Aquaculture had already been distinguished as an important component of global food security and economics. However, aquaculture has expanded at the cost of natural resources and the environment. The vulnerability of the aquaculture industry due to the consequences of global environmental changes and energy price fluctuations has been addressed in various studies. The identification, planning, and implementation of sustainable energy systems are important to ensure the long term economic and environmental sustainability of aquaculture. This research investigated sustainable energy systems for aquaculture using a life cycle approach, allowing for the identification of the most sustainable energy options under different geographical and economic contexts. This also provides useful insights for the sustainable development of aquaculture with energy systems. The main objectives were to develop a statistical model for energy intensity of aquaculture (Chapter 2) and a user-friendly tool that can assist in the decision making of choosing the sustainable energy systems in aquaculture (Chapter 3), and to investigate the applicability of solar hot water systems for aquaculture (Chapter 4) and the potential improvement of the sustainability performance of aquaculture with energy systems (Chapter 5). In the first task, the main influencing factors on the energy use of aquaculture were investigated via a statistical analysis method. Results showed that natural trophic level of species, culture technology, culture system intensity, and local climatic conditions are important factors. With the key variables, an energy intensity prediction model was developed and applied to explore an energy efficient growth strategy for global aquaculture. Energy use in future global aquaculture would be significantly reduced with a selective extensification of global aquaculture. Also, climate change with consideration of temperature and precipitation would help reduce the energy use of global aquaculture as warm climate zones are more dominant in major aquaculture producing countries. In the second task, an MS-Excel based decision support tool was developed to assist the selection of environmentally and economically sustainable energy systems (single source or hybrid sources) in aquaculture. Through a case study, the most sustainable energy options for U.S. aquaponics systems were investigated, considering different geographical and economic contexts in five U.S. states (FL, HI, WA, LA, and ME). Results showed that solar systems (solar photo-voltaic and solar hot water heater) could be the most sustainable energy options for U.S. aquaponics due to their low environmental impacts and economic benefits. In the third task, results showed that heating strategies, setting (indoor or outdoor), and local climatic conditions played a pivotal role in determining the environmental and economic impacts of solar hot water systems in aquaculture. The lowest environmental impact was found with a 20% heating strategy for outdoor aquaculture systems under hot climate conditions, while the most economical case was found with an 80% heating strategy for indoor aquaculture systems under moderate climate conditions. Further improvements of environmental and economic performances could be achieved with consideration of water source (groundwater and surface) and design (horizontally fixed or optimally tilted solar thermal collector). In the fourth task, environmental and economic impacts of alternative energy systems were obtained using the tool which was developed in the second task. Results showed that local geographical and weather characteristics, local energy prices, and incentive availability were important parameters to determine the sustainability performance of alternative energy systems in aquaculture. The use of renewable energy was more sustainable than conventional energy systems in the regions where there are favorable geographical conditions, high electricity and fuel prices, and incentives. The use of solar photovoltaic with a thin-film technology was the most sustainable electricity generation options in most states of the U.S., while the use of natural gas boilers was the most sustainable heating options in most states of the U.S. The sustainability performance of the solar photovoltaic systems can be further improved through either a technological advancement or an incentive, while financial support is more effective for solar hot water systems. The application of anaerobic digestion as a backup system in general will reduce the sustainability of hybrid heating system; however, the hybrid biogas-diesel heating system has better sustainability performance compared with a diesel heating system if it is used for medium to large scale fish farms. This research provides an understanding of energy use characteristics of current aquaculture systems, and insights for the planning of sustainable energy supply systems in aquaculture, considering different growth strategies, effects of climate change, and alternative energy systems with various operational strategies and design factors. Furthermore, the decision-making tool was made to be accessible to fish farmers, state-wide planners, and regulators.

The water supplies of some small inland communities may come in the form of river systems that offer brackish water. Not fit for immediate human consumption, the water can be further processed using reverse osmosis to be converted into drinking water.In very remote areas there are limited energy resources, and for those areas that lie beyond a municipal distribution grid, renewable energy sources may be used. A reverse osmosis system that operates from the limited power generated by a renewable energy system must do so with the utmost of efficiency. Three methods in improving the efficiency of small-scale reverse-osmosis system are investigated, namely high-pressure pump speed control, feed water heating and vacuum pump based energy recovery.

