abstract: Power generation in remote isolated places is a tough problem. Presently, a common source for remote generation is diesel. However, diesel generation is costly and environmental unfriendly. It is promising to replace the diesel generation with some clean and economical generation sources. The concept of renewable generation offers a solution to remote generation. This thesis focuses on evaluation of renewable generation penetration in the remote isolated grid. A small town named Coober Pedy in South Australia is set as an example. The first task is to build the stochastic models of solar irradiation and wind speed based on the local historical data. With the stochastic models, generation fluctuations and generation planning are further discussed. Fluctuation analysis gives an evaluation of storage unit size and costs. Generation planning aims at finding the relationships between penetration level and costs under constraint of energy sufficiency. The results of this study provide the best penetration level that makes the minimum energy costs. In the case of Coober Pedy, cases of wind and photovoltaic penetrations are studied. The additional renewable sources and suspended diesel generation change the electricity costs. Results show that in remote isolated grid, compared to diesel generation, renewable generation can lower the energy costs. / Dissertation/Thesis / M.S. Electrical Engineering 2012

Título original: Remoção de lignina e hemicelulose influencia na acessibilidade à celulose e digestibilidade enzimática / Orientador: Michel Brienzo / Banca: Fernanda Perpetua Casciatori / Banca: Jonas Contiero / Resumo: A biomassa lignocelulósica, como a proveniente da cana-de-açúcar, é uma fonte abundante de resíduo que pode ser usado como matéria-prima na produção de energia. Para melhor aproveitar essa biomassa, moagem e pré-tratamentos podem ser usados para alterar a estrutura do material lignocelulósico, remover lignina e hemicelulose, expondo a celulose e assim aumentando sua acessibilidade. A acessibilidade à celulose tem sido indicada como uma das propriedades mais importantes para uma boa digestibilidade enzimática. Entretanto, as biomassas geradas da cana-de-açúcar possuem características físico-químicas diferentes, respondendo de modo diferente aos pré-tratamentos. Neste contexto, este estudo teve como objetivo verificar os efeitos da remoção de lignina e hemicelulose das biomassas da cana-de-açúcar (fração externa, entrenó, nó e folha) na acessibilidade à celulose. A cana-de-açúcar foi fracionada em fração externa, nó, entrenó e folha. Cada fração passou pelos pré-tratamentos ácido (5, 10, 20 %, m/m massa de ácido por massa de material, a 121°C/30 min), alcalino (5, 10, 20 e 30 % NaOH m/m) e oxidativo (0,5, 1, 2 e 3 horas com clorito de sódio 30 %). As amostras foram caracterizadas quanto ao seu conteúdo de celulose, hemicelulose e lignina. A determinação de acessibilidade foi realizada com corantes Direct, Orange (superfície específica externa), Direct Blue (superfície específica interna) e Vermelho Congo (superfície total). A hidrólise enzimática (15 FPU/g de material, Cellic C... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The lignocellulosic biomass, such as the provided by the sugarcane, is an abundant source of raw materials for energy production. In order to better use this biomass, milling and pretreatments can be employed to alter the structure of the materials, remove lignin and hemicellulose. This effect exposes the cellulose and raises its accessibility, which is is one of the most important property to ensure enzymatic digestibility. However, the biomass generated from the sugarcane have different physicochemical characteristics, giving different responses to the pretreatments. In this context, this study aimed to verify the effects of lignin and hemicellulose removal from the sugarcane biomass (external fraction, node, internode and leaf) on cellulose accessibility. The sugarcane was fractioned in external fraction, node, internode and leaf. Each fraction was pretreated with acid (5, 10, 20 % m/m acid mass per material mass, at 121°C/30 min), alkaline (5, 10, 20, 30 % NaOH m/m) oxidative (0,5, 1, 2,3 h charged with 30 % sodium chlorite). The chemical composition of the samples was determined based on cellulose, hemicellulose and lignin contents. Accessibility was determined by dye adsorption of Direct Orange (external specific surface), Direct Blue (internal specific surface) and Congo Red (total surface). Enzymatic hydrolysis (15 FPU/g of biomass, Cellic Ctec 2 - Novozymes) was used to verify the effects of pretreatments and cellulose accessibility on the glucose yield. All studied... (Complete abstract click electronic access below) / Mestre

