The installation of marine renewable energy devices (MREDs) is progressing rapidly along many coastlines. It has been suggested that MRED arrays could provide stepping-stones for larval dispersal, mediating species range expansions or invasions. As common members of hard-substrate fouling communities and likely colonisers of MREDs, the larval dispersal processes of barnacles (Cirripedia: Thoracia) in the Firth of Lorn (Scotland) are assessed at scales ranging from mm to 10s – 100s km. At the scale of the organism itself, significant differences in larval mass densities and sinking velocities were observed between species of cirripedes, suggesting that larval physiology and morphology play an important role in water column vertical positioning. The importance of vertical positioning to horizontal transport and dispersal of larvae was identified in field surveys of the horizontal and vertical distributions of cirripede larvae, which revealed the interplay of wind-driven and tidally-oscillating currents in determining transport distances. Numerical simulations of larval dispersal based on a threedimensional hydrodynamic model then demonstrated that larvae with shallower abundance distributions often experienced greater horizontal transport, but that net dispersal distances were often greater for larvae deeper in the water column. Overall, simulated transport and dispersal distances were greatest for particles released at habitats further from the coast, such as MREDs, suggesting that the connectivity of these adult populations may be enhanced. Together, larval morphology, vertical positioning, and the coastal proximity of adult habitat could serve as useful indicators of larvae capable of reaching nearby newly installed offshore structures. For locations designated for MRED development in the Firth of Lorn, it is suggested that species with dispersal abilities similar to the cirripedes in this study could feasibly use these structures as stepping-stones for dispersal and range expansion, which could have important consequences when fouling communities are comprised of commercially important or invasive species.

The Centre for Resource Solutions (“CRS”) in the USA has performed a study on tax incentives for renewable energy. The CRS has found that tax incentives are effective, powerful and highly flexible instruments to encourage the development of renewable energy. They have further identified various types of tax incentives and various guidelines for effective tax incentives. The research question was whether the tax incentives and guidelines as identified by the CRS are internationally acceptable and whether South-Africa can consider these tax incentives and guidelines to design and implement a renewable energy tax incentive policy of an international standard in South-Africa. Chapter 1 contains the background, research question, objectives and methodology of this study. In Chapter 2 the advantages and disadvantages of each type of tax incentive, as identified by the CRS, were analysed through a literature study of international views on these tax incentives. In Chapter 3 the guidelines for effective renewable energy tax incentives, as identified by the CRS, were analysed through a literature study of international views on these tax incentives. Chapter 4 contains the conclusion that the tax incentives and guidelines as identified by the CRS are internationally acceptable and that South-Africa can consider these tax incentives and guidelines to design and implement a renewable energy tax incentive policy of an international standard in South-Africa. Copyright / Dissertation (MCom)--University of Pretoria, 2009. / Taxation / unrestricted

In this present world order of growing information, communication and technological advancement, it is primordial that climate change adaptation and mitigation efforts seeks to make people resilient to inevitable climate inconsistency through the exploitation and development of renewable energy sources. Though climate impacts are global, the population most at risk is predominantly from developing countries, particularly poor communities who have experienced multi-layered threats from floods, droughts and energy supply, just to mention a few. This explains why sustainable development is at the heart of all development trajectories in the world today, specifically the post-2015 development tenets. Climate change adaptation and mitigation requires international collaboration from all nations in order to get an effective and unified response to climate change. Building a critical mass for action and an institutional memory to sustain policies and efforts is crucial. A resilient-based approach to climate mitigation and adaptation founded on a crisis-driven reaction to communities vulnerable to climate threat will boost quality of life through the provision and safeguarding of safety nets for the poor. Solar water heaters, a renewable energy source, are here considered as a critical option to South Africa’s coal-driven economy as a means of alleviating energy poverty in rural and low-income communities, to be more precise. Therefore, SWHs have become the epicentre of sustainable development policies and climate change mitigation efforts in South Africa. So far, this device has attracted the attention of local governments in the country who view it as a game changer in the field, particularly towards greenhouse gas emission and energy conservation. The contour of this thesis is to assess the impact of solar water heaters on sustainable development. Although it is generally difficult to assess the real impact of technology on people, that of SWHs was established by asking questions about livelihood before, during and after the introduction of this device.

