The emergence of decentralized energy resources has brought numerous novel and advanced designs of efficient power generation systems with utilisation of renewable energy for locally provided, sustainable and cost-effective energy production. The micro trigeneration system has been a highly anticipated solution to fulfil domestic energy requirements, allowing simultaneous generation of electricity, heating and cooling from one primary source. As a matter of fact, the micro trigeneration system is still under research and development stage, with limited available demonstrations around the world. Current laboratory experimental and simulation studies mainly focus on integrations of mature technologies, whereas many promising alternatives have not been widely explored, for example organic Rankine cycle (ORC) and liquid desiccant cooling technology. The main aim of this thesis is to technically develop and evaluate a novel micro trigeneration system with a combination of scroll-based ORC and membrane-based liquid desiccant cooling (MLDC). In principle, the micro trigeneration system provides highly efficient energy conversion in a decentralized manner, as the scroll-based ORC has superior abilities in generating electricity and providing sufficient thermal output that matches the low-temperature regeneration requirement of the liquid desiccant in the MLDC. In terms of system sustainability, compact linear Fresnel reflectors (CLFR) can be one option of the primary energy source for the micro trigeneration system. A comprehensive literature review has demonstrated that no work has been conducted previously on such a system. In this thesis, the possibility of integrating CLFR to power generation systems has been firstly investigated and a detailed optical design of the CLFR-hybrid system has been conducted through geometrical modelling and experimental work. Results demonstrate that the CLFR-hybrid system with polar orientation is feasible to efficiently convert the absorbed solar energy into thermal energy, which thereby can be utilised for powering the micro trigeneration system. The concept of the novel micro trigeneration system with scroll-based ORC and MLDC has been critically examined and energy performance of the two main components, namely scroll-based ORC and MLDC have been evaluated respectively through both theoretical modelling and experimental work. Experimental tests show that the scroll-based ORC electric output of 564.5W, scroll expander isentropic and volumetric efficiencies of 78% and 83% are achievable at a 1kW capacity. In terms of MLDC, experimental results indicate the importance of system mass balance between the membrane-based dehumidifier and regenerator for continuous operation. Under the steady operating condition of MLDC, a supply air temperature of 20.4°C with dehumidification effectiveness of 0.3 and system COP of 0.70 are attainable at calcium chloride (CaCl2) solution concentration of 36%. Simulations based on a validated and comprehensive system model demonstrate the feasibility of pairing the scroll-based ORC and MLDC for the microre trigeneration system. The exhaust heat from the scroll-based ORC effectively fulfils the regeneration requirement of the MLDC. The inclusion of MLDC facilitates the micro trigeneration system overall efficiency with an increase of approximately 35.49%, compared to that of ORC-based separate power generation. Theoretical results show that the proposed micro trigeneration system has the overall system efficiencies of 38.96% in cogeneration mode and 41.23% in trigeneration mode. The thesis makes contribution to the knowledge of micro trigeneration technology, distributed power generation, energy conversion and air conditioning. Moreover, the presented parametric studies of CLFR, ORC and MLDC can be employed for designing and optimizing the relevant individual components. Regarding the future work, this thesis recommends more in-depth system modelling with a combination of CLFR, ORC and MLDC, logic optimisation of the micro trigeneration system and comprehensive field trial testing of the micro trigeneration system in building context.

Key factors in using variable renewable energy to sustain crop growth were investigated using the Isle of Lewis as a case study. Methods investigated sought to exploit plants' abilities to accommodate a variable solar input by supplementing it with variable renewable energy. The extant solar resource on Lewis was characterised. The mean ratio of photosynthetically active radiation (PAR) to solar radiation (SR) (fE) recorded in 2010 was 0.458. fE was found to be significantly different between the first and last hour of daylight and 12:00 GMT (F, (2, 33) = 7.98, p<0.001) and between winter and summer months (F, (1, 10) = 20.86, p<0.001). This supports the suggestion that fE decreases as the atmospheric path length decreases. Significantly higher mean fE was also identified for the cloudiest days (F, (1, 22) = 6.22, p<0.05). Supplementing sunlight with intermittent, artificial illumination powered using wind energy significantly increased the growth of Brassica hirta. 53.26% of the additional dry weight produced using fixed diurnal illumination was achieved with 35% of the energy using this technique. The dry weight of B. hirta grown with illumination timed with tidal streams was not significantly different from that grown using fixed diurnal patterns. This is potentially important for the use of renewable energy for horticultural illumination. The possibility of using energy to prioritise lighting in well insulated growing structures and the compatibility of electricity production and horticultural demand on Lewis were considered. These findings support the direct use of variable renewable energy to sustain crop growth and promote the concept of using plants to store renewable energy. This is of potential benefit for problems of renewable energy intermittency, the predicted need to increase world food supply and providing economic opportunities for remote areas with a poor solar resource but good supplies of variable renewable energy.

