Records with Subject: Energy Management
Showing records 1 to 25 of 80. [First] Page: 1 2 3 4 Last
A Three-Stage Optimal Approach for Power System Economic Dispatch Considering Microgrids
Wei-Tzer Huang, Kai-Chao Yao, Chun-Ching Wu, Yung-Ruei Chang, Yih-Der Lee, Yuan-Hsiang Ho
February 5, 2019 (v1)
Keywords: distributed energy resources, economic dispatch, improved direct search method, linear programming, microgrid, multi-area
The inclusion of microgrids (MGs) in power systems, especially distribution-substation-level MGs, significantly affects power systems because of the large volumes of import and export power flows. Consequently, power dispatch has become complicated, and finding an optimal solution is difficult. In this study, a three-stage optimal power dispatch model is proposed to solve such dispatch problems. In the proposed model, the entire power system is divided into two parts, namely, the main power grid and MGs. The optimal power dispatch problem is resolved on the basis of multi-area concepts. In stage I, the main power system economic dispatch (ED) problem is solved by sensitive factors. In stage II, the optimal power dispatches of the local MGs are addressed via an improved direct search method. In stage III, the incremental linear models for the entire power system can be established on the basis of the solutions of the previous two stages and can be subjected to linear programming to dete... [more]
Suitability Assessment of an ICE-Based Micro-CCHP Unit in Different Spanish Climatic Zones: Application of an Experimental Model in Transient Simulation
Guillermo Rey, Carlos Ulloa, José Luís Míguez, Antón Cacabelos
February 5, 2019 (v1)
Keywords: Código Técnico de la Edificación (CTE), heating and power, internal combustion engine (ICE), micro-combined cooling, TRNSYS
Tri-generation plants will have an important role in the near future in the residential sector where heating and cooling demands come into play throughout the year. Depending on the building’s location, the characteristics of its enclosure and its use, the thermal loads and demands will be different. This article analyses and compares a combined cooling, heating and power (CCHP) system tested in the laboratory and a single household located in Spain. The cooling capacity is obtained using a reversible heat pump where the compressor is driven directly by a gas engine with internal combustion engine (ICE) technology. The tests were carried out in a work bench at three different operating speeds. A variable-speed model is developed in the TRNSYS simulation environment with an operating strategy following the thermal load (FTL). Once the micro-CCHP system was modeled with experimental data and validated, it was dynamically simulated to analyze its performance in different climatic zones de... [more]
Long Term Expected Revenue of Wind Farms Considering the Bidding Admission Uncertainty
Mazaher Haji Bashi, Gholamreza Yousefi, Claus Leth Bak, Jayakrishnan Radhakrishna Pillai
February 5, 2019 (v1)
Keywords: bidding Admission uncertainty, Genetic Algorithm, long term bidding behavior, market price uncertainty, PAB and UP auctions, wind farm expected revenue
As a long term bidding behavior, bid shading is exhibited by wind farms participating in real Uniform Price (UP) markets. This signifies that the wind farm owners bid far below their true long run marginal cost. In this paper, a method is proposed to consider the uncertainty of bidding admission in the long term expected revenue of wind farms. We show that this consideration could perfectly explain the observed bid shading behavior of wind farm owners. We use a novel market price model with a stochastic model of a wind farm to derive indices describing the uncertainty of bidding admission. The optimal behavior of the wind farm is then obtained by establishing a multi objective optimization problem and subsequently solved using genetic algorithm. The method is applied to the analysis of long term bidding behavior of a wind farm participating in a Pay-as-Bid (PAB) auction such as Iran Electricity Market (IEM). The results demonstrate that wind farm owners change their bid shading behavio... [more]
Distributed Generation Islanding Effect on Distribution Networks and End User Loads Using the Load Sharing Islanding Method
Maen Z. Kreishan, George P. Fotis, Vasiliki Vita, Lambros Ekonomou
February 5, 2019 (v1)
Keywords: distributed generation, distribution networks, islanding, load sharing, Neplan simulation tool
