scholarly journals Stochastic Optimization of Microgrid Operation With Renewable Generation and Energy Storage

2021 ◽  
Author(s):  
Per Aaslid ◽  
Magnus Korpås ◽  
Michael M Belsnes ◽  
Olav Bjarte Fosso
Keyword(s):  
Power Systems ◽  
Programming Model ◽  
Renewable Energy Sources ◽  
Electric Energy ◽  
Renewable Generation ◽  
Stored Energy ◽  
Forecast Horizon ◽  
Term Model ◽  
Dual Dynamic Programming

The operation of electric energy storages (EES) in power systems where variable renewable energy sources (VRES) and EES must contribute to securing the supply can be considered as an arbitrage against scarcity. The value of using stored energy instantly must be balanced against its potential future value and future risk of scarcity. This paper proposes a multi-stage stochastic programming model for the operation of microgrids with VRES, EES and thermal generation that is divided into a short- and a long-term model. The short-term model utilizes information from forecasts updated every six hours, while the long-term model considers the value of stored energy beyond the forecast horizon. The model is solved using stochastic dual dynamic programming and Markov chains, and the results show that the significance of accounting for short- and long-term uncertainty increases for systems with a high degree of variable renewable generation and EES and decreasing dispatchable generation capacity.<br>

scholarly journals Stochastic Optimization of Microgrid Operation With Renewable Generation and Energy Storage

2021 ◽  
Author(s):  
Per Aaslid ◽  
Magnus Korpås ◽  
Michael M Belsnes ◽  
Olav Bjarte Fosso
Keyword(s):  
Power Systems ◽  
Programming Model ◽  
Renewable Energy Sources ◽  
Electric Energy ◽  
Renewable Generation ◽  
Stored Energy ◽  
Forecast Horizon ◽  
Term Model ◽  
Dual Dynamic Programming

The operation of electric energy storages (EES) in power systems where variable renewable energy sources (VRES) and EES must contribute to securing the supply can be considered as an arbitrage against scarcity. The value of using stored energy instantly must be balanced against its potential future value and future risk of scarcity. This paper proposes a multi-stage stochastic programming model for the operation of microgrids with VRES, EES and thermal generation that is divided into a short- and a long-term model. The short-term model utilizes information from forecasts updated every six hours, while the long-term model considers the value of stored energy beyond the forecast horizon. The model is solved using stochastic dual dynamic programming and Markov chains, and the results show that the significance of accounting for short- and long-term uncertainty increases for systems with a high degree of variable renewable generation and EES and decreasing dispatchable generation capacity.<br>

scholarly journals MICROGRID IN POWER DISTRIBUTION SYSTEM

2020 ◽  
Vol 7 (8) ◽  
pp. 387-393
Author(s):  
E. A. Olajuyin ◽  
Olubakinde Eniola
Keyword(s):  
Power Systems ◽  
Power Distribution ◽  
Distribution System ◽  
Mechanical Energy ◽  
New Technology ◽  
Renewable Energy Sources ◽  
Electric Energy ◽  
Stored Energy ◽  
Synchronous Generators ◽  
Power Distribution System

Power is a very important instrument to the development of economy of a nation and it must be stable and available and to meet the demand of the consumers at all times. The quest for power supply has introduced a new technology called microgrid. Micro grids are regarded as small power systems that confine electric energy generating facilities, from both renewable energy sources and conventional synchronous. Generators, and customer loads with respect to produced electric energy. It can be connected to grid or operate in islanding mode. On the other hand, the grid’s dynamics and its stability rely on the amount of stored energy in the micro grid. In a conventional power system with a large number of synchronous generators as the main sources of energy, the mechanical energy in the generators’ rotors, in the form of kinetic energy, serves as the stored energy and feeds the grids in the event of any drastic load changes or if disturbances occur. Microgrid is an alternative idea to support the grid, it can be applied in a street, estates, community or a locality (towns and villages), organizations and establishments. Load forecasting can be further extended to Organizations, Local Government, State and country to determine the energy consumption.

scholarly journals Replacement Reserve for the Italian Power System and Electricity Market

