Scenario-based forecast for the electricity demand in Qatar and the role of energy efficiency improvements

We model the electricity consumption in the market segment that compose the Qatari electricity market. We link electricity consumption to GDP growth and Population Growth. Building on the estimated model, we develop long-range forecasts of electricity consumption from 2017 to 2030 over different scenarios for the economic drivers. In addition, we proxy for electricity efficiency improvements by reducing the long-run elasticity of electricity consumption to GDP and Population. We show that electricity efficiency has a crucial role in controlling the future development of electricity consumption. Energy policies should consider this aspect and support both electricity efficiency improvement programs, as well as a price reform

Novel light trapping techniques for silicon solar cells.

Thin-film silicon photovoltaic (PV) solar cells have attracted significant interest for decades due to the increasing demand for clean and sustainable energy resources. Further reduction of the cost of materials and manufacturing processes is required to reach the grid parity where the cost of electricity from solar PV cells is equal to the cost of other nonrenewable resources. Crystalline and thin-film silicon solar cells are anticipated to continue to be one of the dominant solar PV cell technologies. This anticipation is due to the abundance of silicon and the successful history of a continuous drop in cost in silicon-based PV cells. In this thesis, several designs were investigated to enhance absorption of sunlight in the active layers of silicon-based solar cells. In the first design, a plasmonic enhancement to silicon solar cells using (Titanium nitride) TiN as a replacement for silver is studied. In the second, a new design for tandem thin-film silicon solar cells is proposed using a periodic layer between the two subcells. Finally, a low-cost easily fabricated nanocone facial textures is proposed and showed promising experimental and simulation antireflection properties. 3D electromagnetic analysis was performed using finite difference time domain (FDTD) simulations to all structures and 3D Device simulations were additionally used to study the tandem cell structure. These contributions which were published are believed to contribute towards achieving high efficiency and cost-effective solar cells

Earth-abundant nanostructured catalysts for solar fuel production at room temperature

Improving the performance of solar energy harvesting martials is a challenge facing the renewable energy industry. Over the past few decades, metal oxides have been extensively explored as photoelectrodes for solar-driven production of fuel due to their exceptional stability, semiconducting properties, abundance, and low cost. However, most metal oxides have absorption activity that is limited to the ultraviolet spectral region because of their wide band gap (\u3e 3.0 eV). This is inconvenient because the ultraviolet spectral region contains only 3-5% of all incident solar energy. The current semiconductor technologies resort to either (i) doping as a means of narrowing the band-gap and enhancing light absorption, or (ii) decoration with metals to enhance charge separation. In the first part of the thesis, the synthesis of highly ordered titanium oxynitride nanotube arrays sensitized with Ag nanoparticles (Ag/TiON) was studied for the first time. Ag/TiON proved to be an attractive class of materials for visible-light-driven water splitting. The nanostructure topology of TiO2, TiON and Ag/TiON was investigated using FESEM and TEM. The X-ray photoelectron spectroscopy (XPS) and the energy dispersive X-ray spectroscopy (EDS) analyses confirm the formation of the oxynitride structure. Upon their use to split water photoelectrochemically under AM 1.5 G illumination (100 mW/cm2, 0.1 M KOH), the titanium oxynitride nanotube array films showed significant increase in the photocurrent (6 mA/cm2) compared to the TiO2 nanotubes counterpart (0.15 mA/cm2). Moreover, decorating the TiON nanotubes with Ag nanoparticles (13 ±2 nm in size) resulted in exceptionally high photocurrent reaching 14 mA/cm2 at 1.2 VNHE. This enhancement in the photocurrent is related to the synergistic effects of Ag decoration, nitrogen doping, and the unique structural properties of the fabricated nanotube arrays. In the second part of the thesis, the effect of Ni alloying with Cu on the electrochemical reduction of CO2 was studied. The GAXRD analysis confirmed the formation of mixed Cu-Ni catalysts. Linear sweep scans showed the Cu70Ni30 to have the lowest overpotential (-0.5VNHE) and highest cathodic current (-1.8mA/cm2). Chronoamperometry measurements, at -0.5 VNHE in CO2-saturated 0.1M KOH, confirmed similar pattern when no limiting current was observed for the electrochemical reduction of CO2. This volcano effect of exceptionally high current and low overpotential was unique for 30% Ni and was attributed to CO2 adsorption and superior charge transfer kinetics