In recent years, energy harvesting has been generating great interests among researchers, scientists and engineers alike. One of the major reasons for this increased interest sterns from the desire to have autonomous perpetual power supplies for remote monitoring sensor nodes utilizing some of the already available and otherwise wasted energy in the environment in a very innovative and useful way (and at the same time, maintaining a green environment). Scientists and engineers are constantly looking for ways of obtaining continuous and uninterrupted data from several points of interests especially remote or dangerous locations, using sensors coupled with RF transceivers, without the need of ever replacing or recharging the batteries that power these devices. This is now made possible through energy harvesting technologies which serve as suitable power supply substitutes, in many cases, for low power devices. With the proliferation of wireless energy in the environment through different radio frequency bands as well as natural sources like solar, wind and heat energy, it has become a desirable thing to take advantage of their availability by harvesting and converting them to useful electrical energy forms. The energy so harnessed or harvested could then be utilized in sensor nodes. Now, since these energy sources fluctuate from time to time, and from place to place, there is the need to have a form of energy accumulation, conversion, conditioning and storage. The stored energy would then be reconverted and used by the sensors nodes and/or RF transceivers when needed. The process through which this is done is referred to as energy management. In this research work, many types of energy harvesting transducers were explored including – solar, thermal, electromagnetic and piezo/vibration. A proof of concept approach for an on-demand electromagnetic power generator is then presented towards the end. While most, if not all, of the energy harvesting techniques discussed needed some time to accumulate enough charge to operate their respective systems, the on-demand energy harvester makes energy available as at and when needed. In summary, a system level design is presented with suggested future research works.

In recent years, energy harvesting has been generating great interests among researchers, scientists and engineers alike. One of the major reasons for this increased interest sterns from the desire to have autonomous perpetual power supplies for remote monitoring sensor nodes utilizing some of the already available and otherwise wasted energy in the environment in a very innovative and useful way (and at the same time, maintaining a green environment). Scientists and engineers are constantly looking for ways of obtaining continuous and uninterrupted data from several points of interests especially remote or dangerous locations, using sensors coupled with RF transceivers, without the need of ever replacing or recharging the batteries that power these devices. This is now made possible through energy harvesting technologies which serve as suitable power supply substitutes, in many cases, for low power devices. With the proliferation of wireless energy in the environment through different radio frequency bands as well as natural sources like solar, wind and heat energy, it has become a desirable thing to take advantage of their availability by harvesting and converting them to useful electrical energy forms. The energy so harnessed or harvested could then be utilized in sensor nodes. Now, since these energy sources fluctuate from time to time, and from place to place, there is the need to have a form of energy accumulation, conversion, conditioning and storage. The stored energy would then be reconverted and used by the sensors nodes and/or RF transceivers when needed. The process through which this is done is referred to as energy management. In this research work, many types of energy harvesting transducers were explored including – solar, thermal, electromagnetic and piezo/vibration. A proof of concept approach for an on-demand electromagnetic power generator is then presented towards the end. While most, if not all, of the energy harvesting techniques discussed needed some time to accumulate enough charge to operate their respective systems, the on-demand energy harvester makes energy available as at and when needed. In summary, a system level design is presented with suggested future research works.

