Sharif Digital Repository

The power systems’ net-load variability and uncertainty would aggravate significantly as the penetration of Renewable Energy Resources (RERs) in power systems increases. In response, power system researchers have introduced a new concept, namely flexibility, to quantitatively and systematically deal with unavoidable features of RERs. In power distribution systems as the connection point of power systems with customers, there are many opportunities for improving the flexibility level of systems. Nowadays, the emergence of prosumers has created new opportunities for distribution system operators in providing the system with different services of flexibility in distribution systems. Therefore,... 

The most important challenge in microgrids is the coordination of distributed energy resources (DERs), due to the existence of several DERs with fugacious characteristics. Also, energy management in the microgrid is very important because there may be conflicting needs or poor communication between different elements of the microgrid. In this work, a robust frame associated with a quantum version of the Teaching-Learning-Based Optimization (quantum TLBO) algorithm is proposed for the first time to the microgrid optimal energy management problem. Uncertainties in the load and in the output power of renewable energy sources are modeled using robust optimization (RO). The operation cost of the... 

Darrieus turbines are one of the most widely used turbines in extracting energy from tidal currents. This study aimed to investigate the effect of utilizing helical blades and variable solidity ratio on the efficiency of Darrieus tidal turbines. For this purpose, three types of helical turbines with different solidity ratios have been designed, and computer simulation has been used to investigate the effect of the mentioned parameters on the efficiency of the Darrieus turbines. According to the simulation results, the helical turbine has less efficiency than the straight blade Darrieus turbine. The maximum hydrodynamic efficiency of the Darrieus turbine with straighted blades is 38.5,... 

Providing fresh water for domestic and agricultural purposes has become one of the most pressing issues of the present century. Due to the dependency of conventional desalination on fossil fuels, these methods are associated with carbon dioxide and other greenhouse gas emissions. Therefore, renewable energy-based desalination systems have come to the fore. This study scrutinizes the performance of the solar Humidification-Dehumidification (HDH) desalination systems with subsurface condensers. In this system, solar energy evaporates water, and subsurface condensers condense water vapor into fresh water. Therefore, this system uses two renewable solar and geothermal energy. Due to the lack of... 

The power control of horizontal axis wind turbines can affect significantly the vibration loads and fatigue life of the tower and the blades. In this thesis, we are going to consider both the power control and vibration load mitigation of the tower fore-aft vibration. For this purpose, at first, we developed a fully coupled model of the NREL 5MW turbine. This model considers the full aeroelastic behavior of the blades and tower and is validated by experiment results, comparing the time history data with the FAST (Fatigue, Aerodynamics, Structures, and Turbulence ) code which is developed by NREL (National Renewable Energy Lab in the United States). In the next, to estimate EWV, a novel... 

In this thesis, the resilience of energy supply networks and the application of Agent Based Modeling in the resilience analysis of power microgrids are studied. The main idea is to use microgrids as a solution to make power systems resilient. A microgrid with autonomous agents consisting of renewable resources, non-dispatchable generators, dispatchable generators, residential loads, critical loads, battery storages, and microgrid controller is investigated. Each agent is autonomous and has independent behavior such that the interaction between these agents produces emergent phenomena at the system level in the microgrid. In the developed model, residential consumers try to optimize their... 

Sustainable energy supply and preservation of the environment have become the main motivations to integrate more renewable energy sources in electrical networks. However, with an increasing penetration of renewable energy sources in the modern electrical grids, new challenging issues arise regarding the power system planning, operation, control and protection. An important technical issue is the difficulty in achieving the frequency stability of these systems, as the renewables are often operated at the maximum power point, resulting in less generation units that provide reserve power. Moreover, the rotational inertia of the system is reduced due to the decoupling of the renewable energy... 

Many pieces of evidence of climate change show that humanity should be concerned about the future of its life and the planet. The concentration of carbon dioxide in the atmosphere has reached its highest level. Therefore, in recent years, the reduction of publications and climate issues has been on the agenda of governments. For this reason, governments and various international organizations are looking for a way to change and reform the global energy system. Forecasts indicate a decrease in the share of fossil fuels and an increase in the percentage of renewable energies and hydrogen. Hydrogen has been introduced as the future fuel carrier due to its many advantages such as the... 

