chopper shows more effective in the reduction of DC-link voltage and overshoot grid current in the PV system compared to the DFIG system

Impact of renewable energy utilization and artificial intelligence in achieving sustainable development goals

Many countries around the world are planning to reach 100% renewable energy use by 2050. In this context and due to the recent sharp increase in RE utilization in the global energy mix along with its progressive impact on the world energy sector, the evaluation and investigation of its effect on achieving sustainable development goals are not covered sufficiently. Moreover, an assessment of the emerging role of artificial intelligence for renewable energy utilization toward achieving SDGs is conducted. A total of 17 SDGs were divided into three groups, namely, environment, society, and economy, as per the three key pillars of sustainable development. Renewable energy has a positive impact toward achieving 75 targets across all sustainable development goals by using an expert elicitation method-based consensus. However, it may negatively affect the accomplishment of the 27 targets. In addition, artificial intelligence can help renewable energy enable the attainment of 42 out of 169 targets. However, with the current exponential growth of renewable energy share and artificial intelligence development and addressing certain present limitations, this impact may cover additional targets in the future. Nevertheless, recent research foci overlook essential aspects. The exponential growth of renewable energy share and rapid evolution of artificial intelligence need to be accompanied through the requisite regulatory insight and technology regulation to cover additional targets in the future

Design and control of large-scale grid-connected photovoltaic power plant with fault ride-through

Over the recent years, the installation of photovoltaic (PV) system and integration with electrical grid has become more widespread worldwide. With the significant and rapid increase of photovoltaic power plants (PVPPs) penetration to the electric grid, the power system operation and stability issues become crucial and this leads to continuous evaluation of grid interconnection requirements. For this purpose, the modern grid codes (GCs) require a reliable PV generation system that achieves fault ride-through (FRT) requirements. Therefore, the FRT capability becomes the state of art as one of the challenges faced by the integration of large-scale PV power stations into electrical grid that has not been fully investigated. This research proposes FRT requirements for the connection of PVPPs into Malaysian grid as new requirements. In addition, presents a comprehensive control strategy of large-scale PVPPs to enhance the FRT capability based on modern GCs connection requirements. In order to meet these requirements, there are two major issues that should be addressed. The first one is the ac over-current and dc-link over-voltage that may cause disconnection or damage to the grid inverter. The second one is the injection of reactive current to assist the voltage recovery and support the grid to overcome the voltage sag problem. To address the first issue, the dc-chopper brake controller and current limiter are used to absorb the excessive dc-voltage and limits excessive ac current, respectively, and therefore protect the inverter and ride-through the faults smoothly. After guaranteeing that the inverter is kept connected and protected, this control strategy can also ensure a very important aspect which is the reactive power support through the injection of reactive current based on the standard requirements. Feed-forward decoupling strategy based-dq control is used for smooth voltage fluctuation and reactive current injection. Furthermore, to keep the power balance between both sides of the inverter, PV array can generate a possible amount of active power according to the rating of grid inverter and voltage sag depth by operating in two modes, which are normal and FRT modes. These two modes of operation require fast and precise sag detection strategy to switch the system from normal mode to a faulty mode of operation for an efficient FRT control. For this purpose, RMS detection method has been used. In this research, the large-scale PV plant connected to the MV side of the utility grid, taking the compliance of TNB technical regulations for PVPPs into consideration has been modelled using MATLAB/Simulink with nominal rated peak power of 1500 kW. Analyses of the dynamic response for the proposed PVPP under various types of symmetrical and asymmetrical grid faults also had been investigated. As a conclusion, the PVPP connected to the power grid provided with FRT capability has been developed. The sizing of the suggested PV array is achieved in which the simulation results matched the sizing calculation results. Moreover, the results at the point of common coupling show that the proposed PVPP is compatible with TNB requirements, including the PV-grid connection method, PV inverter type, nominal voltage operating range, total harmonic distortion less than 5%, voltage unbalance less than 1%, frequency fluctuation within ± 0.1 Hz, and power factor higher than 0.9. In addition, the control simulation results presented demonstrate the effectiveness of the overall presented FRT control strategy, which aims to improve the capability of ride-through during grid faults safely, to keep the inverter connected, to ensure the safety of the system equipment, to ensure all values return to pre-fault values as soon as the fault is cleared within almost zero second as compared to the strategy without FRT control which needs around 0.25s, and to provide grid support through active and reactive power control at different types of faults based on the FRT standard requirements

