Proposal of a New Procurement Strategy of Frequency Control Reserves in Power Systems: The Italian Case in the European Framework

Over the last few years, a strong penetration of Intermittent Renewable Energy Sources (IRES) has been in progress in the Italian power system. In this new framework, the dispatching activity must improve its efficiency to ensure adequacy and security of the national electricity system. European market integration initiatives are making this goal achievable, provided that the coherency of market price signals and reserve procurement at the European level are guaranteed. For this reason, the Italian Transmission System Operator (TSO), Terna, started to investigate the opportunity to align the Italian reserve-procurement approach to the one adopted in most European countries, procuring Replacement Reserve (RR) in dedicated auctions held in advance of the day-ahead market. The aim of this new methodology is to improve the coherency of price signals arising from the integrated European day-ahead market, anticipating potential scarcity conditions, thus helping to keep adequacy standards high. This paper describes the characteristics of a possible new reserve-procurement model based on the European benchmark. Comparative simulations are presented, estimating the impact of the new approach in terms of outcomes and costs of both the energy and ancillary services markets in Italy. The results of this study suggest activation of the reserve auction only in the cases in which the TSO expects a potential risk of simultaneous reserve scarcity across European countries.

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Adaptive Robust Optimization-Based Optimal Operation of Microgrids Considering Uncertainties in Arrival and Departure Times of Electric Vehicles

Energies ◽

10.3390/en11102646 ◽

2018 ◽

Vol 11 (10) ◽

pp. 2646 ◽

Cited By ~ 7

Author(s):

Se-Hyeok Choi ◽

Akhtar Hussain ◽

Hak-Man Kim

Keyword(s):

Robust Optimization ◽

Electric Vehicles ◽

Unit Commitment ◽

Renewable Energy Sources ◽

Market Price ◽

Optimal Operation ◽

Worst Case ◽

Price Signals ◽

Power Trading ◽

The Impact

The optimal operation of microgrids is challenging due to the presence of various uncertain factors, i.e., renewable energy sources, loads, market price signals, and arrival and departure times of electric vehicles (EVs). In order to incorporate these uncertainties into the operation model of microgrids, an adaptive robust optimization-based operation method is proposed in this paper. In particular, the focus is on the uncertainties in arrival and departure times of EVs. The optimization problem is divided into inner and outer problems and is solved iteratively by introducing column and constraint cuts. The unit commitment status of dispatchable generators is determined in the outer problem. Then, the worst-case realizations of all the uncertain factors are determined in the inner problem. Based on the values of uncertain factors, the generation amount of dispatchable generators, the amount of power trading with the utility grid, and the charging/discharging amount of storage elements are determined. The performance of the proposed method is evaluated using three different cases, and sensitivity analysis is carried out by varying the number of EVs and the budget of uncertainty. The impact of the budget of uncertainty and number of EVs on the operation cost of the microgrid is also evaluated considering uncertainties in arrival and departure times of EVs.

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Sensitivity Analysis of the Impact of the Sub- Hourly Stochastic Unit Commitment on Power System Dynamics

Energies ◽

10.3390/en13061468 ◽

2020 ◽

Vol 13 (6) ◽

pp. 1468

Author(s):

Taulant Kërçi ◽

Juan S. Giraldo ◽

Federico Milano

Keyword(s):

Power Systems ◽

Power System ◽

System Dynamics ◽

New England ◽

Unit Commitment ◽

Frequency Control ◽

Renewable Energy Sources ◽

Power System Dynamics ◽

Stochastic Unit Commitment ◽

The Impact

Subhourly modeling of power systems and the use of the stochastic optimization are two relevant solutions proposed in the literature to address the integration of stochastic renewable energy sources. With this aim, this paper deals with the effect of different formulations of the subhourly stochastic unit commitment (SUC) problem on power system dynamics. Different SUC models are presented and embedded into time domain simulations (TDS) through a cosimulation platform. The objective of the paper is to study the combined impact of different frequency control/machine parameters and different SUC formulations on the long-term dynamic behaviour of power systems. The analysis is based on extensive Monte Carlo TDS (MC-TDS) and a variety of scenarios based on the New England 39-bus system.

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An Adaptive Load Frequency Control for Power Systems with Renewable Energy Sources

Energies ◽

10.3390/en15020573 ◽

2022 ◽

Vol 15 (2) ◽

pp. 573

Author(s):

Mohamed Mokhtar ◽

Mostafa I. Marei ◽

Mariam A. Sameh ◽

Mahmoud A. Attia

Keyword(s):