As is the case with many countries, Namibia has an economy dependent on fossil fuels. The country is, however, blessed with abundant and diverse - but as yet unexploited - renewable energy (RE) resources that could be used for improving the livelihood of the vast majority of its 2.2 million people. Today the conflict between energy production from fossil fuels and protection of the environment is intensifying and this compels all countries to search for means of resolving this conflict. Developing RE through the enactment of enabling legislation and implementation of relevant policy is one important step towards attaining the ideal of an energy-secure future. This state of affairs is not unique to Namibia, as most countries with abundant RE sources are striving to promote and deploy RE in their respective regimes through appropriate policies and legal frameworks. This study examines Germany and Ghana from, respectively, the developed and developing world, as leading countries that have established a proactive RE regime. However, such a regime can only be successfully achieved if countries, including Namibia, adopt laws and policies that promote and encourage the use of RE in order to move away from fossil fuel dependence to a greener economy. Thus the study seeks to investigate RE resources in Namibia and their potential development. It outlines the current legislation pertaining to the regulation of RE in Namibia. As such, the study further examines the Organisation for Economic Cooperation and Development (OECD) guidelines and draws examples from other regimes, particularly Germany and Ghana, in order to provide a guideline for the enactment of a general Energy Act with a particular chapter on RE. It concludes with recommendations as to how Namibia can secure a sustainable energy future.

The rise in popularity of renewable energy solutions, in particular wind energy systems, has resulted in a greater demand for low-speed direct-drive machines. The Vernier machine has inherent properties such as high torque density, sinusoidal induced voltages and low torque ripple which makes it suitable for low-speed direct-drive wind applications. Additionally, its mechanical structure is as simple as a conventional permanent magnet (PM) machine, whilst eliminating the need for a mechanical gearbox. The research problem addressed by this dissertation relates to the assessment of the Vernier permanent magnet (VPM) machine topology for direct-drive wind applications. It aims to outline a sizing, detailed design and analysis approach for a three-phase VPM wind generator. Furthermore, a comparative study is conducted using two different rotor types and two different stator types, namely; spoke-type and surface-mounted and fractional slot and integral slot respectively. Vernier theory is used to size the designs after which 2D Finite Element Analysis (FEA) simulations are used to analyse and validate the designs. The main outcome of the comparative study is an assessment of the suitability of four topologies for the direct-drive wind application. The design is assessed on parameters which are critical for wind turbine functionality; namely efficiency, torque ripple, torque density and material consumption. The most suitable of the topologies is selected for prototyping. The rotor is made more robust by adding structural features which mechanically secure laminations and PMs to the shaft. The FEA analysis of the prototype showed favourable performance characteristics, albeit with a small cost in power density. The prototype was -thus manufactured with further mechanical reinforcements made to the bearing system. Experimental results reveal the presence of a defect in the windings. Parameters which are dependent on the winding design are much lower than the analytical and FEA values. These parameters include resistance, inductance, and back-EMF. Further work should look into determining the root cause of the prototype defects.

Growing concerns about greenhouse gas emissions as well as electricity prices have led to more serious efforts by the state and federal government to provide promote renewable energy at affordable costs. I examine the effect of policies and incentives on added commercial solar PV capacity while controlling for pro-environmental preferences, energy prices, geographic controls, and demographic controls. I use county-level data that spans twelve northeastern states and the District of Columbia from 2005 through 2013. I utilize the Tobit estimator to account for a mass point of solar PV capacity at zero kilowatts. The results suggest that loans, performance-based incentives, rebates, sales tax waivers, and net metering standards increase the amount of added solar PV capacity. Solar Renewable Energy credits have a small impact on PV capacity growth, while interconnection standard and renewable portfolio standards are not statistically significant. If policy administrators aim to increase the amount of commercial solar PV, then they should consider loans, rebates, and performance-based incentives as the most effective policies.

