Antonio Gatti

Bio: Antonio Gatti is an academic researcher. The author has contributed to research in topics: Electric power system & Wind power. The author has an hindex of 7, co-authored 18 publications receiving 111 citations.

Battery energy storage systems for the provision of primary and secondary frequency regulation in Italy

Abstract: Currently, Non-Programmable Renewable Energy Source (NPRES) generation contributes significantly to demand supply, but participation to ancillary services is still limited to emergency support (e. g. curtailment of energy production in case of over-generation, fast active power reduction in case of large over-frequency transients). Battery Energy Storage Systems (BESSs) can be employed to support the NPRES energy supply and ancillary services provision, allowing to enhance NPRES integration into the power system and to contribute to system reliability and security of supply. This work is focused on the provision of primary and secondary frequency regulation by BESSs, either in a stand-alone configuration or supporting wind or photovoltaic power plants, with particular reference to the Italian system. Simulation results are presented, considering a time series of frequency measured in the continental European grid and the output of the centralized secondary controller of the Italian mainland (published by the Italian TSO, Terna). The energy exchanges between a BESS and the power grid are shown, then a preliminary economic assessment is carried out.

Battery Energy Storage Systems for frequency regulation: Simplified aging evaluation

Abstract: The increasing exploitation of Renewable Energy Sources (RES) is progressively displacing large conventional power plants, thus reducing system operating reserves and stability margins. Therefore new resources for ancillary service provision are needed. Very fast and flexible response capabilities make Battery Energy Storage Systems (BESS) good candidates to this purpose. However, the related cycling operation may cause early performance degradation due to battery aging. Here, attention is focused on primary and secondary frequency regulation by a BESS, in a stand-alone configuration or supporting a RES-based plant. The BESS response to the measured frequency error and to the secondary control signal in mainland Italy is simulated, in terms of power and energy exchanges and State of Charge (SoC) dynamics. A simplified method is proposed to evaluate battery aging due to such operation: starting from typical characteristic curves Maximum number of cycles to end of life versus Depth of Discharge (DoD), a weighted average DoD, accounting for the actual SoC transient, is computed; the battery expected life is the ratio of the maximum number of cycles and the actual number of partial cycles done, both evaluated at the average DoD. This lifetime is finally compared to the BESS investment pay-back period.

Simulation of enhanced frequency response by battery storage systems: The UK versus the continental europe system

Abstract: Nowadays, the large exploitation of Non-Programmable Renewable Energy Source (NPRES) generation for demand fulfillment reduces the operating hours of relevant conventional power plants, which traditionally provide the operating reserves for frequency (and voltage) control. Thus, the power system is becoming more vulnerable, also because NPRES support to ancillary service supply is often very limited. Large and fast frequency deviations, e.g., occur more often, so the risk of instability and blackout increases. New ancillary services and new providers for them are needed. Battery Energy Storage System (BESS) technologies could be good candidates, thanks to their fast response capabilities. In this work, the provision of an Enhanced (fast) Frequency Response (EFR) by a BESS is simulated, with reference to two main European synchronous areas: the UK and the Continental Europe (CE) system. The EFR service is evaluated by using real frequency data and considering the requirements issued by the UK TSO. For the CE system, those requirements are adapted according to the CE frequency behaviour. The energy exchanges requested from and carried out by the BESS, a service performance indicator, and the possible aging related to battery cycling are evaluated.

Open access simulation toolbox for the grid connection of offshore wind farms using multi-terminal HVDC networks

Abstract: Decarbonisation of the European electricity system can become dauntingly costly due to transmission and distribution network issues arising from the integration of intermittent renewable generation sources It is expected that wind energy will be the principal renewable source by 2050 and, as such, a number of initiatives in the academia and in the industry are being carried out to propose solutions to best accommodate the wind resource This paper presents work carried out by DEMO 1 partners within the EU FP7 project BEST PATHS A MATLAB/Simulink toolbox consisting of the necessary building blocks for the simulation and integration of offshore wind farms using enabling technologies such as multiterminal high-voltage direct-current grids is presented To illustrate the toolbox capabilities, a number of system topologies is studied System performance is assessed and measured against a set of key performance indicators To ensure knowledge dissemination, the toolbox has been made available as open access in the BEST PATHS project website

Participation of Battery Energy Storage Systems in the Italian Balancing Market: Management Strategies and Economic Results

Abstract: The possible supply of balancing services by a Battery Energy Storage System (BESS) in the Italian Balancing Market (BM) is considered. A strategy to formulate (downward) bids and (upward) offers is proposed, based on the BM session timetable and on trying to sell the stored energy until the energy left becomes too small; purchase bids are then made to try to recharge the battery. Adopted bid/offer prices are averages of the historical accepted prices or samples from their statistical distribution, and are assumed to be accepted or not based on their comparison to such prices. One year of energy exchanges for the services is simulated and the related costs and revenues are computed. A sensitivity analysis is carried out by varying the adopted bid/offer prices by a fixed percentage. The bidding strategy appears to be promising, but there is room for improvement to reduce the BESS investment payback period and/or to increase the battery expected life against the charge-discharge cycles.

