Wireless sensor networks (WSNs) typically consist of a significant number of inexpensive sensor nodes, each of which is powered by a battery or another finite energy source that is difficult to replace because of the environment they are in or the cost of doing so. The applications of WSNs include military surveillance, disaster management, target tracking and monitoring environmental conditions. In order to increase the lifespan of WSNs, energy-efficient sensing and communication approaches for sensor nodes are essential. Recently, there has been an increase in interest in using unmanned aerial vehicles (UAVs) as portable data collectors for ground sensor nodes in WSN. Several approaches to solving effective communication between sensor nodes and the fusion center have been investigated in this thesis. Because processing, sensing range, transmission bandwidth, and energy consumption are always limited, it is beneficial not to use all the information provided at each sensor node in order to prolong its life span and reduce communication costs. In order to address this problem, first, efficient measurement quantization techniques are proposed using a single fusion center and multiple sensors. The dynamic bit distribution is done among all the sensors and within the measurement elements. The problem is then expanded to include multiple fusion centers, and a novel algorithm is proposed to associate sensors to fusion centers. The bandwidth distribution for targets which are being monitored by several sensors is addressed. Additionally, how to use the situation in which the sensors are in the coverage radius of multiple fusion centers in order to share the targets between them is discussed. Finally, performance bounded data collection algorithms are proposed where the necessary accuracy for each target is specified. In order to determine the minimum number of data collectors needed and their initial placement, an algorithm is proposed. When there are fewer fixed data collectors than there are regions to collect the data from, a coverage path planning method is developed. Since the optimal solution requires an enormous computational requirement and not realistic for real-time online implementation, approximate algorithms are proposed for multi-objective integer optimization problems. In order to assess each suggested algorithm's effectiveness, many simulated scenarios are used together with baselines and simple existing methods. / Thesis / Doctor of Philosophy (PhD)

No / An isolated micro-grid network with limited generating capacity would most likely, end up having operational challenge either due to increasing number of customers, or introduction of new loads onto the network. This is in view of an observed scenario especially in developing countries whereby as load demand increases, installed PV capacity often do not receive commensurate expansion. So, in order to prevent network failure, each user can be allocated certain amount of limited power supply which should not be exceeded. These allotments are dynamic, and they vary at regular time intervals every day depending on their historic load profile data. This work is therefore based on managing power supply from a PV-source operating as an isolated micro-grid with storage capabilities. A power supply scheduling mechanism is introduced which allocates maximum power capacity for every user. Hence communities detached from the grid can enjoy electricity despite shortfalls in power supply capacity. The obtained results evaluated under three scenarios show that allocating energy limits to each user depends on the current capacity of the battery as well as the forecast load demand. This allotment is enforced using variable circuit breakers whose cut-off point is varied based on the prevailing energy demand and supply requirements.

The thesis topic is creating conditions for successful implementation of alternative fuel technologies in passenger cars on the Czech market. Its goal is to develop a comprehensive concept of proposed measures that would create demand for alternative powertrain. It analyzes current situation of the environmental-friendly vehicles market and examines reasons why consumers have not been purposefully searching for these cars so far. The thesis consists of several coherent blocks. The first one deals with general aspects of innovations and development, energy resources, climate protection and car fleet in the Czech Republic. The second part focuses on new alternative technologies from the viewpoint of energy resources and examines the offer on the local market. The third section includes a consumer research focused on information related to potential customers' preferences and compares economic efficiency and costs of selected technologies. The final part presents proposed ways of accomplishing the main goal, while special attention is given to specific recommendations, which would help to create demand and facilitate promotion among consumers.

