Reliability evaluation of an aggregate battery energy storage system in microgrids under dynamic operation

A microgrid (MG) is a discrete energy system consisting of an interconnection of distributed energy sources and loads capable of operating in parallel with or independently from the main power grid. The microgrid concept integrated with renewable energy generation and energy storage systems has gained significant interest recently, triggered by increasing demand for clean, efficient, secure, reliable and sustainable heat and electricity. However, the concept of efficient integration of energy storage systems faces many challenges (e.g., charging, discharging, safety, size, cost, reliability and overall management). Additionally, proper implementation and justification of these technologies in MGs cannot be done without energy management systems, which control various aspects of power management and operation of energy storage systems in microgrids. This review discusses different energy storage technologies that can have high penetration and integration in microgrids. Moreover, their working operations and characteristics are discussed. An overview of the controls of energy management systems for microgrids with distributed energy storage systems is also included in the scope of this review.

The micro-grid deployments are growing with independently, power system designers, manufacturers and researchers for the applications where the loads are more efficient association with extra output sources such as Battery Energy Storage System (BESS), and Photovoltaic (PV) systems. Using renewable source as main sources for micro-grid system also can avoid from the pollution to occur. Energy storage when combined with PV system can provide a stronger economic performance, as well as an added benefit of backup power for critical loads. This project proposed control strategies for integration of BESS and PV in a micro-grid. The operation enables the maximum PV and BESS utilization during different operating condition of the micro-grid, grid connected, islanded mode or a process between these two operations. The project will focus on analyzing the performance between photovoltaic system and battery in the simulations of micro-grids system and validate the simulation result using MATLAB/SIMULINK software. After the simulation was analyzed, the understanding of benefit in using renewable energy source as main power supply with support from battery energy storage to supply the power to the loads and power managements is realized in the different modes on micro-grid which is grid connected or islanded states. When the power generation from PV system was not enough to accommodate electric loads, the BESS or from secondary side of transformer will supply the insufficient power.

This paper presents ancillary voltage control for a distribution feeder by using energy storage system (ESS) in microgrid. The microgrid consists of photovoltaic, wind power, and distribution generator. The active and reactive power control, voltage and frequency droop control for the power converter of ESS are proposed to reduce microgrid impact on the distribution feeder. The voltage variation along the feeder due to change of renewable power generation is derived by executing power flow analysis. The actual voltage fluctuation on the microgrid is measured, which is used to control active and reactive power output of the power converter via energy management system in the microgrid SCADA platform. Three operation scenarios of the microgrid with ESS are tested to verify the effectiveness of the proposed control method. It is found that the power output of ESS can be well regulated to reduce voltage fluctuation on the microgid, which is complied with grid connect code to achieve better voltage control performance for the distribution feeder.

The microgrid represents a controllable electric entity that contains different loads into distributed energy resources. All typical microgrids use two or more sources by which electricity is generated, at least one of which is a renewable source. In this respect the main issues of the energy storage systems (ESS) are the enhancing of the stability of microgrid and power balance. Also the insertion of the energy storage systems is beneficial for both operation modes of microgrids, grid connected and islanded. This chapter begins with an overview of the current state of microgrids and ESS. The island operation mode of microgrids is based on the energy storage system. At the first level the control tasks during this mode of operation are to regulate the voltage and to maintain the frequency at the constant value. The power in each unit is shared among the storage units by secondary control of the energy storage system taking into account the energy level of each of them. Further, the authors present storage technologies of the electrical energy, i.e. converting it into mechanical, chemical, electrochemical, electromagnetic and thermal energy. The widespread mechanical energy storage technology is the pumped hydro (99% of the world total storage capacity) followed by the compressed air energy and flywheel. Afterwards, the fuel cell, biomass and fossil fuel compose the chemical storage domain. Batteries constitute the electrochemical storage technology. Electromagnetic and thermal energy storage technologies are represented by the super capacitors respectively the heat pumps. Both the features of the energy Storage technologies and the main properties will be presented. A comparison of the discharge time of the storage technologies by application is taken into account. The advantages and disadvantages of the storage technologies will be highlighted. The lack of the appropriate standards of interconnecting different kinds of energy sources and ESS to the microgrid is a disadvantage in technology developing. Thereby the IEC/ISO 62264 standards refers to wind turbine technology, while the IEEE 2000 standard refers to photovoltaic interconnection power systems. In order to reduce air pollution and mitigate climate change, in recent years the need to use renewable energy sources in microgrids has become important. In fact, technological development, public and political policies, availability of different renewable energy resources to be used in microgrids, are elements that create real perspectives in widespread development of renewable energies and their required ESS. The environmental impact and the costs of renewable energy resources have been estimated through the life cycle assessment (LCA) methodology, which determines whether the use of renewable sources and ESS is sustainable. A case study regarding a PV system with and without batteries used into a microgrid that supply a wastewater treatment plant situated in Romania will be presented. Life cycle assessment was used to quantify ecological sustainability and costs in both cases compared to a conventional supply of electricity from the grid. Conclusions and measures are drawn in order to increase the utilization of renewable sources and ESS in microgrids. Also the technically, economic and environmental benefits of inserting microgrids are discussed. The bibliographic references will be presented at the end of the chapter.