This work examines issues that are restricting the wider adaptation of sustainable (‘renewable’) energy systems in Australia and elsewhere. Several new innovative areas of opportunity for improving the application of wind and solar PV based systems have been explored and developed. A number of financial and regulatory obstructions to wind and solar systems and grid connection are examined and a number of regulatory changes to the regulatory electricity codes are suggested. / Doctor of Philosophy (PhD)

The present project has made a comprehensive assessment of the effect of Nb doping on various charge-transfer related properties of TiO2. Of particular focus, the electrical properties of Nb-doped TiO2 (0.65 at %) have been investigated using the simultaneous measurement of electrical conductivity and thermoelectric power. This investigation was undertaken at elevated temperatures (1073 K -- 1298 K) in equilibrium with a gas phase of controlled oxygen activity (10-10 Pa < p(O2) < 75 kPa). In addition, the effect of segregation on the surface versus bulk composition of Nb-doped TiO2 was also investigated at a function of temperature and oxygen activity. Specifically, the following determinations were undertaken: The effect of oxygen activity, p(O2) and temperature on both electrical conductivity and thermoelectric power The effect of Nb on the defect disorder and related electrical properties of TiO2 The determination of equilibration kinetics and the associated chemical diffusion data for Nb-doped TiO2 The determination of Nb bulk diffusion in TiO2 The effect of p(O2), temperature and dopant content on Nb segregation and the related surface composition of Nb-doped TiO2 The obtained electrical properties enable the determination of a defect disorder model for Nb-doped TiO2, which may be considered within the following p(O2) regimes: Strongly Reduced Regime. In this regime, the predominant ionic defect was anticipated to be oxygen vacancies compensated electronically by electrons. While the transition to this regime (from higher p(O2)) was clearly observed, the predominant defect disorder existing beyond this transition was not confirmed due to an inability to obtain sufficiently low oxygen activity. Metallic-type conductivity behaviour was observed within this transition region. Reduced Regime I. In this regime, the predominate defect disorder defined by the electronic compensation of incorporated Nb ions by electrons was clearly observed. Reduced Regime II. In this regime, the predominate defect disorder defined by the ionic compensation of incorporated Nb ions by quadruply-charged titanium vacancies, was clearly observed. The present project included the determination of diffusion data which included: Temperature dependence of 93Nb tracer diffusion in single crystal TiO2 over the temperature range 1073 K -- 1573 K Chemical diffusion coefficient over the temperature range 1073 K -- 1298 K and oxygen activity range, 10-10 Pa < p(O2) < 75 kPa These pioneering studies are significant as they enable the prediction of the processing conditions required to reliably 1) incorporate Nb into the TiO2 lattice, and 2) achieve equilibrium with the gas phase. Finally, the present project included investigations on the effect of Nb segregation on the surface composition of Nb-doped TiO2, with the following outcomes: Due to segregation, the surface can be significantly enriched in Nb compared to the bulk The extent of enrichment increases as the bulk Nb content or the oxygen activity is decreased Following enrichment, the surface Nb concentration could be sufficiently high to assume a unique surface phase The outcomes of the present project are significant as they can enable the processing of TiO2 with enhanced charge transport and controlled surface properties.

雖然台灣在太陽能PV科技製造業上位居於領先位置，也採取了FIT來推廣太陽能PV及其他再生能源，但是市場的吸收（以及新計畫的完成）至今仍是進展緩慢；因此再生能源在台灣明顯且矛盾的狀況成了本論文的研究動機 為了理解為什麼有這種狀況，本論文採用了兩個廣泛的觀點： （一）市場障礙觀點：這個觀點提供了一個簡明的總結；在經濟學上國內太陽能PV的安裝，特別是家用投資者在FIT計劃下考慮電網連接。 （二）市場轉型觀點：這個觀點確定了影響並降低台灣再生能源市場的因素或是參與者（政府機關或其他相關團體的人員）。 本論文最後一個章節中提出了可能有助於提高台灣太陽能PV或是其他再生能源的接受度的實用步驟及政策措施。 本研究結果指向複雜且費時的申請手續，反覆修改的相關法令，及設定太低的FIT為至今台灣太陽能PV市場開發成功有限的主要原因。低電價、政府與台電間所發展出的相互依賴狀況以及極力避免破壞現況的密集產業為造成這些狀況的難題。 為了解決這些缺陷，本論文建議立即將FIT上修（至少每千瓦新台幣12.6元）並恢復補貼中小型投資者的資本。削除行政與程序上的障礙是促進在地太陽能PV市場和建立信心的整體方案上非常重要的的一環。論文中的最後一章節提到一個發展框架，並且描述了 一些針對於更棘手並減緩台灣的多元化能源供應問題的可能解決方案。 / The motivation for this research stems from an obvious contradiction in Taiwan’s approach to renewable energy – that while Taiwan remains a leading manufacturer of solar photovoltaics (PV) technology, and has adopted a feed-in-tariff (FIT) to promote solar PV and other renewable energies, market uptake (and completion of new projects) has so far been slow. In order to understand why, this thesis adopts two broad-based perspectives first identified by the International Energy Agency (IEA): (i) the Market Barriers Perspective provides a concise summary of the economics of domestic solar PV installation in Taiwan, specifically for the small scale (residential) investor contemplating grid connection under the FIT scheme; (ii) the Market Transformation Perspective identifies those factors (or actors) contributing to inertia in the renewable energy market in Taiwan. A final section in this thesis is given over to describing practical steps and policy approaches which may help boost solar PV (and other renewable) capacity in Taiwan. The results of this research point to a complicated and time-consuming applications process, repeated changes to relevant legislation, and a FIT which is set too low, as the primary reasons for the limited success to date in developing Taiwan’s small-scale (distributed) solar PV market. These difficulties are compounded by low electricity prices and a mutual dependency that has developed between the government, Taiwan Power, and large energy-intensive industries to avoid any upset to the status quo. In order to address these problem areas this thesis recommends immediately revising the FIT upwards (to at least NT$12.6 per kWh) in conjunction with the reinstatement of capital subsidies for small to medium investors. Removing administrative and procedural barriers is likewise deemed essential to fostering growth in the local solar PV market and establishing confidence in overall program. A Developmental Framework in the final section of this thesis describes some potential solutions to the more intractable problems slowing the diversification of Taiwan’s energy supply.

