The aim of the work presented in this thesis is to study the opto-electronic properties of semi-conducting perovskite materials when being used in unconventional solar cell device configurations. Being a young technology, perovskites as solar cell materials have seen an unparalleled rise in the research community which has driven the fastest performance inflation to power conversion efficiencies competing with the ones of long established single crystalline technologies. The ability to process perovskites inexpensively makes them the new hope in the fight against climate change. Herein device architectures were developed with a special focus on potential commercial applications. Initially the work in this thesis has been motivated by the interest in crystal growth and morphology of perovskite thin-films, which has led to the study of confined crystal growth within microstructures. Controlling the crystal domain geometry enabled the fabrication of enhanced semi-transparent devices. More efforts were directed into the improvement of specifically neutral colour semi-transparent devices, which could be improved via a simple treatment of selectively attaching shunt-blocking layers. Furthermore, a back-contacted perovskite device design was introduced, which allows not only for the fabrication of a new type of perovskite solar cell, but also represent a great material testing platform to study perovskite and electrode characteristics. This led to the discovery of charge transport distances, that exceed those of other thin-film devices. Finally, perovskite-on-silicon tandem solar cell designs were analysed through a rigorous optical model to estimate the expected real world energy yield from such systems. Important implications include the fact that two terminal tandem solar cells come close to four-terminal configurations and can overall compete, in relative terms, well with established single junction silicon cells.

Development and optimisation of a robust energy yield prediction methodology is the ultimate aim of this research. Outdoor performance of the PV module is determined by the influences of a variety of interlinked factors related to the environment and device technologies. There are two basic measurement data sets required for any energy yield prediction model. Firstly, characterisation of specific PV module technology under different operating conditions and secondly site specific meteorological data. Based on these two datasets a calculation procedure is required in any specific location energy yield estimation. This research established a matrix based multi-dimensional measurement set points for module characterisation which is independent of PV technologies. This novel approach has been established by demonstrating an extended correlation of different environmental factors (irradiance, temperature and spectral irradiance) and their influences on the commercial PV device technologies. Utilisation of the site specific meteorological data is the common approach applied in this yield prediction method. A series of modelling approach, including a tri-linear interpolation method is then applied for energy yield calculation. A novel Monte Carlo simulation is demonstrated for uncertainty analysis of irradiance (pyranometer CM 11) & temperature (PT 1000) measurements and ultimately the yield prediction of c-Si and CIGS modules. The degree of uncertainties of irradiance is varies from ??2% to ??6.2% depending on the level of monthly irradiation. The temperature measurement uncertainty is calculated in the range of ??0.18??C to ??0.46%??C in different months of the year. The calculated uncertainty of the energy yield prediction of c-Si and CIGS module are ??2.78% and ??15.45%. This research validated different irradiance translation models to identify the best matched model for UK climate for horizontal to in-plane irradiance. Ultimately, the validation results of the proposed Fast Energy Yield Calculation (FEnYCs), shows a good agreement against measured values i.e. 5.48%, 6.97% and 3.1% for c-Si, a-Si and CIGS module respectively.

