The study aims to enhance the durability of thin-film flexible solar cells by developing a barrier layer that will act as a protective layer against chemical etching during the manufacturing process of the solar cells. This thesis is in collaboration with a Dutch flexible solar company, HyET Solar, which uses a temporary substrate to stack all the layers of the solar cell. The main problem arises when the temporary substrate is required to be removed and replaced by transparent encapsulation. The first layer after the temporary substrate is the TCO that shows defects such as pinholes, which might allow the chemical to penetrate the device and degrade it. The proposed solution is the fabrication of a barrier layer that is deposited before TCO to protect the cell stack from the etching process. Barrier layers were deposited using a scalable, industry-compatible technique, and their performance was assessed through a systematic evaluation of etch resistance and optical transparency. This was followed by optimisation of layer parameters. The findings demonstrate that properly engineered barrier layers can effectively resist chemical etching while maintaining high transparency, thereby enabling their seamless integration into flexible solar modules.

This thesis presents the design and evaluation of a low-power wireless sensor system intended to operate in conjunction with a vibrational piezoelectric energy harvester and a power conditioning circuit inside a plane wing. The system was tested in a controlled laboratory environment under various configurations, including different transmission modes, power levels, and sampling frequencies, to assess its performance, energy efficiency, and stability. Key findings indicate that sampling frequency significantly influences measurement stability. Continuous transmission mode, where data is sent without delay, while offering high temporal resolution, introduced greater variability in temperature readings, likely due to environmental noise and power supply fluctuations. In contrast, burst mode, which only sends 3 measurements in quick succession, achieves a better balance between resolution and stability, suggesting that incorporating intentional delays can mitigate noise sensitivity. Thermal recovery tests revealed that sampling density affects response time, with delayed mode showing slower returns to baseline, possibly due to self-heating or insufficient data resolution. An attempt to implement a low-power sleep mode revealed that actual current consumption did not decrease as expected, indicating an incomplete power-down mode and highlighting the need for further investigation into power management. The power consumption study confirmed that oscillator frequency and transmission power significantly affect current draw, although an anomaly observed at 4 MHz in delayed mode suggests potential efficiency zones in the transceiver’s operation. Integration with the energy harvester demonstrated the system’s ability to function under energy-constrained conditions. Testing with different storage capacitors showed that a 680 𝜇F capacitor provided the best balance between data transmission quality and energy availability. These results highlight trade-offs between energy storage capacity and responsiveness, and emphasize the importance of hardware optimization in energy-autonomous sensor systems.

As the global energy sector shifts towards electrification to achieve a net-zero future, the demand for photovoltaic (PV) systems is expected to surge. By 2050, an estimated 63.4 TW of installed PV capacity will be required, with annual additions reaching up to 4.5 TW, to help limit global temperature rise to below 2°C. This significant expansion will substantially increase the demand for aluminum, a key material in PV systems. This study presents a material flow model to analyze aluminum demand and its environmental impacts in global PV systems from 2020 to 2050. The model captures the flow of aluminum through module frames, mounting systems, and inverters, while also considering the influence of various parameters such as PV efficiency, aluminum intensity of components, component lifetimes, and recycling rates. In the baseline scenario, cumulative aluminum demand is projected to reach 830.98 mega tonnes (Mt) by 2050. However, through advancements in PV efficiency, reduction in material intensity, extension of component lifetimes, and improvement in aluminum recycling rates, the demand could potentially be reduced to 568.65 Mt.

Despite these mitigation strategies, the rapid growth in PV deployment poses significant challenges for aluminum supply, as global aluminum production is projected to be only 176 Mt by 2050, suggesting substantial supply pressures. Moreover, aluminum production is both energy- and carbon-intensive, contributing significantly to global greenhouse gas emissions. The cumulative emissions associated with aluminum use in PV systems are projected to reach 3534 Mt CO₂eq from 2020 to 2050, highlighting the urgent need for decarbonization in aluminum production. The study emphasizes the critical importance of developing a closed-loop aluminum recycling system for PV components to form a circular economy, which could reduce primary aluminum demand and associated emissions. By adopting a multi-faceted approach, including improvements in technology, materials, and recycling processes, the PV industry can mitigate its environmental impact and support the global transition towards sustainable energy.

