1,720,969 research outputs found
Optimization Strategies for the Mitigation of the Impact of Inverter-based Resources on Transmission and Distribution Networks
No full textThis Ph.D. Thesis investigates the integration of Inverter-based Resources (IBRs) into modern power systems, focusing on challenges related to frequency and voltage support in the context of high Renewable Energy Sources (RESs) penetration. Innovative methodologies are developed to optimize the operation of IBRs in transmission and distribution networks, with a particular emphasis on the Italian scenario, thanks to the activities carried out in partnership with the Italian transmission system operator, Terna, and the Italian National Agency for New Technologies, ENEA.
At transmission level, novel algorithms are introduced to determine the optimal techno-economic mix of Synthetic Inertia (SI) providing resources, including Photovoltaic (PV) power plants, Wind Turbines (WT) and Battery Energy Storage Systems (BESSs), and of Synchronous Compensators (SCs) able to limit the Rate of Change of Frequency (RoCoF) of a transmission network within the limits prescribed by grid codes. Moreover, methodologies for the optimal allocation of inertia-providing resources among the market zones are provided. The procedures are validated through simulations in DIgSILENT PowerFactory and are widely applied over the whole 2030 Italian transmission network scenario. Analyses to evaluate the impact of IBRs and HVDC on system Primary Regulating Energy (PRE) are developed and applied to Sicilia and Sardegna market zones, that will represent critical areas in the 2030 Italian transmission network scenario.
At distribution level, two Energy Management Systems (EMSs) are designed for polygenerative Microgrids (MGs) and MGs members of Renewable Energy Communities (RECs). The EMSs optimize active and reactive power flows, while minimizing energy costs and enhancing electric mobility integration, such as vehicle-to-grid and vehicle-to-building technologies. The impact of Distributed Energy Resources (DERs) on local voltage is assessed, along with the role of MGs in improving energy sharing within RECs. Two case studies are considered: a school complex MG and an industrial MG, member of a REC. The analysis shows the enhanced local energy sharing and the improved grid stability.
The findings of this Ph.D. Thesis provide valuable insights for grid operators and policymakers in designing and operating future power systems with high penetration of IBRs, ensuring grid reliability while promoting the integration of DERs and RES
Energy Management System for Optimal Operation of a Prosumer with Renewable Generation and Electric Vehicle Fleet with Vehicle-to-Building
No full textThe transition towards sustainable energy consumption, particularly within the building sector, presents challenges and opportunities for technological advancements in integrating Renewable Energy Sources (RESs) and Electric Vehicles (EVs) into the electric grid. This paper proposes an Energy Management System (EMS) tailored for optimizing the operation of a warehouse prosumer building located in Italy, equipped with Photovoltaic (PV), Wind Turbine (WT) units, and a fleet of EVs for freight delivery, able to provide Vehicle-to-Building (V2B) services. The EMS incorporates RES inverters' capability curves to manage reactive power flows efficiently. The objective function considers operating costs, RES curtailment costs, and penalties for inductive reactive power absorption. Through a detailed sensitivity analysis, this paper aims to analyse the impact of the EV fleet dimension on facility operations, providing insights into key energy and economic metrics, and focusing on the operational advantages offered by V2B service
Inverter-Based Nanogrid Design with Integration of Primary, Secondary and Tertiary Controls – A Case Study
No full textThis paper investigates the performance of a hierarchical control framework in an inverter-based Nanogrid (NG) serving a building. The NG integrates a 21 kW Photovoltaic (PV) array and two 40 kWh Battery Energy Storage Systems (BESS1 and BESS2). Firstly, a Mixed-Integer Quadratically Constrained Programming (MIQCP) Energy Management System (EMS) was implemented in MATLAB/YALMIP and solved with Gurobi, executing a dayahead optimization to minimize cost. Secondly, a simulation was carried out to test the behavior of the NG when undergoing a load increase contingency during islanded mode operation. To this purpose, the NG was implemented in MATLAB/Simulink Simscape. The EMS results highlighted that PV selfconsumption through BESSs is the best solution to minimize the operating costs of the facility. Dynamic simulation showed that the BESSs, by increasing the power output, are able to stop the frequency variation in the NG to 49.8 Hz, efficiently providing a frequency containment action
