Hawai‘i has implemented renewable energy goals that assume continued investments by solar consumers who seem unaware of their role in the policy's success. Without the renewable resource generation that will come from these investments, the state will be unable to achieve its energy mandate. Using Sabatier and Jenkins-Smith's advocacy coalition framework and Ajzen's theory of planned behavior as the foundation, the purpose of this study was to better understand the perspectives of potential solar consumers on the Island of O‘ahu regarding the state's renewable portfolio standards, their level of knowledge regarding consumer impact on this policy, and their perceptions of the roles of the public utilities commission and electric utility company in the implementation of projects associated with achieving the state's energy goals. Data were collected through interviews with 17 participants who represented a small portion of consumers who had begun the solar program application process but had not received approval to install panels at their residences. These data were inductively coded and subjected to a thematic analysis. Key findings indicate that consumers lack sufficient education about the state's energy goals, and that their participation in the policy process is essential for the continued growth of customer-sited solar installations. Implications for positive social change stemming from this study include recommendations for policymakers and solar program developers to engage in more inclusive educational outreach with consumers regarding the state's required renewable energy goals.

The photovoltaic properties of CdTe-based thin films depend on recombination levels formed in the CdTe layer and at the heterojunction. The localized states are resultant of structural defects (metal sublattice, chalcogen sublattice, interstitial), controlled doping, deposition process, and/or post-deposition annealing. The photoluminescence study of CdTe thin films, from both the bulk and heterojunction, can reveal radiative states due to different defects or impurities. Identification of defects allows for potential explanation of their roles and influence on solar cell performance. A thorough understanding of the material properties responsible for solar cell performance is critical in further advancing the efficiency of devices. The presented work is a systematic investigation using photoluminescence to study CdTe thin films with varying deposition processes. The thin (polycrystalline) films explored in this study were deposited by either the elemental vapor transport technique (EVT) or close spaced sublimation (CSS). Two device architectures were investigated, the typical CdTe/CdS device and the CdSeXTe1-X (CST) alloy device. Post-deposition annealing processes were either laser or thermal. The study of the CdTe thin films is grouped in three general categories: (a) EVT films: Intrinsic and Extrinsic (Group V: Sb and P), (b) CST alloys, and (c) Post-deposition Laser Annealed (LA) films. The main goal of this dissertation is to understand the influence of fabrication procedures (deposition conditions, post deposition thermal and chemical treatments, added impurities, and device architecture) on the defect structure of the CdTe thin films. The behavior of the photoluminescence (PL), studied as a function of the measurement temperature and excitation intensity, provides insight to the mechanism causing the radiative recombination levels. Analysis of the PL spectra for CdTe films with intrinsic doping demonstrated stoichiometric control of native defects for both the Cd- and Te-rich conditions. PL spectra of CdTe:Sb films showed unique Sb-related bands. Also, impurity-related defects were identified in the CdTe:P spectra. Spectral analysis support the need for optimization of dopant concentration. The effects of selenium (Se) thickness and post-deposition processing on the formation of CST alloy were demonstrated in the changing PL spectra. The native defects (and complexes) identified in films with thermal anneal processing were the same as those identified in films with laser anneal post-deposition processing. The PL data were collected and other characterization techniques were used to support the defect assignments. A repository of material properties, which include the recombination levels along with structural defect assignment for each of the CdTe deposition processes, is provided. This project will lend the solar cell community information on CdTe defects for different processing conditions, ultimately influencing the fabrication of improved solar cells.