In this paper a realistic medium voltage (MV) network with four different distributed generation technologies (diesel, gas, hydro and wind) along with their excitation and governor control systems is modelled and simulated. Moreover, an exponential model was used to represent the loads in the network. The dynamic and steady state behavior of the four distributed generation technologies was investigated during grid-connected operation and two transition modes to the islanding situation, planned and unplanned. This study aims to address the feasibility of planned islanding operation and to investigate the effect of unplanned islanding. The load sharing islanding method has been used for controlling the distributed generation units during grid-connected and islanding operation. The simulation results were validated through various case studies and have shown that properly planned islanding transition could provide support to critical loads at the event of utility outages. However, a relia... [more]
Analysis of Power Network for Line Reactance Variation to Improve Total Transmission Capacity
Ikram Ullah, Wolfgang Gawlik, Peter Palensky
February 5, 2019 (v1)
Keywords: Available Transfer Capability (ATC), FACTS, PTDF, real power flow Performance Index sensitivity
The increasing growth in power demand and the penetration of renewable distributed generations in competitive electricity market demands large and flexible capacity from the transmission grid to reduce transmission bottlenecks. The bottlenecks cause transmission congestion, reliability problems, restrict competition, and limit the maximum dispatch of low cost generations in the network. The electricity system requires efficient utilization of the current transmission capability to improve the Available Transfer Capability (ATC). To improve the ATC, power flow among the lines can be managed by using Flexible AC Transmission System (FACTS) devices as power flow controllers, which alter the parameters of power lines. It is important to place FACTS devices on suitable lines to vary the reactance for improving Total Transmission Capacity (TTC) of the network and provide flexibility in the power flow. In this paper a transmission network is analyzed based on line parameters variation to impr... [more]
New Requirements of the Voltage/VAR Function for Smart Inverter in Distributed Generation Control
Yun-Su Kim, Gyeong-Hun Kim, Jae-Duck Lee, Changhee Cho
February 5, 2019 (v1)
Keywords: International Electronical Committee 61850, inverter-interfaced distributed generation, smart inverter, Volt/VAR function
International Electronical Committee (IEC) 61850-90-7 is a part of the IEC 61850 series which specifies the advanced functions and object models for power converter based Distributed Energy Resources (DERs). One of its functions, the Voltage/VAR (V/V) control function, is used to enhance the stability and the reliability of the voltage in the distribution system. The conventional V/V function acts mainly for flattening the voltage profile as for a basic grid support function. Currently, other objectives such as the minimization of line loss and the operational costs reduction are coming into the spotlight. In order to attain these objectives, the V/V function and hence the DER units shall actively respond to the change of distribution system conditions. In this paper, the modification of V/V function and new requirements are proposed. To derive new requirements of V/V function, loss minimization is applied to a particle swarm optimization (PSO) algorithm where the condition of voltage... [more]
Definition and Experimental Validation of a Simplified Model for a Microgrid Thermal Network and its Integration into Energy Management Systems
Andrea Bonfiglio, Massimo Brignone, Federico Delfino, Alessandro Nilberto, Renato Procopio
February 5, 2019 (v1)
Keywords: energy management, optimization algorithm, parameter identification, smart grids, thermal network
The present paper aims at defining a simplified but effective model of a thermal network that links the thermal power generation with the resulting temperature time profile in a heated or refrigerated environment. For this purpose, an equivalent electric circuit is proposed together with an experimental procedure to evaluate its input parameters. The paper also highlights the simplicity of implementation of the proposed model into a microgrid Energy Management System. This allows the optimal operation of the thermal network to be achieved on the basis of available data (desired temperature profile) instead of a less realistic basis (such as the desired thermal power profile). The validation of the proposed model is performed on the Savona Campus Smart Polygeneration Microgrid (SPM) with the following steps: (i) identification of the parameters involved in the equivalent circuit (performed by minimizing the difference between the temperature profile, as calculated with the proposed mode... [more]
