The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on February 12, 2010). Thesis advisor: Dr. Galen J. Suppes. Includes bibliographical references.

Thesis--Auburn University, 2010. / Abstract. Includes bibliographic references (p.111-129).

By 2020, at least 20 percent of the gross final consumption of energy in the European Unionshould be produced from renewable energy sources. The cooperative movement as such is not new, buthas a long history in the agricultural and credit sector. Over the last years, energy cooperatives havebecome an important option for decentralized electricity production. The transaction cost theory has beenapplied numerous times to agricultural cooperatives, but not to energy cooperatives. A number of casestudies and a subsequent survey analyzed the main benefits and challenges associated with energycooperatives as well as their relation to each other.The study revealed that while Denmark and Sweden focus mostly on wind power as a source for theirelectricity generation, German cooperatives use a more diversified portfolio. The differences are due tonational legislation and affect the total installed capacity as well as membership numbers. Although theindividual motives to join a cooperative vary, the reasons to establish a cooperative clearly show adedication to support renewable energies. The most important benefits associated with this organizationalform are the positive environmental impact as well as local value creation, ownership aspects and thelimitation of the individual liability. Contrarily, most of the disadvantages discussed concern factors outsideof the cooperatives such as the change of regulatory frame conditions and the insecurity towards thedevelopment of the electricity price. Transaction costs play a minor role since professional governancestructures are in place and the trust among members prevents opportunistic behavior.

Ocean Thermal Energy Conversion (OTEC) is the process of harnessing the temperature differential that exists in the equatorial oceans between the warm surface water and the cool water thousands of feet below to produce electricity. Due to the massive scale of the ocean thermal resources, OTEC power generation is appealing. The purpose of this thesis was to investigate OTEC and assess its potential viability as an energy source from both engineering and economic perspectives. This thesis provides an introduction to the research, and outlines the scope of the project in Chapter 1. Chapter 2 proves an overview of OTEC, from the basic operation and viable locations, to information on some of the major components that make up the plant. Chapter 3 describes the thermodynamics, heat transfer, and fluid mechanics that govern the physical operation of the OTEC plant. Chapter 4 provides an analysis of different plant design parameters to examine effects different parameters have on plant operations and equipment sizing. Chapter 5 describes the cost estimation for an OTEC plant, and provides subsequent analysis by comparing the estimated cost with other technologies and electricity prices from four island communities. The primary research of this thesis was the development of an integrated thermal fluids systems model of a closed-cycle OTEC power plant for the purpose of analyzing the effects of key design parameters on the plant performance. A simple Levelized Cost of Electricity (LCOE) economic model was also developed and integrated with the Thermal Fluid Systems model in order to assess the potential economic viability of a 20 MW OTEC power plant. The analyses from these models suggest that OTEC is definitely viable from an engineering standpoint, but economic viability for a 20 MW plant would likely be limited to small or remote island communities. / text

Since the inception of the Masdar Initiative in 2006, the Emirate of Abu Dhabi has invested a considerable amount of resources to promote renewable sources of energy like solar and wind. With an aim of achieving 7% of its electricity from renewable sources by the year 2020, there is much that the emirate needs to do in order to reduce its reliance on hydrocarbons while still planning capacity for future electricity demand. This report explores the effectiveness of a smart grid infrastructure as a mechanism to afford the flexibility and functionality required to incorporate renewable energy sources into the electric grid, as well as leveraging a real-time data network to attain reductions in peak demand consumption. Specific regulatory structures that exist in Abu Dhabi's electric and telecommunications markets are evaluated to understand the role they will play in dealing with interoperability standards, privacy concerns, and consumer participation issues that influence the effective integration of smart grid into Abu Dhabi's energy future. / text

This thesis addresses the optimization and design of turbine and propeller blades through the use of a lifting line model. An existing turbine optimization methodology has been modified to include viscous terms, non-linear terms, and a hub model. The method is also adapted to the optimization of propellers. Two types of trailing wake geometries are considered: one based on helical wakes which are aligned at the blade (using the so-called "moderately loaded propeller'' assumption), and a second one based on a full wake alignment model in order to represent more accurately the wake geometry and its effect on the efficiency of the rotor. A comparison of the efficiencies and the loading distributions obtained through the present methods is presented, as well as convergence and numerical accuracy studies, and comparisons with existing analytical results. In the case of turbines, various types of constraints are imposed in the optimization method in order to avoid abrupt changes in the designed blade shape. The effect of the constraints on the efficiency of the turbines is studied. Once the optimum loading has been determined, the blade geometry is generated for given chord, thickness and camber distributions. Finally, a low-order potential-based boundary element method and a vortex-lattice method are used to verify the efficiency of the designed turbines. / text

