Thesis (M.A.)--Eastern Illinois University, 2008. / Includes bibliographical references (leaves 39-43).

Thesis (M. Env. St.)--University of Adelaide, Mawson Graduate Centre for Environmental Studies, 1999. / Includes bibliographical references (leaves 114-120).

This thesis involves an examination of the main international, regional and national legal regimes regulating marine renewable energy in England and Wales. Deriving from a complex patchwork of law and policy, developments have ensued in the absence of a distinct governing ‘legal regime’ and within a number of competing paradigms. This original synthesis attempts to identify lacunae, conflicts and connections within and between the span of legal genres that MRE evokes. Against a backdrop of climate change mitigation, the key findings show that despite the presence of political will for offshore renewable energies, MRE development faces a number of legal obstacles, all of which seek to protect other important public and private interests. Although predominantly satisfactory at the international level (international law of the sea), national private property rights, environmental protection laws and regulatory development controls each encompass particular legal incongruities that have the potential to act as barricades to development. This thesis discusses these issues and reaches conclusions as to potential areas for reform.

In a time of a fast growing renewable electricity generation sector, there are challenges regarding the integration of such generation with current transmission infrastructure. Such challenges include problems associated with the intermittent power output of renewable energy sources and the inability to control there output to meet varying electrical demand. Using part of this available energy for the provision of domestic heating loads may help bridge the gap between supply and demand. The use of intermittent electrical energy sources for charging water based thermal energy stores was identified as a research gap. This research project studies the use of intermittent electrical supplies from wind turbines for the provision of space heating and hot water in domestic buildings. It also addresses how solar water heating may be incorporated into the same thermal energy storage unit to create a hybrid system. This thesis outlines and analyses two charge strategies that may be used to promote stratification in water based thermal energy stores when adding intermittent electrical energy. The first makes use of multiple heating elements switched on in sequence (direct system) while the second uses buoyancy forces to take cool water from the bottom of the tank, pass it through the heating element and then place it back in at the top of the tank at a higher temperature (side-arm). The research method includes; 1) a simplified theoretical simulation of direct and side-arm configurations in the transient system simulation software (TRNSYS) to identify system performance when charged from wind and solar energy; 2) a detailed theoretical representation of the side-arm charge mechanism with a modulating valve for TRNSYS; 3) an empirical validation of the detailed theoretical model of the side-arm charge cycle. Outcomes from the simplified theoretical model indicate that the side-arm configuration may have benefits over the direct configuration due to reduced heat loss from the tank, reduced auxiliary energy consumption and increased solar collector performance. The detailed theoretical representation of the side-arm was calibrated using the empirical data gathered. From this, important parameters affecting the performance of the side-arm charge cycle are evaluated. These include the effects of tank height, operating temperature and the power range from the intermittent electrical supply. It is identified that the assumptions made in the simple model are not possible to reproduce in real life and that an analysis using the complex model must be made in order to evaluate any potential benefits of the side-arm over a direct configuration.

This thesis investigates the role of support schemes to promote investment in renewable energy in the Nigerian power sector. The current situation does not favour investment in renewable energy. The argument developed by this thesis shows that the feed-in tariff (FIT) scheme is most suitable for encouraging investment in renewable energy in Nigeria. Drawing from legal analysis of international best practice and established FIT schemes in Germany and China, the research puts forward assertions that the FIT, with a design structure containing a fixed tariff for a guaranteed duration, tariff differentiation and degression, purchase obligation, guaranteed priority and guaranteed access to the grid, review measures and effective administration and implementation can encourage investment in renewable electricity in Nigeria. The thesis goes on to discuss how typical models of the FIT schemes used in the developed world need to be adapted to meet the existing challenges in the Nigerian electricity market if the FIT scheme is to be effective. The principal challenge is that consumers are unable to bear the cost of subsidies to investment in renewable energy. There are the concerns that purchasers of renewable electricity are not creditworthy. There are also general rule of law challenges which may lead to regulatory uncertainties and changes in support offered to investors. These require departures in design from the typical FIT models including those employed by Germany and China. The thesis proposes solutions to the particular difficulties in using an FIT scheme in Nigeria and concludes by providing a legal framework that includes suggested responses. It proposes that the FIT should be financed by the Nigerian state, by establishing a fund from the oil revenue account under the constitution. The risks of non-payment by the purchasers should be removed by establishing government guarantees backed by international financial institutions. Measures such as saving provisions in the law, stabilisation clauses in investment contracts and reliance on the provisions of bilateral investment treaties are important mechanisms that are proposed to check regulatory and investment uncertainties. The thesis presents a proposal for a legal framework for promoting renewable energy in the Nigerian power sector that incorporates these solutions.

No description available.

No description available.

