Sharif Digital Repository

Increased electricity demand coupled with investment in renewable-based generating units has resulted in problems such as transmission congestion and load shedding in modern power systems. In this situation, transmission expansion planning (TEP) studies plays a key role in dealing with the aforementioned problems. On the other hand, deployment of energy storage systems (ESSs) has been regarded as a viable solution for effective exploitation of renewable resources. In this context, this paper develops a novel framework to investigate the impacts of storage facilitates on the transmission expansion planning problem. The presented framework is decomposed to investment and operation subproblems... 

One of the main components of any solar power plant is its thermal heat storage system. Heat storage reduces the cost of power generation by increasing the capacity factor of the system. This paper aims to model and optimize the operation of a consecutive multi-layer Phase Change Material (PCM) thermal heat storage system, named Cascade Latent Heat Storage (CLHS), using the method of characteristics and genetic algorithm. The model is validated through comparison with experimental data available in the literature. The model can predict fluid and PCM temperature, PCM phase and the energy absorbed by PCM. A sensitivity analysis is employed for both the PCM and the fluid parameters. The PCM... 

The power output of gas turbines reduces greatly with the increase of inlet air temperature. Aquifer thermal energy storage (ATES) is employed for cooling of the inlet air of a gas turbine. Water from a confined aquifer is cooled in winter, and is injected back into the aquifer. The stored chilled water is withdrawn in summer to cool the gas turbine inlet air. The heated water is then injected back into the aquifer. A 20 MW Hitachi gas turbine, along with a two-well aquifer were considered for analysis. It was shown that the minimum power output of the gas turbine on the warmest day of the year could be raised from 16.30 to 20.05 MW, and the mean annual power output could be increased from... 

In future smart grids, energy storage systems (EESs) are expected to play an indispensable role in balancing continuous load changes arising from customers' life-style as well as varying output of intermittent energy resources. This, however, needs significant investment that should be justified prior to their implementation. This paper presents a model to find the optimal capacity for ESSs in distribution systems. The model aims at maximizing system owner profit by reducing total electricity procurement costs. The model is formulated as a mixed integer non-linear programming problem. Due to the complexity and large size of the problem, a decouplebased method is proposed wherein optimal... 

In this work, a method for increasing the storage capability of a solar thermal energy system has been discussed. The system includes two tanks with the flexibility in choosing the best storage medium on the basis of the solar collector's outlet temperature. The results show that using such a hybrid storage system, the storable energy can be increased. Comparing the results with those for simple common storage systems, the extent of improvement was calculated. For verification of the results, a small pilot system was assembled. The test apparatus operated during 2008-2009 cold months and the parameters were recorded. Comparison of the theoretical and experimental results showed a good... 

Recently, a class of fractional multi-frequency oscillators, constructed based on using n integrators and n half-order ones, has been introduced, whose steady-state responses contain sinusoidal components with 0.5 (3 n- 1 ) number of selectable frequencies. In this paper, the structure of the introduced multi-frequency oscillator is modified such that, notwithstanding the frequency content preservation, the number of its involved integrators is reduced. With no effect on the frequency content of the generated oscillations, this modification causes that the circuitry implementation of the considered class of multi-frequency oscillators can be done with a less number of energy storage... 

Liquid air energy storage is one of the most recent technologies introduced for grid-scale energy storage. As the title implies, this technology offers energy storage through an air liquefaction process. High energy storage density, no geographical limitation, and applicability for large-scale uses are some of the advantages of this technology. To improve the performance and environmental friendliness of the conventional design of this technology, a novel liquid air energy system combined with high-temperature thermal energy storage, thermoelectric generator, and organic Rankine cycle is proposed in the present article. The thermal energy storage unit removes the need for the conventional... 

Today, energy and fresh water play a vital role in human life and the development of economics and also in industry. The energy density in water desalination process is remarkable, so using the renewable energy sources for this purpose can be interesting especially in the high potential renewable energy sources (solar energy) like Middle East. The simulation and feasibility study of solar water desalination system coupled with lithium battery energy storage is considered in the case study of Iran. For these purposes, a complete simulation of the considered system is done. Then, using simulation results, the economic study is carried out using tem economic method. Also, the parametric study... 

Recently, power system operators have initiated procurement of a new service in electricity markets named flexibleramping product (FRP). With the main goal of enhancing the grid flexibility, this product can provide a remarkable opportunity foran enhanced short-term profitability. Energy storage systems (ESSs) with high ramping capability can leverage their profitabilitywhen properly participating in this market. This study introduces a stochastic optimisation framework for participation of ESSs inthe FRP market. The proposed model formulates the optimal bidding strategy of ESSs considering the real-time energy, flexibleramp-up and ramp-down marginal price signals and the associated... 