This thesis studies the techniques of small-signal impedance measurement in three-phase power systems. Stability issue has become critically important since power electronics are highly applied in power distribution and conversion systems. Controlled output systems cause the risk of instability. In order to obtain the impedance model, an impedance extraction in D-Q reference frame algorithm is developed. This paper also applied Interpolated Fast Fourier Transform to increase accuracy of impedance model. Based on the voltage injection, Phase-Locked Loop, Park Transform, D-Q reference frame, and IPFFT. Three-phase system has been realigned on D-Q coordinate and impedance model is extracted in this form. Firstly, impedance extraction algorithm is designed by MATLAB/Simulink, the algorithm includes PLL, D-Q transform, and IPFFT is used to obtain magnitude and phase angle in frequency domain. Impedance matrices in D-Q frame may be solved through the relation between currents and voltages. Impedance model is made through various tests. Secondly, using the algorithm to test RL circuit to verify with real bode plot of the circuit. Then apply the algorithm on sophisticated circuit model. Finally, implement the algorithm on LabView/Multisim for future hardware tests. This paper clearly describes the objective of the research, the research problem and approaches, and experiment setup. This paper presents work conducted at the Smart Grid Power Systems Laboratory at University of South Florida.

Energy storage technologies have the potential to revolutionize the electric grid by allowing for the integration of renewable generation while increasing the utilization and efficiency of current grid assets. These technologies include pumped hydroelectric storage, compressed air energy storage (CAES), flywheels, batteries, thermal energy storage (TES), super capacitors, and superconducting magnetic energy storage (SMES). While energy storage has been implemented in some areas, its benefits are greatly undervalued by current regulatory frameworks leading to suboptimal outcomes for grid operators, utilities, and ratepayers. Large-scale adoption of storage technologies will require regulatory frameworks that recognize the benefits of grid-scale storage across generation, and transmission and distribution. This thesis discusses the need for storage, currently available and developing storage technologies, and the present regulatory environment.

To slow climate change, humans should take immediate and widespread action. One way to slow climate change is by switching to switch to renewable power plants such as solar fields. Recently, pioneering companies have built solar fields on water bodies. This study found that such a pairing of water and solar could increase production efficiency by 8-10% through panel cooling, save millions of liters of water from evaporation, and produce energy with under-utilized space.

Water and energy crises have forced researchers to seek alternative water and energy sources. Seawater desalination can contribute towards meeting the increasing demand for fresh water using alternative energy sources like low-grade heat. Industrial waste heat, geothermal, solar thermal, could help to ease the energy crisis. Unfortunately, the efficiency of the conventional power cycle becomes uneconomically low with low-grade heat sources, while, at the same time, seawater desalination requires more energy than a conventional water treatment process. However, heat discarded from low-grade heat power cycles could be used as part of desalination energy sources with seawater being used as coolant for the power cycles. Therefore a study of desalination using low-grade heat is of great significance. This research has comprehensively reviewed the current literature and proposes two systems that use low-grade heat for desalination applications or even desalination/power cogeneration. The proposed two cogeneration systems are a supercritical Rankine cycle-type coupled with a reverse osmosis (RO) membrane desalination process, and a power cycle with an ejector coupled with a multi-effect distillation desalination system. The first configuration provides the advantages of making full use of heat sources and is suitable for hybrid systems. The second system has several advantages, such as handling highly concentrated brine without external electricity input as well as the potential of water/power cogeneration when it is not used to treat concentrated brine. Compared to different stand-alone power cycles, the proposed systems could use seawater as coolant to reject low-grade heat from the power cycle to reduce thermal pollution.

Thermal energy storage is a major contributor to bridge the gap between energy demand (consumption) and energy production (supply) by concentrating solar power. The utilization of high latent heat storage capability of phase change materials is one of the keys to an efficient way to store thermal energy. However, some of the limitations of the existing technology are the high volumetric expansion and low thermal conductivity of phase change materials (PCMs), low energy density, low operation temperatures and high cost. The present work deals with encapsulated PCM system, which operates at temperatures above 500°C and takes advantage of the heat transfer modes at such high temperatures to overcome the aforementioned limitations of PCMs. Encapsulation with sodium silicate coating on preformed PCM pellets were investigated. A low cost, high temperature metal, carbon steel has been used as a capsule for PCMs with a melting point above 500° C. Sodium silicate and high temperature paints were used for oxidation protection of steel at high temperatures. The emissivity of the coatings to enhance heat transfer was investigated.