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2916
Author(s):  
Mauro Caprabianca ◽  
Maria Carmen Falvo ◽  
Lorenzo Papi ◽  
Lucrezia Promutico ◽  
Viviana Rossetti ◽  
...  
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electricity Market ◽  
Renewable Energy Sources ◽  
Real Data ◽  
Forecast Horizon ◽  
European Guidelines ◽  
Central Platform ◽  
System Operator ◽  
New Methodologies

Over the last years, power systems around the globe experienced deep changes in their operation, mainly induced by the widespread of Intermittent Renewable Energy Sources (IRES). These changes involved a review of market and operational rules, in the direction of a stronger integration. At European level, this integration is in progress, driven by the new European guidelines and network codes, which deal with multiple issues, from market design to operational security. In this framework, the project TERRE (Trans European Replacement Reserve Exchange) is aimed at the realization of a European central platform, called LIBRA, for the exchange of balancing resources and, in particular, for the activation of the procured Replacement Reserve (RR) resources. The Italian Transmission System Operator (TSO), TERNA, is a participant of the project and it is testing new methodologies for the sizing of RR and its required activation throughout the TERRE process. The aim of the new methodologies is to find areas of potential improvement in the sizing of RR requirements and activation, which open up the possibility for a reduction of the procurement cost, without endangering the security of the power system. This paper describes a new RR sizing methodology, proposed by TERNA, which is based on a persistence method, showing its results on real data and highlighting key advantages and potential limitations of this approach. In order to overcome these limitations, a literature review on alternative approaches has been carried out, identifying nowcasting techniques as a relevant alternative for the very short term forecast horizon. These one could be further investigated and tested in the future, using the proposed persistence method as a benchmark.

scholarly journals Optimal Coordination of Aggregated Hydro-Storage with Residential Demand Response in Highly Renewable Generation Power System: The Case Study of Finland

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1037 ◽  
Author(s):  
Arslan Bashir ◽  
Matti Lehtonen
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Demand Response ◽  
Renewable Energy Sources ◽  
Renewable Generation ◽  
Generation Structure ◽  
Optimal Coordination ◽  
Residential Demand ◽  
Generation Power

Current energy policy-driven targets have led to increasing deployment of renewable energy sources in electrical grids. However, due to the limited flexibility of current power systems, the rapidly growing number of installations of renewable energy systems has resulted in rising levels of generation curtailments. This paper probes the benefits of simultaneously coordinating aggregated hydro-reservoir storage with residential demand response (DR) for mitigating both load and generation curtailments in highly renewable generation power systems. DR services are provided by electric water heaters, thermal storages, electric vehicles, and heating, ventilation and air-conditioning (HVAC) loads. Accordingly, an optimization model is presented to minimize the mismatch between demand and supply in the Finnish power system. The model considers proportions of base-load generation comprising nuclear, and combined heat and power (CHP) plants (both CHP-city and CHP-industry), as well as future penetration scenarios of solar and wind power that are constructed, reflecting the present generation structure in Finland. The findings show that DR coordinated with hydropower is an efficient curtailment mitigation tool given the uncertainty in renewable generation. A comprehensive sensitivity analysis is also carried out to depict how higher penetration can reduce carbon emissions from electricity co-generation in the near future.

scholarly journals Long- and Short-Term Comparative Analysis of Renewable Energy Sources

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3610
Author(s):  
Dawid Buła ◽  
Dariusz Grabowski ◽  
Andrzej Lange ◽  
Marcin Maciążek ◽  
Marian Pasko
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Renewable Energy Sources ◽  
Mass Effect ◽  
Distribution Networks ◽  
Energy Sources ◽  
Short Term ◽  
Starting Point ◽  
Power And Energy

Network working conditions are influenced noticeably by the connection of renewable energy sources to distribution networks. This becomes more and more important due to the increase in renewable energy source penetration over the last few years. This in turn can lead to a mass effect. As a result, the classical open network model with simple unidirectional direction of energy flow has been replaced with an active model that includes many local energy sources. This paper deals with the analysis of long- and short-term changes in power and energy generated by three types of renewable energy sources with similar rated power and which operate in the same region (i.e., located no more than tens of kilometers away). The obtained results can be a starting point for a broader evaluation of the influence of renewable energy sources on power quality in power systems, which can be both positive (supply reliability) and negative (voltage fluctuations and higher harmonics in current and voltage waveforms). It is important not only to correctly place but also to assure the diversity of such sources as it has been confirmed by the source variability coefficient. The long-term analysis allows us also to estimate the annual repeatability of energy production and, furthermore, the profitability of investment in renewable sources in a given region.