A Comprehensive Review on Structural Topologies, Power Levels, Energy Storage Systems, and Standards for Electric Vehicle Charging Stations and Their Impacts on Grid

Abstract: The penetration of electric vehicles (EVs) in the transportation sector is increasing but conventional internal combustion engine (ICE) based vehicles dominates. To accelerate the adoption of EVs and to achieve sustainable transportation, the bottlenecks need to be elevated that mainly include the high cost EVs, range anxiety, lack of EV charging infrastructure, and the pollution of the grid due to EV chargers. The high cost of EVs is due to costly energy storage systems (ESS) with high energy density. This paper provides a comprehensive review of EV technology that mainly includes electric vehicle supply equipment (EVSE), ESS, and EV chargers. A detailed discussion is presented on the state-of-the-art of EV chargers that include on-/off-board chargers. Different topologies are discussed with low-/high-frequency transformers. The different available power levels for charging are discussed. To reduce the range anxiety the EV chargers based on inductive power transfer (IPT) are discussed. The last part of the paper focuses on the negative impact of EV chargers along with the remedies that can be adopted. The international standards decided by different institutions and adopted universally are discussed in the latter part of this paper and finally, this paper concludes with the near to future advancement in EV technology.

A Comprehensive Review of Recent Advances in Smart Grids: A Sustainable Future with Renewable Energy Resources

Abstract: The smart grid is an unprecedented opportunity to shift the current energy industry into a new era of a modernized network where the power generation, transmission, and distribution are intelligently, responsively, and cooperatively managed through a bi-directional automation system. Although the domains of smart grid applications and technologies vary in functions and forms, they generally share common potentials such as intelligent energy curtailment, efficient integration of Demand Response, Distributed Renewable Generation, and Energy Storage. This paper presents a comprehensive review categorically on the recent advances and previous research developments of the smart grid paradigm over the last two decades. The main intent of the study is to provide an application-focused survey where every category and sub-category herein are thoroughly and independently investigated. The preamble of the paper highlights the concept and the structure of the smart grids. The work presented intensively and extensively reviews the recent advances on the energy data management in smart grids, pricing modalities in a modernized power grid, and the predominant components of the smart grid. The paper thoroughly enumerates the recent advances in the area of network reliability. On the other hand, the reliance on smart cities on advanced communication infrastructure promotes more concerns regarding data integrity. Therefore, the paper dedicates a sub-section to highlight the challenges and the state-of-the-art of cybersecurity. Furthermore, highlighting the emerging developments in the pricing mechanisms concludes the review.

Coordination of MMCs With Hybrid DC Circuit Breakers for HVDC Grid Protection

Abstract: A high-voltage direct-current (HVDC) grid protection strategy to suppress dc fault currents and prevent overcurrent in the arms of modular multilevel converters (MMCs) is proposed in this paper. The strategy is based on the coordination of half-bridge MMCs and hybrid dc circuit breakers (DCCBs). This is achieved by allowing MMC submodules to be temporarily bypassed prior to the opening of the DCCBs. Once the fault is isolated by the DCCBs, the MMCs will restore to normal operation. The performance of the proposed method is assessed and compared to when MMCs are blocked and when no corrective action is taken. To achieve this, an algorithm for fault detection and discrimination is used and its impact on MMC bypassing is discussed. To assess its effectiveness, the proposed algorithm is demonstrated in PSCAD/EMTDC using a four-terminal HVDC system. Simulation results show that the coordination of MMCs and DCCBs can significantly reduce dc fault current and the absorbed current energy by more than 70% and 90%, respectively, while keeping MMC arm currents small.

A Battery Energy Management Strategy for U.K. Enhanced Frequency Response and Triad Avoidance

Abstract: This paper describes a control algorithm for a battery energy storage system (BESS) to deliver a charge/discharge power output in response to changes in the grid frequency constrained by the National Grid Electricity Transmission (NGET)—the primary electricity transmission network operator in the U.K.—while managing the state of charge of the BESS to optimize the availability of the system. Furthermore, this paper investigates using the BESS in order to maximize triad avoidance benefit revenues while layering other services. Simulation using a 2 MW/1 MWh lithium–titanate BESS validated model is carried out to explore possible scenarios using the proposed algorithms. Finally, experimental results of the 2 MW/1 MWh Willenhall Energy Storage System verify the performance of the proposed algorithms.

Modular Multilevel Converter With Partially Rated Integrated Energy Storage Suitable for Frequency Support and Ancillary Service Provision

Abstract: Grid scale energy storage systems (ESSs) have received significant interest in recent years due to their ability to reduce/defer investment in transmission/distribution networks, as well their ability to act as primary reserve sources and provide emergency support to the transmission system. This paper investigates the dual purposing of an HVdc-Scale modular multilevel converter (MMC), allowing it to also act as an ESS. This has potential application in primary frequency response provision and other services such as de-coupled power oscillation damping. In the proposed topology, a certain percentage of sub-modules (SM) within the MMC have their capacitor interfaced through a dc–dc converter to an energy storage element (ESE), formed of a battery or ultracapacitor. By applying appropriate control, energy can be exchanged from the ESE to the main SM capacitor of each ESE-SM, and from there to either the ac or dc bus. It was found that for some operating points, an injection of circulating current was required to facilitate exchanging energy with the ESE-SMs. Analysis shows that, for instance, an additional power injection to ac or dc terminal of 0.1 per unit (10%) is possible with only 4% of the SMs replaced by full-bridge ESE-SMs, and no additional SMs added.