A Solid-State Transformer as Enabling Technology for Microgrids for Integration into the Power Distribution System: An Overview

Renewable electrical energy (such as: solar and wind energies) generation in microgrids (MGs), is gaining attention to reduce greenhouse gas emissions. Microgrid operators (MOs) aim to create self-sufficient, environmentally sustainable grids, increasing the capacity of renewable energy sources (RESs) by up to 100%. Despite of the benefits of this trend, challenges arise from non-controlled characteristics of these power generations and their seasonal variations, causing fluctuations and renewable energy curtailment. Although the technical solutions; such as: the demand response (DR) programs, and the conventional electrical energy storage systems (EESSs) can help, however those may face limitations in countries with high seasonal energy generation and consumption variations. This paper introduces cryptocurrency mining loads (CMLs) as innovative virtual energy storage systems (VESSs), named cryptocurrency energy storage systems (CESSs). It proposes a structure to store excess renewable energy in cryptocurrency units (CCUs) like Bitcoin (BTC). CESSs can be charged during off-peak intervals and, conversely, they discharge during high-demand periods to reduce the overall operational cost of MGs. Furthermore, it presents a new energy management system (EMS) formulation for the optimal operation of MGs in the presence of CESSs, providing an opportunity to generate additional electricity from RESs and to mitigate renewable energy curtailment. This paper explores the optimal operation conditions of both islanded and grid-connected MG with the proposed CESS. Utilizing a dataset from an island in Finland as a practical MG, its effectiveness is demonstrated through several case studies. The results of one case study in this paper demonstrate that the proposed CESS can decrease the operating cost of the MG by about 46.5%. Additionally, it is showed that by application of CESS the renewable energy curtailment is significantly reduced, and approached zero.

Impact of energy storage system and distributed energy resources on bidding strategy of micro-grid in deregulated environment

The role of energy storage systems in resilience enhancement of health care centers with critical loads

Microgrids (MGs) are a critical component in modern power systems, comprising interconnected loads and distributed energy resources (DERs) that can operate autonomously or in conjunction with the main grid. This review examines the role of MGs in advancing smart grid technologies, emphasizing the optimal integration of renewable energy sources (RES) and energy storage systems (ESS) to enhance their resilience and efficiency. It provides a detailed analysis of various MG architectures, including AC, DC, and hybrid topologies, alongside their operational modes. The paper highlights the pivotal role of control systems in optimizing energy management within MGs. Additionally, the challenges associated with MG integration, such as harmonic distortion, system stability, and regulatory constraints, are discussed. The review further explores the application of intelligent control strategies, including Fuzzy Logic Controllers (FLCs) and Genetic Algorithms (GAs), to optimize battery energy storage systems (BESS) and improve overall MG performance. The findings emphasize the need for innovative optimization techniques and intelligent control systems to overcome current limitations, thus enhancing the potential of MGs in future energy systems

Plummeting costs of Renewable Energy Sources (RES), Energy Storage Systems (ESS) and technological advancements in ICT has resulted in the mushroom growth of Microgrids (MG) around the world. Due to the high composition of variable, inflexible and uncertain RESs in MGs, at times of low RES output, MGs have to either unwillingly reduce consumption, turn on polluting conventional generators or purchase expensive electricity from the main grid. Conversely, at times of high RES output, there are instances where RESs have to be forcefully curtailed to maintain the stability of the network. In this paper, we introduce a novel Transactive Energy (TE) trading approach to reduce the effect of the inconvenient characteristics of RES generation in MGs. This is achieved by optimized sharing of resources across MGs through an aggregator agent, thus, further reducing the dependency on the main grid. Since resources are shared across MGs, blockchain as a technology tool is considered to accurately record transactions and remunerate participating assets.