Silicon carbide (SiC) and silicon oxide (SiOx) have garnered increased attention to reduce the parasitic absorption at the p layer when compared to p-aSi.An outstanding question is how the integration of p-SiC and p-SiOx impacts the metastability of the solr cells. Previous work in the PVMD group at TU Delft has studied the stability of the p-nc-SiOx in detail revealing from experimental results that stable efficiency remains elusive.
This thesis investigates the impact of p-a-SiC on the light-induced degradation (LID) of p-i-n solar cells, aiming to compare its degradation performance with that of p-nc-SiOx. Prior to comparison, p-a-SiC fabrication via plasma-enhanced chemical vapor deposition (PECVD) is extensively explored, as it serves as a widely used light absorber in thin-film silicon solar cells. Various parameters such as power pressure and gas flow rate of the source gas for silicon carbide formation are meticulously studied to achieve optimal P-a-SiC performance. Once the optimal fabrication conditions are identified, light absorption experiments are conducted and characterized using JV and EQE measurements to assess LID performance.

Degradation of PV modules reduces their operational lifetime, resulting in an increased levelised cost of electricity (LCOE) and shortening the useful lifetime of valuable materials. One of the leading cause of degradation is moisture. Understanding how this moisture diffuses through PV materials and in different conditions can help prolong modules’ lifetime. This thesis investigates moisture ingress in PV modules, specifically looking at non-Fickian diffusion and material degradation as alternative, and potentially more accurate, ways of modelling it. To simulate
non-Fickian diffusion, a dual-transport method is used; the study finds the approach to deliver more accurate results for EVA, but not for PET. To simulate material degradation, an adapted version of the diffusion coefficient equation is proposed, incorporating a degradation constant based on the materials’ properties. The findings are then used to analyse the behaviour of other PV materials and behaviour in different climates. The simulations find very slow moisture ingress for ionomer under non-Fickian diffusion and a strong deviation from Fickian diffusion. In EVA/PET simulations, non-Fickian behaviour is found to deviate more from Fickian behaviour in warmer climates. Degradation constants are found for the other PV materials. The approach shows promising results for the TPO/PET and ionomer/PET simulations, showing degradation in proportion with their material properties. However, simulations that include EVA appear to strongly limit moisture diffusion, indicating a revision of the EVA degradation constant should be made. TPO/PET degradation simulations in show minimal degradation over 20 years in different climates, but more material degradation in colder climates is found.

Throughout the development of crystalline-silicon/perovskite tandem solar cells, the degradation rate of the perovskite top cells has become a limiting parameter. Currently, perovskite faces stability issues, mainly caused by corrosion and the light-soaking effect. This work investigates the degradation rate of the perovskite top cell, where a model is created to determine the parameters from the single diode model that change the IV-curve of a solar cell and lifetime energy yield simulations were performed to find the maximum tolerable degradation rate of perovskite in a tandem module to obtain a higher energy yield compared to a single-junction module Using experimental data from the King Abdullah University of Science and Technology (KAUST), where the external parameters from the measurements were provided, the changes over time in the ideality factor, saturation current, shunt resistance, and series resistance were estimated, using a numerical model. Linear trend lines through the fitting parameters over time were used and lifetime energy yield simulations were performed. For these simulations, a crystalline-silicon/perovskite tandem cell with an efficiency of 31.1% was compared to to a single-junction cell with an efficiency of 23.9%, where the single-junction cell’s optics are the same as the tandem cell’s bottom cell. To perform lifetime energy yield simulations, the PVMD toolbox is used.
Simulating the lifetime energy yield over 10 years, a perovskite degradation rate of 27.5%/year was found using the electrical parameters under STC, where the power output decreased from 4.95W to 0.24W per cell. Comparing 2T and 4T configurations, where the cell optics were kept the same, degradation rates of 21.2%/year and 9.5%/year were found for 2T and 4T, respectively. Looking at different geographical locations, degradation rates of 19%, 20%, 20.6% and 21.2% per year were found for Delft, Lagos, Lisbon and Shanghai, respectively. These differences were caused by current mismatch between the top and bottom cell, where the highest mismatch of 0.55 mA/cm2 was found in Shanghai.
To determine the maximum tolerable degradation rate of the perovskite top cell resulting in a higher lifetime energy yield for a tandem module compared to a single-junction module over 25 years, various degradation rates were analyzed. The perovskite degradation rate must be lower than 1.5%/year and 3.1%/year for 2T and 4T configurations, respectively, assuming no degradation in the silicon single-junction cell and the tandem cell’s bottom cell.