Solar Resource for Urban Communities in the Baja California Peninsula, Mexico
Alberto-Jesús Perea-Moreno, Quetzalcoatl Hernandez-Escobedo
January 31, 2019 (v1)
Keywords: assessment, Baja California Peninsula, geographic information system (GIS), solar irradiation, urban communities
Several studies have determined that Mexico has great renewable energy potential, and one of its most abundant resources is solar energy, a source that could be exploited to provide development opportunities to its population, however it is necessary to calculate the amount of this source available. The aim of this study was to assess solar irradiance at urban communities in the Baja California Peninsula. For this purpose data recorded every 10 min during 6 years (2010⁻2015) by the Automatic Meteorological Stations (AMSs) and Synoptic Automatic Meteorological Stations (SAMSs) of the National Meteorological System of Mexico (NMS) were analyzed. Satellite data from the Surface and Meteorology Energy System (SMSE) were also used, and a linear regression was performed to compare the measured and satellite data. The highest R-square value found was 0.97 and the lowest was 0.82. Daily patterns show that Cabo San Lucas had the highest average solar irradiation/day, with 1000 W/m². Considering... [more]
Cost-Effectiveness Comparison of Coupler Designs of Wireless Power Transfer for Electric Vehicle Dynamic Charging
Weitong Chen, Chunhua Liu, Christopher H.T. Lee, Zhiqiang Shan
January 31, 2019 (v1)
Keywords: cost-effectiveness, dynamic charging, electric vehicle, electromagnetic field analysis, wireless power transfer
This paper presents a cost-effectiveness comparison of coupler designs for wireless power transfer (WPT), meant for electric vehicle (EV) dynamic charging. The design comparison of three common types of couplers is first based on the raw material cost, output power, transfer efficiency, tolerance of horizontal offset, and flux density. Then, the optimal cost-effectiveness combination is selected for EV dynamic charging. The corresponding performances of the proposed charging system are compared and analyzed by both simulation and experimentation. The results verify the validity of the proposed dynamic charging system for EVs.
Using CPE Function to Size Capacitor Storage for Electric Vehicles and Quantifying Battery Degradation during Different Driving Cycles
Cong Zhang, Haitao Min, Yuanbin Yu, Dai Wang, Justin Luke, Daniel Opila, Samveg Saxena
January 31, 2019 (v1)
Keywords: battery, continuous power-energy, electric vehicle, hybrid energy storage system, super-capacitor
Range anxiety and battery cycle life are two major factors which restrict the development of electric vehicles. Battery degradation can be reduced by adding supercapacitors to create a Hybrid Energy Storage System. This paper proposes a systematic approach to configure the hybrid energy storage system and quantifies the battery degradation for electric vehicles when using supercapacitors. A continuous power-energy function is proposed to establish supercapacitor size based on national household travel survey statistics. By analyzing continuous driving action in standard driving cycles and special driving phases (start up and acceleration), the supercapacitor size is calculated to provide a compromise between the capacitor size and battery degradation. Estimating the battery degradation after 10 years, the battery capacity loss value decreases 17.55% and 21.6%, respectively, under the urban dynamometer driving schedule and the US06. Furthermore, the battery lifespan of the continuous po... [more]
Effects of Power Tracking Algorithms on Lifetime of Power Electronic Devices Used in Solar Systems
Canras Batunlu, Mohamad Alrweq, Alhussein Albarbar
January 31, 2019 (v1)
Keywords: availability of photovoltaic solar systems, power management algorithms (PMAs), thermal stress of boost converters
