scholarly journals Proposal of Priority Schemes for Controlling Electric Vehicle Charging and Discharging in a Workplace Power System with High Penetration of Photovoltaic Systems

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7483
Author(s):  
Helindu Cumaratunga ◽  
Masaki Imanaka ◽  
Muneaki Kurimoto ◽  
Shigeyuki Sugimoto ◽  
Takeyoshi Kato
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Vehicles ◽  
Electric Load ◽  
Electric Vehicle Charging ◽  
High Penetration ◽  
Flexible Resources ◽  
Load Dispatching ◽  
Priority Schemes ◽  
Workplace Power

Using Electric Vehicles (EV) as Flexible Resources (FR) to increase surplus Photovoltaic (PV) power utilisation is a well-researched topic. Our previous study showed that EVs are viable as supplementary FRs in large capacity PV power systems, where EVs are likely to gather (i.e., workplaces). However, that study assumed all EVs to have identical arrival and departure times (availability), and battery capacities. As these characteristics may vary between EVs and affect their performance as FRs, this study expands the modelling of EVs to consider a variety of availabilities and battery capacities. To effectively utilise a variety of EVs as FRs, an Optimisation Electric-load Dispatching model is used to formulate priority schemes for charging and discharging the EVs based on their potential to contribute to the power system. The priority schemes are evaluated by simulating the annual operation of the power system both with and without the priority schemes, and comparing results. The power system is simulated using a Unit-Scheduling and Time-series Electric-load Dispatching model. The priority schemes reduced annual CO2 emissions by nearly 1%, compared to the case without the priority schemes. The performances of different EVs as FRs when the priority schemes are used and not used are also analysed.

scholarly journals Comparing Power-System- and User-Oriented Battery Electric Vehicle Charging Representation and its Implications on Energy System Modeling

2020 ◽  
Author(s):  
Niklas Wulff ◽  
Felix Steck ◽  
Hans Christian Gils ◽  
Carsten Hoyer-Klick ◽  
Bent van den Adel ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Electric Vehicle ◽  
Electric Vehicles ◽  
System Optimization ◽  
Energy System ◽  
Battery Electric Vehicle ◽  
Electric Vehicle Charging ◽  
Vehicle Charging

Battery electric vehicles provide an opportunity to balance supply and demand in future power systems with high shares of fluctuating renewable energy. Compared to other storage systems such as pumped-storage hydroelectricity, electric vehicle energy demand is highly dependent on charging and connection choices of vehicle users. We present a model framework of a utility-based stock and flow model, a utility-based microsimulation of charging decisions, and an energy system model including respective interfaces to assess how the representation of battery electric vehicle charging affects energy system optimization results. We then apply the framework to a scenario study for controlled charging of nine million electric vehicles in Germany in 2030. Assuming a respective fleet power demand of 27 TWh, we analyze the difference between power-system-based and vehicle user-based charging decisions in two respective scenarios. Our results show that taking into account vehicle users’ charging and connection decisions significantly decreases the load shifting potential of controlled charging. The analysis of marginal values of equations and variables of the optimization problem yields valuable insights on the importance of specific constraints and optimization variables. In particular, state-of-charge assumptions and representing fast charging drive curtailment of renewable energy feed-in and required gas power plant flexibility. A detailed representation of fleet charge connection is less important. Peak load can be significantly reduced by 5% and 3% in both scenarios, respectively. Shifted load is very robust across sensitivity analyses while other model results such as curtailment are more sensitive to factors such as underlying data years. Analyzing the importance of increased BEV fleet battery availability for power systems with different weather and electricity demand characteristics should be further scrutinized.

scholarly journals Comparing Power-System and User-Oriented Battery Electric Vehicle Charging Representation and Its Implications on Energy System Modeling