Transition towards a low carbon economy raises concerns of loss of security of supply with high penetrations of renewable generation displacing traditional fossil fuel based generation. While wind and wave resources are increasingly forecastable, they are stochastic in nature. The tidal current resource, although variable has the advantage of being deterministic and truly predictable. With the first Crown Estate leasing round complete for wave and tidal current energy, plans are in place to install 1000 MW of tidal capacity in the Pentland Firth and Orkney waters. The aim of the work presented in this thesis is to examine the role tidal current energy can realistically play in the future electricity mix. To achieve this objective it was first necessary to develop new methodologies to capture the temporal and spatial variability of tidal current dynamics over long timescales and identify metrics relevant in a tidal energy context. These methodologies were developed for project scale resource characterisation, and provided a basis for development of a national scale dataset. The creation of project and national scale tidal datasets capture spatial and temporal variability at a level beyond previous insight, as demonstrated in case studies of three important early stage tidal current energy development sites. The provision of a robust national scale dataset enabled the development of realistic scenarios for the growth of the tidal current energy sector in UK waters. Assessing the various scenarios proposed indicates that first-generation technology solutions have the potential to generate up to 31 TWh/yr (over 8% of 2009 UK electricity demand). However, only 14 TWh/yr can be sensibly generated after incorporating realistic economic and environmental limitations proposed in this study. The preceding development of methodologies, datasets and scenarios enabled statistical analysis of the matching characteristics of future tidal energy generation potential with the present UK electricity demand and trends of electricity usage. This analysis demonstrated that the UK tidal current energy resource is much more in phase than has previously been understood, highlighting the flaws in previous studies suggesting that a combined portfolio of sites around the UK can deliver firm power. As there is negligible firm production, base-load contribution is insignificant. However, the time-series generated from this analysis identifies the role tidal current energy can play in meeting future energy demand and offer significant benefit for the operation of the electricity system as part of an integrated portfolio.

Made available in DSpace on 2016-12-12T20:12:32Z (GMT). No. of bitstreams: 1 PGEF15MA051.pdf: 1474402 bytes, checksum: caefe48730a523187b058411009c1fc0 (MD5) Previous issue date: 2015-07-22 / The pellets produced from forest biomass appear alternatively in obtaining thermal and electrical energy. Biomass compressed manufacturing must meet some standards of quality that are based on standards, however it is known that in Brazil there is no specific standard for the manufacture of that product. In this way, the study sought to determine the quality of the pellets from forest biomass produced in Santa Catarina, based on international standards, aiming at the proposal of criteria for the establishment of a State quality standards for this energy resource. Nine samples were collected in the State, in which they were certain the properties: physical (size, apparent density and density of unit), mechanical (durability and fine content) and energy (moisture content; immediate analysis and calorific value) of pellets. After the completion of the analysis the data were compared with the standards: European (CEN/TS 14961), North American (USA PFI), Italian (CTI-R 04/5), German (DIN 51735), Swedish (SS 187120), Austria (Onörm M7135) and with the international standard ISO 17225-2. From this, a proposal of normalization for the State of Santa Catarina. The average values of the properties were: 6.58 mm diameter; 17,31 mm length; apparent density of 663,46 kg/m³; 1,70 unit density kg/m³; 7,89% moisture content; volatile content of 81,29%; fixed carbon of 18,33%; from 0,38% ash content; 4827 superior calorific value Kcal/kg; durability of 99,07% and percentage of 1,05% fines. The pellets produced in Santa Catarina feature hig The shavings of Pinus spp. is used by all producers of pellet formation of the State, thus, a norm for this energy resource does not require subdivisions depending on the raw material used. The standard should present only categories depending on the final use of the product, which is directed at the service sector and the manufacturing sector. All properties reviewed are important indicators of the quality of the pellets and must appear in the standard. On the information researched and results obtained, it becomes possible to propose a standardization for pellets in Santa Catarina. The quality and meet the requirements laid down by the main international standards / Os péletes produzidos a partir de biomassa florestal surgem como alternativa na obtenção de energia térmica e elétrica. A fabricação dos compactados de biomassa precisa atender alguns padrões de qualidade que são fundamentados por normas, no entanto sabe-se que, no Brasil não existe uma norma específica para a fabricação desse produto. Desta forma, o trabalho buscou determinar a qualidade dos péletes de biomassa florestal produzidos em Santa Catarina, com base em normas internacionais, visando à proposição de critérios para a elaboração de uma normalização estadual de qualidade para este recurso energético. Foram coletadas nove amostras no estado, nas quais foram determinadas as propriedades: físicas (dimensões, densidade aparente e densidade da unidade), mecânicas (durabilidade e teor de finos) e energéticas (teor de umidade; análise imediata e poder calorífico) dos péletes. Após a realização das análises os dados foram comparados com as normas europeia (CEN/TS 14961), norte-americana (EUA PFI), italiana (CTI-R 04/5), alemã (DIN 51735), sueca (SS 187120), austríaca (Onörm M7135) e com a norma internacional ISO 17225-2. A partir disso, foi elaborada uma proposição de normalização para o estado de Santa Catarina. Os valores médios das propriedades foram: diâmetro de 6,58 mm; comprimento de 17,31 mm; densidade aparente de 663,46 kg/m³; densidade da unidade de 1,70 kg/m³; teor de umidade de 7,89 %; teor de materiais voláteis de 81,29 %; carbono fixo de 18,33%; teor de cinzas de 0,38 %; poder calorífico superior de 4827 Kcal/kg; durabilidade de 99,07% e porcentagem de finos de 1,05 %. Os péletes produzidos em Santa Catarina apresentam elevada qualidade e atendem as exigências estabelecidas pelas principais normas internacionais. A maravalha de Pinus spp. é utilizada por todos os produtores de péletes do estado, dessa forma, uma norma para esse recurso energético não requer subdivisões em função da matéria-prima utilizada. É necessário que a norma apresente categorias em função do uso final do produto, que é direcionado ao setor de serviços e setor industrial. Todas as propriedades analisadas são importantes indicadores da qualidade dos péletes e precisam constar na norma. Diante das informações pesquisadas e resultados obtidos, é possível a proposição de uma normalização para péletes em Santa Catarina