This paper investigates the impact of Plug-in Electric Vehicles (PEVs) on the voltage improvement and loss reduction in MicroGrids (MG). The proposed model in this paper aims to minimize the total expected voltage deviation of the MG, while being subject to economic policies. The studied MG consists of PEVs, Renewable Energy Sources (RES), Energy Storage Systems (ESSs), and Distributed Generations (DGs), and the MG is able to participate in day-ahead energy markets. The uncertainties in arrival and departure time of PEVs, RES outputs, and day-ahead market prices are stochastically taken into account and the PEVs are modelled to be capable of charging or discharging active power and/or absorbing or injecting reactive power. A four-quadrant operation mode of a PEV is developed in this paper and incorporated in a mix-integer non-linear programming (MINLP) optimization formulation. The advantages of exploiting PEVs in an MG for enhancing voltage profile and loss reductions are then scrutinized. In order to demonstrate the effectiveness of the proposed model, various case studies are conducted on a modified 18-bust IEEE test system.

This paper presents a robust frequency control in an islanded ac microgrid (MG). The microgrid considered in this paper consists of distributed energy sources (DES). These include micro-turbine (MT), diesel engine generator (DEG), fuel cell (FC), renewable energy sources like wind turbine (WT), photovoltaic panels (PV), and energy storage systems like battery energy storage system (BESS) and flywheel energy storage system (FESS). The load fluctuation, wind power fluctuation and solar irradiation fluctuation often influence the frequency of the MG. So to tackle this problem, a proportional-integral-derivative controller (PID) is designed and optimized by using the stochastic fractal search (SFS) algorithm. The proposed controller is very effective and able to eliminate the frequency deviation in a short time. The time-domain simulation results obtained by SFS based PID controller are compared with the results obtained by SFS based PI controller to show the effectiveness of the proposed controller. From the comparison, it can be observed that proposed controller gives better frequency stability and hence improves the frequency of the MG significantly.

This paper proposes the particle swarm optimization (PSO) technique-based proportional integral derivative (PID) controller suggested for frequency regulation of a micro grid (MG) system. MG system integrates with thermal power generating units, renewable energy sources (RES) like photovoltaic (PV), wind energy generators (WTG), and Energy storage systems (ESS) such as fuel cell (FC) and battery energy storage system (BESS). Indentifying the supremacy of proposed technique-based controller and supremacy is examined with three objective functions (integral absolute error [IAE], integral time absolute error [ITAE], and integral squared error [ISE]). The results of the system are compared with conventional PID controller results. From the comparison, it is clearly evident that PSO-PID controller gives better performance over conventional methods in terms of various time domain specific parameters such as settling time, peak overshoot, and undershoot. In both methods, ITAE objective function used controller produce more effective response in MG under sudden load demand situation.

Microgrids (MGs) provide solutions to various problems in power systems by integrating non-renewable and renewable energy sources like combined heat and power (CHP) plants and distributed energy resources (DER). This paper has developed an optimization framework for economic dispatch of microgrids, including heat storage tanks and to increase the flexibility of CHP plants and boiler units. In addition, conventional power generators, intermittent energy resources such as photovoltaic (PV) units, wind turbines and battery energy storage system (BESS) are modelled in a modified IEEE 33 bus test system MG operating in islanded mode. Local generation and DER penetration can help system operators to satisfy energy demands with no need to purchase power from the grid. The main goal of the proposed paper is to optimally and economically dispatch heat and electricity considering impacts of heat buffer tank and battery energy storage, taking into account the technical constraints like AC/DC power flow limitations and the effects of dual dependency of produced heat and power by CHP units. The MG is studied within a time horizon of 24 hours and obtained results are analyzed for comparison.

The main benefit of operating a distribution grid as a microgrid (MG) is the additional security of supply due to its local electricity generation and islanding possibility. In this work, we investigate the technical ability and the economic viability of a MG with renewable generation to provide also frequency control (FC) to upper voltage levels as an additional source of revenue in grid-connected mode. To compensate for the variable generation of renewable energy sources and facilitate opportunities to bid in FC markets, we include a battery energy storage system (BESS). In order to determine the potential of the MG in the different FC markets, the problem is formulated as a multi-period optimal power flow with a rolling horizon of 24 hours. In order to evaluate the business case for such a system, we carry out an ex-post analysis in which we include the investment cost of a BESS and determine the life cycle benefits using the revenue streams calculated by the proposed optimization scheme. I.