<p>Summary</p><p>This report is about how Chile can find its way towards a sustainable power production. The two major Chilean electric systems are modeled and optimized by a special optimization program for energy systems called MODEST. The model is then altered so that new sustainable energy sources can be put into the system. If these new energy sources are more economically beneficial they will enter the system. The time period that is modeled is the years 2006 to 2010 and the demand for electricity is rising between these years. 7 different scenarios where the terms for fossil fuels and renewable energies are changed in different ways is tested to see what can be done to introduce more sustainable energy into the system. The different changes include tax on carbon dioxide emissions, subsidies for new sustainable energy sources and limits in carbon dioxide emissions. The results show that:</p><p>• Taxes are an ineffective way to get more sustainable energy but can work to reduce emissions. The tax could be used to fund subsidies for cleaner energies.</p><p>• Subsidies can work to bring in more sustainable energy and if there is a possibility to use the clean development mechanisms available within the Kyoto protocol. Then it does not have to be subsidies but investments from companies in countries that have signed the Kyoto protocol.</p><p>• Waste to energy is the most cost effective new energy source, although it is questionable however this is really a renewable energy source. The author thinks that although it might not be renewable it is certainly sustainable within a foreseeable future.</p><p>• A natural gas shortage will have serious effects on the system and should be avoided at least until there are enough alternative fuels available. It is therefore important to continue encourage the development of sustainable power sources.</p><p>• Carbon dioxide limits could be used in Chile. If they are at reasonable levels they do not need to cost that much and could really help the sustainable energy sources to become more interesting for investors.</p>

<p>Electric energy conversion is an important issue in today's society as our daily lives largely depend on the supplies of energy. Two energy sources are studied for conversion in the present thesis, ocean waves and hydropower. The work focuses on the generator and the transmission of its output to the electric grid.</p><p>Different approaches have been used, over the years, to convert the energy in ocean waves, and the method presently used is based on a point absorber (buoy) directly coupled to a linear generator on the seabed. A varying alternating voltage is induced with such configuration, where both the amplitude and the frequency changes continuously. The target is to connect several units in a farm, and thereby decrease the fluctuations in power production. This is shown to be possible to accomplish with a rectifier connected to each generator. Transmission systems can be designed with converters and transformers to connect the farm to the electric grid onshore. Several aspects of the concept are considered as well as interconnection issues. Analytical calculations verified by finite element simulations and measured data are used to model the behaviour of a linear generator. A series expanded expression for the ideal no-load flux and EMF (electromotive force) is derived, which can be developed into an analytical transmission design tool.</p><p>Hydropower has been used for more than a century. Today many of the stations from the mid 1900's are up for refurbishment. Studies with finite element calculations show that a higher electric efficiency can be obtained with a high voltage cable wound generator.</p>

Thesis (Ph.D.)--RAND Graduate School, 2007. / Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references.

A scholarship from the Swedish International Development Cooperation Agency (SIDA) made it possible for the authors to collect primary data on location in Vietnam. Through a study of three organizations we aimed to create an understanding of the Clean Development Mechanism. Despite all the natural resources and the potential of renewable energy in Vietnam, a large percent of the electricity production comes from coal and other sources that contribute to carbon dioxide emissions. However, there are organizations working nationwide with implementing renewable energy projects and educating the Vietnamese. Since the birth of carbon market in connection with the Kyoto Protocol new possibilities have emerged as e.g the Clean Development Mechanism. For example high quality carbon offsetting companies are working on projects that reduce greenhouse gas emissions. The purpose of this thesis is to study and describe how three organizations are working with renewable energy in rural areas in Vietnam and their connection to Clean Development Mechanism. We have carried out an explorative study with an inductive approach. Our three semi-structured interviews were conducted as personal interviews at location in Vietnam. We also had two informative meetings, also in Vietnam. Beyond, we had e-mail correspondents with a number of professionals in their field. Due to the heavy bureaucracy the Governmental process rate is slow, which are making projects such as in the area of renewable energy difficult to initiate. Also the Governmental interest in renewable energy as a source of generating electricity is limited. However, new policies are on the agenda which might increase the support for organisations working towards a sustainable development.