Coolworld Waalwijk, a cooling machines rental service experiences marginal growth due to the rise of cooling systems for temporarily use. Their testing facility is heavily occupied for testing systems up to 800 kW. Besides the willingness to more sustainable practices, the urge rises for implementation of new energy solutions to their 500 MWh annual consumption for both heat and electrical demand.

Currently, investments in solar-generated energy have become cheaper than fossil fuel alternatives and the rise of newly developed technology such as PVT panels is ever-increasing. This is especially relevant when considering the PV energy generation losses that occur when exposed to high temperatures. This is where Coolworld comes in. In seeking a sustainable alternative energy resource, their residual cold could actively cool solar panels, enhancing their performance.

This master's thesis aims to gain insight into the energy-intensive processes and losses at Coolworld Waalwijk's testing facility and to identify sustainable solutions. With the outcome, an Energy Management Strategy (EMS) will be created, Additionally, it includes an analysis of a PV/Thermal system, with Coolworld as a case study.

The use of DC microgrids in combination with photovoltaic (PV) energy generation sources results in higher efficiencies by avoiding AC to DC conversion. Moreover, bipolar DC grids allow for more system flexibility and increased reliability at the cost of an additional conductor when compared to unipolar DC. However, maximum power point tracking (MPPT) converters are still required in order to optimize the power delivered to the microgrid by PV systems. The development of more efficient and cost-effective DC-DC MPPT converters will be proven vital considering the expected growth in solar PV installation as a consequence of the relentlessly increasing global energy demand.

The objective of this thesis is to design a DC-DC MPPT converter for bipolar DC microgrids based on gallium nitride (GaN) high-electron-mobility transistors (HEMTs). GaN transistors are wide-bandgap semiconductor devices that can operate at very high switching frequencies due to their superior electron mobility compared to other semiconductor materials used in electronic switching. Increasing the operational frequency of an electronic converter allows for smaller passive components, which in turn has the potential to result in system size and cost reductions. A complete electrical and thermal analysis of the performance of these components is simulated and presented in this report, and the implications of employing these devices for the selected application are evaluated. The design overview of the DC-DC MPPT converter using these GaN HEMTs is also showcased in this work, as well as the results obtained from testing the assembled DC-DC MPPT converter for bipolar DC microgrids. The main conclusions of this work aim to clarify the advantages of GaN devices in MPPT applications, as well as demonstrate a design solution to the integration of MPPT converters to DC microgrids. The project was developed in collaboration with the company DC Opportunities, and the designed converter was assembled and tested in their laboratory.

