Perovskite-based photovoltaic is one of the most promising classes of emerging solar cell technologies. This material class combines several advantageous properties, including low exciton binding energy, high charge carrier diffusion length and high optical absorption. Despite these excellent attributes, some challenges remain in perovskite research. Most notably the device stabilities and lifetimes need to be significantly improved in order to push this technology towards commercialization. Defect physics in perovskite photovoltaics has been shown to be a main factor in understanding long-term device instabilities. However, the number of measurement techniques that can track changes in the ionic landscape during device degradation is very limited, as the perovskite layer is buried under charge extraction layers and metallic contacts. In this thesis argon gas-cluster ion beam etching is combined with x-ray and ultraviolet photoelectron spectroscopy to achieve high resolution energetic and compositional depth profiles. In contrast to most layer-to-layer techniques this method can be applied after any operation time of the photovoltaic and therefore nicely investigate potential changes in the defect landscape. In the first part of this thesis, the impact of argon gas-cluster etching on the perovskite structure is investigated in order to identify potential damage that prevents this technique from being viable for perovskite materials. It is found that metallic lead is gradually created and a small preferential etching effect of the organic cations takes place during the depth profiling, but it is demonstrated that the major part of the crystal structure stays intact and that the energetics of the sample remains very stable. Moreover, it is demonstrated that fitting of the obtained ultraviolet photoelectron spectroscopy spectra leads to high resolution energetic and compositional depth profiles, which are suitable to identify potential loss mechanisms in full photovoltaic devices. In the second part, we investigate the increase in device performance of a perovskite photovoltaic during the first subsequent measurements under full illumination, which is a common example of a short-term instability. Ultraviolet photoelectron spectroscopy depth profiles reveal a strong band bending effect appearing after biasing the device which consequently leads to an increase in device open-circuit voltage. Density functional theory simulations link this band bending effect to the accumulation of iodine interstitials at the interface between the perovskite and the electron transport layer. In the final part, long-term degradation of perovskite photovoltaics is studied by investigating the impact of ionic additives on the perovskite active layer, which increases the lifetime of these devices significantly. It is found that most properties of the perovskite layer remain unaffected by the ionic additive, e.g. microstructure, energetic disorder and photoluminescence. Photoelectron spectroscopy depth profiling revealed an accumulation of iodine at the interface towards the electron transport layer, which is significantly reduced in additive-containing samples. Deep-level transient spectroscopy revealed a new mobile defect species in the ionic additive samples and at the same time a reduction of iodine diffusivity.

As part of Nigeria’s drive to increase electricity production capacity and shift to renewable sources, a new 50 MW photovoltaic (PV) plant is proposed for a town in north-west Nigeria. Rather than using conventional monofacial modules and fixed mounting, it is of interest to consider a selection of new technologies which are attracting growing attention in the global utility PV market. These can increase energy output, and could be used to advantage in this 50 MW plant. However, the technologies, namely bifacial modules and solar tracking, are more expensive than their conventional counterparts, while their relative performance depends on the latitude and climate of the plant location. Thus their economic benefit cannot be taken for granted. The aim of this study is to propose multiple designs for the 50 MW plant using different combinations of module and mounting technologies, finding their economic order of merit by estimating their respective levelised costs of electricity (LCOEs).Using the simulation software PVsyst, the electricity production of different plant layouts and component configurations was estimated. Key parameters such as tilt angle and pitch distance were varied in order to optimise each configuration of technologies. Having sourced economic data from the industry and literature, lifetime plant costs were calculated, which in combination with lifetime electricity production, were used to estimate the LCOE.As expected, results indicated that the optimum configuration was bifacial modules mounted on horizontal single-axis tracking (SAT), followed by monofacial modules on horizontal SAT. Fixed installations had greater LCOEs by a reasonable margin, while the LCOE difference between monofacial and bifacial modules on fixed mounting was within the error of the calculation, meaning this choice relies on more accurate input data. A sensitivity analysis allowed uncertainty in the results to be gauged, and highlighted the factors which most influence LCOE, so that efforts to increase profitability can be focussed in the right places. Finally, suggestions are offered to help optimise bifacial and tracking installations by comparison with conventional plants.The conclusions drawn herein will be specifically relevant to the Swedish developer and EPC contractor Svenska Solenergigruppen which, in due course, will submit a plant design proposal to the project developer of the 50 MW plant. However, it is hoped that this work will act as a guide for any EPC contractor or developer working on a utility PV plant in sub-Saharan Africa, allowing efficient design of an optimal system.