With the Scottish Government's commitment to sourcing 100% of the national electricity demand from renewable sources by 2020, within the global framework of climate change mitigation, the potential of the marine environment around the Highlands and Islands Region of Scotland to add to Scotland's renewables portfolio has led to the expansion of the wave and tidal industries in recent years. Nevertheless, to date, there has been limited research conducted on the social systems around marine renewable energy development, excluding offshore wind. In answer to this deficit, this study explores a well-established concept within the academic arenas of business, health, and rural development, among others, of agents for change (AFCs), within the context of the rapidly emerging wave energy sector. Two case studies, Lewis in the Outer Hebrides, and Orkney, were chosen based on their localities and the interest that they have garnered from wave energy developers due to their high energy marine environments. A grounded approach was taken to data collection and a social power analysis was conducted in order to find AFCs working within or closely with the wave energy industry that were not part of structured or hierarchical organisations. One emergent theme was that there was a noteworthy barrier to wave energy development in the case studies and to the work that the agents for change were doing in the form of a complex dynamic between financial investments in the sector, national grid, national energy policy, and the technology itself. The agents for change were found to act as catalysts for the wave energy industry through their perseverance and visionary approach to development. The motivations of the AFCs is discussed and the shifting roles that they took as a project progresses is described and compared to other change process models, namely Lewin (1958) and Kotter (1995).