An increasing penetration of renewable energy sources in the global energy market necessitates an increasing amount of energy storage. Batteries are an excellent source of short term storage, used in vehicles, home storage and mobile applications. However modern technologies such as Li-ion batteries face resource scarcity and hence introduce geopolitical dependence. To this end Si-air batteries were recently, in 2009, explored in an attempt to devise a battery with high energy density and abundant materials.
The Si-air battery makes use of a silicon anode and an porous carbon cathode, to allow the circulation of air into the battery. Two electrolytes have been looked at in the past, KOH and the Room Temperature Ionic Liquid (RTIL) EMIm(HF)2.3F. The Si-air battery has excellent energy density in theory, with volumetric density being theoretically as high as 1 · 104 Wh/L. However, this theoretical energy density is as of yet far from reached, current research uses electrolytes which have a parasitic corrosion reaction with the silicon anode. This work aims to explore the usage of a new RTIL, BMPyr[NTf2], as the electrolyte in this battery. This RTIL has seen usage in Zn-air batteries, however it is yet untested for Si-air. The objective is to determine the discharge characteristics for a Si-air battery using this RTIL through comparison with KOH, with focus on the conductivity.
To do so first the relationship between conductivity and discharge potential for KOH was determined experimentally. The result found is that the discharge potential using KOH decreases with decreasing conductivity, however, this decrease is much larger than what can be solely attributed to the conductivity. Next the chosen RTIL BMPyr[NTf2], having a conductivity of 2.2 mS/cm at room temperature in a pristine state, was used in the battery discharges, where it was established to have an OCP of 0.7-0.8 V. From measurements no detectable consumption of Si was found after 1 hour of OCP. Further during the discharges it was found that the potential drops rapidly when discharge current is equal or greater to 2.5 μA. In an attempt to decrease the resistance in the battery cell a new design was created where the distance between the two electrodes is
decreased from 2 cm to 0.8 cm, using this second design a maximum OCP of 1.1 V was measured.
Finally by mixing in 1wt% and 3wt% water into the RTIL two mixtures are obtained with conductivity of 2.6 mS/Cm and 3.0 mS/cm at room temperature. Discharging these two mixtures at 20 nA, 100 nA, 500 nA and 2.5 μA it was found that for the 1 wt% the highest potential was found for 20 nA at 0.8 V. Meanwhile for the 3 wt% mixture the 20 nA discharge exhibited significantly lower potential at 0.4 V. For the 100 nA, 500 nA and 2.5 μA increasing conductivity led to increased potential, however similar to the KOH experiment, this difference in potential is larger than what is to be expected from purely conductivity changes. Finally, reproducibility of these experiments is low as a series of discharges with the same materials and current showed different potentials. These results combined lead to the conclusion of this work, thatthe relationship between conductivity and potential for the RTIL BMPyr[NTf2] is inconclusive, there are unknown factors influencing the discharge potential.

The purpose of this thesis research was to perform a photovoltaic (PV) performance assessment and comparison between a small-scale land-based PV system and an off-shore off-grid floating PV system. Also from this research design guidelines for off-grid off-shore floating PV systems were developed. The research experiment was carried out in The Netherlands, with one system floating in the North Sea and one system standing on-land. To be able to have a fair comparison two identical 4.32 𝑘𝑊 PV arrays were built simultaneously, consisting of two parallel strings, each with six 360 𝑊𝑝 bifacial PV modules connected in series. Each of the two systems was equipped with a monitoring set up consisting of temperature sensors, pyranometers, reference cells, power meters and an inclinometer for the off-shore system. Additional measurements concerning wind, wave and water temperatures off-shore were taken from the Royal Netherlands Meteorological Institute (KNMI) weather station Hollandse Kust Zuid Alpha (HKZA), which was situated in the same region of the North Sea. The two PV experimental set-ups were compared between 15th November 2022 and 1st January 2023. On the DC side being measured, the on-land PV system recorded 96.3 𝑘𝑊ℎ while the off-shore PV system recorded 93.4 𝑘𝑊ℎ, which was subject to lower irradiance levels. The performance ratio (PR) found off-shore during the period of research was 0.92 while on-land this value was 0.934 between the two PV strings, however these values should be re-validated due to a potential malfunction of the Hall effect sensors. The PR off-shore was higher than expected from literature for a similar system being simulated. With respect to module temperatures recorded off-shore, a low thermal variation was found when compared to on-land, with the average module temperature off-shore being 11.3 𝑜𝐶 higher than on-land during this period of research. Ambient temperatures as well as irradiance on the Plane of Array (POA) were found to have a larger influence on the module temperatures for the on-land system than for the off-shore system. Module temperatures throughout the PV array off-shore were found to be the equal. Additionally, four OFPV linear regression models derived from the empirical measurements were presented and compared with existing empirical FPV models found in literature, which were found to be subject to be site and design specific. Additional environmental effects on the module temperature concerning wind, wave and water temperatures were presented, highlighting the dominant effect of the water with respect to module temperatures. The off-shore floating PV system withstood waves of up to 3.4 meters while the system maximum tilts were found to be to be 13.33 𝑜 and 17.36 𝑜 for the X and Y axis of the PV floater respectively. No permanent soiling due to bio-fouling or salt deposition was detected after one month of measurements but dynamic soiling, in the form of bio-fouling, snow and water splashing were identified, with the latter being the most predominant. The work done through this thesis lays the foundation for further research and comparisons of off-shore floating PV systems. It is recommended to perform this comparison for a period of a complete year to yield annual conclusions.

