scholarly journals Study on a New Operational Mode of Economic Operation of Islanded Microgrids Using Electric Springs

2018 ◽  
Vol 160 ◽  
pp. 04004
Author(s):  
Zhiyu Zhao ◽  
Keyou Wang ◽  
Guojie Li ◽  
Xiuchen Jiang ◽  
Yin Zhang

With the increasing penetration of intermittent renewable energy sources (RESs) into microgrids, the original operation mode of power generation determined by load demand faces severe challenges due to the uncertainties of the RESs power output. The electric springs(ESs), as an emerging technology has been verified to be effective in enabling load demand to follow power generation and stabilizing fluctuation of RESs output. This paper presents a new mode of economic operation for island microgrids including non-critical loads with embedded electric springs. Its connotation includes that i) the capacity of energy storage can be reduced through the interaction of the energy storage system (ESS) and the electric springs, ii) the electric springs reduce the stress of peak load regulation and operational cost and iii) the demand of microgrids system for ramping ability of generation units is reduced with the buffer of the electric springs. Numerical results show that the coordinated operation between electric springs and energy storage system of microgrids can bring down the investment cost for the ESS and short-term operational cost in the aspect of economic dispatch, reducing requirements for the capacity and ramp ability of the energy storage system in microgrids. Energy buffering can be achieved with lower cost and the load demand can follow power generation in the new operational mode of islanded microgrids using electric springs.

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2649 ◽  
Author(s):  
Jiashen Teh

The demand response and battery energy storage system (BESS) will play a key role in the future of low carbon networks, coupled with new developments of battery technology driven mainly by the integration of renewable energy sources. However, studies that investigate the impacts of BESS and its demand response on the adequacy of a power supply are lacking. Thus, a need exists to address this important gap. Hence, this paper investigates the adequacy of a generating system that is highly integrated with wind power in meeting load demand. In adequacy studies, the impacts of demand response and battery energy storage system are considered. The demand response program is applied using the peak clipping and valley filling techniques at various percentages of the peak load. Three practical strategies of the BESS operation model are described in this paper, and all their impacts on the adequacy of the generating system are evaluated. The reliability impacts of various wind penetration levels on the generating system are also explored. Finally, different charging and discharging rates and capacities of the BESS are considered when evaluating their impacts on the adequacy of the generating system.


Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3358 ◽  
Author(s):  
Karl Stein ◽  
Moe Tun ◽  
Marc Matsuura ◽  
Richard Rocheleau

In response to increasing integration of renewable energy sources on electric grid systems, battery energy storage systems (BESSs) are being deployed world-wide to provide grid services, including fast frequency regulation. Without mitigating technologies, such as BESSs, highly variable renewables can cause operational and reliability problems on isolated grids. Prior to the deployment of a BESS, an electric utility company will typically perform modeling to estimate cost benefits and determine grid impacts. While there may be a comparison of grid operations before and after BESS installation, passive monitoring typically does not provide information needed to tune the BESS such that the desired services are maintained, while also minimizing the cycling of the BESS. This paper presents the results of testing from a live grid using a method that systematically characterizes the performance of a BESS. The method is sensitive enough to discern how changes in tuning parameters effect both grid service and the cycling of the BESS. This paper discusses the application of this methodology to a 1 MW BESS regulating the entire island of Hawaii (180 MW peak load) in-situ. Significant mitigation of renewable volatility was demonstrated while minimizing BESS cycling.


Proceedings ◽  
2020 ◽  
Vol 58 (1) ◽  
pp. 16
Author(s):  
Rafael S. Salles ◽  
A. C. Zambroni de Souza ◽  
Paulo F. Ribeiro

The advance of the distributed generation in Brazil makes it essential to investigate the applications and transformations that the use of these new arrangements may entail. The use of non-centralized generation technologies associated with energy storage is interesting for several sectors of the energy market, even if the market is in the process of maturing these technologies. In the context of the time-of-use rate, these changes have allowed the consumer to use strategies to save energy bill costs, especially when its moment of most considerable consumption coincides with that of the highest tariff. In this paper, a Battery Energy Storage System (BESS) is used to perform commercial peak load reduction in a microgrid in connected mode. The microgrid also has a Photovoltaic (PV) Generator Farm as Renewable Energy Sources (RES) to provide load consumption and also to assist BESS in the peak shaving operation. The modeling and simulation of the system are performed by MATLAB/Simulink. The analysis demonstrates that the peak load reduction produces the expected financial benefits under a Brazilian time-of-use rate known as White Rate, in addition to carrying out the operation in a manner consistent with the technique from an electrical point of view. The software Homer Grid validates the potential savings. Thus, the results showed that the use of energy storage associated with renewable generation under a peak shaving strategy allows greater freedom for the consumer in the face of costs with main grid purchases.