Renewable Energy ◽

Power Systems ◽

System Performance ◽

Frequency Control ◽

Renewable Energy Sources ◽

Adaptive Controller ◽

Load Frequency Control ◽

Energy Sources ◽

Load Variations

The frequency of power systems is very sensitive to load variations. Additionally, with the increased penetration of renewable energy sources in electrical grids, stabilizing the system frequency becomes more challenging. Therefore, Load Frequency Control (LFC) is used to keep the frequency within its acceptable limits. In this paper, an adaptive controller is proposed to enhance the system performance under load variations. Moreover, the proposed controller overcomes the disturbances resulting from the natural operation of the renewable energy sources such as Wave Energy Conversion System (WECS) and Photovoltaic (PV) system. The superiority of the proposed controller compared to the classical LFC schemes is that it has auto tuned parameters. The validation of the proposed controller is carried out through four case studies. The first case study is dedicated to a two-area LFC system under load variations. The WECS is considered as a disturbance for the second case study. Moreover, to demonstrate the superiority of the proposed controller, the dynamic performance is compared with previous work based on an optimized controller in the third case study. Finally in the fourth case study, a sensitivity analysis is carried out through parameters variations in the nonlinear PV-thermal hybrid system. The novel application of the adaptive controller into the LFC leads to enhance the system performance under disturbance of different sources of renewable energy. Moreover, a robustness test is presented to validate the reliability of the proposed controller.

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Optimization Technique Inspired Load Frequency Controller for Multi Area Power System with Renewable Energy Source

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/850/1/012017 ◽

2021 ◽

Vol 850 (1) ◽

pp. 012017

Author(s):

J Shri Saranyaa ◽

A Peer Fathima ◽

Asutosh Mishra ◽

Rushali Ghosh ◽

Shalmali Das

Keyword(s):

Renewable Energy ◽

Power Systems ◽

Control Method ◽

Frequency Control ◽

Renewable Energy Sources ◽

Optimization Technique ◽

Optimization Method ◽

Load Frequency Control ◽

Load Frequency ◽

The Individual

Abstract Modern day scenario has an increasing power demand due to the growing development which indeed increases the load on the generation which might cause turbulence in the system and may bounce out of stability. The governor itself can’t handle such frequent load changes and adjust the generation amount to keep the frequency between the margins. This paper proposes an approach towards such predicament to incorporate an optimization method in order to ensure stability of the system despite the drastic changes in demand. Load frequency control is a control method for maintaining the frequency of the system during the change in demand. Use of controllers has proven to be effective in controlling the frequency deviations in the power systems and the response of the controller is further improved using optimization technique for better stability. The PID controller tuned by Particle Swarm Optimization is employed in multi-area system which reduces the time response by a considerable amount and the deviation settles much quicker despite the rapid load changes. The proposed controller is executed further for renewable energy sources connected to the individual areas and demonstration proves that the optimized controller is efficient enough in handling the frequency deviations when wind and solar with sunlight penetration is incorporated.

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Indices to Assess the Integration of Renewable Energy Resources on Transmission Systems

Conference Papers in Energy ◽

10.1155/2013/324562 ◽

2013 ◽

Vol 2013 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Alexandros I. Nikolaidis ◽

Francisco M. Gonzalez-Longatt ◽

C. A. Charalambous

Keyword(s):

Renewable Energy ◽

Power Systems ◽

Renewable Energy Sources ◽

Ghg Emissions ◽

Electrical Network ◽

Transmission Network ◽

Renewable Energy Resources ◽

Continuous Increase ◽

And Control ◽

The Impact

The continuous increase on the penetration levels of Renewable Energy Sources (RESs) in power systems has led to radical changes on the design, operation, and control of the electrical network. This paper investigates the influence of these changes on the operation of a transmission network by developing a set of indices, spanning from power losses to GHG emissions reduction. These indices are attempting to quantify any impacts therefore providing a tool for assessing the RES penetration in transmission networks, mainly for isolated systems. These individual indices are assigned an analogous weight and are mingled to provide a single multiobjective index that performs a final evaluation. These indices are used to evaluate the impact of the integration of RES into the classic WSCC 3-machine, 9-bus transmission network.

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Impact of Primary Frequency Control of Offshore HVDC Grids on Interarea Modes of Power Systems

Energies ◽

10.3390/en12203879 ◽

2019 ◽

Vol 12 (20) ◽

pp. 3879 ◽

Cited By ~ 2

Author(s):

Ali Bidadfar ◽

Oscar Saborío-Romano ◽

Vladislav Akhmatov ◽

Nicolaos A. Cutululis ◽

Poul E. Sørensen

Keyword(s):

Power Systems ◽

Frequency Control ◽

Wind Farms ◽

Offshore Wind ◽

Offshore Wind Farms ◽

Dc Voltage ◽

Simultaneous Use ◽

Primary Frequency ◽

Primary Frequency Control ◽

The Impact

Offshore high-voltage DC (HVDC) grids are developing as a technically reliable and economical solution to transfer more offshore wind power to onshore power systems. It is also foreseen that the offshore HVDC grids pave the way for offshore wind participation in power systems’ balancing process through frequency support. The primary frequency control mechanism in an HVDC grid can be either centralized using communication links between HVDC terminals or decentralized by the simultaneous use of DC voltage and frequency droop controls. This paper investigates the impact of both types of primary frequency control of offshore HVDC grids on onshore power system dynamics. Parametric presentation of power systems’ electro-mechanical dynamics and HVDC controls is developed to analytically prove that the primary frequency control can improve the damping of interarea modes of onshore power systems. The key findings of the paper include showing that the simultaneous use of frequency and DC voltage droop controls on onshore converters results in an autonomous share of damping torque between onshore power systems even without any participation of offshore wind farms in the frequency control. It is also found that the resulting damping from the frequency control of offshore HVDC is not always reliable as it can be nullified by the power limits of HVDC converters or wind farms. Therefore, using power oscillation damping control in parallel with frequency control is suggested. The analytical findings are verified by simulations on a three-terminal offshore HVDC grid.