The power output of gas turbines (GT) reduces greatly with the increase of the inlet air temperature. This is a serious problem because gas turbines have been used traditionally to provide electricity during the peak power demands, and the peak power demands in many areas occur on summer afternoons. An aquifer thermal energy storage (ATES) was employed for cooling of the inlet air of the GT. Water from a confined aquifer was cooled in winter and was injected back into the aquifer. The stored chilled water was withdrawn in summer to cool the GT inlet air. The heated water was then injected back into the aquifer. A 20 MW GT power plant with 6 and 12 h of operation per day, along with a... 

In future smart grids, energy storage systems (EESs) and demand response (DR) are expected to have an important role in balancing load changes arising from life-style of consumers and varying output of some renewable energy resources. However, activating DR and installing ESSs need huge investment forcing system owner to justify their effectiveness prior to any implementation. This paper presents a model to find the optimal capacity of EESs in distribution systems with demand responding to electricity price changes. The model aims at maximizing system owner profit by lessening total electricity provision costs. The model is formulated as a mixed integer non-linear programming problem. Due to... 

Energy storage is one of the most important components of renewable energy systems. Among different methods, thermal energy storage (TES) in forms of sensible or latent has been the subject of many studies in the past decades. The main difficulty in optimal design of storage tanks is associated with low thermal conductivity of the storing (solid or phase change) material. In fact, the distribution of thermal energy from a source to the body of storing material poses a volume to point problem which is the subject of constructal theory. Therefore, the objective of the present paper is to investigate the transient behavior of a rectangular thermal energy storage tank equipped with fin... 

This paper provides a new multi-objective (MO) framework for expansion studies of energy storage systems (ESSs) in high wind penetrated power system. The proposed approach well considers the issues originated from the wind power curtailment via introducing expected of wind curtailment cost as an objective function of the studies. All other imposed costs of installing storage units are modeled as expected of total social cost. Also, the effect of uncertainties is modeled through an internal scenario analysis. In this regard, two criteria including maximum regrets of wind curtailment cost and total social cost are considered as the other objectives of the proposed MO optimization procedure.... 

This paper provides a new multi-objective (MO) framework for expansion studies of energy storage systems (ESSs) in high wind penetrated power system. The proposed approach well considers the issues originated from the wind power curtailment via introducing expected of wind curtailment cost as an objective function of the studies. All other imposed costs of installing storage units are modeled as expected of total social cost. Also, the effect of uncertainties is modeled through an internal scenario analysis. In this regard, two criteria including maximum regrets of wind curtailment cost and total social cost are considered as the other objectives of the proposed MO optimization procedure.... 

Inkjet-printing (IJP) technology is recognized as a significant breakthrough in manufacturing high-performance electrochemical energy storage systems. In comparison to conventional fabrication protocols, this printing technique offers various advantages, such as contact-less high-resolution patterning capability; low-cost, controlled material deposition; process simplicity; and compatibility with a variety of substrates. Due to these outstanding merits, significant research efforts have been devoted to utilizing IJP technology in developing electrochemical energy storage devices, particularly in supercapacitors (SCs). These attempts have focused on fabricating the key components of SCs,... 

Utilizing the differential scanning calorimetry (DSC) and Vickers hardness tests, the relationship between the stored energy and indentation hardness of copper after compression test is achieved experimentally. Three dislocation models are utilized to develop the relationships between the stored energy and hardness for justifying the experimental relationship. The relationships show that the stored energy is increased by increasing the hardness, non-linearly. By comparing the models' results with the experimental data, the validity of each model at different ranges of hardness is determined. © 2008 Springer Science+Business Media, LLC  

In recent years, increased integration of renewable energy sources (RES) calls for extensive and costly investments in transmission networks. In response, power system decision-makers try to apply alternative solutions aimed to decrease the imposed investment costs. In this context, the presence of large-scale energy storage systems (ESSs) in transmission network can be a practical option for deferring investment in expansion plans of transmission lines, alleviating system congestions, and attaining higher flexibility. In this paper, an efficient model is proposed for co-planning expansion studies of compressed air energy storage (CAES) units and transmission networks. The associated... 

In this article, a new general approach has been presented for exact and efficient extraction of eigenpolarizations in anisotropic electromagnetic media with arbitrary constitutive relations. It is shown that the plane wave propagation eigenpolarizations in a linear homogeneous time-independent anisotropic media without free sources, can be obtained through extremizing the difference between stored electric and magnetic energies as a variational functional. It is demonstrated that at these stationary points the wave equation is satisfied by showing that each of the Maxwell curl equations may be obtained by using the other equation as a constraint. Furthermore, it is proven that the theorem...