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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

A Study of Vehicle-to-Vehicle Power Transfer Operation in V2G-Equipped Microgrid

Tamang, Amit Kumar January 2014 (has links)
Bidirectional vehicle-to-grid (V2G) system utilizes the batteries of parked electric-drive-vehicles to provide energy storage and backup services in a power system. Such services in a V2G-equipped microgrid system can be used as an enabler of enhancing the renewable energy source (RES) penetration by storing the energy during the surplus of RES supply and supplying the energy during the lack of RES supply. In this research, we aim at enhancing the storage capacity of V2G system by introducing a novel vehicle-to-vehicle power transfer operation that runs on the top of V2G services. The vehicle-to-vehicle (V2V) operation transfers the energy from the source vehicles (which are parked for relatively longer times) to the destination vehicles (which are parked for relatively shorter times). The depleted energy of the source vehicles is fulfilled by the surplus RES supply in the future. In this way, the destination vehicles are effectively charged by RES supply, thereby enhancing the storage capacity of the V2G system. We can also say that the V2V operation would become beneficial only when there is a sufficient amount of surplus RES supply in the future. We propose a decision rule to distinguish if a vehicle should be a source vehicle or a destination vehicle during the V2V operation. The decision rule is designed based on the two factors, namely the state-of-charge of vehicle’s battery, and the remaining time of vehicle to depart. In this research, we conduct a comprehensive study to analyze the impacts of state-of-charge and mobility pattern of vehicles on different performance metrics via simulation. The results shows that in order to achieve better performance of V2V operation, the state-of-charge of vehicle’s battery should be given more priority over the remaining time of vehicle to depart. The vehicle mobility pattern with unexpected departure greatly reduced the overall performance of the V2G system.
272

Sustainable Energy Source for Water Pumping at Puttalam Salt Limited

Kamaldeen, Mohammed Rizwan January 2014 (has links)
The cost of grid based electrical and diesel sea water pumping to salt fields is one of the major cost components out of the total production cost in Puttalam Salt Limited, situated in northern part of Sri Lanka. In order to explore ways and means to improve the energy efficiency and alternative resources to meet the energy requirement a feasibility study was conducted using power system simulation software, (HOMER) and also detailed technical, environmental and financial tools.    This research study is conducted to evaluate the performances and applicability and propose the most suitable sustainable renewable energy source and methodology for water pumping to salt fields instead of currently utilized grid based and fossil fueled energy supply.   Preliminary results obtained by simulation software shows that direct wind mill pumping and solar PV water pumping was found to be unfeasible due to its limited pumping capacity and high investment cost. More over solar PV does not seems much feasible due to its high cost of energy (0.234 US $/kWh) compared to wind powered rivals in this type of applications.   Based on comparisons of the analysis it is seen that the wind/ grid combined configuration of 04 units of AOC15/50 model (50kW manufactured by AOC Renewable Energy - Canada) wind turbine units with 150kw inverter seems to be a logical supplement for water pumping energy requirement than using grid based electricity which costs 0.201 US $/ kWh. The solution in this research affords an attractive 60% annual average renewable fraction as well as an approximate 215.8 tCO2(eq) of annual Carbon Footprint saving. Also it assures a moderate Discounted Payback Period of 6 years and 5months with a 15% of Internal Rate of Return.
273

Repurposed Battery Energy Storage System for use in applications of Renewable Energy Generation

Williams, Dexter M. T. J. 18 September 2012 (has links)
Electric and hybrid electric vehicles’ batteries not only have great potential for alleviating the world’s gasoline consumption problem, but may also stand poised to secure the world’s renewable energy generation. Electric and hybrid electric vehicles’ batteries that have reached the end of their cycle life in vehicles may still have the capacity to be repurposed into stationary utility energy storage. However, the phenomenon known as battery aging must be given careful consideration in the construction of a repurposed battery energy storage system. The battery aging phenomenon reduces the battery’s nominal voltage, capacity and current rating, while increasing its internal resistance. These factors were taken into consideration for the development of the Repurposed Battery Energy Storage System (RBESS). The system utilizes a method called Multi-Level Interlaced Pulse Charging (MLIPC) which was developed for the RBESS to manage the battery’s voltage, current, and energy to extend the useful cycle life of the batteries. The repurposed battery energy storage system has been modeled in PSCAD/EMTDC and tested in a constructed hardware implementation of the system.
274

Coupled operation of a wind farm and pumped storage facility: techno-economic modelling and stochastic optimization.

Wild, Kristin 22 December 2011 (has links)
This thesis applies a stochastic programming approach to the techno-economic analysis of a wind farm coupled with a pumped storage facility. The production of an optimal day-ahead generating schedule is considered. Wind forecasts contain an element of random error, and several methods of addressing this uncertainty in the optimization process are compared. The methods include robust and reliability-based design optimization in addition to a combination of both approaches, and results indicate that reliability-based design optimization is best-suited to this particular problem. Based on a set of wind forecast error scenarios and historical data, a probability-weighted forecast wind generation scenario set is developed. Reliability constraints are imposed to meet a minimum of 80% of the generating schedule time intervals. This methodology is applied to a case study on Vancouver Island. Preliminary results show that when compared to the base case of a standalone wind farm on Vancouver Island, a wind farm coupled with pumped storage can prove to be economically competitive with pumped storage capital costs below $1.53 million/MW installed pumped storage capacity and a firm energy price of $130/MWh. / Graduate
275

Managing sustainable demand-side infrastructure for power system ancillary services