In photovoltaic solar energy systems, power management algorithms (PMAs), usually called maximum power point tracking (MPPT) algorithms, are widely used for extracting maximum available power at every point in time. However, tracking the maximum power has negative effects on the availability of solar energy systems. This is due, mainly, to the created disturbances and thermal stresses on the associated power electronic converters (PECs). This work investigates the effects of PMA on the lifetime consumption, thermal stresses and failures on DC-DC converters used in solar systems. Firstly theoretical analysis and modelling of photovoltaic solar systems including converter’s electro thermal characteristics were developed. Subsequently, experiments on photovoltaic solar systems were carried out using two different PMAs, namely, perturb and observe (P&O) and incremental conductance (IC). Real-time data was collected, under different operating conditions, including thermal behavior using... [more]
A Study on Electric Vehicle Heat Pump Systems in Cold Climates
Ziqi Zhang, Wanyong Li, Junye Shi, Jiangping Chen
January 31, 2019 (v1)
Keywords: economized vapor injection, electric vehicle, heat pump
Electric vehicle heat pumps are drawing more and more attention due to their energy-saving and high efficiency designs. Some problems remain, however, in the usage of the heat pumps in electric vehicles, such as a drainage problem regarding the external heat exchangers while in heat pump mode, and the decrease in heating performance when operated in a cold climate. In this article, an R134a economized vapor injection (EVI) heat pump system was built and tested. The drainage problem common amongst external heat exchangers was solved by an optimized 5 mm diameter tube-and-fin heat exchanger, which can meet both the needs of a condenser and evaporator based on simulation and test results. The EVI system was also tested under several ambient temperatures. It was found that the EVI was a benefit to the system heating capacity. Under a −20 °C ambient temperature, an average improvement of 57.7% in heating capacity was achieved with EVI and the maximum capacity was 2097 W, with a coefficient... [more]
Energy Saving in Water Distribution Network through Pump as Turbine Generators: Economic and Environmental Analysis
Mauro De Marchis, Barbara Milici, Roberto Volpe, Antonio Messineo
January 31, 2019 (v1)
Keywords: energy recovery, greenhouse gas (GHG), pump as turbine (PAT), Renewable and Sustainable Energy, water distribution network
Complex systems of water distribution networks (WDS) are used to supply water to users. WDSs are systems where a lot of distributed energy is available. Historically, this energy is artificially dissipated by pressure reduction valves (PRVs), thanks to which water utilities manage the pressure level in selected nodes of the network. The present study explores the use of economic hydraulic machines, pumps as turbines (PATs) to produce energy in a small network located in a town close to Palermo (Italy). The main idea is to avoid dissipation in favor of renewable energy production. The proposed study is applied to a WDN typical of the Mediterranean countries, where the users, to collect water during the period of water scarcity conditions, install private tanks. The presence of private tanks deeply modifies the network from its designed condition. In the proposed analysis, the economic benefit of PATs application in water distribution networks has been investigated, accounting for the pr... [more]
Novel Interleaved Converter with Extra-High Voltage Gain to Process Low-Voltage Renewable-Energy Generation
Chih-Lung Shen, Po-Chieh Chiu, Yan-Chi Lee
January 31, 2019 (v1)
Keywords: Fuel Cells, high step-up converter, interleaved converter, low voltage stress, photovoltaic (PV) panel
This paper presents a novel interleaved converter (NIC) with extra-high voltage gain to process the power of low-voltage renewable-energy generators such as photovoltaic (PV) panel, wind turbine, and fuel cells. The NIC can boost a low input voltage to a much higher voltage level to inject renewable energy to DC bus for grid applications. Since the NIC has two circuit branches in parallel at frond end to share input current, it is suitable for high power applications. In addition, the NIC is controlled in an interleaving pattern, which has the advantages that the NIC has lower input current ripple, and the frequency of the ripple is twice the switching frequency. Two coupled inductors and two switched capacitors are incorporated to achieve a much higher voltage gain than conventional high step-up converters. The proposed NIC has intrinsic features such as leakage energy totally recycling and low voltage stress on power semiconductor. Thorough theoretical analysis and key parameter desi... [more]