It is essential to make performance measurements of photovoltaics modules in order to quantify the power they will produce under operational conditions. Performance measurements are fundamental throughout the photovoltaic industry, from product development to quality control in manufacturing and installation in the field. Rapid and economic evaluation of photovoltaic performance requires measurements using pulsed illumination solar simulators. However some devices have characteristics which can cause difficulties making these measurements. The aim of this thesis is to overcome these measurement problems focusing particularly on two of the most prevalent and pressing of these problematic characteristics: high capacitance and metastability. A new method for measuring high capacitance modules in a pulsed simulator, based on tailor made voltage ramps, was developed. The voltage ramp is tailor made such that the measurement time is minimised while maintaining high accuracy (0.5 %), allowing the measurement of high capacitance modules in a single 10ms illumination pulse. The necessary inputs for this method are the capacitance and dark current as a function of voltage for each module. In order to make these measurements, at the high forward bias voltages required, a new system was developed. The tailored voltage ramp can be created individually for each module, since the process is rapid an automatic. This makes the method applicable to a production line or to test house measurements. In addition to their use as inputs for the voltage ramp design, the capacitance and dark current also contain other valuable information, including effective minority carrier lifetime. In several thin film technologies, such as CIGS, the efficiency is not a fixed value, rather the module is metastable and the efficiency changes depending on the previous exposure /preconditioning of the device. Preconditioning is normally applied to these devices before measurement in order to put them in a specific state that is repeatable and representative of outdoor operation. Improved preconditioning practices are vital for performance measurements in CIGS modules. Therefore the preconditioning behaviour of a variety of CIGS modules from different manufacturers was investigated. The effect of preconditioning varied for different modules, commonly the fill factor improved substantially, but often changes in open circuit voltage were also seen and in some cases also substantial changes in short circuit current. The rates of preconditioning and relaxation were found to follow stretched exponential behaviour, such that the changes occur linearly on a logarithmic timescale over several orders of magnitude in time. The total time for performance stabilisation was found to vary significantly between different types of module. Because of this stretched exponential behaviour, even though the module took days to fully relax to the dark state, there was significant relaxation within the tens of minutes that it would normally take a module to cool down after light soaking before it could be measured. The major implication of observed kinetics is that in order to achieve repeatable measurement the timing in each element of a preconditioning routine should be controlled such that the fractional error in the duration of each step is small. During the investigation an unexpectedly short timescale preconditioning effect was observed, which occurs on a millisecond timescale and relaxes in seconds. It was shown that the measurement artefacts introduced using this method can be eliminated by using electrical forward bias until immediately before the measurement. Another measurement system was developed to track the dark current and C-V characteristic of the modules during electrical bias preconditioning and subsequent relaxation. These measurements demonstrate that more than one process involved during preconditioning in CIGS. Changes occur both in the doping in the bulk of the absorber and also in charge accumulation occurring near to the absorber / buffer interface. The theoretical models for preconditioning in CIGS were reviewed and compared to the experimental results. A rate model was developed based on the theory of the metastable VSe-VCu defect. This model was shown to correspond well to the rates of preconditioning and relaxation in CIGS. The non-exponential behaviour was shown to be compatible with a distribution of activation energies for the transition between different defect states. The difference in the time taken for modules to stabilise is explained by differences in doping density and the density of VSe-VCu defects. The work presented facilitates more accurate, economical performance measurements for high capacitance devices and CIGS devices, thereby contributing to the large scale implementation of photovoltaics as power source.

In this study, the financial and economic viable of perovskite-SHJ tandem solar cells were determined using a detailed bottom-up cost model and energy-yield calculations. Attention to specific advancements in perovskite solar cell layer technology and large-scale deposition have been taken into account to create a realistic, viable commercial scale option for tandem production. A reference tandem technology is used to determine the overall manufacturing cost and minimum sustainable price. Models used show that the tandem technology has the potential to be cost competitive with existing silicon technology given the uncertainty and sensitivity of the values used in this study. It was examined further how non-STC energy yield and service life contributes to the overall economic viability of the tandem module within residential, commercial and utility scale of application. Given the reference tandem module, it is expected to be competitive at the residential level with existing silicon technology if perovskite layers' service life is greater than 20 years. In commercial and utility application, the tandem model is not economically viable due to the reductions seen in the area- and project-related installation costs for existing technology. This thesis concludes by presenting the current limitations in perovskite technology that would inhibit adaptation of this into commercial-scale production and presents alternative applications in which tandem modules would be more favourable.

This thesis presents an energy prediction tool for photovoltaic (PV) modules, based on the measure-correlate-predict principle. The tool allows quantification of the impact of the different environmental factors influencing PV device efficiency for different sites as they deviate from standardised test conditions and combines their effects for energy yield prediction of different module technologies operating in different climates. Amongst these environmental influences, the impact of angle of incidence has been particularly under-researched. In this work, a systematic investigation of the influence of angle of incidence on PV module performance is realised. This is achieved using both short-term module characterisation and long-term energy yield measurement campaigns. A customised purpose built dual axis tracker for mounting paired sets of modules on a fixed south-facing, 45-degree tilted rack is used to investigate the differences in module performance. The quality and quantity of the composition of the incident irradiance is described for various sky conditions at high latitude locations. Furthermore, an understanding of the entangled effects on photocurrent of both the angle of incidence and spectral variation is presented. This is achieved by analysing data from a system developed especially in this work which integrates an instantaneous all-sky mapping of irradiance from a monochromatic CCD camera with precision measurements of small-aperture normal irradiance from a collimated pyranometer in the short-term measurement campaign. The proposed energy prediction tool is validated using long-term datasets from several locations and is compared to other current methods. This was conducted under the European-funded PV-Catapult and IP Performance projects. The tool's prediction uncertainty falls within the ±5% for crystalline and ±10% for thin films, which is the same accuracy as other methods and within the measurement uncertainty of outdoor measurements.