Parkinson, Simon Christopher 22 December 2011 (has links)
Widespread access to renewable electricity is seen as a viable method to mitigate carbon emissions, although problematic are the issues associated with the integration of the generation systems within current power system configurations. Wind power plants are the primary large-scale renewable generation technology applied globally, but display considerable short-term supply variability that is difficult to predict. Power systems are currently not designed to operate under these conditions, and results in the need to increase operating reserve in order to guarantee stability. Often, operating conventional generation as reserve is both technically and economically inefficient, which can overshadow positive benefits associated with renewable energy exploitation. The purpose of this thesis is to introduce and assess an alternative method of enhancing power system operations through the control of electric loads. In particular, this thesis focuses on managing highly-distributed sustainable demand-side infrastructure, in the form of heat pumps, electric vehicles, and electrolyzers, as dispatchable short-term energy balancing resources. The main contribution of the thesis is an optimal control strategy capable of simultaneously balancing grid- and demand-side objectives. The viability of the load control strategy is assessed through model-based simulations that explicitly track end-use functionality of responsive devices within a power systems analysis typically implemented to observe the effects of integrated wind energy systems. Results indicate that there is great potential for the proposed method to displace the need for increased reserve capacity in systems considering a high penetration of wind energy, thereby allowing conventional generation to operate more efficiently and avoid the need for possible capacity expansions. / Graduate
276

Some Aspects of Microgrid Planning and Optimal Distribution Operation in the Presence of Electric Vehicles

Hafez, Omar 20 December 2011 (has links)
Increase in energy demand is one of the major challenges that utilities are faced with, thus resulting in an increase in environmental pollution and global warming. The transport sector has a significant share of the energy demand and is a major contribution of emissions to the environment. In Canada, almost 35% of the total energy demand is from the transport sector and it is the second largest source of greenhouse gas (GHG) emissions. The government of Ontario has aimed to move toward a green energy economy, thus resulting in increased penetration of renewable energy sources as well as Plug-in hybrid electric vehicle (PHEV) technology. Penetration of renewable energy sources into microgrids are gradually being recognized as important alternatives in supply side planning. This thesis focuses on the optimal design, planning, sizing and operation of a hybrid, renewable energy based microgrid with the goal of minimizing the lifecycle cost, while taking into account environmental emissions. Four different configurations including a diesel-only, a fully renewable-based, a diesel-renewable mixed, and an external-grid connected microgrid are designed, to compare and evaluate their economics, operational performance and environmental emissions. Analysis is also carried out to determine the break-even economics for a grid-connected microgrid. The well-known energy modeling software for hybrid renewable energy systems, HOMER, is used in the studies reported in this thesis. An optimal power flow (OPF) based optimization framework considering two different objectives, minimizing feeder losses and PHEV charging cost, are presented to understand the impact of PHEV charging on distribution networks. Three different charging periods are considered and the impact of the Ontario Time-of-Use (TOU) tariff on PHEV charging schedules is examined. The impact of PHEV charging on distribution systems in the presence of renewable energy sources is discussed by extending the developed OPF based model to include the contribution of renewable energy sources. The proposed model is evaluated under a variety of scenarios.
277

Limitations on tidal-in-stream power generation in a strait

Atwater, Joel 05 1900 (has links)
In the quest to reduce the release of carbon dioxide to limit the effects of global climate change, tidal-in-stream energy is being investigated as one of many possible sustainable means of generating electricity. In this scheme, turbines are placed in a tidal flow and kinetic energy is extracted. With the goal of producing maximum power, there is an ideal amount of resistance these turbines should provide; too little resistance will not a develop a sufficient pressure differential, while too much resistance will choke the flow. Tidal flow in a strait is driven by the difference in sea-level along the channel and is impeded by friction; the interplay between the driving and resistive forces determines the flow rate and thus the extractible power. The use of kinetic energy flux, previously employed as a metric for extractible power, is found to be unreliable as it does not account for the increased resistance the turbines provide in retarding the flow. The limits on extraction from a channel are dependant on the relationship between head loss and velocity. If head loss increases with the square of the velocity, a maximum of 38% of the total fluid power may be extracted; this maximum decreases to 25\% if head loss increases linearly with velocity. Using these values, the estimated power potential of BC's Inside Passage is 477MW, 13% of previous assessments. If a flow has the ability to divert through a parallel channel around the installed turbines, there are further limits on production. The magnitude of this diversion is a function of the relative resistance of impeded and diversion channels. As power extraction increases, the flow will slow from its natural rate. This reduction in velocity precipitously decreases the power density the flow, requiring additional turbine area per unit of power. As such, the infrastructure costs per watt may rise five to eight times as additional turbines are installed. This places significant economic limitations on utility-scale tidal energy production.
278

A study of renewable energy internal combustion engine system using TRNSYS

Nellutla, Sharath. January 2005 (has links)
Thesis (M.S.)--University of Nevada, Reno, 2005. / "May, 2005." Includes bibliographical references (leaves 98-99). Online version available on the World Wide Web.
279

Small scale renewable energy storage system using hydrogen combustion

Robbins, Curt. January 2008 (has links)
Thesis (M.S.)--University of Nevada, Reno, 2008. / "August 2008." Includes bibliographical references (leaf 81). Online version available on the World Wide Web.
280

Bioconversion of cellulose into electrical energy in microbial fuel cells

Rismani-Yazdi, Hamid. January 2008 (has links)
Thesis (Ph. D.)--Ohio State University, 2008.

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