scholarly journals A Case Study of a Virtual Power Plant (VPP) as a Data Acquisition Tool for PV Energy Forecasting

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6200
Author(s):  
Tomasz Popławski ◽  
Sebastian Dudzik ◽  
Piotr Szeląg ◽  
Janusz Baran
Keyword(s):  
Power Plant ◽  
Power Systems ◽  
Power Plants ◽  
Distribution Systems ◽  
Missing Values ◽  
Renewable Energy Sources ◽  
Electric Energy ◽  
Electricity Production ◽  
Virtual Power ◽  
Virtual Power Plants

This article describes problems related to the operation of a virtual micro power plant at the Faculty of Electrical Engineering (FEE), Czestochowa University of Technology (CUT). In the era of dynamic development of renewable energy sources, it is necessary to create alternative electricity management systems for existing power systems, including power transmission and distribution systems. Virtual power plants (VPPs) are such an alternative. So far, there has been no unified standard for a VPP operation. The article presents components that make up the VPP at the FEE and describes their physical and logical structure. The presented solution is a combination of several units operating in the internal power grid of the FEE, i.e., wind turbines, energy storage (ES), photovoltaic panels (PV) and car charging stations. Their operation is coordinated by a common control system. One of the research goals described in the article is to optimize the operation of these components to minimize consumption of the electric energy from the external supply network. An analysis of data from the VPP management system was carried out to create mathematical models for prediction of the consumed power and the power produced by the PVs. These models allowed us to achieve the assumed objective. The article also presents the VPP data processing results in terms of detecting outliers and missing values. In addition to the issues discussed above, the authors also proposed to apply the Prophet model for short-term forecasting of the PV farm electricity production. It is a statistical model that has so far been used for social and business research. The authors implemented it effectively for technical analysis purposes. It was shown that the results of the PV energy production forecasting using the Prophet model are acceptable despite occurrences of missing data in the investigated time series.

scholarly journals Risk Analysis of the Power System Protection Delayed Triggers in Power Network Integrating Renewable Energy Sources in Fault Dynamic States

2020 ◽  
Author(s):  
Mateusz Szablicki ◽  
Piotr Rzepka ◽  
Adrian Halinka
Keyword(s):  
Power Systems ◽  
Power System ◽  
Renewable Energy Sources ◽  
Operation Time ◽  
Power Network ◽  
Renewable Generation ◽  
System Protection ◽  
Energy Needs ◽  
Digital Protection ◽  
Decision Algorithms

In the development of power systems it is indicated very often, that transformation of power systems should be carried out in accordance with the idea of energy democracy. This will develop energy communities, that are trying to meet energy needs by using local renewable generation sources. This may result with a temporary low load on the MV lines connecting the community grid and the power system. Such state may cause incorrect operation of power protection systems. This can cause an extended protection operation time, due to decision algorithms inactivity at low values of measurement currents. Therefore, the detailed MV lines overcurrent digital protection model and a dynamic model of the power network were developed. The simulation results are showing that the settings of the parameters activating the protection decision algorithms affect their operation time in dynamic conditions. The conclusion is that the development of the power protection automatics must be carried out in the same time (preferably in advance) with the change of the power system operation model. This is very important for future power systems with high penetration energy communities and renewable generation sources.

scholarly journals Assessment of Power System Adequacy with Renewable Energy Sources and Energy Storage Systems

2018 ◽  
Vol 58 ◽  
pp. 01012 ◽  
Author(s):  
Dmitry Krupenev
Keyword(s):  
Renewable Energy ◽  
Energy Storage ◽  
Power Systems ◽  
Power System ◽  
Storage Systems ◽  
Renewable Energy Sources ◽  
Experimental Studies ◽  
Electric Energy ◽  
Energy Sources ◽  
Energy Storage Systems