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1093 ◽  
Author(s):  
Niklas Wulff ◽  
Felix Steck ◽  
Hans Christian Gils ◽  
Carsten Hoyer-Klick ◽  
Bent van den Adel ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Electric Vehicle ◽  
Electric Vehicles ◽  
System Optimization ◽  
Energy System ◽  
Battery Electric Vehicle ◽  
Electric Vehicle Charging ◽  
Vehicle Charging

Battery electric vehicles (BEV) provide an opportunity to balance supply and demand in future power systems with high shares of fluctuating renewable energy. Compared to other storage systems such as pumped-storage hydroelectricity, electric vehicle energy demand is highly dependent on charging and connection choices of vehicle users. We present a model framework of a utility-based stock and flow model, a utility-based microsimulation of charging decisions, and an energy system model including respective interfaces to assess how the representation of battery electric vehicle charging affects energy system optimization results. We then apply the framework to a scenario study for controlled charging of nine million electric vehicles in Germany in 2030. Assuming a respective fleet power demand of 27 TWh, we analyze the difference between power-system-based and vehicle user-based charging decisions in two respective scenarios. Our results show that taking into account vehicle users’ charging and connection decisions significantly decreases the load shifting potential of controlled charging. The analysis of marginal values of equations and variables of the optimization problem yields valuable insights on the importance of specific constraints and optimization variables. Assumptions on fleet battery availability and a detailed representation of fast charging are found to have a strong impact on wind curtailment, renewable energy feed-in, and required gas power plant flexibility. A representation of fleet connection to the grid in high temporal detail is less important. Peak load can be reduced by 5% and 3% in both scenarios, respectively. Shifted load is robust across sensitivity analyses while other model results such as curtailment are more sensitive to factors such as underlying data years. Analyzing the importance of increased BEV fleet battery availability for power systems with different weather and electricity demand characteristics should be further scrutinized.

scholarly journals The Flexible Operation of Coal Power and Its Renewable Integration Potential in China

2019 ◽  
Vol 11 (16) ◽  
pp. 4424 ◽  
Author(s):  
Chunning Na ◽  
Huan Pan ◽  
Yuhong Zhu ◽  
Jiahai Yuan ◽  
Lixia Ding ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Large Scale ◽  
Renewable Integration ◽  
Flexible Resources ◽  
Feasible Option ◽  
Coal Power ◽  
Simulation Results ◽  
Flexible Operation

At present time, China’s power systems face significant challenges in integrating large-scale renewable energy and reducing the curtailed renewable energy. In order to avoid the curtailment of renewable energy, the power systems need significant flexibility requirements in China. In regions where coal is still heavily relied upon for generating electricity, the flexible operations of coal power units will be the most feasible option to face these challenges. The study first focused on the reasons why the flexible operation of existing coal power units would potentially promote the integration of renewable energy in China and then reviewed the impacts on the performance levels of the units. A simple flexibility operation model was constructed to estimate the integration potential with the existing coal power units under several different scenarios. This study’s simulation results revealed that the existing retrofitted coal power units could provide flexibility in the promotion of the integration of renewable energy in a certain extent. However, the integration potential increment of 20% of the rated power for the coal power units was found to be lower than that of 30% of the rated power. Therefore, by considering the performance impacts of the coal power units with low performances in load operations, it was considered to not be economical for those units to operate at lower than 30% of the rated power. It was believed that once the capacity share of the renewable energy had achieved a continuously growing trend, the existing coal power units would fail to meet the flexibility requirements. Therefore, it was recommended in this study that other flexible resources should be deployed in the power systems for the purpose of reducing the curtailment of renewable energy. Furthermore, based on this study’s obtained evidence, in order to realize a power system with high proportions of renewable energy, China should strive to establish a power system with adequate flexible resources in the future.

scholarly journals Load area aggregation considering integration of electric vehicles to the system