Esta dissertação tem como objetivo a elaboração de um estudo a respeito da interferência das variações de temperatura ambiente e umidade relativa do ar no comportamento da demanda de energia elétrica e formação do Custo Marginal de Operação (CMO) no Brasil. A partir da busca do entendimento das etapas do processo de Planejamento da Operação e da Programação da Operação Diária, para o atendimento da carga do Sistema Interligado Nacional (SIN), cujos processos são detalhados ao longo deste trabalho, é feita uma análise comparativa entre os valores programados e realizados tanto de geração, quanto da demanda de energia elétrica, de forma a se tentar quantificar o quanto as variáveis temperatura ambiente e umidade relativa do ar influenciam no resultado da operação hidrotérmica diária. Após a quantificação dessa influência em termos de aumento de consumo de energia elétrica, é realizada uma nova simulação de despacho hidrotérmico, utilizando para isso um modelo de otimização comercialmente disponível, com o objetivo de se avaliar quais são os desvios no CMO, quando da ocorrência de desvios na curva diária de demanda de energia elétrica programada. São abordados ao longo deste estudo os seguintes itens: histórico do processo de planejamento, o planejamento da operação energética, a influência da temperatura ambiente e umidade relativa do ar no comportamento da demanda de energia elétrica, finalmente é proposto um estudo de caso para se avaliar qual a relação entre as variáveis climáticas estudadas e os desvios na curva de demanda de energia elétrica e CMO do SIN. / This thesis aims at the elaboration of a study regarding the interference of changes in temperature and relative humidity in the behavior of the demand for electric power and formation of the Marginal Cost of Operation (CMO) in Brazil. From the search for understanding of the steps involved in Operation Planning and Programming of Operation Daily, to meet the burden of the National Interconnected System (SIN), whose cases are detailed throughout this work, is a comparative analysis between the values planned and performed both for generating, as the demand for electricity in order to try to quantify how much the variable temperature and relative humidity influence the outcome of the operation hydrothermal daily. After the quantification of that influence in terms of increased consumption of electricity, a new simulation is performed in order hydrothermal, using it to a type of commercially available optimization, in order to assess what are the differences in CMO, at the time deviations from the curve of daily demand for electricity scheduled. Are addressed throughout this study the following items: the historical process of planning, energy planning the operation, the influence of temperature and relative humidity in the behavior of the demand for electricity, is finally offered a case study to evaluate what is the relationship between climatic variables and studied the differences in the curve of demand for electricity and CMO of the SIN.

Thesis (Ph.D.)--University of Canterbury, 2009. / Typescript (photocopy). "March 2009." "Supervisors: Professor Les Oxley and Professor John Gibson." Includes bibliographical references (p. 325-359). Also available via the World Wide Web.

Esta dissertação tem como objetivo a elaboração de um estudo a respeito da interferência das variações de temperatura ambiente e umidade relativa do ar no comportamento da demanda de energia elétrica e formação do Custo Marginal de Operação (CMO) no Brasil. A partir da busca do entendimento das etapas do processo de Planejamento da Operação e da Programação da Operação Diária, para o atendimento da carga do Sistema Interligado Nacional (SIN), cujos processos são detalhados ao longo deste trabalho, é feita uma análise comparativa entre os valores programados e realizados tanto de geração, quanto da demanda de energia elétrica, de forma a se tentar quantificar o quanto as variáveis temperatura ambiente e umidade relativa do ar influenciam no resultado da operação hidrotérmica diária. Após a quantificação dessa influência em termos de aumento de consumo de energia elétrica, é realizada uma nova simulação de despacho hidrotérmico, utilizando para isso um modelo de otimização comercialmente disponível, com o objetivo de se avaliar quais são os desvios no CMO, quando da ocorrência de desvios na curva diária de demanda de energia elétrica programada. São abordados ao longo deste estudo os seguintes itens: histórico do processo de planejamento, o planejamento da operação energética, a influência da temperatura ambiente e umidade relativa do ar no comportamento da demanda de energia elétrica, finalmente é proposto um estudo de caso para se avaliar qual a relação entre as variáveis climáticas estudadas e os desvios na curva de demanda de energia elétrica e CMO do SIN. / This thesis aims at the elaboration of a study regarding the interference of changes in temperature and relative humidity in the behavior of the demand for electric power and formation of the Marginal Cost of Operation (CMO) in Brazil. From the search for understanding of the steps involved in Operation Planning and Programming of Operation Daily, to meet the burden of the National Interconnected System (SIN), whose cases are detailed throughout this work, is a comparative analysis between the values planned and performed both for generating, as the demand for electricity in order to try to quantify how much the variable temperature and relative humidity influence the outcome of the operation hydrothermal daily. After the quantification of that influence in terms of increased consumption of electricity, a new simulation is performed in order hydrothermal, using it to a type of commercially available optimization, in order to assess what are the differences in CMO, at the time deviations from the curve of daily demand for electricity scheduled. Are addressed throughout this study the following items: the historical process of planning, energy planning the operation, the influence of temperature and relative humidity in the behavior of the demand for electricity, is finally offered a case study to evaluate what is the relationship between climatic variables and studied the differences in the curve of demand for electricity and CMO of the SIN.