Energy Management System for a Prosumer with Vehicle-to-Home: a Case Study in Italy
No full textThis paper proposes an Energy Management System (EMS) based on a Mixed-Integer Linear Programming (MILP) optimisation model, implemented in Matlab/Yalmip and solved by Gurobi, used to manage a private house acting as a prosumer in the province of Bolzano, Italy. The house is equipped with a Photovoltaic (PV) plant and a Battery Energy Storage System (BESS). The building is connected to the low-voltage distribution grid and the integration of an Electric Vehicle (EV) with a dedicated charging wall-box is considered as a further scenario. In the first phase of the analysis, the performance of the system is examined without the inclusion of the EV, comparing the results of the developed EMS with real-world data. This phase aims to test the effectiveness of the proposed EMS, if compared to the one supplied by the PV and BESS provider: in the two representative months, January and August, the proposed EMS allows a reduction of net operating costs of 10.0 % and 1.9 % respectively. In the second phase of the analysis, the integration of the EV into the household context is considered, enabling Vehicle-to-Home (V2H). Economic and energy Key Performance Indicators (KPIs) show the effectiveness of the proposed EMS and the beneficial effects of EV and V2H integration, as proved by a Self-Consumption Rate (SCR) of 92.9 % in January and by a Self-Sufficiency Rate (SSR) of 99.9 % in August
Optimal Operation of an Innovative Electric Vehicle Charging Hub directly fed by Renewables
No full textThe reduction of Green House Gases (GHGs) emissions has been the top priority of the European Union (EU) in recent times. The increase in use of Electric Vehicles (EVs) to combat climate change is viable only with the use of Renewable Energy Sources (RESs) to power them. Since the Paris Agreement in 2015, the integration of RESs into the charging infrastructure has increased in the EU. The increasing market share of EVs in various categories has called for immediate changes in the EV charging infrastructure and in the operation of charging hubs. This paper aims to present an Energy Management System (EMS) to efficiently manage an EV charging hub fed by RESs, reducing the daily costs of operation and GHG emissions. The mathematical model of the EMS is developed in Matlab as a Mixed Integer Linear Programming (MILP) model. The MILP-based EMS is applied to the real-world case of an innovative EV charging hub located in the Ligurian region of Italy and the results of the optimization are reported
Techno-Economic Strategies to Define Inertia Needs in Future Transmission Networks
No full textIn the evolving landscape of the Italian generation scenario, renewable generation is gradually supplanting traditional power plants, causing a reduction of electric system inertia and potential inertia shortages. This study compares two different methodologies for estimating the necessary inertia to be integrated into the Italian Transmission Network by the year 2030, aiming to constrain the derivative of frequency according to predefined thresholds. The analysis encompasses renewable and conventional sources for additional inertia provision. Furthermore, the described approaches offer optimal combinations of these technologies based on techno-economic considerations. The 2030 scenario is delineated utilizing data sourced from Terna S.p.A, the Italian transmission system operator
Monitoring and Energy Simulation Analysis of a Mechanical Workshop with Photovoltaic System and Electric Mobility Infrastructures Integration
No full textThe industrial sector is a significant part of the global economy, responsible for most energy consumption and worldwide emissions. In particular, mechanical workshops are very widespread in Italy; they are experts in the production, machining and marketing of precision engineering products. In this paper, an Italian mechanical workshop involved in mechanical production, has been studied. The electrical loads were monitored and analyzed over a period of four years and an energy model was developed to determine the electrical consumption of heat pumps used for the air conditioning of the building. The annual electricity production of a PV system installed on the roof was also analyzed. The annual trends were compared in order to assess the benefits achievable through the installation of a storage system. In the overall scenario of the company's electrification, an optimization model was also developed to determine the benefits to be gained from the implementation of electric mobility infrastructures: the optimal size of batteries and the number of EVs charging stations were determined based on the economic analysis