Modeling and Control of Grid-Connected Photovoltaic Power Plant With Fault Ride-Through Capability

According to modern grid codes (GCs), high penetration of photovoltaic power plants (PVPPs) to the utility grid requires a reliable PV generation system by achieving fault ride-through (FRT) requirements. In order to meet these requirements, there are two major issues that should be addressed to keep the inverter connected during grid fault. The two issues are the ac over-current and dc-link over-voltage that may cause disconnection or damage to the grid inverter. In this paper, the control of single-stage PVPP inverters is developed to address these issues and enhance FRT capability. The proposed control scheme introduces the dc brake chopper circuit and current limiter to protect the inverter and ride through the fault smoothly with no perceptible overcompensation. A 1.5 MW PVPP connected into the Malaysian grid and modeled in simulink is utilized to explain the proposed control scheme. The simulation results presented demonstrate the effectiveness of the overall proposed control strategy to ride through different types of faults and to help to ensure the safety of the system equipmen

Grid‐connected photovoltaic power plants: A review of the recent integration requirements in modern grid codes

The high integration of photovoltaic power plants (PVPPs) has started to affect the operation, stability, and security of utility grids. Thus, many countries have established new requirements for grid integration of solar photovoltaics to address the issues in stability and security of the power grid. In this paper, a comprehensive study of the recent international grid codes requirement concerning the penetration of PVPPs into electrical grids is provided. Firstly, the paper discusses the trends of PVPPs worldwide and the significance of improving grid codes' requirements. In addition, the comparison of common requirements covered in the majority of international grid codes considers high‐ and low‐voltage ride‐through capabilities, voltage and frequency regulation, and active and reactive power support requirements. Finally, a broad discussion on the compliance technology challenges and global harmonization of international grid codes that the PVPPs have to address is presented. The study summarizes the most recent international regulation regarding photovoltaic integration and research findings on the compliance of these regulations and proposed recommendations for future research. It also can assist power system operators to compare their existing requirements with other universal operators or establish their own regulations for the first time. Additionally, this research assists photovoltaic manufacturers and developers to get more accurate understanding from the recent global requirements enforced by the modern grid codes

Modeling and Ddynamics Study of Large Scale PV System Connected Malaysian Grid under Different Fault Conditions

The installation of photovoltaic power plants and integration with electric grid has become more widespread. Asnthere is a significant increase in the size and capacity of grid-connected power plants, the stability and reliability of the grid become more important. A 1.5 MW PV station connected to the distribution side of the Malaysian grid via a voltage source inverter is modeled and simulated using Matlab/Simulink. This study presents the modeling of PV module behavior and characteristics based on the mathematical model equivalent circuit. The Simulink was run to simulate PV array sizing depending on perturb and observed maximum power point technique to enhance the efficiency of modules, and obtain maximum available power using variable perturbation step size dependent on power changes. The simulation result was matched to the results of sizing calculation. The inverter control system modeling and park transformation were carried out. Phase locked loop was used to track the grid frequency and voltage. The Malaysian grid-connected PV system is designed and modeled according to the regulations and guidelines of Tenaga Nasional Berhad concerning grid-integration of PV power generation system to LV and MV networks. Finally, this paper analyzes the dynamic response of the proposed PV plant under various types of symmetrical and non-symmetrical grid faults. The results indicated that the short circuit faults in the distribution grid side had disturbing effects on the optimal operation performance of PV systems. Whereas, the influence of grid faults depends on the fault type. In addition to that, the simulation result proved that the symmetrical fault has higher impact on PV system operationmthan non-symmetrical faults

Sizing and Design of PV Array for Photovoltaic Power Plant Connected Grid Inverter

Over the past few years, installation of photovoltaic power plants (PVPPs) are considered as one of the most promising technologies at many of countries around the world, in order to meet the growing demand of energy. The DC side (PV generators and MPPT) of a 1.5 MW PV power plant connected to the inverter is modeled and simulated using Matlab/Simulink. The sizing of the suggested PVPP is achieved, such as array sizing and enhanced perturb and observe maximum power point tracking (MPPT) technique, in order to overcome the disadvantages of conventional method such as oscillation and slowly tracking under sudden change of atmospheric conditions. The MATLAB/Simulink was run to simulate the PV array sizing and its characteristics depending on enhanced MPPT technique to improve the efficiency of the modules and getting maximum available power. The simulation result has been matched the sizing theoretical calculation results