Avec l’augmentation de la part des énergies renouvelables intermittentes (solaire et éolien) dans les mix énergétiques, des problèmes dans la stabilité de la fourniture d’électricité peuvent se présenter. La solution pour compenser ces fluctuations réside dans la production flexible de biogaz. Le biogaz peut en effet être stocké puis utilisé en période de demande; sa production doit donc être assurée de manière flexible, contrairement à ce qui est fait actuellement sur la majorité des digesteurs. L’objectif de la thèse était d’étudier et de déterminer les limites de digesteurs biogaz en fonctionnement flexible. Trois réacteurs de 15L, alimentés avec trois mélanges différents de deux substrats solides, ont été alimentés pendant 550 jours en fonctionnement flexible. Il a été démontré au cours de cette thèse que le fonctionnement flexible avec des surcharges organiques ponctuelles n’avait aucune incidence négative à long terme sur la production de méthane. La flexibilité instantanée a été définie comme la marge entre le maximum de production sur un réacteur et sa production de base. Elle a été fortement influencée par la charge de base du réacteur et par les cinétiques de dégradation des substrats utilisés en surcharge, mais très peu par l’intensité des surcharges appliquées. L’utilisation de substrats rapidement dégradables en surcharge a permis d’atteindre un maximum de production de 1 à 1,2 LCH4/Lréacteur.j dans les premières 24 heures, même sur des réacteurs alimentés de base avec du fumier, conduisant à des flexibilités allant de +92 à +150%. Ce plafond dépend de la vitesse d’hydrolyse des substrats et il peut être relevé en utilisant des composés plus simples à dégrader en surcharge (type glycérol). Un mode opératoire prêt à être validé sur des installations pilote a été défini ; il précise la démarche à suivre pour la détermination du maximum de production et le niveau de la charge de base à adopter, pour une flexibilisation optimale de la production de méthane sur les CSTR. Un modèle simple, basé sur deux vitesses de dégradation, a également été développé et proposé pour simuler un fonctionnement flexible sur un réacteur. / With the increasing share of intermittent renewable energies in the electricity mix, some stability problems are expected in the grid. The solution consists in using biogas as buffer energy. Biogas can be stored, then used on-demand. As the storage is limited, biogas production should be flexible. The aim of this thesis was to study and determine the limits of anaerobic reactors in a flexible operation. Three 15L reactors, fed with three different mixtures of two solid substrates, were fed for 550 days in flexible operation. It was demonstrated in this thesis that flexible operation with one-off overloads had no negative impact on methane production on long-term. The flexibility was defined as the margin between the maximum production on a reactor and its baseload production. It was strongly influenced by the baseload of the reactor and the substrates used in overloads, but not by the intensity of the overloads applied. The use of readily degradable substrates in overloads allowed a maximum production of 1 to 1.2 LCH4/Lreactor.d to be achieved in the first 24 hours, even in reactors fed mainly with manure, leading to flexibility ranging from +92 to + 150%. This ceiling depends on the rate of hydrolysis of the substrates. It can be increased by using compounds that are of a simpler structure (glycerol for example). An operational strategy ready to be validated on pilot plants has been defined; it specifies the approach for the determination of the maximum production and the level of the baseload to be adopted, for an optimal flexibilization of the methane production on CSTRs. A simple model, based on two degradation rates, has also been developed to simulate flexible operation of anaerobic reactors.