Abstract / Resumé The Ontario provincial government faces the challenge of getting public support in the implementation of its RE policy. This thesis aims at investigating the effects of environmental values and political ideology on public support for renewable energy policy in Ottawa, Canada. Data was collected through open-ended interviews with fifty respondents in and around Ottawa, transcribed, coded and analysed using the NVivo software. Results indicate that environmental values and political ideology affect public support for renewable energy policy, but economic factors also play a role. The provincial government can think of ways to reduce the cost of electricity, invest on education and the creation of awareness on the benefits of renewable energy and the different initiatives that are offered by the RE policy to increase public support. Public ownership of RE projects and more democratic policy-making could also increase public support. Le gouvernement provincial de l'Ontario fait face au défi d'obtenir le soutien public dans la mise en œuvre de sa politique d'ER. Cette thèse vise à étudier les effets des valeurs environnementales et de l'idéologie politique sur le soutien public à la politique sur l'énergie renouvelable à Ottawa, au Canada. Les données ont été recueillies par les entrevues ouvertes avec une cinquantaine de répondants à Ottawa et dans les environs. Ils ont été transcrits, codées et analysées à l'aide du logiciel NVivo. Les résultats indiquent que les valeurs environnementales et l'idéologie politique affectent le soutien public à la politique d'énergie renouvelable, mais les facteurs économiques jouent également un rôle. Le gouvernement provincial peut réfléchir à des moyens de réduire le coût de l'électricité, investir dans l'éducation et sensibiliser les gens aux avantages de l'ER et aux différentes initiatives offertes par la politique sur l'ER pour accroître le soutien public. La propriété publique de projets d'ER et l'élaboration de politiques plus démocratiques pourrait également accroître le soutien public.

This research was established due to an increase of interest in renewable energy sources and utilisation of various wastes and biomass. Gasification is currently one of the most promising thermal-chemical conversion techniques for recovering energy from waste, and the pyrolytic behaviour of secondary refuse fuel (SRF) briquettes and biomass-derived fuels is the starting point for the process. The purpose of this study was to evaluate the pyrolytic characteristics of SRF briquettes and biomass materials, suggest a kinetic model for simulating the pyrolytic process and obtaining the kinetic parameters, and then predict the yield of volatile products in pyrolysis. Knowledge of the chemical composition, the thermal behaviour and the reactivity of SRF briquettes and their blends with other materials, such as biomass and plastic during pyrolysis is very important for the effective design operation of gasification units. The kinetics of the pyrolysis of simulated SRF briquettes, SRF briquettes and pulverised biomass samples was successfully modelled by a scheme consisting of two independent general order parallel reactions of the main components which were hemicellulose, cellulose, lignin and plastic. The kinetic parameters estimated through the model were comparable with those reported in the literature. In this research, activation energy values varied between 30 – 70 kJ/mol for lignin pyrolysis, 96 – 137 kJ/mol for hemicellulose and cellulose pyrolysis, and about 260 kJ/mol for plastic pyrolysis. Biomass has a very high volatile content. Adding biomass into SRF briquettes could increase the volatile yield. Increasing the plastic content of SRF briquettes could increase the volatile yield, the derivative thermogravimetric (DTG) peak height and the repeatability of pyrolysis. Inorganic component could shift the cellulose pyrolysis to a lower temperature and cause the hemicellulose pyrolysis and the cellulose pyrolysis highly overlapped, but it could have a positive effect by acting as catalysts and lower the activation energy in the pyrolysis of hemicellulose and cellulose. Molasses used as a binder could improve the DTG peak height and restrain the curve shifting effect of inorganic component on the hemicellulose and cellulose pyrolysis, but couldn’t restrain the lignin pyrolysis at low temperatures during the hemicellulose and cellulose pyrolysis. Molasses could restrain the effect of the lignin pyrolysis at high temperatures on the plastic pyrolysis. Mechanical biological treatment (MBT) process could highly improve the volatile yield and improve the DTG peak height of SRF briquettes.

