Increasing Turkey's power system flexibility for grid integration of 50% renewable energy share

Power system operators are in search of proven solutions to improve the penetration levels of distributed generators (DGs) in the grid while minimizing cost. This transition is driven, among others, by global climate concerns, the growing power demand, the need for greater flexibility, the ageing grid infrastructure and the need to diversify sources of energy production. Distributed renewables would not easily substitute the conventional electric grid system, perhaps because the latter is a well-established technology and it would not be prudent to abandon it, while the new distributed renewable energy technologies are generally not adequately developed to support the total load. Thus, it is becoming increasingly necessary to consider sustainable options such as integrating renewable energy sources into the existing power grid. This study is a review that is mainly hinged on distributed generation (DG) classification, the challenges of DG to grid integration, practical options used in DG integration, lessons learned from some countries with successful DG to grid integration, push factors in the growth of DGs and the merits of DG to grid integration. These standpoints of DG to grid interconnection are critical in conducting grid planning and operational studies, which should be conducted in strict observance of aspects such as optimal technology selection, optimal capacity and a suitable connection point of DGs in the network. Therefore, the perspectives highlighted regarding DG can assist power system engineers, developers of DG plants and policymakers in developing a power network that is stable, efficient and reliable.

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Evaluation Method of Power System Flexibility for Renewable Energy Accommodation

8th Renewable Power Generation Conference (RPG 2019) ◽

10.1049/cp.2019.0387 ◽

2019 ◽

Author(s):

Kunpeng Tian ◽

Weiqing Sun ◽

Ce Yang ◽

Dong Han ◽

Wei Zhang ◽

...

Keyword(s):

Renewable Energy ◽

Power System ◽

Evaluation Method ◽

Energy Accommodation ◽

Power System Flexibility

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Analyzing the Impact of Variability and Uncertainty on Power System Flexibility

Applied Sciences ◽

10.3390/app9030561 ◽

2019 ◽

Vol 9 (3) ◽

pp. 561 ◽

Cited By ~ 5

Author(s):

Chang-Gi Min

Keyword(s):

Sensitivity Analysis ◽

Renewable Energy ◽

Power System ◽

Energy Resources ◽

Renewable Energy Resources ◽

Specific System ◽

Efficient Operation ◽

The Impact ◽

Power System Flexibility ◽

Flexibility Index

This study investigates the impact of variability and uncertainty on the flexibility of a power system. The variability and uncertainty make it harder to maintain the balance between load and generation. However, most existing studies on flexibility evaluation have not distinguished between the effects of variability and uncertainty. The countermeasures to address variability and uncertainty differ; thus, applying strategies individually tailored to variability and uncertainty is helpful for more efficient operation and planning of a power system. The first contribution of this study is in separating the variability and uncertainty, and determining which is more influential in terms of flexibility in specific system situations. A flexibility index, named the ramping capability shortage probability (RSP), is used to quantify the extent to which the variability and uncertainty affect the flexibility. The second contribution is to generate various scenarios for variability and uncertainty based on a modified IEEE-RTS-96, to evaluate the flexibility. The penetration level of renewable energy resources is kept the same in each scenario. The results of a sensitivity analysis show that variability is more effective than uncertainty for high and medium net loads.

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Impact of Renewable Energy Sources on Power System Flexibility Requirements

Energies ◽

10.3390/en14102813 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2813

Author(s):

Valeri Mladenov ◽

Vesselin Chobanov ◽

Angel Georgiev

Keyword(s):

Renewable Energy ◽

Power System ◽

Renewable Energy Sources ◽

Supply And Demand ◽

Energy Sources ◽

Electricity System ◽

System Operator ◽

Critical Requirement ◽

Net Load ◽

Power System Flexibility

A power system can be defined as flexible if it can within economic and technological boundaries respond quickly and adequately to variations in supply and demand. The ongoing penetration of variable and intermittent renewable energy sources (RES) like wind and solar imposes additional and more critical requirement on power system flexibility. In this paper we propose a method to quantify these requirements based on the comparison of seven demand side parameters describing the statistical properties of the net load and the residual load of the referred power system. Each one of these parameters reflects a separate requirement on the available conventional generation in hourly and daily time scales—ramp up and ramp-down capabilities, technological minimum of generation, daily variation of generation. The proposed approach can be used to predict the requirements for generation flexibility according to the expected scenario of RES penetration in the future development of energy power system. It has been applied and integrated from the Bulgarian Transmission System Operator (TSO) which name is the Bulgarian Electricity System Operator (ESO).