Microgrid is an emerging technology in the eld of electrical engineering which employs the concept of Distributed Energy Resources (DERs) in order to generate electricity in a small sized power system. The main objectives of this dissertation are to: 1- design a new control for lower level control of DERs in microgrids, 2- implement distributed upper level control for DERs in microgrids and 3- apply analytical approaches in order to analyze DERs in microgrids. The control in each DER can be divided into two main categories: lower and upper level. Lower level control is the main objective of control in each DER. For example, the lower level control in Photovoltaic (PV) is in charge of transferring the maximum power from sun into the main grid. Unlike the lower level control, the upper level control is an additional control loop on top of the lower level controls. For example, Voltage/Frequency (VF) controllers are installed on top of Active/Reactive (PQ) power controller in energy storage devices as upper level control. In this dissertation, for the lower level control improvements, two widely used DERs are selected (PV, and oshore wind farm) and new control algorithms are developed in order to improve the performance of lower level controllers in these DERs. For the PV lower level improvement, a new control methodology is proposed in order to minimize the maximum power tracking error in PV lower level controller. Second contribution in lower level control is for the oshore wind farm applications based on Multi-Terminal High Voltage Direct Current (MTDC) transmission; a new control is designed in order to minimize the losses in transmission lines through lower level control of High Voltage Direct Current (HVDC) converters. For the upper level control, this dissertation considers the energy storage as another mostly used type of DER in microgrids. The lower level control for energy storage is in charge of controlling the PQ of the energy storage. The main contribution in the upper level control is to implement the distributed control algorithm based on consensus theory for battery energy storages in order to maximize the efficiency, energy management as well as synchronizing the performance of parallel energy storage devices in microgrids. In this case, the consensus based distributed control algorithm with limited information exchange between neighboring energy storage units is proposed and implemented to validate the claim. The third contribution of this research is to apply advanced analysis techniques to evaluate the performance of the DERs in microgrids. Two approaches are introduced for microgrid modeling in this research. Firstly, an impedance modeling technique is used to model the oshore wind farm connected to the main AC grid through HVDC transmission line. Multiple Input Multiple Output (MIMO) Nyquist analysis and singular value analysis are used to assess the interactions between HVDC converter and grid. Secondly, an unbalanced microgrid is considered and Dynamic Phasor (DP) analysis is applied in order to nd the stability limitations under different scenarios. This dissertation has led to seven journal papers (five published, one journal in revision process and one journal submitted recently) and four conference papers.

No description available.