An air source heat pump (ASHP) water heater is a renewable and energy efficient hot water heating technology. ASHP water heaters are fast gaining maturity in the South African market and in Africa at large due to their low energy consumption (about 67 percent lower than conventional geysers), relatively low installation and operation cost, their environmental friendly nature and possibly the ease to retrofit with the old inefficient technologies. Furthermore, ASHP water heaters make use of some of the most recent advancement in refrigeration technologies enhancing their performance through a wide range of weather conditions. However, residential ASHP water heaters which come at the tail of a series of highly sophisticated models still harbour primitive control designs. One of such control system is the intermittent (on/off) control whereby the ASHP unit responds to a temperature differential threshold rather than instantaneous temperature fluctuations. Unfortunately, this control method contributes to a rapid deterioration of the compressor and other actuators due to high starting current during transient states and partial loading. Capacity control is a better alterative as it offers a more reliable system’s performance as well as a better protection for the system components. However, the drawbacks of implementing such a technology on residential ASHP water heaters is the initial purchasing cost. We use a systematic approach in this research to circumvent the purchasing cost and complete redesign hysteresis. The first step was centered around a hypothetical analysis of the performance of the heat exchangers in a bid to uncover the weakness during the operation of a residential ASHP water heater. It was observed that at ambient temperatures above 22°C notably during summer and winter afternoons, water only harnesses about 75 percent of the total heat rejected. Furthermore, the actuators keep doing work for about 15-20 minutes even after the heat transfer process has ceased completely. Following these observations, a sequential flow algorithm was developed aimed at matching the consumption point to weather variables like ambient temperature and secondly to most efficiently synchronize actuator components for a better energy management. This novel control method can save up to 58 percent of energy compared to the conventional on/off method during summer afternoons and averagely 20 percent during the rest of the day. It also has the merit to be cost effective as it barely requires no component retrofitting.