To tackle the effect of climate change while meeting the ever-growing demand of energy, a high scale of integration of renewable energy resources has been performed in the past decade. Solar Photovoltaics have played a monumental role in this process, thus contributing in the fulfillment of the energy demand. The scalability and the flexibility of use has led to a significant development in the technologies implemented for assimilation of Solar PV. In addition, the development in power electronics has made the process of integration seamless. Due to Solar PV's dependency on irradiation there is an ever growing need for establishment of an improved control on power converters.
The aim of this thesis is to implement Maximum Power Point Tracking and Droop control algorithms on PV powered DC-DC Converters while considering the dynamics of Solar PV. Mathematical modelling is used to model the PV generator to consider its dynamics along with the dynamics of the converters to establish control. The output of these converters is connected to a DC Microgrid. After completion of the modelling process, the internal control design was performed followed by the implementation of both the algorithms. The project was performed at the lab of the company DC-Opportunities.
The findings of this research are presented in the current document. Its goal is to outline the procedure taken from the start of the project and the literature review all the way through the design and testing of the power electronic converters. Finally, suggestions for the future are offered, which might serve as a roadmap for more advancements.

Wireless charging technology, in particular, Inductive Power Transfer (IPT), has been evolving during the last decades, and it’s starting to become attractive for electric mobility applications. The working principle of the IPT technology is based on two coils separated by an air gap and magnetically coupled together; since the medium to transfer the energy is the air between the coils, the magnetic circuit of this system becomes remarkably important, as the magnetic flux need to be constrained as much as possible for the sake of securing the magnetic linkage between the coils. In this thesis, the design process of the casing of the coils is presented, such casing will ensure that the coils are always kept fixed according to their design.

From this point, the first goal of this thesis arises: Design an accurate and modular casing for the coils of a 50 kW IPT system that will fix such elements in the correct position, and which will allow for easy
changes/upgrades in the coil if required. The design process of such casing was to first do the CAD model of the coils, and then do the CAD model of the casing, by considering the following criteria: accurate dimensions, easy and fast to manufacture and assemble, modular-designed, light, adequately cooled, and robust. The result of such design was a casing that was actually manufactured and assembled, and that is currently being used to test a 50 kW IPT prototype system.

Besides procuring an efficient coil design for the IPT systems, it’s important to understand the dynamic behavior of the IPT electric system. One of the elements that could potentially influence the electric behavior of such system is known as parasitic capacitance. From here, the second objective of this thesis arises: Derive the parasitic capacitance of the coils in order to perform a better circuit modeling and to predict a possible over-voltage across such capacitance.

The methodology to derive the parasitic capacitance of the coils was first to perform an electromagnetic fields FEM simulation on the coils in order to obtain a set of parameters such as the coils impedance, resonance frequency and inductance. With these parameters and a set of equations, it was possible then to derive the parasitic capacitance of each coil. Finally, with this information, it was possible to build a (virtual) equivalent circuit of the IPT system and evaluate the voltage across the parasitic capacitance. It was concluded from this thesis that the parasitic capacitance at the standard operating frequency (85 kHz) does not represent a risk of over-voltage, but as the frequency goes close to the resonance frequency (1.46 MHz), the electric field across the capacitor could reach values up to 14 kV/mm.