Recently, commercial softwares for PV system simulation released bifacial extensions. While research laboratories have developed their own simulation tools, in both cases it is imperative to display their applicability, as well as continuously assess their accuracy and/or limitations in practice, i.e. for different bifacial PV systems and field conditions. This paper presents a design and energy yield simulation study of two bifacial PV systems installed and operating in Nordic climate conditions, i.e. in Vestby, Norway ( System 1) and in Halmstad, Sweden (System 2). The aim of this study is: • To validate and compare the accuracy of two bifacial PV simulation tools newly featured in the software platforms of PVsyst and Polysun respectively, against real-field energy yield data. Each investigated system is modeled and analyzed with both simulation tools, resulting in four individual case stu dies. Further details on the systems’ monitoring set-up, the data input, modeling steps, and the involved uncertainties are presented in this paper. The results of the four case studies show higher percent deviations (both monthly and hourly data) between simulated energy results and real energy results during winter periods compared to summer periods. System 1 had a lower bifacial gain (around 2%) than System 2 which ranges from 2% in summer periods to 25% during winter. The collected field data had too high of an uncertainty to determine whether the bifacial PV simulation extensions are accurate within a certain tolerance. The reason for higher simulation inaccuracy in the winter is due to: lower production, higher uncertainty in albedo, and more diffuse irradiation. It is recommended for the bifacial PV simulation extensions include options for considering a variable albedo. The bifacial gain in System 2 was higher in the winter because of the higher albedo value given whereas in System 1, the albedo value was kept constant. Further parametric studies should be conducted on the bifacial gain using vertical mounted bifacial PV modules oriented east and west for Nordic climate conditions.

Concentrator photovoltaics is a promising renewable energy technology, especially for utility or large-scale deployments. Like all new technologies, it has obstacles and setbacks to overcome. More specifically, the optics in a concentrator photovoltaics system introduce non-uniform spatial and spectral illumination on the cell, which can change under different operating conditions. This work was put together to discover a new characterization technique capable of analyzing the performance of a concentrator photovoltaics and provide insight to the field on what is happening within the system, linking modeling results seen in the literature to these experimental outcomes. The thesis is composed of three journal papers written by the candidate, who’s contributions are outlined at the beginning of each chapter. In order to study the illumination profiles on the cells, a new method to characterize the optical components had to be developed. Previous version lacked the ability to control the temperature of the lens and had low spectral resolution of the irradiance profiles. To improve, a novel indoor measurement method was developed capable of spectrally imaging concentrator photovoltaics optics and recreate outdoor operating conditions in a controllable environment. With the calibrated system, our test-bench is capable of measuring the spectral distribution with a 10μm2 resolution and characterizing the output of a system to within 3%. Exploiting this experimental technique, the individual effects of module misalignment, cell to primary distance, and lens temperature was studied for three leading technologies associated with the three generations of concentrator photovoltaics optical architectures. Focusing on Fresnel-based concentrator optics, the performance of silicone on a glass module without a secondary optic is the most sensitive to operating conditions, where lens temperature can decrease the absolute efficiency resulting in a difference of 11% in the annual energy yield. The next two generations have secondary optics but are designed slightly differently. The truncated inverted pyramid, designed independently of the primary optic, favoured higher lens temperature values and there was only a difference of 1% in the energy yield calculation. The primary and secondary optics in the 4-fold Fresnel-Kohler are designed together, due to new development tools, and showed the highest stability under the different operating conditions, demonstrating that concentrator photovoltaics is on the right track to overcoming its onset issue. As the technology matures, future designs can improve on the issues characterized within this thesis.