This study shows a detailed report on the morphological, structural and optical properties of CdSe QDs synthesised by the hot injection method. Cadmium acetate dihydrate and Se powder were used as cadmium and selenide precursors, respectively. Various QD sizes were achieved by synthesizing in temperature range of 150ºC, 175ºC, 200ºC, 225ºC, 250ºC, 275ºC and 300ºC, respectively. The as synthesized QDs by the hot injection method were cross-examined for their morphological, structural and optical using HRTEM, FTIR, XRD, RS, and UV-Vis spectroscopy techniques respectively. FTIR analysis has revealed vibrations at 738, 738, 738, 738, 735, 735 and 733 cm-1 for the QDs synthesized at various temperatures of 150, 175, 200, 225, 250, 275, and 300℃, respectively. The presence of the above mentioned peaks confirms the presence of Cd-Se bond in our samples. XRD analysis of CdSe QDs revealed diffraction peaks at 2 angles of 16.66 , 25.20 , 34.77 , 40.9 , 45.39 and 49.1 for 150 17.4 , 25.22 , 34.85 , 41.7 , 44.45 and 47.5 for the QDs synthesized at various temperatures of 175 17.07 , 25.19 , 34.85 , 41.34 , 44.41 and 48.86 for 200 ; 16.34 , 25.20 , 34.76 , 40.6 , 44.74 and 49.48 for 225 ; 17.44 , 25.17 , 34.19 , 41.7 , 44.45 , 49.24 for 250 ; 16.70 , 25.16 , 34.85 , 40.32 , 45.1 and 49.1 7 for 275 ;and 17.35 , 25.18 , 35.13 , 41.63 , 45.7 , 49.48 for 300 . These XRD peaks relate to crystal planes of (100), (002), (102), (220), (103) and (112) which belong to hexagonal Wurtzite CdSe crystal structure. Additionally XRD analysis has revealed a general peak shift to higher 2 values was observed for CdSe QDs. HRTEM analysis showed that the synthesised CdSe QDs have a spherical shape and are monodispersed. Moreover, HRTEM analysis has revealed CdSe QDs modal crystallite size of 1.79 nm, 1.81 nm, 2.06 nm, 2.08 nm, 2.11 nm, 3.10 nm and 3.12 nm for the QDs synthesized at various temperatures of 150ºC, 175ºC, 200ºC, 225ºC, 250ºC, 275ºC and 300ºC, respectively. HRTEM results were in mutual agreement with XRD results. Additionally, the SAED images showed intense electron diffraction rings, which confirmed that the as-synthesised CdSe QDs have a Wurtzite crystal structure. RS analysis showed that CdSe QDs have LO and 2LO vibrational modes which are characteristic peaks for CdSe. The presence of these peaks in Raman spectra further supports our previous observation from XRD analysis and HRTEM analysis that the synthesized CdSe QDs have a Wurtzite crystal structure. The effect of synthesis temperature Raman peak shift, FHWH and peak intensity has been cross examined in this work, Moreover, the effect of increasing temperature on the peak shift, FWHM and peak intensity is discussed in detail below. UV-Vis analysis revealed an absorbance of CdSe QDs in higher wavelengths as temperature was increased. Furthermore, the Yu et al 2003 relation was used to calculate QD size and band gap energy of CdSe QDs. The results showed that QD size increases with increasing synthesis temperature, which is in agreement with HRTEM and XRD results.

Little is known about the impact of marine renewable energy installations upon the marine environment and those who use it. Harnessing marine energy will involve the offshore siting of energy extraction devices and their associated infrastructure. This will alter the local environment and substantially modify use and access for a variety of marine stakeholders, potentially leading to conflict. Using the Ecosystem Approach (EA) as a conceptual framework, this thesis aimed to answer the question: What is the potential for conflict between the marine renewable energy industry and marine stakeholders, and how can this be mitigated? The research consisted of three components which used a variety of methods: i) stakeholder identification through a review of the literature and use of a novel interactive mapping method; ii) an investigation of the potential consequences for the priority stakeholder which used a mail survey and in-depth interviews; and iii) an exploration of potential mitigation which used ecosystem modelling. The stakeholder most likely to be affected by marine renewable energy device (MRED) deployment was the fishing industry. Potential consequences included: navigation and safety hazards, loss of access and alternative employment. Further exploration revealed that a loss of livelihood was the all-encompassing concern for fishers, and that skills shortages (transferable skills) may mean that should a loss of livelihood occur there may not be acceptable alternative employment. The modelling exercise indicated that it is not currently possible to definitively predict whether any opportunities which may be created by MRED installation will mitigate any negative effects, and that exclusion zones may actually decrease catches for most fleets. The findings of this study have implications for ‘conflict-free’ development of the marine renewable energy industry. To address this, several policy recommendations were offered as regards to operationalising the EA in terms of marine renewable energy.

