The research focus of this thesis is on modelling techniques for river kinetic turbines, to develop predictive numerical tools to further the design of this emerging hydro technology. The performance benefits of enclosing the turbine in a shroud are quantified numerically and an optimized shroud design is developed. The optimum performing model is then used to study river kinetic turbines, including different anchoring systems to enhance performance. Two different turbine numerical models are studied to simulate the rotor. Four different computational fluid dynamics (CFD) turbulence models are compared against a series of particle image velocimetry (PIV) experiments involving highly-separated diffuser-flow and nozzle-flow conditions. The risk of cavitation is briefly discussed as well as riverbed boundary layer losses. This study is part of an effort to develop this emerging technology for distributed power generation in provinces like Manitoba that have a river system well adapted for this technology.

This research examines energy poverty in the Daniel McIntyre and St. Matthews (DMSM) neighbourhoods in the city of Winnipeg. Energy poverty, defined as households spending more than 6% of their income on energy expenditures, affects as many as 50% of households in DMSM. Energy poverty can be alleviated through energy retrofits for dwellings such as weather stripping; increasing insulation in exterior walls, the attic and basement; and installing a high-efficiency furnace. The recommendations include: establishing consistent housing and energy efficiency policies; increasing the flexibility of utility on-bill financing; levying the necessary capital for energy retrofits through municipal financing mechanisms; increasing the knowledge and capacity of local residents; increasing the knowledge and capacity of local contractors for sustainable design and construction; creating a provincial strategy to increase the energy efficiency of social housing; developing low-income energy efficiency programs for rental properties; and increasing access to renewable energy sources.

Developing renewable alternatives for energy production is one of the main methods for climate change mitigation and sustainable development. As the key component in permanent magnets, neodymium is considered as one of the most critical elements in the rare earth family in the development of modern society. It plays a significant role in increasing efficiency and reducing weight in many applications like hard disc drives, audio equipment, direct- driven gearless and conventional wind turbine design, as well as electric vehicles designs with NiMH batteries. The emerging problem of neodymium production is the peak neodymium issue, which implies a potential risk of supply in the future due to the unsustainable production pathway. Now, China is producing more than 90% of the rare earth elements with an around 40% reserves and is facing severe problems of environmental pollution, smuggling, and increasing domestic demand. This paper makes efforts to see if the risk of supply would constrain future wind power development with a special focus on the China’s dominance in production and policies. By fitting historic production data with three curve models (logistic, Gompertz, and Richards) and designing future demand based on IEA’s scenarios, the projections of future supply and demand trends of neodymium was obtained. This paper shows that though neodymium-based wind turbine construction might not be the cause for neodymium shortage, it would be confronted with material constraints in the future. Thus, more consideration should be taken in the investment of wind turbines with permanent magnet. Also, a mineral strategy, which integrates technological innovation, joint effort from different stakeholders, and better resource management, is required for a sustainable production of neodymium in the long run.

Renewable power generation from the controlled mixing of sea and fresh water is relatively unexplored when compared to the development for solar, wind, and other sustainable power alternatives. When global river discharge was taken into account, an estimated 2.6 TW of obtainable energy exists in untapped salinity gradients. Reverse electrodialysis is one proposed power-generating mechanism for harnessing energy from brackish environments and relies on the transport of aqueous salt ions through an apparatus of ion-exchange membranes. In this thesis, operational parameters, including flow direction, salinity composition, and membrane selectivity, are investigated. For optimal performance, I have employed counter-current flow mode with monovalent ion selective membranes and pure 0.5 M NaCl saline solution. The results show that a maximum open circuit voltage (OCV) level of 2.01 V is obtained with an active membrane area of 0.0756 m². The presence of multivalent ions in the feed solutions hinders OCV levels, but the effects are reduced with monovalent-selective membranes. Preliminary results are insightful; in order to increase the commercially viability of this technology, future work is needed to enhance the performance properties of the ion exchange membranes.

Crystalline silicon solar cells translate energy from the sun into electrical energy via the photoelectric effect. This technology has the potential to simultaneously reduce carbon emissions and our dependence on fossil fuels. The cost of photovoltaic energy, however, is still higher than the cost of electricity off of the grid which hampers this technologies adoption. Raising solar cell efficiency without significantly raising the cost is crucial to lowering the cost of photovoltaic produced energy. One technology which holds promise to increase solar cell efficiency is a selective emitter solar cell. In this work the benefit of selective emitter solar cells is quantified through numerical modeling. Further, the use of ultraviolet laser to create a laser doped selective emitter solar cell is explored. Through optimization of the laser doping process to minimize laser induced defects it is shown that this process can increase solar cell efficiency to over 19.1%. Additionally, 2D and 3D numerical modeling are performed to determine the limitations screen printed interdigitated back contact solar cells and the practical efficiency limit for crystalline Si solar cells.