Cooperative Energy Management of Hybrid DC Renewable Grid Using Decentralized Control Strategies
Mehrdad Beykverdi, Abolfazl Jalilvand, Mehdi Ehsan
January 31, 2019 (v1)
Keywords: DC microgrid, decentralized control, droop control, energy management, hybrid unit, islanded mode
This paper attempted to control a hybrid DC microgrid in islanded operation mode using decentralized power management strategies. Proposed adaptive I/V characteristic for hybrid photovoltaic (PV) and battery energy storage system (BESS) and wind turbine generator (WTG) adapts the distributed energy resources (DER) behavior independently in accordance with the load demand. Hence, the PV module can spend its maximum power on load demand and spend the extra power for charging the BESS, which will regulate DC bus voltage and maintain the power balance within the microgrid. When load demand is beyond the maximum generation power of PV unit, WTG will supply the energy shortage. The proposed control system was applied on the DC microgrid in order to achieve control objectives through a decentralized procedure, without telecommunication links. In order to validate the proposed strategies, the control system was implemented on a DC microgrid within MATLAB/SIMULINK, where the simulation results... [more]
Modeling and Optimization of the Thermal Performance of a Wood-Cement Block in a Low-Energy House Construction
Iole Nardi, Tullio de Rubeis, Edoardo Buzzi, Stefano Sfarra, Dario Ambrosini, Domenica Paoletti
January 31, 2019 (v1)
Keywords: Ansys® simulation, sustainable material, wood-cement block
The reduction of building energy consumption requires appropriate planning and design of the building’s envelope. In the last years, new innovative materials and construction technologies used in new or refurbished buildings have been developed in order to achieve this objective, which are also needed for reducing greenhouse gases emissions and building maintenance costs. In this work, the thermal conductance of a brick, made of wood and cement, used in a low-rise building, was investigated with a heat flow meter (HFM) and with numerical simulation using the Ansys® software package (Canonsburg, PA, USA). Due to their influence on the buildings’ thermal efficiency, it is important to choose an appropriate design for the building blocks. Results obtained by the finite element modeling of the construction material and by in-situ analysis conducted on a real building are compared, and furthermore a thermal optimization of the shape of the material is suggested.
A Regional Time-of-Use Electricity Price Based Optimal Charging Strategy for Electrical Vehicles
Jun Yang, Jiejun Chen, Lei Chen, Feng Wang, Peiyuan Xie, Cilin Zeng
January 31, 2019 (v1)
Keywords: electric vehicles, node layer model, optimization scheduling, regional layer model, RTOU electricity price model, user responsivity
With the popularization of electric vehicles (EVs), the out-of-order charging behaviors of large numbers of EVs will bring new challenges to the safe and economic operation of power systems. This paper studies an optimal charging strategy for EVs. For that a typical urban zone is divided into four regions, a regional time-of-use (RTOU) electricity price model is proposed to guide EVs when and where to charge considering spatial and temporal characteristics. In light of the elastic coefficient, the user response to the RTOU electricity price is analyzed, and also a bilayer optimization charging strategy including regional-layer and node-layer models is suggested to schedule the EVs. On the one hand, the regional layer model is designed to coordinate the EVs located in different time and space. On the other hand, the node layer model is built to schedule the EVs to charge in certain nodes. According to the simulations of an IEEE 33-bus distribution network, the performance of the propose... [more]
A Conservation Voltage Reduction Scheme for a Distribution Systems with Intermittent Distributed Generators
Pyeong-Ik Hwang, Seung-Il Moon, Seon-Ju Ahn
January 31, 2019 (v1)
Keywords: conservation voltage reduction, distributed generator, distribution system, reactive power control, volt/var control