The rapidly growing number of renewable energy technologies has started changing the infrastructure of the conventional energy sector, which was based on one-directional power flow. Bidirectional flows are created in the network with the integration of renewable technologies. The electricity network and system operators face many new challenges created due to renewable energy sources. Renewable energy sources are characterized by an intermittent and stochastic character which affects the power production from renewable energy technologies. Thus, the produced energy may pose challenges to the grid when it is higher than demand since the excess power is injected into the grid and it causes overvoltage problems.
BESS can contribute in facing the problems created by renewable energy technologies. They offer environmental benefits, they contribute to the integration of renewable technologies and they enhance grid’s reliability. These factors have as a result an increase in the integration of batteries in the electricity network. This research has as a goal to develop a control and coordination method for multiple BESS in a low voltage distribution network in order to address overvoltage and undervoltage issues caused by high penetration of PV units. There are many control strategies used in order to control the increasing number of batteries so that normal operation of the energy system is sustained. The main control strategies are centralized control, decentralized control and distributed control.
In this thesis study, a coordination control strategy of multiple BESS was developed to address the network's voltage violation issues caused by the high penetration of PV units. The coordination control strategy is based on a consensus algorithm that determines each battery's contribution to the network. The goal of this control strategy is to maintain the voltage within the limits. When a battery is not available due to a state of charge limit violation or maintenance, the amount of power that this battery would contribute under normal operation is distributed equally from the neighboring batteries until the battery becomes available again. This control strategy is a combination of distributed control, as it entails communication between neighboring batteries which share information together, and local control. The developed coordination control strategy is compared to a decentralized control strategy, which is widely used in distribution networks in order to control the contribution of batteries. Moreover, one of the batteries is emulated in the laboratory in order to examine the behavior and contribution of the battery, with the coordination control strategy implemented, in real-time application in comparison to the simulation.
The findings of this thesis study contribute to the research of mitigating voltage limit violations caused by renewable energy technologies by demonstrating the effectiveness and benefits of the proposed control and by providing a comparison of the proposed control to a decentralized control strategy, commonly used in distribution networks for controlling the contribution of BESS, for voltage regulation. Furthermore, the laboratory results contribute in the potential implementation of the proposed control in real distribution networks.

The European Green Deal states that it wants to develop 40 GW of electrolyzer capacity by 2030 in North Africa to combat climate change. Using PV power as the primary energy source, a system is designed that can produce green hydrogen and ammonia to investigate how the location and the capacity of the components can be optimized to produce at the lowest possible levelized costs. This way the competitiveness of green hydrogen and ammonia can be examined against hydrogen and ammonia produced using fossil fuels. Incorporating batteries for electricity storage, a salt cavern for hydrogen storage and cryogenic tanks for nitrogen storage, the system is designed to work as flexible as possible to cope with the variations in PV output.

Scaled to an industrial scale output of 200.000 ton-NH3 per year, the resulting LCOH in 2030 will be 1.63 €/kg-H2, and the LCOA will be 0.394 €/kg-NH3. The competitiveness with fossil fuel-based production is dependent on the price of natural gas, which in this case will need to be higher than 3.16 $/MBTu or 12.25 €/MWh (converted using a USD/EUR rate of 0.88 and a conversion factor of 0.29308 MWh/MBTU, and taking into account a carbon price of 100 €/ton-CO2-eq) for green hydrogen to be competitive. For green ammonia to be cheaper, the gas price must be greater than 4.49 $/MBTu or 17.41 €/MWh.

A sensitivity analysis shows that if the CAPEX and OPEX cost of the five most contributing components to the levelized cost would be 50% higher, the LCOH (2.4770 €/kg-H2) and LCOA (0.5817 €/kg-NH3) would still compare favourably to blue hydrogen and ammonia with a natural gas price of 7.71 $/MBTu (29.89 €/MWh) and 9.04 $/MBTu (35.05 €/MWh). By analyzing the operations of the salt cavern, it is discovered that 6.4% of the salt cavern is used from the available capacity of 3300 ton-H2. Even when the necessary yearly output of ammonia is raised 2 or 4 times, the salt cavern uses only 12.7% and 16.8% of the available capacity. Overall this research shows that green hydrogen and ammonia can compete with hydrogen and ammonia produced from fossil fuels in 2030 and that the possibilities of salt cavern storage for hydrogen are greater than expected because a capacity of 250 ton-H2 is enough for a yearly production of 200.000 ton NH3.

Several studies have posed that international cooperative initiatives lead by businesses could aid in mitigating global warming in ways that are additional to national policies. However, evaluations on their progress are rare due to many informational issues. This research gap is worrisome since such initiatives can also have negative effects on global commitment due to effort fragmentation and greenwashing.

This thesis evaluates progress in two initiatives that have featured prominently in the literature: the Science Based Targets initiative (SBTi) and RE100. The group of companies evaluated was reduced to the Fortune Global 500, a ranking of the largest firms by revenue.

Large datasets were created with the targets set by these companies, their emissions and energy use, among others. Progress was evaluated in four aspects: the ambition of targets, the robustness of their disclosure of sustainability metrics, the implementation of changes to their energy profiles, and finally the substantive progress seen in their collective carbon footprint.

