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Title: Optimal sizing of hybrid renewable systems to improve electricity supply reliability in Iraqi domestic dwellings
Author: Alshamri, Hussain Ali Hatam
Awarding Body: University of Leeds
Current Institution: University of Leeds
Date of Award: 2019
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his project aims to evaluate wind and solar power availability in Iraq in order to support and design an optimized hybrid renewables system for use in domestic sectors. The unreliable energy supply is one of the main challenges that the residential sector faces in Iraq. This project assessed to what extent the investment in Hybrid Renewable Energy System (HRES) is feasible and efficient to overcome the problem of unreliable supply at reasonable cost. Several researchers have tried to assess wind and solar resources in Iraq using low-resolution databases from a limited number of weather stations, but they were unable to produce a comprehensive evaluation of renewable energy in Iraq. This research identified and developed techniques that allow more accurate mapping of wind resources in Iraq than has been possible previously. In addition, the thesis developed a unique technique to optimize the best design of HRES that has sufficient flexibility to deal with various climatic conditions and economic challenges using wind turbines, solar panels, and rechargeable batteries. In order to assess the potential wind power in Iraq, many wind resource evaluation techniques based on the spatial and temporal microscale and mesoscale were reviewed. In addition, the availability of several wind data resources was considered and discussed using observed and estimated data. To evaluate wind resources for the whole of Iraq, a downscaling model using reanalysis data from Modern-era retrospective analysis for research and applications (MERRA) and a land-use map as the basis of the surface roughness map for the whole of the country has been developed. Following this, a power curve model was used to estimate potential wind power production from several types of small wind turbines. The most fundamental techniques were used to evaluate and calculate solar power production. In addition, the most important solar databases were used to evaluate the solar radiation for the whole of Iraq. To evaluate solar resources in Iraq, the most validated solar dataset was employed to evaluate annual solar energy production for the whole of the country. In addition, the hourly solar energy production model based on wind speed and ambient temperature impact (HSEP-WT model) was developed to estimate the hourly solar system output, combining the effects of wind speed with the impact of ambient temperature on cell temperature, aiming to make the solar power evaluation more realistic. The hybrid system, which has multiple renewable technologies, is considered the most useful approach to satisfy energy demand in the residential sector. Accordingly, several methodologies to size and optimize a hybrid system in terms of reliability and cost parameters were reviewed. Consequently, a novel computational model has been designed to size and optimize HRES, which is deemed suitable to maintain supply in domestic properties that suffer continually from unscheduled outages from the national grid. The process of optimization examined several energy flow strategies and economical solutions to decrease the total cost of a project and to increase the reliability of HRES. The results of this thesis have shown, that the downscaling model succeeded in increasing the resolution and accuracy of estimated wind speed and confirmed that the model should be applied, based on the local variables of the boundary layer. In addition, the wind power production demonstrated that the most productive locations in Iraq are concentrated above the water surfaces and the area that extends from central to east and south-east of Iraq. Also, these areas have shown low cost of energy and a payback period lower than eight years. Furthermore, solar power production confirmed that the most productive locations are located in the west of Iraq. Also, most places in Iraq have shown low cost of energy and a short payback period. Finally, the optimized technique for identifying optimal combinations of wind, solar and battery technologies for domestic scale renewable energy provision was developed in an unique design using MATLAB by integrating an on-grid and off-grid system (On-off-grid Op-HRES). This system has been developed to resolve the problem of frequent and unscheduled outage for some hours per day from the national grid. The On-off-grid Op-HRES system is examined according to different scenarios of grid Increasing Block Tariffs (IBT) prices, strategies of energy flow management (discharge and without discharge battery in case of on-grid) and based on different land covers and various weather conditions (wind speed and solar radiation). The On-off-grid Op-HRES system was successful in reducing the cost of energy and increasing the reliability of the system when using HRES in areas that have high wind speed and high solar radiation. In addition, when applying the strategy of non-discharging the storage system when connected to the grid as well as using relatively high electricity prices from the national grid, HRES has shown excellent performance in terms of cost and reliability by reducing the Levelized Cost of Energy (LCE), Payback Period (PBP), Loss of Power Supply Probability (LPSP) and Grid Power Absorption Probability (GPAP). Lastly, the availability of wind speed has played an exceptional role in terms of increasing reliability of HRES, even in areas that have low solar radiation.
Supervisor: Cockerill, Tim ; Tomlin, Alison Sponsor: MOHESR
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available