2015 ◽  
Vol 35 (1Sup) ◽  
pp. 42-49 ◽  
Author(s):  
Luis Fernando Rodríguez-García ◽  
Sandra Milena Pérez-Londoño ◽  
Juan José Mora-Flórez
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Vehicles ◽  
System Analysis ◽  
Original System ◽  
Computational Effort ◽  
Computational Technique ◽  
Equivalent Network ◽  
Optimal Dispatch ◽  
Equivalent Load

<span>Current electric power systems have an increasing penetration of electric vehicles, and its effect has to be considered in different <span>studies, such as optimal dispatch or voltage stability, among others. Additionally, considering that power system analysis becomes <span>complex when the number of buses increase, this paper presents a methodology for aggregation of load areas that use a measurement-based load modeling approach based on an evolutionary computational technique and a classical reduction method. This aggregate <span>load area model is proposed to reduce areas that consider electric vehicle (EV) load models. The proposed method provides a static <span>equivalent load model and an equivalent network that can be used to reduce the computational effort required by power system<br /><span>studies. In order to validate the application of the proposed methodology, a 30-bus power system considering several disturbances <span>and levels of penetration of the electric vehicles was used. The results show that the equivalent network model allows the reproduction <span>of different events with an acceptable accuracy when it is compared to the original system behavior.</span></span></span></span></span></span></span><br /><br class="Apple-interchange-newline" /></span>

scholarly journals Integrating Photovoltaic Systems in Power System: Power Quality Impacts and Optimal Planning Challenges

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Aida Fazliana Abdul Kadir ◽  
Tamer Khatib ◽  
Wilfried Elmenreich
Keyword(s):  
Power Systems ◽  
Power System ◽  
Power Quality ◽  
Distribution System ◽  
Power Flow ◽  
Harmonic Distortion ◽  
Integrated System ◽  
Optimal Planning ◽  
High Penetration ◽  
Bidirectional Power Flow

This paper is an overview of some of the main issues in photovoltaic based distributed generation (PVDG). A discussion of the harmonic distortion produced by PVDG units is presented. The maximum permissible penetration level of PVDG in distribution system is also considered. The general procedures of optimal planning for PVDG placement and sizing are also explained in this paper. The result of this review shows that there are different challenges for integrating PVDG in the power systems. One of these challenges is integrated system reliability whereas the amount of power produced by renewable energy source is consistent. Thus, the high penetration of PVDG into grid can decrease the reliability of the power system network. On the other hand, power quality is considered one of the challenges of PVDG whereas the high penetration of PVDGs can lead to more harmonic propagation into the power system network. In addition to that, voltage fluctuation of the integrated PVDG and reverse power flow are two important challenges to this technology. Finally, protection of power system with integrated PVDG is one of the most critical challenges to this technology as the current protection schemes are designed for unidirectional not bidirectional power flow pattern.

scholarly journals Challenges for Future Flexible Electric Power Systems

2021 ◽  
Vol 1 (1) ◽  
pp. 1-7
Author(s):  
Ali Feliachi
Keyword(s):  
Power Systems ◽  
Electric Power ◽  
Electric Vehicles ◽  
Renewable Resources ◽  
Electric Power Systems ◽  
Storage Devices ◽  
High Penetration ◽  
New Challenges ◽  
And Control ◽  
And Storage

This paper describes some of the challenges that face the operation of future electric power systems. These systems are becoming more flexible and agile. Their physical structures and connections are continuously changing as microgrids, electric vehicles, and other generation and storage devices are connected/disconnected from the grid, which result in new challenges for the operation, management, and control of the systems of the future that incorporate active participation of the consumers, and high penetration of intermittent nature renewable resources such as wind and solar.

scholarly journals Marginal Uncertainty Cost Functions for Solar Photovoltaic, Wind Energy, Hydro Generators, and Plug-In Electric Vehicles