This report presents an overview of the engineering considerations involved in the design of grid-scale battery energy storage systems. Grid-scale is defined here as systems over 1 MW in rated power, typically operated by a utility, independent power producer, or Independent System Operator (ISO). The physical components of a BESS are presented and explained, including power electronics, an introduction to various commercially available battery technologies, necessary control systems, and balance of plant hardware. Also presented are a variety of real-world applications of battery energy storage systems, showing how the specific application determines what mix of technology will be selected when designing the system, as well as explaining the foundation for the control algorithms. / text

Hybrid renewable energy systems (HRESs) have become increasingly popular, especially for isolated regions. This thesis describes the design of a HRES for the isolated Ha'apai Island group in Tonga following a devastating cyclone which happened in 2014. Several renewable power generation and storage possibilities were investigated; solar, wind and battery were found to be feasible for Ha'apai. The conceptual design of a new energy storage system, the Subterranean Ocean Energy Storage System (SOESS), is also discussed as a possible alternative to batteries and a more viable substitute for an ocean renewable energy storage (ORES) system. For the proposed Ha'apai system, the optimum system configuration (solar 450 kW, wind 550 kW, battery 1,216 kAh/4,864 kW) with 90% renewable penetration was obtained using the HOMER software. Based on the optimum system configuration, load flow simulations of both the previous system and the proposed HRES were performed in DIgSILENT PowerFactory. The results of the load flow analysis show that all the transformers and transmission lines in both systems operate safely in both peak and nominal load conditions, and that the voltage levels of all LV buses are within the acceptable range of ±5%. The detailed system topology of the proposed HRES is discussed from the system implementation point of view. A unique set point control algorithm for the start-up/shut-down of the diesel generators was developed. The system dynamic performance was simulated according to the control logic during the three main switching events in DIgSILENT PowerFactory. The dynamic simulation results indicate that the proposed system would operate safely with acceptable voltage and frequency oscillations. This thesis could be used as a template for the design of other isolated HRESs with high renewable penetrations.

With many states recently enacting either renewable energy mandates or goals,the small hydropower industry has a unique opportunity to supply a growing portion of U.S. electricity supply. But the procedure to obtain a license for project development is unwieldy, increasingly wrought with regulatory hurdles at both the state and Federal levels. Government incentives exist that promote the development of small hydropower,but are insufficient to overcome the regulatory barriers faced by the industry. Although it is possible for small hydropower to supply a growing share of energy production in the U.S., it is unlikely that the full potential will be realized without substantial changes to the renewable energy regulatory system. This study describes the current state of the regulatory system governing the development of small hydropower facilities in the United States. A basic overview of hydroelectric technology is discussed, followed by a detailed description of the process through which a project developer must apply for a Federal license to construct and operate a hydropower project. The current state of the U.S. small hydropower industry is examined, considering the potential opportunity for the industry to supply a growing share of the U.S. electricity supply. This analysis is supplemented by a discussion of the costs of project construction and an investigation into the regulatory barriers to project development. / text

With the limited reserves of fossil fuels and the environmental problems associated with their use, the world is moving towards cleaner, renewable, and sustainable sources of energy. Biomass is a promising feedstock towards attaining this goal because it is abundant, renewable, and can be considered as a carbon neutral source of energy. Syngas can be further processed to produce liquid fuels, hydrogen, high value chemicals, or it can be converted to heat and power using turbines. Most of the downstream processing of syngas occurs at high pressures, which requires cost intensive gas compression. It has been considered to be techno-economically advantageous to generate pressurized syngas by performing high-pressure gasification. Gasification utilizes high temperatures and an oxidizing gas to convert biomass to synthesis gas (syngas, a mixture of CO and H2). Most of the past studies on gasification used process conditions that did not simulate an industrial gasification operation. This work aims at understanding the chemical and physical transformations taking place during high-pressure biomass gasification at heating rates of practical significance. We have adopted an approach of breaking down the gasification process into two steps: 1) Pyrolysis or devolatalization (fast step), and 2) Char gasification (slow step). This approach allows us to understand pyrolysis and char gasification separately and also to study the effect of pyrolysis conditions on the char gasification kinetics. Alkali and alkaline earth metals in biomass are known to catalyze the gasification reaction. This potentially makes biomass feedstock a cheap source of catalyst during coal gasification. This work also explores catalytic interactions in biomass-coal blends during co-gasification of the mixed feeds. The results of this study can be divided into four parts: (a) pyrolysis of loblolly pine; (b) gasification of pine chars; (c) pyrolysis and gasification of switchgrass; (d) co-gasification of pine/switchgrass with lignite and bituminous coals.