This thesis presents new control approaches for improving the performance, stability, and efficiency of a single-phase grid-connected voltage source inverter (VSI) with an LCL filter that is used in renewable energy power conditioning applications. There are two main controllers that need to be designed: an external DC-bus voltage controller to balance the power flow coming into the VSI, and an internal current controller to control the current injected by the VSI into the utility grid. This thesis aims to find well-tailored control approaches for the aforementioned control loops. First, the stability and behavioral characteristics of the open-loop VSI with an LCL filter are explored using a Poincaré map, and the open-loop system is found to have marginal stability. A current control method is proposed, called composite nonlinear feedback (CNF), which offers significantly improved overall performance compared to the state-of-the-art proportional resonant (PR) controller with state feedback. To reduce the overall number of sensors in the system, two different observers are implemented to estimate the VSI state variables: (1) the Luenberger observer (LO), and (2) the sliding mode observer (SMO). To balance the system power flow, a new DC-bus voltage droop control method is proposed, that provides fast performance during transients. This control approach includes a novel discrete DC-bus voltage sensing technique, which effectively removes the double frequency ripple from the DC-bus voltage signal and prevents it from propagating into the current control loop. A variant on the DC-bus voltage droop control method, called adaptive droop control is proposed, which adaptively changes the droop gains in order to regulate the DC-bus voltage to a constant value. Finally, another variant on the DC-bus voltage droop control method is proposed, called optimized adaptive droop control, which adaptively changes the gains of the controller in order to minimize the overall system power losses. A stability analysis is conducted using the singular perturbation control theory, which allows a nonlinear dynamical system to be broken down into subsystems with different time scales. The results of the stability analysis confirm that the proposed closed-loop grid-connected VSI with an LCL filter is locally stable. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2013-09-30 13:47:56.337

This dissertation includes three studies that examine the remarkable rise of China’s renewable energy industry and its technological contributions to the global industry. China has emerged as the world’s largest carbon emitter by a large margin, and many of its cities experience high levels of air pollution. The Chinese government has turned to wind – and later solar – as alternative power sources to help decarbonize its electricity system and ameliorate increasingly urgent air pollution problems. Through these efforts, China has markedly expanded the share of renewable energy in its energy mix, and in the process absorbed a fair amount of relatively advanced technology, establishing itself as a competitive location to manufacture clean power equipment. In short order China has bolstered its international standing as a renewable energy powerhouse. The first study evaluates the question of whether China's wind industry has become an important source of clean energy technology innovation. Results indicate that while China has delivered enormous progress in terms of wind capacity, the outcomes were more limited in terms of innovation and cost competitiveness. Chinese wind turbine manufacturers have secured few international patents and achieved moderate learning rates relative to the global industry’s historical learning rate. The success of China’s transition to a low-carbon energy system will be key to achieve the global level of emissions reductions needed to avoid large negative consequences from climate change. The second study shows that China made progress in bringing down the levelized cost of wind electricity and cost of carbon mitigation. However, widespread grid-connection issues and wind curtailment rates caused much higher-than-anticipated costs of renewable energy integration. China has emerged as the global manufacturing center for solar photovoltaic products, and Chinese firms have entered all stages of the supply chain in short order. The third study provides detailed expert assessments of the technological and nontechnological factors that led to the surprised success of China’s silicon photovoltaic industry. Expert judgments suggest that continued declines in in module and system costs and improvements in performance will allow solar photovoltaic to be competitive with fossil fuels in China.

The concentration photovoltaics (CPV) application promises to produce lower price electricity with less semiconductor usage in comparison with the common flat plate PV module. The compound parabolic concentrator (CPC) shows great potential in both economics and efficiency in low the concentration photovoltaics (LCPV) system because it does not require a tracking system and is able to concentrate light with a large incident angle range. A detailed investigation has previously been carried out regarding the novel CPC module purposed (Su et al., 2012a). The validation of the experiment shows the Lens-Walled CPC gives a superior optical and electrical performance compared with other CPCs. Non-uniform light distribution is a common issue with all CPC designs as it has a major influence on the concentration of solar cell performance. In order to study the effects of non-uniform distributed light on solar cell behavior in-depth, two simulation approaching methods including array modelling and finite element modelling (FEM) were carried out. Both simulation approaches observed a reduction in the solar cell fill factor (FF) under non-uniform distributed light. The high resistive losses in the cell are the main cause of this phenomenon. Three simulation models with different cell grid designs were studied to further study the influence of non-uniform distributed light. The light profiles from three different CPCs were implemented with the FEM model. The result shows although solid CPC has the highest current output in a certain condition, the Lens-Walled CPC has the most uniform light distribution, which reduces the influence from non-uniform light distribution to solar cell performance.