This study aims to synthesize nanostructured hematite films using spray pyrolysis at different deposition temperatures. L-arginine was used to transform the irregular shaped nanoparticles to uniform nanospheres by chemical bath deposition at 90°C for 48 h. We also investigated the variation of L-arginine: iron precursor concentrations from 1:1 to 3:1, respectively. Likewise, hematite films doped with zinc (Zn), silver (Ag), and Zn/Ag were synthesized using spray pyrolysis. All the films were annealed at temperatures ranging from 450 to 500°C for complete hematite phase transformation. The films were used as photoanodes in photoelectrochemical (PEC) water splitting experiments. X-ray diffraction confirmed the formation of the corundum hexagonal structure of hematite with space group. Raman spectroscopy further confirmed the polycrystalline hematite symmetry with two Eg and five A1g vibrational phonon modes. UV-Vis absorption showed a variation of absorbance with bandgaps that ranged from 2.10 to 1.90 eV. Scanning electron microscopy reported the shape transformation of nanoparticles to nanospheres that ranged in size from 6 to 100 nm. The study showed that the nanostructured films synthesized at temperatures of 430 and 400°C have the highest photocurrent densities of 6 and 1.52 µAcm-2, respectively. There was an improvement of the photocurrent density from 6.4 to 10 µAcm-2 after the transformation of pristine irregularly shaped hematite nanoparticles to spherical hematite. However, on the variation of L-arginine: iron precursor concentrations, a photocurrent of 9.8 µAcm-2 was obtained for 3:1 sample. Also, an improvement of photocurrent from 17 to 89 µAcm-2 was observed for films prepared at 30 and 50 mM iron precursor concentration, respectively. In addition, there was a significant increase in the photocurrent density from 40 to 813 µAcm-2 for pristine and Zn/Ag hematite films, respectively. Ultrafast transient absorption spectroscopy was used to study the electron-hole recombination rates and lifetimes. The results indicated four lifetimes obtained from global analysis with a reduction in the electron-hole recombination rate in the femtosecond and nanosecond range, both for L-arginine/hematite and doped samples. From this study, we were able to prove that the nanostructured and doped hematite films had a longer charge carrier lifetime compared to bulk hematite. / Thesis (PhD)--University of Pretoria, 2021. / African Laser Center (ALC) National Research Foundation (NRF) Grant no. N0115/115463 (SARChI, M.D.) University of Pretoria / Physics / PhD / Restricted

Decarbonizing the electricity system (i.e. eliminating generation from fossil fuels and replacing it with non-emitting sources) is widely considered a necessary step to limiting anthropogenic emissions and minimizing the impacts of climate change. Selecting which non-emitting generators should replace existing fossil fuel sources, and when to build them, is critical to the success of this transition. The optimal pathway to decarbonisation is highly region-specific. It is impacted by both factors such as availability of renewable resources, existing generation resources, and government policy. This dissertation presents a techno-economic model that is used to assess the decarbonisation of the combined British Columbia and Alberta electricity system. It is found that high levels of decarbonisation are possible through a combination of new wind generation, particularly in Alberta, and increased trade between Alberta, British Columbia, and the United States. Following on this finding, the variability related to high penetrations of renewable generation is introduced to the model and its impact is assessed. These results indicate that variability will be an important constraint in planning decarbonized energy systems. Finally, the representation of British Columbia’s existing hydroelectric resources is expanded to determine the ability to buffer variable renewable generation with these resources. This study finds that, while existing hydroelectric resources can support much of the variability in a highly renewable energy system, additional technologies and/or policies are needed to reach a fully zero-carbon system. The findings in this thesis show that British Columbia and Alberta, with an expanded interconnection between the provinces, can reach high penetrations of variable renewable energy. The majority of this generation consists of wind energy in Alberta, which is abundant and low-cost compared to other generation options. While comparatively little generation is added in British Columbia, the existing hydroelectric resources in the province provide significant flexibility to support the variability of this wind generation. / Graduate