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6375
Author(s):  
Elkin D. Reyes ◽  
Arturo S. Bretas ◽  
Sergio Rivera
Keyword(s):  
Power Systems ◽  
Wind Energy ◽  
Electric Vehicles ◽  
Smart Grids ◽  
Electrical Power ◽  
Energy Generation ◽  
Cost Functions ◽  
Solar Photovoltaic ◽  
Electrical Power Systems ◽  
High Penetration

The high penetration of renewable sources of energy in electrical power systems implies an increase in the uncertainty variables of the economic dispatch (ED). Uncertainty costs are a metric to quantify the variability introduced from renewable energy generation, that is to say: wind energy generation (WEG), run-of-the-river hydro generators (RHG), and solar photovoltaic generation (PVG). On other side, there are associated uncertainties to the charge/uncharge of plug-in electric vehicles (PEV). Thus, in this paper, the uncertainty cost functions (UCF) and their marginal expressions as a way of modeling and assessment of stochasticity in power systems with high penetration of smart grids elements is presented. In this work, a mathematical analysis is presented using the first and second derivatives of the UCF, where the marginal uncertainty cost functions (MUCF) and the UCF’s minimums for PVG, WEG, PEV, and RHG are derived. Further, a model validation is presented, considering comparative test results from the state of the art of the UCF minimum, developed in a previous study, to the minimum reached with the presented (MUCF) solution.

The Evolution from Electric Grid to Smart Grid

2014 ◽  
pp. 259-281
Author(s):  
Jesus Fraile-Ardanuy ◽  
Dionisio Ramirez ◽  
Sergio Martinez ◽  
Jairo Gonzalez ◽  
Roberto Alvaro
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Power ◽  
Electricity Markets ◽  
Smart Grids ◽  
Demand Management ◽  
Electric Power System ◽  
System Control ◽  
Electric Grid ◽  
High Penetration

In this chapter, an overview of electric power systems is presented. The purpose is to describe the structure and operation of the power system and its evolution to the new smart grids. The first section gives an introduction about the electric grid and its evolution. Then, there is a section with a brief description of the different components of the electric power system: generation, transmission, distribution, and consumption. The third section is related to power system control, explaining why control actions are necessary in the power system to maintain the balance between supply and consumption and to keep constant the system frequency (at 50 or 60 Hz). In order to understand future applications of electric vehicles, it is important to present a fourth section related to fundamentals of the electricity markets. The chapter finishes with a description of the future power systems with high penetration of intermittent renewable energies, energy storage capacity, active demand management, and integration with telecommunication infrastructure.

scholarly journals Optimal Dispatch of High-Penetration Renewable Energy Integrated Power System Based on Flexible Resources

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3456 ◽  
Author(s):  
Jiawei Feng ◽  
Junyou Yang ◽  
Haixin Wang ◽  
Huichao Ji ◽  
Martin Onyeka Okoye ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Power System ◽  
Optimal Operation ◽  
Pollutant Emissions ◽  
Optimal Dispatch ◽  
High Penetration ◽  
Flexible Resources ◽  
The Stability ◽  
Net Load ◽  
Integrated Power System

The volatility and uncertainty of high-penetration renewable energy (RE) challenge the stability of the power system. To tackle this challenge, an optimal dispatch of high-penetration RE based on flexible resources (FRs) is proposed to enhance the ability of the power system to cope with uncertain disturbances. Firstly, the flexibility of a high-penetration RE integrated power system is analyzed. The flexibility margin of power supply and flexible adaptability of RE are then introduced as the evaluation indices for optimal operation. Finally, a multi-objective optimal dispatch model for power system flexibility enhancement based on FRs under the constraint of flexibility indices is proposed. The simulation results show that the proposed optimal dispatch can effectively enhance the flexibility of the power system and the penetration of RE and reduce pollutant emissions. Compared with the conventional method, the daily average emissions of CO2, SO2, and NOx with the proposed method are reduced by about 83,600 kg, 870 kg, and 370 kg, respectively, the maximum allowable volatility of net load is increased by 7.63%, and the average volatility of net load is reduced by 2.67%.

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