Beach‐cast kelp (principally Laminaria spp.), known as macroalgal wrack, has been suggested as a feedstock for biofuel. However, to be extracted sustainably it is necessary to understand its ecological role and predict the impacts of its removal. Field‐based observations combined with food web modelling were used to predict the ecosystem effects of removing wrack from beaches of the Uists, western Scotland. Beaches with wrack were associated with enriched benthic infauna (polychaetes) on the lower shore, and wrack mounds supported abundant macroinvertebrates (mainly Diptera larvae and oligochaetes); with some of the highest biomasses reported globally for beaches. These fauna are valuable prey to shorebirds, as demonstrated by a strong positive relationship (R2 = 0.82) between wader abundances and the percentage cover of wrack on beaches. Inshore, drifting macroalgae was associated with elevated abundances of detritivorous hyperbenthic fauna (mysids, isopods and gammarid amphipods). In addition, the volume of drifting macroalgae inshore was a significant predictor (along with physical beach characteristics) for the abundance of decapods and fish. Food web models and network analysis indicated that beaches which accumulate wrack had a greater diversity of trophic links and more functional redundancy, making their food webs more resilient to perturbations. Such perturbations may include stressors induced by climate change, such as increased erosion of sediments during storms, elevated atmospheric and sea surface temperatures and elevated CO2 concentrations. Model simulations of wrack harvesting predicted an immediate decline in primary consumers in direct proportion to the quantity of wrack removed, and a slow decline in shorebirds in response to reduced prey. Primary consumers were predicted to recover to their pre‐harvest biomasses within 1 to 2 years regardless of harvesting intensity, but recovery times for shorebirds were an order of magnitude longer, and increased with harvesting intensity. Harvesting more than 50% wrack predicted a ‘collapse’ in wader populations within 25 years, and recovery times of 45‐60 years were estimated if >70% wrack was removed. The findings of this thesis suggest wrack provides essential food and shelter to coastal fauna, and its large‐scale removal would have significant negative impacts to the ecosystem functioning.

The coastal waters off western Scotland are inhabited by two small under-studied common bottlenose dolphin (Tursiops truncatus) communities: the Inner Hebrides and the Sound of Barra (SoB) community. The region is considered for future developments for the marine renewables industry, which have the potential to negatively impact these communities; however the assessment of impacts and the development of plans to minimise these are currently hampered by a lack of knowledge about the dolphin's distribution and residency patterns, and spatial and temporal mobility. Using a variety of research methods (dedicated cetacean surveys and targeted photo-ID trips, acoustic monitoring and the collection of opportunistic photo-ID and sightings data from the general public) the current study examined local dolphin spatial and temporal mobility patterns by investigation of their spatial distribution and temporal occurrence. Collectively, the results revealed the presence of two socially and geographically separated (at least 2006-2013) resident communities which both demonstrated year-round presence and long-term site-fidelity, but maintained different ranging patterns. Long-term presence of individuals from the Inner Hebrides community dated back to 2001 and dolphins from this community ranged widely in nearshore waters throughout the entire currently known communal range, and practically used the entire range throughout the year. The SoB community, on the other hand, appeared to have a more restricted distribution, and appeared female-dominated. Summer censuses of the SoB community revealed annual estimates of ≤15 dolphins, with four individuals first identified in 1995, and at least eight calves born since 2005. Acoustic presence of dolphins in the SoB varied through the year, and in relation to the tidal and diel cycles. This study demonstrated that the integration of complementary methodological approaches is useful in investigating mobility patterns of low-density populations, and given the indications for social and spatial isolation, these communities should be managed independently.

This thesis considers the effect of disruptive waves and turbulence on a horizontal axis tidal stream turbine (TST), in terms of performance and survivability. The TST reaction to transient fluid flow is modelled analytically using Blade Element Momentum Theory (BEMT). Standard BEMT corrections are evaluated for the TST application and an alternative optimisation method is proposed for the steady state BEMT, improving compatibility with transient and depth dependent inflow, as well as the non-dimensionalisation constant needed to calculate the performance coefficients. Also, an alternative BEMT tip and hub loss implementation has led to a significant improvement of the turbine axial force prediction and in the high induction region. Validation studies are presented for BEMT coupled with regular, nonlinear wave theory and good agreement is found with published experimental data. A novel method to simulate irregular sea states is developed to couple with BEMT and a combined reactive coupling of waves and current is implemented. The TST performance in an irregular sea state is considered against turbine performance with real ADCP data and a good agreement is found. This work evaluates the BEMT implementation for the specific application of modelling TST's and significantly improves the fundamental theory, applicability and quality of results in this case.