Stakeholder engagement-dialogue is proposed as a method of responding to the sustainable energy challenges facing South Africa. Establishing the renewable energy sector requires constructive engagement including consumers, energy suppliers, regulators and government. The purpose of this research is an attempt to gain a deeper understanding of the stakeholder engagement process - specifically dialogue - being used by government to establish the renewable energy sector. It evaluates the effectiveness of the current dialogue and the role this dialogue can play in establishing the renewable energy sector. Initially, the study analyses the dialogue contained in fifty public domain internet articles on renewable energy. This data is validated by face-to-face interviews with nine stakeholders. The analysis focuses on comparing the dialogue against an acceptable dialogue framework. Evidence from both sets of data suggests that the dialogue, although inclusive and open, lacks tolerance, empowerment and transparency. The study further found that effective dialogue should contain clarity, policies and trust. Moreover, findings from the research indicate that stakeholder dialogue can play a vital role in establishing the renewable energy sector but this dialogue needs to be with relevant stakeholders. This research adds to the existing literature in dialogue in that it proposes three additional dimensions for effective dialogue. Copyright / Dissertation (MBA)--University of Pretoria, 2010. / Gordon Institute of Business Science (GIBS) / unrestricted

Many countries are advancing down the road of electricity privatization, deregulation, and competition as a solution to their growing electricity demand and other challenges posed by the monopolistic nature of the existing structure. Presently, Nigeria has a supply deficit of electricity as a result of the growing demand. This imbalance has negatively affected the economy of the country and the social-economic well-being of the population. Hence, there is an urgent need to reform the power sector for greater efficiency and better performance. The objectives of the reform are to meet the growing power demand by increasing the electric power generation and also by increasing competitiveness through the participation of more private sector entities. The renewable energy integration is one way of increasing the electricity generation in the country in order to cater for the growing demand adequately. Examples of the renewable energy that is available in the country include wind, geothermal, solar and hydro. They are considered to be environmentally friendly, replenishable and do not contribute to the climate change phenomena. The country presently generates the bulk of its electricity from both thermal (85%) and hydroelectric (15%) power plants. While electricity generation from the thermal power stations constitutes the largest share of greenhouse emission, this is mostly from burning coal and natural gas. The effect of this high proportion of greenhouse emission causes climate change which is referred to as a variation in the climate system statistical properties over a long period of time. It has been observed that many of the activities of human beings are contributory factors to the release of these greenhouse gases (GHG). But, as the traditional sources of energy continue to threaten the present and future existence on the planet earth, it is, therefore, imperative to increase the integration of the variable renewable energy sources in a sustainable and eco-friendly manner over a long period of time. The variability and the uncertainties of the renewable energy source's output, present a major challenge in the design of an efficient electricity market in a deregulated environment. The system deregulation and the use of renewable sources for the generation of electricity are major changes presently being experienced in power system. In a deregulated power system, the integration of renewable generation and its penetration affects both the physical and the economic operations. The main focus of this research is on the integration of wind energy into Nigerian power systems. Up till now, research on the availability of the wind energy and its economic impacts has been limited in Nigeria. Generally, the previous study of wind energy availability in Nigeria has been limited in scope. The wind energy assessment study has not been detailed enough to be able to ascertain the wind energy potential of the country. To cope with this shortcoming, a detailed statistical wind modeling and forecasting methodology have been used in this thesis to determine the amount of extractable wind energy in six selected locations in Nigeria using historical wind speed data for 30 years. The accuracy test of the statistical models was also carried using the Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and Chi-Square methods to determine the inherent error margin in the modeling and analysis. It is found that the error margin of the evaluations falls within the expected permissible tolerance range. For a more detailed wind assessment study of the Nigeria weather, the seasonal variation of the weather conditions as it affects the wind speed and availability during the two major seasons of dry and rainy was considered. A Self-Adaptive Differential Evolution (SADE) was used to solve the economic load dispatch problem that considers the valve-point effects and the transmission losses subject to many constraints. The results obtained were compared with those obtained using the "standard" Differential Evolution (DE), Genetic Algorithm (GA), and traditional Gradient Descent method. The results of the SADE obtained when compared with the GA, DE, and Gradient descent show the superiority of SADE over all the other methods. The research work shows that the wind energy is available in commercial quantity for generation of electricity in Nigeria. And, if tapped would help reduce the gap between the demand and supply of electricity in the country. It was also demonstrated that the wind energy integration into the power systems affects the generators total production cost.