It was found that among the two initiatives, SBTi appears posed for larger emissions mitigation, while RE100 is better at promoting more effective renewable energy purchasing practices. However, direct emission reductions are mostly concentrated on a reduced number of firms in energy intensive sectors, with the remaining members focusing on reductions through indirect methods that might not be additional at the global level. Similarly, it was found that informational barriers remain high even in these firms, with a plethora of inconsistencies that complicate year-by-year comparisons.

Green hydrogen can be produced from various renewable energy sources like PV, wind, geothermal and biomass. Especially PV or wind sourced hydrogen production systems are becoming more prevalent as a solution to produce green hydrogen, owing to their regional abundance. In this master thesis project, a PV-grid powered electrolyser shall be taken into consideration. The electrolyser is an equipment that produces hydrogen through electrolysis. Here, an alkaline electrolyser is taken into consideration, which is a DC load and hence, it requires a rectifier to convert the AC power from the grid and from the PV plant (DC PV power will be converted to AC through an inverter) into DC power. The amount of hydrogen produced is proportional to the amount of current flowing into the electrolyser. As the electrolyser operates, the process of electrolysis will, more often than not, produce heat. The heat produced during electrolysis, along with the ambient conditions, will result in variation of the temperature of the electrolyser. Some systems make use of a thermostat to control the temperature of the electrolyser whereas some employ a cooling system to extract heat and utilise it to perform useful work. If there is no system to control or maintain its temperature, the electrolyser is bound to have varying temperature while it is operational. This research aims to develop a control strategy for a PV-grid powered electrolyser to ensure the optimal operation of the electrolyser despite its varying temperature. The need for such a control strategy for the electrolyser rises due to the dependence of the I-V characteristics of the electrolyser on the temperature. As the temperature of the electrolyser increases, the I-V curve shifts in such a way that a given current value will be produced at a lower value of voltage. Since the amount of hydrogen produced depends on the amount of current flowing into the electrolyser, the control strategy aims to maintain the input current to the electrolyser at the rated value irrespective of the change in the temperature of the electrolyser. The control strategy is tested on Simulink with the help of an electrolyser emulator into which data is fed through a look-up table. Real-time data for irradiance and ambient temperature has been used to perform day-long simulations. Based on the results obtained, the average efficiency of the converter was found to be 93.88%.

This research is aimed at designing and optimising a fully renewable energy system for the GCC countries of the Arabian Peninsula for the year 2050 . This includes deriving the energy potential of open-field PV and wind technologies in the region. Apart from the electricity demand of the power sector, the hydrogen demand of the steel, ammonia and road&rail transport sectors is also considered, as well as the export of hydrogen in the liquid form. Different scenarios are considered for a better understanding of the operation of the system. Li-ion batteries and gaseous hydrogen vessels are employed to balance production and demand, while reconversion technologies are also part of the system together with powerlines and hydrogen pipelines. The study shows that the potential of onshore wind and solar energy is way greater than total energy demand, while offshore wind potential is of a comparable size to total energy demand. On average, solar energy is the cheapest source of electricity at 2.9 €c/kWh, followed by onshore wind at 4.9 €c/kWh and offshore wind at 9.9 €c/kWh. However, the minimum cost registered by solar and onshore wind technologies is almost the same at around 2.2 €c/kWh, while offshore turbines do not fall below 5.0 €c/kWh. In a cooperation scenario considering local electricity and hydrogen demand, total annual costs are equal to 130 €bln/year, 21% less than a similar scenario where countries are isolated from each other. Twice as much electricity is produced through wind turbines than PV farms under the cooperation scheme, whereas solar energy slightly dominates the electricity mix in the isolation scenario. Besides, the system relies more on curtailment and battery storage than reconversion. The coupling of the power and hydrogen sectors leads to a total costs reduction of 7%. The LCOE found for the system is of 6.1 €c/kWh, which is around 20% more than the current LCOE of modern gas turbines in the region. The LCOH of gaseous and liquid hydrogen at the port is of 2.5 and 3.0 €/kg respectively, which is 2-3 times more expensive than crude oil and several times more expensive than LNG based on current breakeven costs in the region.