Le contexte global de réchauffement climatique et de fin programmée des carburants d'origine fossile a conduit depuis quelques décennies au développement des biocarburants. Les nombreux inconvénients liés à la première génération de biocarburants ont peu à peu donné naissance aux biocarburants de seconde génération dont l'avantage notable est d'utiliser la partie ligno-cellulosique des plantes. La principale voie de conversion envisagée consiste en une gazeification suivie d'une synthèse Fisher-Tropsch. Mais la dispersion énergétique et géographique de la biomasse ainsi que les nombreuses contraintes liées au processus de fabrication nécessitent la mise au point d'un préconditionnement adéquat. Le matériau utilisé devra en effet être homogène, concentré énergétiquement, stockable et facilement transportable. Il devra aussi être facilement broyable en vue de son injection sous pression dans les gazéifieurs. Une voie de prétraitement possible consiste à torréfier la biomasse. Le présent travail s'inscrit dans cette thématique puisqu'il a permis une caractérisation chimique, énergétique et mécanique du bois (Pinus pinaster et Quercus robur) traité thermiquement (T°C<300°C). Dans une première partie du travail, des analyses chimiques et énergétiques de bois traités thermiquement à différentes intensités ont été réalisées. Les résultats ont permis de quantifier la dégradation chimique et la densification énergétique lorsque l'intensité du traitement augmente. Il s'avère que la perte de masse est un excellent indicateur de ces modifications : des relations de prédiction de l'évolution de ces propriétés ont été établies. Un dispositif d'impact original a été développé dans la seconde partie du travail. Les résultats obtenus montrent une augmentation de la broyabilité du bois lorsque l'intensité de son traitement thermique augmente. Avec l'intensité du traitement, le bois perd d'abord sa résilience, puis son comportement fibreux.Cela permet la formation de fines particules particulièrement adaptées aux processus de fabrication des biocarburants de seconde génération. / Biofuels are developed worldwide since the few last decades to face two major problems of our societies: global warming and peak oil. Due to many disadvantages of the first generation of biofuel, a second generation is developed, whose major advantage is to use the lignocellulosic part of plants. One interesting way to produce this kind of biofuel is a gasification followed by a Fisher-Tropsch synthesis. However, a pretreatment is needed because raw biomass is not suitable for a direct use in gasifier. The role of the pretreatment is to homogenize product properties, to ease storage and transport, to concentrate the energy content. Moreover, its grindability has also to be improved since fine particles are required to supply the gasifier. The present work proposes a comprehensive chemical, energetic and mechanical characterization of wood (Pinus pinaster and Quercus robur) with different treatment intensities (T°C<300°C). The first part proposes a full set of chemical and energy analysis on heat-treated woods. The mass loss was confirmed as a synthetic indicator of the effect of treatment intensity on the degree of chemical degradation and energy concentration. Therefore, analytical expressions allowing the prediction of energy and chemical properties as a function of the overall mass loss are provided. The second part of the work consists in the development and use of a novel impact device. Results obtained in radial and tangential directions show that the heat treatment improves the wood grindability. As the treatment intensity increases, wood first losses its resilience first, followed by a loss of its fibrous behavior. The later eases its transformation into small particles suitable for gasification process.

The intent of this thesis is to analyse the sustainability of producing bio-ethanol from cane molasses in Indonesia and its potential to replace gasoline in the transportation sector. A field trip was conducted in East Java, Indonesia, and data was gathered for analysis. Life cycle assessment (LCA) was performed to analyse the net emissions and energy consumption in the process chain. The greenhouse gas (GHG) emissions of the life cycle are 17.45 gCO2e per MJ of ethanol produced. In comparison to gasoline, this results in a 78% reduction in GHG emissions in the complete process chain. Net Energy Value (NEV) and Net Renewable Energy Value (NREV) were 6.65 MJ/l and 24 MJ/l. Energy yield ratio (ER) was 9.43 MJ of ethanol per MJ of fossil energy consumed in the process. Economic allocation was chosen for allocating resources between sugar and molasses. Sensitivity analysis of various parameters was performed. The emissions and energy values are highly sensitive to sugarcane yield, ethanol yield and the price of molasses. Alternative management options were considered for optimizing the life cycle. Utilizing ethanol from all the mills in Indonesia has a potential to replace 2.3% of all motor gasoline imports. This translates in import savings of 2.3 trillion IDR per year. Use of anaerobic digestion or oxidation ponds for waste water treatment is unviable due to high costs and issues with gas leakage. Utilizing 15% of cane trash in the mill can enable grid independency. Environmental impacts due to land use change (Direct &amp; Indirect) can be crucial in overall GHG calculations. Governmental regulation is necessary to remove current economic hurdles to aid a smoother transition towards bioethanol production and utilization. / Harnessing agricultural feedstock and residues for bioethanol production - towards a sustainable biofuel strategy in Indonesia

Wind farms are costly projects and prior to the construction, comprehensive wind resource assessment processes are carried out in order to predict the future energy yield with a reliable accuracy. These estimations are made to constitute a basis for the financial assessment of the project. However, predicting the future always accommodates some uncertainties and sometimes these assessments might overestimate the production. Many different factors might account for a discrepancy between the pre-construction wind resource assessment and the operational production data. This thesis investigates an underperforming wind farm in order to ascertain the reasons of a discrepancy case. To investigate the case, the relevant data and information along with the actual production data of three years are shared with the author. Prior to the construction, a wind resource assessment was carried out by an independent wind consultancy company and the work overestimated the annual energy production (AEP) by 19.1% based on the average production value of available three years. An extensive literature review is performed to identify the possible contributing causes of the discrepancy. The data provided is investigated and a new wind resource assessment is carried out. The underestimation of the wind farm losses are studied extensively as a potential reason of the underperformance. For the AEP estimations, WAsP in WindPro interface and WindSim are employed. The use of WindSim led to about 2-2.5% less AEP estimations compared to the results of WAsP. In order to evaluate the influence of long term correlations on the AEP estimations, the climatology datasets are created using the two different reanalysis datasets (MERRA and CFSR-E) as long term references. WindSim results based on the climatology data obtained using the MERRA and CFSR-E datasets as long term references overestimated the results by 10.9% and 8.2% respectively.