The 2008 Climate Change Act set legally-binding carbon reduction targets. Demand side management (DSM) includes energy use reduction and peak shaving and offers significant potential to reduce the amount of carbon used by the electricity grid. The demand side management (DSM) schemes that have tried to meet this challenge have been dominated by engineering-based approaches and so favour tools like automation (which aims to make shifting invisible) and pricing (which requires customer response) to shift demand. These approaches tend to focus on the tools for change and take little account of people and energy-use practices. This thesis argues that these approaches are limited and therefore unlikely to produce the level of response that will be needed in future. The thesis therefore investigates the potential for time-shifting domestic energy demand but takes a different angle by trying to understand how people use energy in their daily lives, whether this use can be shifted and some of the implications of shifting it. The centrepiece of the work is an empirical study of eleven households energy-use practices. The interdisciplinary methodology involved in-house observations, interviews, photographs, metered energy data and disruptive interventions. The data was collected in two phases. Initially, a twenty-four hour observation was carried out in each household to find out how energy was implicated in everyday practices. Next, a series of three challenges were carried out, aimed at assessing the implications of disrupting practices by time-shifting food preparation, laundry and work/ leisure. A practice theory approach is used to shift the focus of attention from appliances, tools for change, behaviour or even people, to practices. The central finding of this work is that practices were flexible. This finding is nuanced, in the light of the empirical research, by an extended discussion on the nature of practices; in particular, the relationship between practices and agency and the temporal-spatial locatedness of practices. The findings demonstrate that, in this study at least, expanding the range of demand response options was possible. The research suggests numerous possibilities for extending the potential of practices to shift in time and space, shift the energy used in practices or substitute practices for other non-energy-using practices, though there are no simple technological or behavioural fixes . More profoundly, however, the thesis concludes that infrastructures of provision , such as the electricity grid and the companies that run it, underpin and facilitate energy-use practices irrespective of the time of day and year. In this context technology-led demand response schemes may ultimately contribute to the problem they purport to solve. A more fundamental interrogation of demand and the infrastructures that serve it is therefore necessary and is almost entirely absent from the demand response debate.

Most of the detached houses in Sweden were built more than 30 years ago, and most of them are oldand need a deep renovation. The renovation is an excellent opportunity to apply the energy measure witha combination of renewable energy such as PV solar, which could be a great option to reduce energyconsumption and contribute to reducing greenhouse emissions. For this reason, selecting effectiverenovation scenarios for buildings could be important and challenging. One of these challenges isapplying typical scenarios for one archetype's buildings. A building could be in the same archetypeswith similar geometry and properties but in different directions. In this study, the researcher aims toinvestigate the yearly heat demand energy saving of buildings from one archetype, the same renovationscenario, and the same area but in four different directions, 0-30-60-90 degrees from the south (casestudies).This project's additional aim is to examine the electricity generation from PV when installedon one and both sides for four houses in the same area in four different directions, 0-30-60-90 degreesfrom the south. Design Builder software was used as a graphical user interface through the Energy Plus engine. In thisway, the heat demand of case studies was simulated for different scenarios (Standard renovation andadvanced renovation) in the Växjö region. The results from the simulation of the houses with differentdirections showed that the heat demand energy decreased by, on average, 20% for standard and 28% foradvanced renovation. The comparison of the case studies with the same renovation scenario concludesthat they are no differences in the heat energy savings, which means the direction of the building has nobig impact on the energy saving of the renovation scenario in the Växjö region. The installation side ofthe PV has no impact on the annual electricity generation from PV for the house with a direction of 0degrees from the south. For the other houses, the yearly electricity generation from the PV increased by36.8% with one side on the roof (South direction). House number 4 is the best direction to install PVwith one side on the roof (south direction), and house 3 is the next best direction to install PV on oneside. When installed on both sides of the roof, the annual electricity generation from the PV decreased by5,3% with four houses in different directions. The changes are not so high may be due to the weather ofthe Växjö, which is 65 % cloudy according to the weather data file from TMY. Another reason is thatthe PV was installed on both sides of the pitched roof. When the houses have different directions, 0 to90 degrees from the south, that may be increased the electricity generation from the PV on one side andreduce it on the other.

The North American forest industry has long been an important part of North America’s economy. The industry has traditionally been the only industrial demand on timberland creating a long established balance between the supply (timberland) and the demand (manufacturing). Recently the forest industry has been troubled due to the collapse of the solid wood products largest market, housing, and a global recession. These troubled times have lead many operation in the industry to curtail operations. Since the industry curtailed, high oil prices and increasing environmental concern have advocated the investment in renewable energy sources. As a renewable energy source, biomass holds great potential for satisfying a portion of our continental energy demands. This increased demand for timberland products could be very profitable to the timberland owners but also holds many concerns to the extent of additional supply that can be harvested from our timberlands. Further complicating the balance of supply and demand are the large global and domestic effects that are reducing the total amount of timberland and increasing the demand for the remaining timberlands. The supply and demand changes have the potential to make the forest industry evermore important part of the North American economy but care must be taken to not over extend our resources.