Thin-film flexible solar panels can be utilized on many surfaces where conventional solar panels are hard to be used such as side walls of buildings, ship roofs or curved surfaces. In conventional solar cells, glass is used to protect the panels from external damage. However due to its heavy weight and rigidity, glass is not an option for thin-film flexible solar cells. HyET Solar, a company based in the Netherlands that produces flexible thin-film solar cells uses a transparent foil produced using a roll-to-roll process to encapsulate and protect their solar panels. In order to reduce the amount of materials used and cut the costs, a thinner foil is being developed. Producing the thinner foil in a roll-to-roll process causes different defects in the foil, among which half sinusoidal waves forming mostly in the bottom side of the foil, these waves are called wrinkles. The process of manufacturing the top encapsulant layer involves changing temperatures and mechanical stresses applied on the foil. Therefore, two models were developed to understand the effect of three process parameters (web force, web speed and temperatures of each production zone) on wrinkle formation. First, a thermal model of the process using ANSYS program was developed to understand the temperature profile of the produced foil along the process. Then, a mechanical model that uses the output of the thermal model and the applied mechanical forces to study the effect of the investigated production parameters on wrinkle formation was worked out. The results show that operating at higher temperatures and reducing the thickness of the foil are directly responsible for decreasing the threshold of the critical stress that causes wrinkle formation and thus reducing the range and the magnitude of the force to 1.4 N is needed to perform the process without forming wrinkles in the foil. Varying web speed between 0.3 m/min and 3m/min is found to have a minor effect when varied under high temperatures. Finally, decreasing the temperature of the first and second zones by 10 °C is found to extend the range of the web force that can be applied. Performing the process under lower temperatures or reducing the mechanical forces that act on the foil will reduce wrinkle formation in the developed foil; web speed should not be considered in mitigating wrinkle formation.

One of the main reasons that the efficiency drops from cell to module is the conduction losses. To increase the efficiency of the PV module, the produced charge carriers in the semiconductor materials should be transferred to the PV module terminals with minimum conduction losses. As an alternative to the conventional cells and modules interconnections, in this thesis project, efficient ways to incorporate Wireless Power Transfer (WPT) techniques into PV cell and module architecture are being sought.

The main objectives of this research are to understand how WPT techniques can be efficiently incorporated into PV devices, such as PV cells and modules, find out whether these techniques in theory and in practice are efficient enough and suggest the best design approach as a guideline for near future prototyping.
Many different WPT methods were studied in theoretical level, such as the Capacitive Power Transfer (CPT), the Inductive Power Transfer (IPT) and the Magnetic Resonant Coupling (MRC). Based on the main advantages and disadvantages of these methods, the most efficient seems to be the MRC, which eventually was used as the main method of transferring power wirelessly in the systems of this thesis project.

The systems that were developed and studied consist of a PV generator made of a single IBC solar cell or a PV generator that consists of 16 connected in series IBC solar cells, an inverter that converts the direct current (DC) of the generators into alternating current (AC) and two resonant circuits, the primary and the secondary one. Between these circuits, the power is transferred wirelessly from the primary to the secondary one, through the magnetic field that is created.

During this project, the main mathematical models were developed and were used for simulations in both Matlab and Simulink. The main goals of these simulations were to find out which type of coils, as far as the shape, the cross section and the values of turn width, turn spacing, distance between the coils and number of turns are concerned, and which compensation topology would help the systems to develop higher efficiencies.

According to the results, when ideal DC to AC conversion at the primary side of the system is assumed, the most ideal option seems to be the Series-Series compensation topology with planar coils of circular shape and rectangular cross-section, for which the systems developed efficiencies higher than 85% when the circuits were connected with one solar cell and above 98% when the circuits were connected with one module of 16 solar cells.

In 2017, Hurricane Maria proved how fragile Puerto Rico’s grid is to natural disasters. The consequence of this fragility was the longest power blackout in the history of the U.S., which affected 3.3 million people, lasted for 3.4 billion customer-hours, and resulted in economic losses estimated in 95 billion USD. The solution, then, is energy resilience, defined here as the overall ability of an electricity system to prevent, mitigate, and recover from wide-area, long-duration outages. Accordingly, the aim of this study is to quantify the value of the energy resilience that solar microgrids can provide to electricity users in Puerto Rico.