https://www.um.edu.mt/library/oar/handle/123456789/106743 2026-04-20T21:23:38Z https://www.um.edu.mt/library/oar/handle/123456789/141615 Title: On the use of measure-correlate-predict methodologies and energy demand forecasting to assess energy storage capabilities for offshore wind farms Abstract: Energy storage is crucial for the continued penetration of renewable energy. One of the most important reasons for this is that, for a given point of time, the availability of renewable energy resources rarely matches the demand for electrical energy. The integration of offshore windfarms with energy storage facilities, requires a capital-intensive investment which can only be justified by an adequate return on investment (ROI). Currently, Measure-Correlate-Predict (MCP) analysis is used to assess the viability of offshore windfarms while energy demand forecasting is normally used to manage and plan the electricity grid infrastructure. This research combined wind energy prediction methodologies with Energy Demand Forecasting (EDF) methodologies to size the energy storage capacity for an offshore windfarm and evaluated the economic feasibility. This research analysed various regression techniques for MCP analysis. Data from a Light Detection and Ranging (LiDAR) system were utilised. The study was extended to analyse the behaviour of a hypothetical floating windfarm, situated off the Northern Coast of the Island of Malta. The effect of using the different regression techniques for MCP analysis on the power output from the windfarm could therefore be evaluated. The second part of the research used a combination of ARIMA and regression techniques to forecast the energy demand over several years. The output from the windfarm was applied to a model which integrated the said windfarm to an Energy Storage System (ESS) and the electricity grid. Measurement matrices were used to compare the behaviour of the combined windfarm, ESS and electricity grid, based on the actual and predicted data from the various regression techniques used for the MCP analysis and EDF. This created a matrix of results which was used to determine the optimal combination of regression techniques used for MCP analysis and EDF, following which, the optimal capacity of the ESS was established. The long-term behaviour of the windfarm and the of the energy storage system were also predicted. The Levelised Cost of Energy (LCOE) for the windfarm and the Levelised Cost of Storage (LCOS) for the Energy Storage System were also calculated, using different windfarm scenarios, and analysing the error due to the use of the MCP and EDF methodologies. This research therefore established a methodology for combining MCP and EDF to determine the optimal capacity of an ESS which was coupled to an offshore windfarm and the electricity grid. The error in establishing this capacity was determined. The end result was the determination of the LCOE of the windfarm and the LCOS of the ESS based on the combination of MCP analysis and EDF, together with the error introduced due to the use of the two methodologies. Description: Ph.D.(Melit.) 2023-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/119496 Title: Wave response modelling and innovative cooling technologies for offshore photovoltaics Abstract: Solar energy is becoming increasingly popular, especially with countries racing to meet renewable energy share targets and achieve energy independence. However, inefficiencies in solar cells result in most absorbed energy being converted into heat, with only a small fraction being used to generate electrical energy. While onshore solar installations have been predominant, offshore photovoltaics (PV) are emerging as a promising technology with vast untapped potential. Offshore photovoltaics refer to installing solar panels on floating structures or platforms in bodies of water, such as oceans, seas, and lakes. This approach offers several advantages over traditional onshore solar installations. Firstly, offshore photovoltaics can overcome the limitations posed by land availability, especially in densely populated areas or regions with limited suitable land for solar installations. Additionally, offshore photovoltaics can help to mitigate visual impacts and landuse conflicts associated with onshore installations, as they are located away from populated areas. Moreover, floating solar platforms open up possibilities for location sharing with other marine-based activities, such as aquaculture or water treatment, creating opportunities for integrated and sustainable use of marine resources. However, it is essential to address challenges related to technology development, installation logistics, environmental impacts, and cost-effectiveness to fully realise offshore photovoltaics' potential. This thesis analyses the different parameters that could negatively affect the efficiency of offshore PV panels and focuses primarily on the incident solar radiation and the effect of temperature. A decrease in the insolation on PV panels directly results in a reduction in energy generation. Furthermore, an increase in solar cell temperatures results in a decreased conversion efficiency and, as a result, a decreased energy yield. Since no long-term offshore photovoltaic installation exists, various research and technology gaps still need to be addressed. For instance, floating structures will have some response to incoming waves. This response is highly dependent on the design of the floating structure and will have some effect on the insolation on offshore photovoltaic systems. However, there are currently no tools available that an offshore system designer can use to quantify this effect and optimise their design. This research presents a new simulation tool termed Offshore Solar Irradiance Calculator (OSIC) that can quantify this effect. The development of this tool is outlined in this thesis, and parametric analyses are presented, showing the impact of wave response motion on fixed