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Operational Planning and Bidding for District Heating Systems with Uncertain Renewable Energy Production

Energies ◽

10.3390/en11123310 ◽

2018 ◽

Vol 11 (12) ◽

pp. 3310 ◽

Cited By ~ 4

Author(s):

Ignacio Blanco ◽

Daniela Guericke ◽

Anders Andersen ◽

Henrik Madsen

Keyword(s):

Renewable Energy ◽

Power Systems ◽

Power System ◽

Electricity Markets ◽

Electricity Market ◽

Renewable Energy Sources ◽

District Heating ◽

Operational Planning ◽

Solution Approach ◽

The Impact

In countries with an extended use of district heating (DH), the integrated operation of DH and power systems can increase the flexibility of the power system, achieving a higher integration of renewable energy sources (RES). DH operators can not only provide flexibility to the power system by acting on the electricity market, but also profit from the situation to lower the overall system cost. However, the operational planning and bidding includes several uncertain components at the time of planning: electricity prices as well as heat and power production from RES. In this publication, we propose a planning method based on stochastic programming that supports DH operators by scheduling the production and creating bids for the day-ahead and balancing electricity markets. We apply our solution approach to a real case study in Denmark and perform an extensive analysis of the production and trading behavior of the DH system. The analysis provides insights on system costs, how DH system can provide regulating power, and the impact of RES on the planning.

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Demand Flexibility Management for Buildings-to-Grid Integration with Uncertain Generation

Energies ◽

10.3390/en13246532 ◽

2020 ◽

Vol 13 (24) ◽

pp. 6532

Author(s):

Vahab Rostampour ◽

Thom S. Badings ◽

Jacquelien M. A. Scherpen

Keyword(s):

Power Generation ◽

Power Systems ◽

Wind Power ◽

Distribution System ◽

Large Scale ◽

Wind Power Generation ◽

Forecast Errors ◽

Monte Carlo Simulation Study ◽

System Operator ◽

The Impact

We present a Buildings-to-Grid (BtG) integration framework with intermittent wind-power generation and demand flexibility management provided by buildings. First, we extend the existing BtG models by introducing uncertain wind-power generation and reformulating the interactions between the Transmission System Operator (TSO), Distribution System Operators (DSO), and buildings. We then develop a unified BtG control framework to deal with forecast errors in the wind power, by considering ancillary services from both reserves and demand-side flexibility. The resulting framework is formulated as a finite-horizon stochastic model predictive control (MPC) problem, which is generally hard to solve due to the unknown distribution of the wind-power generation. To overcome this limitation, we present a tractable robust reformulation, together with probabilistic feasibility guarantees. We demonstrate that the proposed demand flexibility management can substitute the traditional reserve scheduling services in power systems with high levels of uncertain generation. Moreover, we show that this change does not jeopardize the stability of the grid or violate thermal comfort constraints of buildings. We finally provide a large-scale Monte Carlo simulation study to confirm the impact of achievements.

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Replacement Reserve for the Italian Power System and Electricity Market

Energies ◽

10.3390/en13112916 ◽

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.

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Assessing the Plurality of Actors and Policy Interactions: Agent-Based Modelling of Renewable Energy Market Integration

Complexity ◽

10.1155/2017/7494313 ◽

2017 ◽

Vol 2017 ◽

pp. 1-24 ◽

Cited By ~ 10

Author(s):

Marc Deissenroth ◽

Martin Klein ◽

Kristina Nienhaus ◽

Matthias Reeg

Keyword(s):

Renewable Energy ◽

Market Integration ◽

Renewable Energy Sources ◽

Policy Instruments ◽

Energy Market ◽

Agent Based ◽

Policy Interactions ◽

Agent Based Modelling ◽

The Impact

The ongoing deployment of renewable energy sources (RES) calls for an enhanced integration of RES into energy markets, accompanied by a new set of regulations. In Germany, for instance, the feed-in tariff legislation for renewables has been successively replaced by first optional and then obligatory marketing of RES on competitive wholesale markets. This paper introduces an agent-based model that allows studying the impact of changing energy policy instruments on the economic performance of RES operators and marketers. The model structure, its components, and linkages are presented in detail; an additional case study demonstrates the capability of our sociotechnical model. We find that changes in the political framework cannot be mapped directly to RES operators as behaviour of intermediary market actors has to be considered as well. Characteristics and strategies of intermediaries are thus an important factor for successful RES marketing and further deployment. It is shown that the model is able to assess the emergence and stability of market niches.

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