Optimal allocation and sizing of electric vehicle charging infrastructure for green last-mile logistics
No full textThe transition towards electric mobility is being promoted by the European Union as a countermeasure to the greenhouse gas emissions in road transportation. Consequently, the adoption of electric vehicle fleets for freight movement and last-mile deliveries is in progress: this transition is viable if sufficient electric charging infrastructures are available within their operating routes. However, allocation of chargers at city centres may pose problems related to congestions in the power distribution network during peak hours, along with possible peaks in renewable energy sources production. This paper presents a mathematical programming formulation for the optimal allocation and sizing of an electric vehicle charging infrastructure within an urban area in which a fleet of electric vehicles for freight delivery operates. The considered urban area is divided into peripheral and internal zones, with the former able to host depots and large electric vehicle charging hubs and the latter hosting smaller electric vehicle charging areas. The optimization problem, formulated as a mixed-integer linear programming problem, aims to allocate and size the photovoltaic units, the battery energy storage systems and the electric vehicle chargers to be installed in each zone, depending on local requirements, while allowing the electric vehicle fleet to satisfy the predefined logistic demand in the considered zones. The model is applied to a delivery fleet operating in the city of Milan, Italy, considering various scenarios and making some sensitivity analyses for evaluating the impact of economic parameters on the optimal configuration of the facility. The results show that photovoltaic units are a viable solution towards sustainable logistics, while the installation of battery energy storage systems is not always favorable. Quick alternating current chargers and vehicle-to-grid chargers are generally preferable, while fast direct current chargers are economically viable only under certain conditions
Energy Management System for a Smart Green Nanogrid feeding a Research Laboratory with Autonomous Mobile Robots
No full textThis paper proposes a mixed-integer linear programming optimization model used to define an energy management system tailored for nanogrids in buildings, integrating renewable energy sources, battery energy storage systems and task-executing autonomous mobile robots. Focused on a nanogrid to be realised at the Savona Campus of the University of Genoa, the energy management system optimizes power flows and robot task scheduling in order to minimize the operating costs, the curtailment of the photovoltaic source and the number of unperformed tasks. Its novelty lies in combining energy and task planning constraints, offering significant potential for sustainable building energy management. Copyright (C) 2024 The Authors. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/
Impact of Inverter-Based Resources on Inertia Provision and RoCoF Limitation
No full textThe ongoing replacement of traditional power plants with Photovoltaic (PV), Wind Turbine (WT) and Battery Energy Storage System (BESS) power plants will lead to problems of inertia shortage in future power systems. Thus, the provision of Synthetic Inertia (SI) by Inverter-Based Resources (IBRs) will be crucial in order to deliver effective Rate of Change of Frequency (RoCoF) mitigation actions. The present paper presents a methodology to assess the impact of IBRs on the available inertia in future power systems. The study, carried out in partnership with Terna, the Italian transmission system operator, focuses on a critical market zone in the 2030 Italian scenario. First, the availability of inertia by synchronous generators and already-installed Synchronous Compensators (SCs) is assessed, along with the need of inertia (i.e., the inertia necessary to limit the zonal RoCoF at the limit value following a reference contingency). If the need is larger than the availability, the intervention of IBRs is considered to limit the RoCoF. In particular, a sensitivity analysis is carried out varying both the limit value of RoCoF and the overloading capability of IBRs inverters, showing that the predominant SI contribution will be delivered by BESSs. Regarding RoCoF containment, if the limit value is set at 2 Hz/s IBRs are able to make the gap negative over the whole year. On the other hand, if a more stressful condition is considered (i.e., limit value set at 1 Hz/s), the installation of additional SCs may become necessary to make the inertia gap negative for the whole year under whatever IBRs overloading capability scenario
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