and tracking offshore PV installations. The findings of this research show that wave responses can affect incident radiation, ranging from a slight increase of 0.26% to a decrease of more than 12% for high amplitude wave responses. These findings could have significant impact on the design of offshore PV systems. Moreover, this thesis also presents a patented Innovative Photovoltaic Cooling System (IPCoSy) that addresses limitations in existing PV cooling technologies. The cooling system involves the addition of a water chamber at the back of a conventional PV module, resulting in uniform cooling and a decreased pump switching frequency. The findings of this research showed that the positive effects of this cooling technology range from more than 10% increase in PV electrical energy yield, and thermal efficiencies of up to 56%. The development, testing and future recommendations of this technology are all presented in this research. Therefore, this research contributes new knowledge toward optimising offshore photovoltaic installations through wave response modelling and innovative cooling technologies. Furthermore, this thesis contributes knowledge to improve the PV industry and presents technology that could also change the current concept of a PV module and revolutionise the integration of renewable energy in buildings and industry. Description: Ph.D.(Melit.) 2023-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/118613 Title: Applying GIS tools to assess the potential of vertical solar photovoltaics on arterial roads in Malta Abstract: This thesis focuses on the deep analysis of the added value of installing vertical solar photovoltaics on arterial roads in Malta. The main justification for carrying out this study is two-fold. On one hand, the EU’s 2030 targets aim at significantly increasing the contribution of renewable energy in the overall energy consumption and therefore the obligations of each Member State have become more pressing. Given that Malta has limited space or unsuitable space on roofs and land, it becomes imperative to think outside the box and evaluate the potential of other available spaces, especially given that the cost of photovoltaics has dropped significantly and therefore one can now afford to install them in different configurations that might produce less output than the optimal position, but still remain competitive. The second justification for carrying out this study is that the EU has recently dedicated significant targeted budget for recovery after the SARS-CoV-2 pandemic. Around 78 million Euro has been budgeted for Malta to invest in addressing climate neutrality through enhanced energy efficiency, which specifically includes investments in renewable energy along footpaths, roads, and public spaces. The aim of the project is to evaluate the potential sites along arterial roads that can be considered for installing vertical solar PV systems, also acting as sound barriers or for reducing incoming traffic glare at night. The objectives include GIS analysis of all relevant arterial roads and adjacent sub-stations, evaluate existing shading impacts due to topology or other obstacles, calculate the expected energy output and associated carbon dioxide savings and evaluate the economic impacts or benefits of such projects. The methodology makes use of several GIS tools to map and hierarchically categorise potential sites along arterial roads suitable for vertical PV installations. Other software was used to evaluate the expected energy outputs and the economic implications. Results showed a potential for generating 31,726 MWh/year, which amounts to a 12% increase when compared to the total renewable energy generation of 2021 and this is equivalent to 1.4% of the total electrical energy consumed in Malta. The economic analysis indicated that such projects are feasible and can be implemented by potential private investors, but the substations can be a cost hinderance, so it was proposed that a public-private partnership would further popularise these investments. Description: M.Sc.(Melit.) Sust.Energy 2023-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/118611 Title: Optimising decorative etching for defect identification in semiconductors Abstract: This work involves the optimisation of acid-based etching techniques of silicon wafers for solar cell manufacture. Solar photovoltaics have a vital role in the transition to renewable energy and so it is important to work to improve their efficiency. Defects present in the silicon wafers have important implications on their performance. Chemical etching is a useful process for quantifying these defects and for polishing silicon wafers. Experiments were carried out in this work to optimise polishing and defect etches. A method to chemically polish wafers to produce a smooth surface was devised. Two widely used defect-delineating etches, Secco and Wright etches, were studied and a procedure for these etching techniques was produced. Defects were delineated by these etching solutions and different types of defects were differentiated by observation under a light microscope. The etch rate and defect density were determined and the difference between the two defect etching techniques was highlighted. The accuracy of the defect density determination was confirmed using the Light Scattering Tomography tool. Defects in both as-grown and heat-treated silicon wafer samples were delineated and observed. The results show that these defect etches can be used to identify surface defects and accurately determine bulk defect density. Differences in the defects present in as-grown and heat-treated silicon could be seen using these etching techniques. The Secco etch was found to be more suited for delineating oxygen precipitates and oxygen-induced stacking faults in heat-treated samples while the Wright etch was better for sub-micron oxygen precipitates in as-grown samples. Description: M.Sc.(Melit.) Sust.Energy 2023-01-01T00:00:00Z