In this paper, a conservation voltage reduction (CVR) scheme is proposed for a distribution system with intermittent distributed generators (DGs), such as photovoltaics and wind turbines. The CVR is a scheme designed to reduce energy consumption by lowering the voltages supplied to customers. Therefore, an unexpected under-voltage violation can occur due to the variation of active power output from the intermittent DGs. In order to prevent the under-voltage violation and improve the CVR effect, a new reactive power controller which complies with the IEEE Std. 1547TM, and a parameter determination method for the controller are proposed. In addition, an optimal power flow (OPF) problem to determine references for the resources of CVR is formulated with consideration of the intermittent DGs. The proposed method is validated using a modified IEEE 123-node test feeder. With the proposed method, the voltages of the test system are maintained to be greater than the lower bound, even though th... [more]
Dispatching of Wind/Battery Energy Storage Hybrid Systems Using Inner Point Method-Based Model Predictive Control
Deyou Yang, Jiaxin Wen, Ka-wing Chan, Guowei Cai
January 30, 2019 (v1)
Keywords: battery energy storage, combination active output, dispatching curve, wind power
The application of large scale energy storage makes wind farms more dispatchable, which lowers operating risks to the grid from interconnected large scale wind farms. In order to make full use of the flexibility and controllability of energy storage to improve the schedulability of wind farms, this paper presents a rolling and dispatching control strategy with a battery energy storage system (BESS) based on model predictive control (MPC). The proposed control scheme firstly plans expected output, i.e., dispatching order, of a wind/battery energy storage hybrid system based on the predicted output of the wind farm, then calculates the order in the predictive horizon with the receding horizon optimization and the limitations of energy storage such as state of charge and depth of charge/discharge to maintain the combination of active output of the wind farm and the BESS to track dispatching order at the extreme. The paper shows and analyses the effectiveness of the proposed strategy with... [more]
Coordinated Scheme of Under-Frequency Load Shedding with Intelligent Appliances in a Cyber Physical Power System
Qi Wang, Yi Tang, Feng Li, Mengya Li, Yang Li, Ming Ni
January 30, 2019 (v1)
Keywords: cyber physical power system, demand response, intelligent home appliance, under-frequency load shedding
The construction of a cyber physical system in a power grid provides more potential control strategies for the power grid. With the rapid employment of intelligent terminal equipment (e.g., smart meters and intelligent appliances) in the environment of a smart grid, abundant dynamic response information could be introduced to support a secure and stable power system. Combining demand response technology with the traditional under-frequency load shedding (UFLS) scheme, a new UFLS strategy-determining method involving intelligent appliances is put forward to achieve the coordinated control of quick response resources and the traditional control resources. Based on this method, intelligent appliances can be used to meet the regulatory requirements of system operation in advance and prevent significant frequency drop, thereby improving the flexibility and stability of the system. Time-domain simulation verifies the effectiveness of the scheme, which is able to mitigate frequency drop and r... [more]
Activity-Aware Energy-Efficient Automation of Smart Buildings
Brian L. Thomas, Diane J. Cook
January 30, 2019 (v1)
Keywords: activity prediction, activity recognition, building automation, cyber-physical systems (CPS), smart cities
This paper introduces the idea of activity-aware cyber-physical systems (CPS). Activity-aware systems allow smart city services to adapt to the needs of individual residents by being sensitive to their daily tasks. The paper first defines activity recognition and activity prediction algorithms that form the foundation of activity-aware CPS and implement a prototype activity-aware building automation system, called CASAS activity aware resource learning (CARL). Evaluation of CARL on real sensor data shows not only an accurate ability to sense and predict activities but an effective means of automation buildings that reduces energy consumption while being sensitive to user activities in the building. Our ideas are demonstrated in the context of a smart home but can be utilized in a variety of smart city settings including smart offices, smart hospitals, and smart communities.