Water and wastewater treatment is a critical service provided for protecting human health and the environment. Over the past decade, increasing attention has been placed on energy consumption in water and wastewater systems for the following reasons: (1) Water and energy are two interrelated resources. The nexus between water and energy can intensify the crises of fresh water and fossil fuel shortages; (2) The demand of water/wastewater treatment services is expected to continue to increase with increasing population, economic development and land use change in the foreseeable future; and (3) There is a great potential to mitigate energy use in water and wastewater systems by recovering resources in wastewater treatment systems. As a result, the goal of this dissertation study is to assess the life cycle energy use of both water supply systems and wastewater treatment systems, explore the potential of integrated resource recovery to reduce energy consumption in wastewater systems, and understand the major factors impacting the life cycle energy use of water systems. To achieve the goal, an input-output-based hybrid embodied energy model was developed for calculating life cycle energy in water and wastewater systems in the US. This approach is more comprehensive and less labor intensive than the traditional life cycle assessment. Additionally, this model is flexible in terms of data availability. It can give a rough estimation of embodied energy in water systems with limited data input. Given more site specific data, the model can modify the embodied energy of different energy paths involved in water related sectors. Using the input-output-based hybrid embodied energy model, the life cycle energy of a groundwater supply system (Kalamazoo, Michigan) and a surface water supply system (Tampa, Florida) was compared. The two systems evaluated have comparable total energy embodiments based on unit water production. However, the onsite energy use of the groundwater supply system is approximately 27% greater than the surface water supply system. This was primarily due to more extensive pumping requirements. On the other hand, the groundwater system uses approximately 31% less indirect energy than the surface water system, mainly because of fewer chemicals used for treatment. The results from this and other studies were also compiled to provide a relative comparison of embodied energy for major water supply options. The comparison shows that desalination is the most energy intensive option among all the water sources. The embodied energy and benefits of reclaimed water depend on local situations and additional treatment needed to ensure treated wastewater suitable for the desired application. A review was conducted on the current resource recovery technologies in wastewater treatment systems. It reveals that there are very limited life cycle studies on the resource recovery technologies applied in the municipal wastewater treatment systems and their integrations. Hence, a life cycle study was carried out to investigate the carbon neutrality in a state-of-art wastewater treatment plant in Tampa, FL. Three resource recovery methods were specifically investigated: onsite energy generation through combined heat and power systems, nutrient recycling through biosolids land application, and water reuse for residential irrigation. The embodied energy and the associated carbon footprint were estimated using the input-output-based hybrid embodied energy model and carbon emission factors. It was shown that the integrated resource (energy, nutrient and water) recovery has the potential to offset all the direct operational energy; however, it is not able to offset the total embodied energy of the treatment plant to achieve carbon neutrality. Among the three resource recovery methods, water reuse has the highest potential of offsetting carbon footprint, while nutrient recycling has the lowest. A final application of the model was to study on the correlation between embodied energy in regional water supply systems and demographic and environmental characteristics. It shows that energy embodied in water supply systems in a region is related to and can be estimated by population, land use patterns, especially percentage of urban land and water source, and water sources. This model provides an alternative way to quickly estimate embodied energy of water supply in a region. The estimated embodied energy of water supply can further be used as a supporting tool for decision making and planning.