Examensarbetet som presenteras i denna rapport är ett delprojekt utfört i samarbete med Glava Energy Center och redovisar framtagningen av ett PV-system för den eldrivna båten Bowter. I rapporten utfördes en energianalys där solinstrålning i olika plan studerades och analyserades. Möjligheter att utöka antalet solceller baserat på båtens design undersöktes, där båtens horisontella badbrygga samt vertikala långsidor bedömdes vara de ytor som var lämpliga för placering. Förslag på konfigurationer av PV-systemet dimensionerades och den förväntade mängden genererad energi och laddning beräknades. Systemet som togs fram skulle enligt beräkningar i genomsnitt generera mellan 1,06–2,22kWh energi per dag och kosta omkring tio tusen kronor. Energianalysen visade att solceller placerade i 30–40° lutning i genomsnitt skulle kunna generera mellan 20–43 procent mer energi och laddning än den valda vertikala placeringen. Med båtens nuvarande design utan några möjligheter för placering av solceller i lutande plan går därmed denna potentiella mängd energi förlorad. Praktiska mätningar av energi via reflektioner från vattenytan visar heller inga övertygande tecken på att rädda upp för denna mängd förlorad energi. Simuleringar av det framtagna systemet genomfördes och jämfördes med det beräknade genomsnittet, vilket visade att man skulle kunna förvänta sig cirka 25 procent mer energi under klara förhållanden och 76 procent mindre energi under svåra väderförhållanden med långvariga och heltäckande moln. Av resultaten drogs slutsatsen att det mest praktiska alternativet för maximal systemeffekt är att möjliggöra placering av fler solceller i horisontellt plan via t.ex. en takdel och på den vägen erhålla ett mer pålitligt och förutsägbart resultat som både skulle vara mer effektivt samt ekonomiskt fördelaktigt i jämförelse med det framtagna systemet. / The thesis work presented in this report is a sub-project carried out in collaboration with Glava Energy Center and reports on the development of a PV system for the electric boat Bowter. In the report, an energy analysis was performed where solar irradiance in different planes was studied and analyzed. Opportunities to increase the number of solar cells based on the boat's design were investigated, where the boat's horizontal swim platform and vertical sides were determined to be the areas that were suitable for placement. Proposals for configurations of the PV system were sized and the expected amount of generated energy and charge capacity were calculated. According to calculations the proposed system would on average generate between 1.06–2.22kWh of energy per day and cost around SEK 10,000. The energy analysis showed that solar cells placed at an angle of 30–40° could on average generate between 20–43 percent more energy and charge than the chosen vertical placement. With the boat's current design without any possibilities for placing solar cells in an inclined plane, this potential amount of energy is lost. Practical measurements of energy via reflections from the water surface show no convincing signs of compensating for this amount of lost energy. Simulations of the proposed system were carried out and compared with the calculated average, which showed that one could count on about 25 percent more energy in clear conditions and 76 percent less energy in harsh weather conditions with long-lasting and overcast clouds. From the results, it was concluded that the most practical alternative for maximum system power is to enable the placement of additional solar cells in a horizontal plane via e.g. a roof section and in that way obtain a more reliable and predictable result that would be both more efficient and economically advantageous in comparison with the proposed system.

Small and medium-scale companies are trying to minimise their carbon footprint and improve their cash flow, renewable installations are increasing all over the Europe and are expected to do so in following years. However, their dependency on the weather cause pressure on matching the production with demand. An option how to challenge this problem is by using energy storage. The aim of this project is to determine techno-economic benefits of Stirling engine and high temperature thermal energy storage for installation in energy user system and identify key factors that affect the operation of such system. In order to determine these factors simulations in Matlab were conducted. The Matlab linear programming tool Optisolve using dual-simplex algorithm was used. The sensitivity analysis was conducted to test the energy system behaviour. Economic evaluation was done calculating discounted savings. From the results, it can be seen the significant benefit of SE-HT-TES installation is the increased self-consumption of the electricity from PV installation. While the self-consumption in cases when there was no energy storage implemented was around 67 % and in one case as low as 50 % with the SE-HT-TES the value has increased up to 100 %. Energy cost savings are 4.7 % of the cost for the original data set and go up to 6.2 % when simulation with load shift was executed. Simulations have also shown that energy customer with predictable energy demand pattern can achieve higher savings with the very same system. It was also confirmed that for users whose private renewable production does not match load potential savings are 30 % higher compared to the system where energy load peak is matching the PV production peak. Simulations also shown that the customers located in areas with higher electricity price volatility can benefit from such system greatly.

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<p> Integrating solar energy into the electric vehicle (EV) market alleviates the demand for</p> <p>fossil fuels used to generate the electricity used to power these vehicles. Integrated solar panels</p> <p>provide a new method of power generation for an electric vehicle, but researchers must consider</p> <p>new dependent variables such as drag in the figure of vehicle efficiency. For the solar array to be</p> <p>deemed a viable option for power generation, the solar array must generate enough energy to</p> <p>overcome the added weight and aerodynamic drag forces the solar system introduces. The thesis</p> <p>explores the application of photovoltaic modules for power generation in an EV system.</p> <p>Researchers installed an off-the-shelf solar module on the roof of an EV and investigated the</p> <p>system to explore the efficiency tradeoffs. The research sought to identify an optimized solar</p> <p>panel configuration for minimized drag based on maximized panel surface irradiance, cooling,</p> <p>and array output voltage parameters. The study utilized computational fluid dynamics modeling,</p> <p>wind tunnel testing, and full-scale track testing to analyze the system. The results of this study</p> <p>provide an optimized configuration for a Renogy RNG-100D atop a Chevrolet Bolt. The system</p> <p>was considered optimal at a tilt angle of zero degrees when in motion. The performance benefits</p> <p>due to the increased angle of the solar panel tilt were deemed insufficient in overcoming the</p> <p>aerodynamic drag forces introduced into the system while in motion.</p>