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

South Africa relies heavily on fossil fuels, particularly coal, to generate electricity and it is a well known fact that the use of fossil fuels contributes to climate change, as it produces greenhouse gases (GHGs). In fact, internationally South Africa is the 17th highest emitter of GHGs (Congressional Research Service (CRS), 2008). Coupled with the environmental consequences of fossil fuel use, South Africa has a further responsibility of addressing the inherited backlog of electricity provision to the rural, and previously disadvantaged communities. In an attempt to address these two problems, the government issued the White Paper on Renewable Energy. In this paper, renewable energy alternatives are proposed to replace a portion of traditional electricity generating methods. Concentrator photovoltaic (CPV) energy generation is one such renewable option available to government. CPV uses optic elements (such as lenses) to concentrate sunlight onto solar cells. Owing to the light being concentrated, the cells in CPV use less semiconductor material, which makes them more efficient in comparison to conventional photovoltaic (PV) cells. CPV is a technology that operates well in regions with high solar radiation. As such, South Africa is particularly well suited for this technology, with average solar radiation levels ranging from 4.5 to 6.5 05 ℎ/. CPV is also well suited for off-grid application, which addresses electricity demand in remote rural areas. This study is an economic project analysis of the installation, operation, maintenance, and decommissioning of CPV technology in a rural area in the Eastern Cape, South Africa. The study area chosen for this purpose is the Tyefu settlement in the Eastern Cape. Tyefu was deemed ideal for this type of analysis due to four characteristics. Firstly, Tyefu is a remote rural settlement at the end of the national grid. Secondly, the community is very poor and previously disadvantaged. Thirdly, many households are without Eskom generated electricity. Lastly, the study area is located in an area with ideal irradiance levels for CPV. Two methods of economic project analysis are applied to this case study, namely a costbenefit analysis (CBA) and a cost-effectiveness analysis (CEA). Additionally, two types of CBA are performed, namely a private CBA and a social CBA. The private CBA evaluates the Tyefu electrification project from a private investor's perspective and the social CBA evaluates the project from society's point of view. The CEAs carried out compare the costeffectiveness of the traditional PV technology to that of CPV in terms of private and social costs. The private costs and benefits of the CPV project were identified and valued in terms of market prices. Then, this cost benefit profile was used to calculate net benefits which in turn were discounted to present values using a private discount rate of 6.42 percent. Three decision making criteria were generated, namely the net present value (NPV), the internal rate of return (IRR) and the benefit cost ratio (BCR). Sensitivity analysis was carried out by varying the private discount rate and the bidding price. The social costs and benefits of the CPV project were identified and valued in terms of shadow prices. This cost benefit profile was used to calculate net benefits. The net benefits were discounted to present values using a composite social discount rate equal to 5.97 percent. The same decision making criteria used in the private CBA were used in the social CBA and a sensitivity analysis was completed by varying the social discount rate. In terms of the private CEA, the costs were identified and valued in terms of market prices. All costs were brought to present values using the private discount rate of 6.42 percent. In terms of the social CEA, the costs were identified and valued in terms of shadow prices. All costs were brought to present values using the social discount rate of 5.97 percent. The cost-effectiveness (CE) ratios calculated have identical denominators since the annual output for both technologies are identical - both CPV and PV systems deliver 30 300 kWh per annum. This output is based on the demand of the given case study. The private CBA showed unfavourable results. The private CBA has a NPV of R2 046 629.01, the IRR is undefined (this is due to no sign change being present in the cost benefit profile), and has a BCR of 0.365. However, the social CBA yielded positive results, with a NPV of R125 616.64, an IRR of 8 percent (which exceeds the social discount rate of 5.97 percent), and a BCR of 1.045. The CEA showed that the CPV is more cost-effective than the traditional PV both in terms of private and social costs. The private CE ratio of CPV is R4.23/kWh compared to PV's CE ratio of R4.39/kWh. Similarly, the social CE ratio of CPV is R3.51/kWh compared to PV's CE ratio of R3.69/kWh. CPV rollout appears to be socially efficient on a small scale according to the social CBA. Consequently, the CPV project is not seen as desirable in terms of the private CBA as the benefit (income received per kWh) in the private analysis is too small to outweigh the costs of implementing and running a CPV plant in Tyefu. On the other hand, a redeeming factor is that CPV may be feasible privately, for large scale applications. A major reason for the CPV project not being appealing to private investors is that the maximum bidding price of R2.85/kWh (as at August 2011) is not high enough for private investors to undertake the CPV project. The sensitivity analysis of the bidding price showed that the bidding price of R2.85/kWh needs to be increased in the range of 250 percent (R7.13/kWh) and 300 percent (R8.55/kWh) for a great enough incentive to exist for private investors. It is thus recommended that policymakers take this into consideration when formulating policy. In terms of the social CBA, it is recommended that government undertake CPV projects of this kind, as it will be a socially desirable allocation of resources. If government were to pursue these types of projects, it is recommended that CPV be implemented as it is more cost effective than PV.

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.

The growth of the industry and population of South Africa urges to seek new sources of electric power, hence the need to look at alternative power sources. Power output from some renewable energy sources is highly volatile. For instance power output from wind turbines or photovoltaic solar panels fluctuates between zero and the maximum rated power out. To optimize the overall power output a model was designed to determine the best trade-off between production from two or more renewable energy sources putting emphasis on wind and solar. Different measures of risk, such as coefficient of variation (CV) and value at risk (VAR), were used to determine the best hybrid renewable energy system (HRES) configuration. Depending on the investors’ expected returns (demand) and risk averseness, they will be able to use the model to choose the best configuration that suites their needs. In general it was found that investing in a diversified HRES is better than investing in individual power sources.

The wind industry has arrived at a state of technological maturity and is occasionally already today cost-competitive to conventional sources of energy. This thesis investigates the process of innovation that took place within the industry. A theoretical background into economical theory of innovation together with a status quo assessment of today's wind industry serves as introduction to the topic. In the analytical part, inducement mechanisms and functions of technological development will be identified as crucial drivers for innovation within the sector. The key findings of this thesis lead to conclude that it is now the responsibility of the industry to becoming fully cost-competitive to conventional sources. The advancement of technological lifecycle will primarily depend on turbine manufacturers and their capability to drive innovation more independently from governments.

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.