The developments in mobile/portable electronics and alternative energy vehicles prompted engineers and researchers to develop electrochemical energy storage devices called supercapacitors, as the third generation type capacitors. Most of the research and development on supercapacitors focus on electrode materials, electrolytes and hybridization. Some attempts have been directed towards increasing the energy density by employing electroactive materials, such as metal oxides and conducting polymers (CPs). However, the high cost and toxicity of applicable metal oxides and poor long term stability of CPs paved the way to alternative electrode materials. The electroactive materials with carbon particles in composites have been used substantially to improve the stability of supercapacitors. Furthermore, the use of carbon particles and CPs could significantly reduce the cost of supercapacitor electrodes compared to metal oxides. Recent developments in carbon allotropes, such as carbon nanotubes (CNTs) and especially graphene (G), have found applications in supercapacitors because of their enhanced double layer capacitance due to the large surface area, electrochemical stability, and excellent mechanical and thermal properties. The main objective of the research presented in this dissertation is to increase the energy density of supercapacitors by the development of nanocomposite materials composed of graphene and different CPs, such as: (a) polyaniline derivatives (polyaniline (PANI), methoxy (-OCH3) aniline (POA) and methyl (-CH3) aniline (POT), (b) poly(3-4 ethylenedioxythiophene) (PEDOT) and (c) polypyrrole (PPy). The research was carried out in two phases, namely, (i) the development and performance evaluation of G-CP (graphene in conducting polymers) electrodes for supercapacitors, and (ii) the fabrication and testing of the coin cell supercapacitors with G-CP electrodes. In the first phase, the synthesis of different morphological structures of CPs as well as their composites with graphene was carried out, and the synthesized nanostructures were characterized by different physical, chemical and thermal characterization techniques, such as Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), UV-visible spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, Raman spectroscopy, BET surface area pore size distribution analysis and Thermogravimetric Analysis (TGA). The electrochemical properties of G-CP nanocomposite-based supercapacitors were investigated using Cyclic Voltammetry (CV), galvanostatic charge-discharge and Electrochemical Impedance Spectroscopy (EIS) techniques in different electrolytes, such as acidic (2M H2SO4 and HCl), organic ( 0.2 M LiClO4) and ionic liquid (1M BMIM-PF6) electrolytes. A comparative study was carried out to investigate the capacitive properties of G-PANI derivatives for supercapacitor applications. The methyl substituted polyaniline with graphene as a nanocomposite (G-POT) exhibited a better capacitance (425 F/g) than the G-PANI or the G-POA nanocomposite due to the electron donating group of G-POT. The relaxation time constants of 0.6, 2.5, and 5s for the G-POT, G-PANI and G-POA nanocomposite-based supercapacitors were calculated from the complex model by using the experimental EIS data. The specific capacitances of two-electrode system supercapacitor cells were estimated as 425, 400, 380, 305 and 267 F/g for G-POT, G-PANI, G-POA, G-PEDOT and G-PPy, respectively. The improvements in specific capacitance were observed due to the increased surface area with mesoporous nanocomposite structures (5~10 nm pore size distribution) and the pseudocapacitance effect due to the redox properties of the CPs. Further, the operating voltage of G-CP supercapacitors was increased to 3.5 V by employing an ionic liquid electrolyte, compared to 1.5 V operating voltage when aqueous electrolytes were used. On top of the gain in the operating voltage, the graphene nano-filler of the nanocomposite prevented the degradation of the CPs in the long term charging and discharging processes. In the second phase, after studying the material's chemistry and capacitive properties in three-electrode and two-electrode configuration-based basic electrochemical test cells, coin cell type supercapacitors were fabricated using G-CP nanocomposite electrodes to validate the tested G-CPs as devices. The fabrication process was optimized for the applied force and the number of spacers in crimping the two electrodes together. The pseudocapacitance and double layer capacitance values were extracted by fitting experimental EIS data to a proposed equivalent circuit, and the pseudocapacitive effect was found to be higher with G-PANI derivative nanocomposites than with the other studied G-CP nanocomposites due to the multiple redox states of G-PANI derivatives. The increased specific capacitance, voltage and small relaxation time constants of the G-CPs paved the way for the fabrication of safe, stable and high energy density supercapacitors.

This dissertation is a collection of previously-published manuscript and conference papers. In this dissertation, we will deal with a stochastic unit commitment problem with cooling systems for gas generators, a robust unit commitment problem with demand response and uncertain wind generation, and a power grid vulnerability analysis with transmission line switching. The latter two problems correspond to our theoretical contributions in two-stage robust optimization, i.e., how to efficiently solve a two-stage robust optimization, and how to deal with mixed-integer recourse in robust optimization. Due to copyright issue, this dissertation does not include any methodology papers written by the author during his PhD study. Readers are referred to the author's website for a complete list of publications.