Nowadays, electrical energy is one of the crucial requirements in human beings’ lives. Since the majority of the world’s energy is met by fossil fuel, the problems such as global warming, the reduction of fossil fuel resources, and unpredictable oscillation of the prices of such fuels have led to a serious crisis for the people of the world. Furthermore, due to the increasing energy demand, the economic development of most countries has a strong correlation with fossil fuel prices. The abovementioned problems have made a lot of countries take alternative policies in terms of generating energy, one of which is using renewable energy resources. This approach is reported to be clean and... 

Hydrogen storage in porous subsurface formations, such as aquifers or depleted hydrocarbon reservoirs because of their high storage capacity, has gained momentum as a promising approach to balance the renewable energy supply and demand. However, the poor understanding of hydrogen flow dynamics in porous media is the main obstacle to the development and widespread application of underground hydrogen storage (UHS). For example, the main uncertainty is lack of detailed understanding of hydrogen flow dynamics in the natural porous media which leads to the unknown volume of recoverable hydrogen for this cyclic process. In this research, by developing a visual microfluidic apparatus to handle... 

Energy and environment crisis in past decades raised concerns about fossil fuels use and has accelerated renewable energy application in terms of solar electric, solar thermal and wind turbines. Due to the fluctuating nature in renewable resources, renewable electric power generation has a stochastic nature that makes it difficult to use by the electricity consumers. Energy storage plays a key role to put more control on renewable power generation.Lead-acid battery is a storage technology that is widely used in photovoltaic systems. Battery investment and maintenance costs account for a big part of photovoltaic system costs. Charging and discharging profiles of the battery has a great impact... 

The penetration of variable energy resources together with the utilization of price sensitive loads have intensified supply and demand uncertainties in power systems. Accordingly, system operators and market participants are now seeking for new ways of managing risks within the power system. In this thesis, the risk management is studied from the viewpoints of market participants, transactive market operators and wholesale market operators. In this regard, the optimal bidding strategy of a market participant who participate in wholesale or transactive electricity markets is studied in chapter 3. To reach this goal, behaviors of both risk-neutral and risk-averse agents are modeled taking into... 

The limitation of fossil fuel sources and environmental damage caused by use of these fuels have made researches on applications of renewable energy, especially solar energy, to be an important issue in recent years. An important issue that arises in the use of photovoltaic panels is the reduction of their efficiency with increasing their temperature. By increase of a degree of Celsius, the efficiency of the photovoltaic panel decreases by 0.45%. The aim of this project is to reduce the temperature of the photovoltaic panel by using porous medium and air. The porous medium used as fins under the panel.Experimental results have shown that by using the medium placed under the photovoltaic... 

Nowadays, energy has become a vital issue. Earth to Air Heat Exchanger (EAHE) is a technique that promotes energy saving. EAHE is a non-conventional technique that utilizes the thermal potential of the geothermal energy for space cooling/heating. In the agricultural sector, using the grounds energy for air conditioning of greenhouses can be highly effective. In this study, a transient implicit computational fluid dynamics model is developed to simulate the thermal performance of EAHEs. The developed model is validated against available experimental studies in the literature. Good agreement between simulated results and experimental data is obtained. In the following, the heat exchanger is... 

Solar panels are still rather expensive equipments. At current electricity prices, it takes several years to return the investment made to install them in a household. Smarter use of their produced energy can help reduce this break-even time, and hence, would motivate more households to be willing to install and use them which would finally result in a more sustainable society with less reliance on fossil fuels. Electricity prices usually differ at different times of day with the common, but unfortunate, property that the price is maximized at evenings when the solar energy production is minimal or non-existent while at the peak production of the solar panels, i.e., around noon, the price is... 

One of the main methods to reduce fuel consumption and emissions is using renewable energy resources. This research proposes a hybrid renewable energy system on a container ship which includes one photovoltaic solar system, and one kite system. The photovoltaic system produces a part of the ship's electric power consumption and the kite system produces propulsion force using wind energy and transmitting this force to the ship through towing rope. Different components of these renewable energy systems are connected with the internet of things technology. In the internet of things structure design section, in addition to the conceptual design of different layers with emphasis on the processing... 

Power distribution systems are experiencing restructuring owning to the increasing trend of integrating renewable energy sources as well as privatization in the network. In this regard, the dependence of power generation by renewable energy sources on meteorological characteristics would challenge the conventional procedures of operating the system. Respectively, while the expansion of renewable energy sources would facilitate supplying the demand loads locally; the issues associated with the uncertainty and variability of power generation by these units should be addressed in future operational schemes of distribution systems. This condition has resulted in the development of the...