The kinetic energy present in tidal currents and other water courses has long been appreciated as a vast resource of renewable energy. The work presented in this doctoral thesis is devoted to both the characteristics of the hydro-kinetic resource and the technology for energy conversion. An assessment of the tidal energy resource in Norwegian waters has been carried out based on available data in pilot books. More than 100 sites have been identified as interesting with a total estimated theoretical resource—i.e. the kinetic energy in the undisturbed flow—in the range of 17 TWh. A second study was performed to analyse the velocity distributions presented by tidal currents, regulated rivers and unregulated rivers. The focus is on the possible degree of utilization (or capacity factor), the fraction of converted energy and the ratio of maximum to rated velocity, all of which are believed to be important characteristics of the resource affecting the economic viability of a hydro-kinetic energy converter. The concept for hydro-kinetic energy conversion studied in this thesis comprises a vertical axis turbine coupled to a directly driven permanent magnet generator. One such cable wound laboratory generator has been constructed and an experimental setup for deployment in the river Dalälven has been finalized as part of this thesis work. It has been shown, through simulations and experiments, that the generator design at hand can meet the system requirements in the expected range of operation. Experience from winding the prototype generators suggests that improvements of the stator slot geometry can be implemented and, according to simulations, decrease the stator weight by 11% and decrease the load angle by 17%. The decrease in load angle opens the possibility to reduce the amount of permanent magnetic material in the design.

With the recent increase in utility-scale wind energy development and current climate variation in the desert southwest US, researchers have become increasingly concerned with the reaction of wildlife and critical habitat. Understanding the relationships among monitoring efforts, climate, industrial landscapes and wildlife is critical to effective management. Given the need for information available on how these potential stressors affect terrestrial wildlife, my objective was to determine how climate variation, wind energy facilities (WEF) and monitoring efforts by researchers influence behavior and survivorship in a population of the federally threatened desert tortoise (Gopherus agassizii). Data were collected via surveys, motion-sensor camera trapping and radio-telemetry during the span of two decades at a WEF in California. Using capture-mark-recapture survivorship analysis and generalized linear mixed-effects models, I acquired long-term estimates of survivorship, activity, and levels of stress response to researchers and climate. From this study I found that researchers as well as abiotic effects influence the probability of voiding, a possible stress induced behavior in desert tortoises. Additionally, we found that tortoise activity and survival is constrained by winter precipitation and habitat types. Further research is needed on proximate mechanisms of wind turbines (noise and vibration) and their effects on desert tortoise behavior.

There are many sources of free energy available in the form of heat that is often simply wasted for want of an effective way to convert it into useful energy such as electricity. The aim of this research project is to design and build a low temperature differential Stirling engine capable of generating electric power from heat sources such as waste hot water or geothermal springs. The engine that has been developed is a research prototype model of a new type of design featuring a rotating displacer which is actuated by a pair of stepper motors. The rotating displacer design enables the use of readily available and comparatively cheap and robust steam pipe as the housing for the engine, and it also avoids problems associated with sealing and heat exchange that would be present in a large engine of a more traditional configuration. Owing to the fact that this engine is a research prototype, it has the ability to have some of its critical operating parameters such as phase angle and stroke length adjusted to investigate the effects on performance. When the next phase of development takes place most of these parameters will be fixed at the optimum values which will make manufacture cheaper and easier. Unfortunately, construction of the prototype engine has not been completed at the time of writing so no power producing results have been achieved; however thorough results are presented on the operation of the control system for the stepper motors which actuate the displacer. Additionally, after a thorough history and background of Stirling engines was researched, the understanding gained of how these engines work has enabled a design process to take place which has hopefully led to a successful design. Analysis of various aspects of the engine have been carried out and results look promising for the engine to produce around 500 Watts of electrical power output whilst running on hot water up to around 90°C.

Switchgrass (Panicum virgatum), a native warm-season grass, has been investigated as a renewable energy crop that may provide viable wildlife habitat. This study investigated small mammal populations in switchgrass, hay, and corn to assess the relative habitat quality. Four, three-night trapping sessions were conducted at four locations in Kentucky using Sherman livetraps. Trapping occurred in spring (before first hay harvest), summer, fall (before switchgrass and corn harvest), and winter (post-harvest). Relative abundance of small mammals, calculated using a capture per unit effort index (per 100 trapnights), and mean taxonomic richness were used to compare habitats. Switchgrass had a significantly greater mean taxonomic richness than hay but not corn; however, four genera were captured in switchgrass and only two in corn. Switchgrass had a greater relative abundance of small mammals than hay during the summer, and corn and hay during the fall. Vegetative cover was positively correlated with relative abundance of small mammals. No-till corn and three year old switchgrass had a greater relative abundance of small mammals than conventionally tilled corn and two year old switchgrass, respectively. In conclusion, switchgrass stands managed as a renewable energy crop has the potential to be viable wildlife habitat for some small mammal species.

The objective of this thesis is to include strategic and tactical level decisions into the biorefinery supply chain design for a specific region while comparing multiple conversion technologies and biomass feedstocks. The allocation of biomass feedstocks, products, and the respective supply chain configuration locations are determined while ensuring the regions monthly biomass availability and product market demand constraints are met. This research considers all actions required to bring the bio-based products to market from harvesting, storing, and processing the biomass to market distribution. Two different conversion technologies are chosen for comparison: one advanced conversion technology and one conventional technology. Potential investors and policy makers will be able to use this region specific tool by maximizing annual profitability to evaluate potential lignocellulosic biomass feedstocks and conversion technologies for the production of energy, fuels, and chemicals. The tool utilizes ILOG OPL software for optimization while interfacing with Microsoft Excel for parameter inputs and results output. From the sensitivity analysis, further insight is gained to what key drivers greatly influence the performance of each supply chain. The results demonstrate the practicality of this tool, which then can be further analyzed through other models such as discrete event simulation.