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Investigating the Effect of Uncertainty Characteristics of Renewable Energy Resources on Power System Flexibility

Applied Sciences ◽

10.3390/app11125381 ◽

2021 ◽

Vol 11 (12) ◽

pp. 5381

Author(s):

Changgi Min

Keyword(s):

Renewable Energy ◽

Power System ◽

Forecast Error ◽

Energy Resources ◽

Renewable Energy Resources ◽

Load Forecast ◽

Simulation Results ◽

Net Load ◽

Power System Flexibility ◽

Skewness And Kurtosis

This study investigates the effect of uncertainty characteristics of renewable energy resources on the flexibility of a power system. The more renewable energy resources introduced, the greater the imbalance between load and generation. Securing the flexibility of the system is becoming important to manage this situation. The degree of flexibility cannot be independent of the uncertainty of the power system. However, most existing studies on flexibility have not explicitly considered the effects of uncertainty characteristics. Therefore, this study proposes a method to quantitatively analyze the effect of uncertainty characteristics on power system flexibility. Here, the uncertainties of the power system indicate the net load forecast error, which can be represented as a probability distribution. Of the characteristics of the net load forecast error, skewness and kurtosis were considered. The net load forecast error was modeled with a Pearson distribution, which has been widely used to generate the probability density function with skewness and kurtosis. Scenarios for the forecast net load, skewness, and kurtosis were generated, and their effects on flexibility were evaluated. The simulation results for the scenarios based on a modified IEEE-RTS-96 revealed that skewness is more effective than kurtosis. The proposed method can help system operators to efficiently respond to changes in the uncertainty characteristics of renewable energy resources.

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Comprehensive Overview of Power System Flexibility during the Scenario of High Penetration of Renewable Energy in Utility Grid

Energies ◽

10.3390/en15020516 ◽

2022 ◽

Vol 15 (2) ◽

pp. 516

Author(s):

Ekata Kaushik ◽

Vivek Prakash ◽

Om Prakash Mahela ◽

Baseem Khan ◽

Adel El-Shahat ◽

...

Keyword(s):

Renewable Energy ◽

Power System ◽

Wide Spectrum ◽

Comprehensive Overview ◽

High Penetration ◽

Long Duration ◽

Challenges And Opportunities ◽

Utility Grid ◽

Power System Flexibility ◽

High Share

Increased deployment of variable renewable energy (VRE) has posed significant challenges to ensure reliable power system operations. As VRE penetration increases beyond 80%, the power system will require long duration energy storage and flexibility. Detailed uncertainty analysis, identifying challenges, and opportunities to provide sufficient flexibility will help to achieve smooth operations of power system networks during the scenario of high share of VRE sources. Hence, this paper presents a comprehensive overview of the power system flexibility (PSF). The intention of this review is to provide a wide spectrum of power system flexibility, PSF drivers, PSF resources, PSF provisions, methods used for assessment of flexibility and flexibility planning to the researchers, academicians, power system planners, and engineers working on the integration of VRE into the utility grid to achieve high share of these sources. More than 100 research papers on the basic concepts of PSF, drivers of the PSF, resources of PSF, requirement of the PSF, metrics used for assessment of the flexibility, methods and approaches used for measurement of flexibility level in network of the power system, and methods used for the PSF planning and flexibility provisions have been thoroughly reviewed and classified for quick reference considering different dimensions.

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Multi-Technical Flexibility Retrofit Planning of Thermal Power Units Considering High Penetration Variable Renewable Energy: The Case of China

Sustainability ◽

10.3390/su12093543 ◽

2020 ◽

Vol 12 (9) ◽

pp. 3543

Author(s):

Jiaomin Liu ◽

Tong Guo ◽

Yue Wang ◽

Yonggang Li ◽

Shanshan Xu

Keyword(s):

Renewable Energy ◽

Power System ◽

Thermal Power ◽

Operational Parameters ◽

Operational Costs ◽

High Penetration ◽

Proposed Model ◽

And Performance ◽

Power System Flexibility

High penetration variable renewable energy introduces flexibility issues to the power system. For countries with coal as their main energy source, retrofitting existing thermal power units is one of the most realistic and feasible measures to improve power system flexibility. Multiple retrofit options will almost certainly be available for each individual power plant—all with distinct investment costs and performance implications. Therefore, this paper develops a multi-technical flexibility retrofit planning model to inform investment decisions of thermal power units in the short term. The model is formulated as a mix linear programming, with the goal of minimizing the systems overall investment and operational costs. In particular, a linear formulation is proposed to solve the coupling problem of retrofitting and operating, and take account of the changes in various units’ operational parameters after retrofit. The correctness and effectiveness of the proposed models are verified by a case study through a modified IEEE-30 bus system. The results demonstrate that it is necessary to consider the complementariness of multiple technologies between units. Besides, the proposed model could minimize the overall system investment and operational costs, and provide advice to planners and power generation companies.

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