The conversion of native forest to agricultural land has been an on-going issue threatening the health of New Zealand’s freshwater systems. However, despite the fact that this has been occurring since early European settlement, our understanding of the mechanistic relationships between riparian vegetation and stream condition are poorly developed. This research investigated: (i) how forests affect downstream benthic macroinvertebrate communities in pasture and the environmental factors driving community change; (ii) how upstream forest size impacted the rate of change in downstream environmental drivers and associated macroinvertebrate community structure; and (iii) whether the addition of coarse particulate organic matter (a single potential driver of forest community structure) can reset community structure to that of a forested state. Physico-chemical conditions, basal energy resources, and macroinvertebrates were surveyed in several New Zealand headwater streams. At Mount Egmont National Park, 10-12 sites were surveyed across a longitudinal forest-pasture gradient in each of five streams flowing from continuous forest to dairy farmland. My results showed that forests can have marked effects downstream. From the forest edge, water temperatures increased consistently, with a rise of approximately 0.2ºC per 100 m of downstream distance. By contrast, coarse particulate organic matter (CPOM) decreased rapidly downstream of the forest, however, low levels of “forest-derived” CPOM were still present 300m downstream from the forest edge. These environmental changes drove significant shifts in macroinvertebrate community structure. Moreover, pasture communities were markedly different from those in forest, despite being only 100 m from the forest edge. In particular, total macroinvertebrate and EPT richness and densities decreased, and communities shifted from evenly distributed allochthonous-based communities to autochthonous-based communities, highly dominated by molluscs (e.g., Potamopyrgus spp.) Subsequent surveys of 6-8 sites across a longitudinal forest-pasture gradient in each of eleven streams flowing from forest fragments of different sizes into grazed pastures throughout the Canterbury region, indicated that stream temperature increased more rapidly downstream of small- and medium-sized fragments, than larger fragments. A Berger-Parker dominance index also indicated that macroinvertebrates responded principally to water temperature, with communities being more highly dominated by temperature-tolerant molluscs in streams flowing from small-sized forest fragments. Several headwater streams in Canterbury were also highly retentive, with marked CPOM rarely exported beyond 50 m downstream of the forest. Experimental additions of leaf litter to the pasture reaches of the same streams dramatically increased amounts of stored benthic CPOM. Although non-significant, trends indicated that EPT and shredder densities increased at litter addition sites, providing promise that CPOM can function as a mechanism directly enhancing healthy stream communities. My findings support the contention that when the replanting of entire stream reaches is infeasible, the use of riparian management strategies which focus on the planting of intermittent patches along stream banks can potentially improve stream habitat and community health downstream.

Hybrid Energy Resource System (HERS) is studied and applied aroundworld in recent years. Control and monitor of them are quite important in realapplication. HERS also has the equirement to integral with power grid such asdistribution grid networks. Therefore, to design and implement the informationcommunication system following IEC 61850, which is most promising standard fordesign of substation communication and automation system, is necessary. This paperpresents the design of Information Communication Technology (ICT) architectureand Unified Modeling Language (UML) models and final implementation through LabVIEW programming for Smart Energy Container. Applying design following IEC61850 series standards allow the HERS can communicate and interoperate with other IEC61850 devices and SCADA systems. The implementation is applied to SmartEnergy Container which contains wind power, solar power, battery energy storagesystem, and hydrogen energy storage system. Verification and testing results shows thedesign is qualified to control and monitor Smart Energy Container. / Smart Energy Container

An emerging category of energy systems, consisting of power generation equipment coupled with thermally-activated components, has evolved as Cooling, Heating, and Power (CHP). The application of CHP systems to buildings has developed into a new paradigm ? Cooling, Heating, and Power for Buildings (CHP-B). This instructional module has been developed to introduce undergraduate engineering students to CHP-B. In the typical ME curriculum, a number of courses could contain topics related to CHP. Thermodynamics, heat transfer, thermal systems design, heat and power, alternate energy systems, and HVAC courses are appropriate for CHP topics. However, the types of material needed for this mix of courses vary. In thermodynamics, basic problems involving a CHP flavor are needed, but in an alternate energy systems course much more CHP detail and content would be required. This series of lectures on CHP-B contains both a stand-alone CHP treatment and a compilation of problems/exercises.