DG Mix and Energy Storage Units for Optimal Planning of Self-Sufficient Micro Energy Grids
Aboelsood Zidan, Hossam A. Gabbar
January 7, 2019 (v1)
Keywords: combined heat and power, gas-power, Genetic Algorithm, micro energy grid, multi-objective, renewable, self-sufficient
Micro energy grids have many merits and promising applications under the smart grid vision. There are demanding procedures for their optimal planning and performance enhancement. One of the key features of a micro energy grid is its ability to separate and isolate itself from the main electrical network to continue feeding its own islanded portion. In this paper, an optimal sizing and operation strategy for micro energy grids equipped with renewable and non-renewable based distributed generation (DG) and storage are presented. The general optimization objective is to define the best DG mix and energy storage units for self-sufficient micro energy grids. A multi-objective genetic algorithm (GA) was applied to solve the planning problem at a minimum optimization goal of overall cost (including investment cost, operation and maintenance cost, and fuel cost) and carbon dioxide emission. The constraints include power and heat demands constraints, and DGs capacity limits. The candidate techn... [more]
Effectiveness of Using Phase Change Materials on Reducing Summer Overheating Issues in UK Residential Buildings with Identification of Influential Factors
Marine Auzeby, Shen Wei, Chris Underwood, Jess Tindall, Chao Chen, Haoshu Ling, Richard Buswell
January 7, 2019 (v1)
Keywords: overheating, phase change material (PCM), residential buildings, thermal storage
The UK is currently suffering great overheating issues in summer, especially in residential buildings where no air-conditioning has been installed. This overheating will seriously affect people’s comfort and even health, especially for elderly people. Phase change materials (PCMs) have been considered as a useful passive method, which absorb excessive heat when the room is hot and release the stored heat when the room is cool. This research has adopted a simulation method in DesignBuilder to evaluate the effectiveness of using PCMs to reduce the overheating issues in UK residential applications and has analyzed potential factors that will influence the effectiveness of overheating. The factors include environment-related (location of the building, global warming/climate change) and construction-related (location of the PCM, insulation, heavyweight/lightweight construction). This research provides useful evidence about using PCMs in UK residential applications and the results are helpfu... [more]
Efficient Use of Energy Resources on French Farms: An Analysis through Technical Efficiency
Mohamed Ghali, Laure Latruffe, Karine Daniel
January 7, 2019 (v1)
Keywords: Data Envelopment Analysis, energy resources, farms, France, technical efficiency
Integrating natural resources and ecological services in the production process is crucial to implement sustainable agriculture. However, the measurement of natural resource efficiency remains difficult. This paper aims at contributing to this issue, by investigating French farms’ use and excess (slack) of energy resources through Data Envelopment Analyses (DEA). Results show that disentangling energy resources from the rest of intermediate consumption highlights energy use excess which is masked when considering intermediate consumption as a whole. The analysis of the determinants of energy use excess and of intermediate consumption shows a discrepancy in results, which policy-makers should take into account when designing energy policies. In addition, results show that large and highly capital intensive farms perform better in terms of energy use excess, while the dependence on public subsidies is a constraint.
Multi-Objective Optimal Sizing for Battery Storage of PV-Based Microgrid with Demand Response
Nan Zhou, Nian Liu, Jianhua Zhang, Jinyong Lei
January 7, 2019 (v1)
Keywords: battery energy storage system (BESS), investment and benefit model, multi-objective optimization, multi-period demand response (DR), non-dominated sorting genetic algorithm II (NSGA-II) algorithm, photovoltaic consumptive rate, time-of-use (TOU) price
In order to solve the influence of uncertain photovoltaic power (PV) on the stable operation of microgrid (MG), demand response (DR) and battery energy storage system (BESS) need to be introduced simultaneously into the operation optimal scheduling of PV-based microgrid (PV-MG). Therefore, it is of great significance for commercial investment decisions of PV-MG to consider the influence of DR on BESS optimal sizing. Under the peak-valley time-of-use (TOU) price, this paper builds cross-time DR models based on price elasticity matrix. Furthermore, through the introduction of DR and BESS into PV-MG scheduling optimization, the MG investment and benefit model is proposed. Considering the constraint condition such as co-ordination of supply and demand, electricity price elasticity and energy loss of storage system, the improved non-dominated sorting genetic algorithm II (NSGA-II) is utilized to solve the multi-objective optimal allocation model of the BESS with the target of maximum PV con... [more]
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