2017 ◽  
Vol 68 (11) ◽  
pp. 2641-2645
Author(s):  
Alexandru Ciocan ◽  
Ovidiu Mihai Balan ◽  
Mihaela Ramona Buga ◽  
Tudor Prisecaru ◽  
Mohand Tazerout

The current paper presents an energy storage system that stores the excessive energy, provided by a hybrid system of renewable energy sources, in the form of compressed air and thermal heat. Using energy storage systems together with renewable energy sources represents a major challenge that could ensure the transition to a viable economic future and a decarbonized economy. Thermodynamic calculations are conducted to investigate the performance of such systems by using Matlab simulation tools. The results indicate the values of primary and global efficiencies for various operating scenarios for the energy storage systems which use compressed air as medium storage, and shows that these could be very effective systems, proving the possibility to supply to the final user three types of energy: electricity, heat and cold function of his needs.


Electronics ◽  
2021 ◽  
Vol 10 (13) ◽  
pp. 1598
Author(s):  
Dongmin Kim ◽  
Kipo Yoon ◽  
Soo Hyoung Lee ◽  
Jung-Wook Park

The energy storage system (ESS) is developing into a very important element for the stable operation of power systems. An ESS is characterized by rapid control, free charging, and discharging. Because of these characteristics, it can efficiently respond to sudden events that affect the power system and can help to resolve congested lines caused by the excessive output of distributed generators (DGs) using renewable energy sources (RESs). In order to efficiently and economically install new ESSs in the power system, the following two factors must be considered: the optimal installation placements and the optimal sizes of ESSs. Many studies have explored the optimal installation placement and the sizing of ESSs by using analytical approaches, mathematical optimization techniques, and artificial intelligence. This paper presents an algorithm to determine the optimal installation placement and sizing of ESSs for a virtual multi-slack (VMS) operation based on a power sensitivity analysis in a stand-alone microgrid. Through the proposed algorithm, the optimal installation placement can be determined by a simple calculation based on a power sensitivity matrix, and the optimal sizing of the ESS for the determined placement can be obtained at the same time. The algorithm is verified through several case studies in a stand-alone microgrid based on practical power system data. The results of the proposed algorithm show that installing ESSs in the optimal placement could improve the voltage stability of the microgrid. The sizing of the newly installed ESS was also properly determined.


2019 ◽  
Vol 137 ◽  
pp. 01007 ◽  
Author(s):  
Sebastian Lepszy

Due to the random nature of the production, the use of renewable energy sources requires the use of technologies that allow adjustment of electricity production to demand. One of the ways that enable this task is the use of energy storage systems. The article focuses on the analysis of the cost-effectiveness of energy storage from the grid. In particular, the technology was evaluated using underground hydrogen storage generated in electrolysers. Economic analyzes use historical data from the Polish energy market. The obtained results illustrate, among other things, the proportions between the main technology modules selected optimally in technical and economic terms.


2021 ◽  
Vol 69 (2) ◽  
pp. 5-12
Author(s):  
Zheng Li ◽  
Yan Qin ◽  
Xin Cao ◽  
Shaodong Hou ◽  
Hexu Sun

In order to meet the load demand of power system, BP based on genetic algorithm is applied to the typical daily load forecasting in summer. The demand change of summer load is analysed. Simulation results show the accuracy of the algorithm. In terms of power supply, the reserves of fossil energy are drying up. According to the prediction of authoritative organizations, the world's coal can be mined for 216 years. As a renewable energy, wind power has no carbon emissions compared with traditional fossil energy. At present, it is generally believed that wind energy and solar energy are green power in the full sense, and they are inexhaustible clean power. The model of wind power solar hydrogen hybrid energy system is established. The control strategy of battery power compensation for delayed power of hydrogen production is adopted, and different operation modes are divided. The simulation results show that the system considering the control strategy can well meet the load demand. Battery energy storage system is difficult to respond to short-term peak power fluctuations. Super capacitor is used to suppress it. This paper studies the battery supercapacitor complementary energy storage system and its control strategy. When the line impedance of each generation unit in power grid is not equal, its output reactive power will be affected by the line impedance and distributed unevenly. A droop coefficient selection method of reactive power sharing is proposed. Energy storage device is needed to balance power and maintain DC voltage stability in the DC side of microgrid. Therefore, a new droop control strategy is proposed. By detecting the DC voltage, dynamically translating the droop characteristic curve, adjusting the output power, maintaining the DC voltage in a reasonable range, reducing the capacity of the DC side energy storage device. Photovoltaic grid connected inverter chooses the new droop control strategy.


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