The paper deals with the problem of the accounting of renewable energy sources and energy storage systems in assessment of power system adequacy. Development of renewable energy sources and energy storage systems in the present day power systems is one of the main focuses. In power systems of some countries the share of electric energy generated by renewable energy sources is above 50 % in the energy balance. Therefore, the plans on development of the present day power systems must be elaborated with the proper accounting of operation of renewable energy sources and energy storage systems and the sound capacity reserves in terms of these facilities. The paper presents the algorithms for the accounting of renewable energy sources and energy storage systems. The experimental studies performed illustrate feasibility of the suggested algorithms.

scholarly journals Emulation Strategies and Economic Dispatch for Inverter-Based Renewable Generation under VSG Control Participating in Multiple Temporal Frequency Control

2020 ◽  
Vol 10 (4) ◽  
pp. 1303
Author(s):  
Weichao Zhang ◽  
Xiangwu Yan ◽  
Hanyan Huang
Keyword(s):  
Power Systems ◽  
Frequency Control ◽  
Renewable Energy Sources ◽  
Temporal Frequency ◽  
Economic Dispatch ◽  
Synchronous Generator ◽  
System Stability ◽  
Frequency Regulation ◽  
Renewable Generation ◽  
Frequency Responses

As the increasing penetration of inverter-based generation (IBG) and the consequent displacement of traditional synchronous generators (SGs), the system stability and reliability deteriorate for two reasons: first, the overall inertia decreases since the power electronic interfaces (PEIs) are almost inertia-less; second, renewable generation profiles are largely influenced by stochastic meteorological conditions. To strengthen power systems, the concept of the virtual synchronous generator (VSG) has been proposed, which controls the external characteristics of PEIs to emulate those of SGs. Currently, PEIs could perform short-term inertial and primary frequency responses through the VSG algorithm. For renewable energy sources (RES), deloading strategies enable the generation units to possess active power reserves for system frequency responses. Additionally, the deloading strategies could provide the potential for renewable generation to possess long-term frequency regulation abilities. This paper focuses on emulation strategies and economic dispatch for IBG units to perform multiple temporal frequency control. By referring to the well-established knowledge systems of generation and operation in conventional power systems, the current VSG algorithm is extended and complemented by the emulation of secondary and tertiary regulations. The reliability criteria are proposed, considering the loss of load probability (LOLP) and renewable spillage probability (RSP). The reliability criteria are presented in two scenarios, including the renewable units operated in maximum power point tracking (MPPT) and VSG modes. A LOLP-based economic dispatch (ED) approach is solved to acquire the generation and reserve schemes. The emulation strategies and the proposed approach are verified by simulation.

scholarly journals Positive Correlations between Short-Term and Average Long-Term Fluctuations in Wind Power Output

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1861
Author(s):  
Chiyori T. Urabe ◽  
Tetsuo Saitou ◽  
Kazuto Kataoka ◽  
Takashi Ikegami ◽  
Kazuhiko Ogimoto
Keyword(s):  
Power Systems ◽  
Wind Power ◽  
Power Output ◽  
Renewable Energy Sources ◽  
Electrical Power ◽  
Weather Conditions ◽  
Electricity Sector ◽  
Linear Functions ◽  
Short Term

Wind power has been increasingly deployed in the last decade to decarbonize the electricity sector. Wind power output changes intermittently depending on weather conditions. In electrical power systems with high shares of variable renewable energy sources, such as wind power, system operators aim to respond flexibly to fluctuations in output. Here, we investigated very short-term fluctuations, short-term fluctuations (STFs), and long-term fluctuations (LTFs) in wind power output by analyzing historical output data for two northern and one southern balancing areas in Japan. We found a relationship between STFs and the average LTFs. The percentiles of the STFs in each month are approximated by linear functions of the monthly average LTFs. Furthermore, the absolute value of the slope of this function decreases with wind power capacity in the balancing area. The LTFs reflect the trend in wind power output. The results indicate that the flexibility required for power systems can be estimated based on wind power predictions. This finding could facilitate the design of the balancing market in Japan.

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