<p>As energy demands for the world increase, the necessity for alternate sources of energy are critical. Just in the United States alone, 92 quadrillion British thermal units (Btu) were used in 2020. As political and geographical pressures surrounding oil increase, along with the growing concern for climate, the drive to explore alternative and renewable means for harvesting energy is on the rise. Solar cells, also known as photovoltaics (PVs), are an attractive renewable source and have been developed as an alternative energy means for over 60 years. When considering losses due to atmospheric absorption and scattering, the Earth’s surface gets about 1000 W/m2 of energy from the sun, which is why there are research efforts around the world trying to maximize the efficiency of solar cells.</p> <p>Organic-inorganic halide perovskites provide for ideal absorbing layers that feature long carrier lifetime and diffusion lengths, strong photoluminescence, and promising tunability. Furthermore, the solution-processing methods used to make these perovskites ensure that the solar cells will remain low-cost and have easy scale-up possibilities. The main problem perovskites is that they degrade in the presence of water, thus leading to decreased device performance.</p> <p>In this work two approaches are investigated to increase moisture stability. The first investigates incorporation of thiols as pseudohalides into the 2D perovskite structure. Instead of the theorized perovskite, two novel 2D compounds were created, Pb₂X(S-C₆H₅)₃ (X= I, Br, Cl) and PbI_1.524(S-C₆H₅)_0.476. While not perovskites, this study gives insight into the effect that the thiol may have on determining structure when comparing –S-C₆H₅ with –SCN groups. Future work will explore more electronegative thiols that will be used to make moisture resistant, tunable 2D perovskites.</p> <p>The second approach is to incorporate longer organic ammonium cations into the perovskite structure to produce quasi-2D perovskite films fabricate them into devices. Adding in electronically insulating ligands leads to a stricter requirement for vertically aligned 2D films and special care must be taken to have efficient charge collection. The current field has successfully incorporated short ligands such as butylammonium (BA) into PVs, however the extension to larger and more beneficially hydrophobic ligands has been very scarce. In this work, a novel solvent engineering system is developed to create vertically aligned quasi-2D perovskite absorbing layers based off of a bithiophene ligand (2T). These absorbing layers are then characterized and incorporated into efficient PV devices. Generalizations to solvent conditions related to ligand choice is discussed herein, creating deep insights into incorporating more conjugated ligands into devices.</p>

The aim of this Thesis is to consider a methodological framework suitable to support a primary and primitive investigation and evaluation of the technical applicability and energy feasibility of a specific Energy Island model in Greece. For such purpose, the general concept and the potential applications of Energy Island are presented, and the present situation of the Greek energy sector and RES technologies in Greece are outlined. In order to attempt to evaluate the technical performance of a specific Energy Island model in Greece, a theoretical and hypothetical Multi-Criteria Decision Analysis (MCDA) process is developed and conducted. The methodological framework developed and applied for the present case study pertains to a theoretical decision-making process for the selection of the optimum Energy Island scenario in Greece amongst four (4) alternatives. As derived from the extracted results of the applied MCDA model, the hypothetical scenario with the highest annual energy production and the least environmental and technological issues ranks optimal for all the implicated stakeholders and is considered the most preferred alternative. This Thesis concludes that the perspective of the various applications of the concept of the Energy Island model has the potential to contribute to more efficient utilization of the available RES technologies in Greece, in order to accelerate the decarbonization of the Greek energy system as well as to assure the security of the system, by replacing the existing conventional fossil fuel generation plants with clean offshore renewable energy.

<p dir="ltr">The safe and reliable delivery of electricity is critical for the functioning of our modern society. However, high-impact, low-probability (HILP) catastrophic events (such as extreme weather caused by climate change, or cyber-physical attacks) pose an ever-growing threat to the power grid. At the same time, modern advancements in computational capabilities, communication infrastructure, and measurement technologies provide opportunities for new operation and control strategies that enhance the resilience of electric power systems to such HILP events. In this work, optimization-based operation and control approaches are proposed to improve resilience in two power systems applications. First, a real-time linearized-trajectory model-predictive controller (LTMPC) is developed for ensuring voltage, frequency, and transient (rotor angle) stability in systems engineered to operate as microgrids. Such microgrids are capable of seamlessly transitioning from grid-connected operation to an islanded mode and thus, enhance system resilience. The proposed LTMPC enables rapid deployment of such systems by reducing engineering costs and development time while maintaining stable operation. On the other hand, some power systems, such as distribution feeders, are not designed to operate as standalone microgrids. For these cases, a method is proposed for forming ad-hoc microgrids from intact sections of the damaged feeder in the aftermath of a HILP event. A feeder operating center-on-a-laptop (FOCAL) is introduced that coordinates the control of possibly hundreds of inverter-interfaced distributed energy resources (e.g., rooftop solar, battery storage) to improve system resilience. Theoretical analysis as well as numerical case studies and simulations of the proposed strategies are presented for both applications.</p>