1,720,980 research outputs found
Impact of energy communities on the distribution network: An Italian case study
Full text linkIn this paper, a methodology for evaluating the potential impact of Energy Communities (ECs) on medium-voltage (MV) distribution networks is presented. To account for the various configurations and scenarios of ECs, a stochastic approach has been developed; it is based on a Monte Carlo simulation that generates a variety of EC configurations, varying the size and number of new generators, points of common coupling, and primary energy sources in the generation mix (wind, hydro, photovoltaics). The procedure proposed has the aim of evaluating all the possible configurations that could impact the grid's infrastructure. Following the execution of an hourly load flow procedure for the entire year for each configuration, output variables are processed obtaining analytical results to identify trends in losses, line and transformer loading, as well as voltage violations. The proposed methodology was applied to two case studies based on real MV networks. The first is relevant to an urban area with a high energy demand but limited generator capacity, while the latter is related to a mountainous, sparsely populated area with low energy demand and an abundance of renewable energy production. The results show that promoting coupling between loads and generators is a key factor for ensuring grid compliance (i.e. minimizing the grid impact) in the development of EC
A Game Theoretic Approach for Energy Sharing in the Italian Renewable Energy Communities
Full text linkWith the Clean Energy Package, the European Union introduced the concept of Renewable Energy Communities: groups of citizens, small and medium enterprises and local authorities that decide to join forces to equip themselves with systems to produce and share energy from renewable energy sources. The Italian legislation recently started an experimental phase in which renewable energy communities receive an incentivising tariff for the energy produced and shared within the community. This paper faces the problem of creating a new renewable energy community in two steps. First, a mathematical model of the energy flows among the members of the community is characterised according to the Italian schema. This model is used to find the optimal portfolio for the energy community, given energy requests and local source availability. Secondly, the Shapley value, a particular solution of cooperative games known to be the most fair method to allocate costs and profits of shared infrastructures, is proposed to distribute benefits among community members. The methodology has been applied to a case study based on a real low voltage network, and the economics for consumers and producers in participating to the project have been evaluated. The proposed solution, simulated adopting real economic parameters defined in the Italian regulatory framework, results to be economically viable from the point of view of the investors with a profitability index of 1.36 and, at the same time, aligned with the social purposes of the energy communities
A novel software package for the robust design of off-grid power systems
No full textOff-grid power systems represent one of the key solutions for rural electrification. Most of the analyses or tools already present in literature do not consider the final users' energy needs as the starting point of the process nor they consider the inherent uncertainties about loads and resources. Comprehensive stochastic procedures that look at the atypical features of rural contexts and include estimation errors into the design phase are strongly required. In this paper, we present Poli. NRG (POLItecnico di Milano - Network Robust desiGn): a novel software package for the robust design of off-grid electric power systems. Poli. NRG is composed of four blocks which separately face the different design phases: (i) the data inputs gathering block provides a methodology to collect field data as regards weather condition and load demand; (ii) the inputs processing block elaborates the inputs to obtain load and sources profiles over the entire lifetime of the plant; (iii) the system modelling and simulation block simulates different off-grid system configurations and evaluates the related techno-economic performances; (iv) the output formulation block finds the most robust design for the targeted context through specific optimization methods. After a comprehensive description of the software, we have applied it to size a PV + BESS microgrid system to supply power to a peri-urban area of Uganda. The results confirm that parameters' uncertainties deeply affect the design of the system and motivate the robust design approach proposed. Poli. NRG is devoted to map those uncertainties and provide information for decision makers
Smart Charging Algorithm for Flexibility Provision with Electric Vehicle Fleets
No full textThe penetration of electric vehicles (EVs) is quickly increasing. On one side, they are welcome to reduce the carbon footprint of the mobility sector. On the other hand, they can have a negative impact on the power system, given the high requested power rates at low or medium voltages. To prevent this, smart charging and vehicle-to-grid algorithms must be elaborated and exploited. In this study, we propose an EV parking garage providing ancillary services on the Italian Balancing Market. The average power withdrawal is estimated based on real world data. The available power for provision of upward and downward tertiary frequency regulation are then computed. A bid on the market is performed via a Balancing Service Provider and a market simulator returns the outcome in terms of acceptance or rejection. The results include the power profiles, the reliability of the garage performance on market and the economics. The savings for energy withdrawn are around 8% of the total cost. The provided flexibility in the daily simulation is up to 5 MW for a parking with 1100 EVs. The reliability of the provision is of 99%. Improvements can include a better modeling of the market and testing different regulatory frameworks
Battery modeling for microgrid design: A comparison between lithium-ion and lead acid technologies
Full text linkBattery energy storage systems are fundamental components in microgrids operations, therefore it is important to adopt models suitable to properly evaluate the performance of these electrical systems. Different methodologies for battery modeling have been developed and tested in this work: (i) Empirical model, in which batteries are described by analytic expressions not based on electrochemical processes; (ii) Equivalent electrical circuit model, in which batteries are described in terms of electrical quantities. These approaches allow to adapt the model to different battery technologies: both the emerging Li-ion and the consolidated lead acid are considered in this paper. The proposed models are implemented in the software Poli. NRG, a Matlab based procedure for microgrid sizing developed by Energy Department of Politecnico di Milano. Simulations are based on a real case study relevant to a microgrid in a rural area: Ngarenanyuki Secondary School in Tanzania. The proposed methodology is used to design a new microgrid based on photovoltaic and energy storage system, comparing the results obtained adopting different modeling approaches and different technologies. Eventually, results are critically analyzed and discussed in order to compare accuracy, computational effort, costs and opportunities
Renewable Energy Communities in Valle d'Aosta Region: development perspectives
No full textIn March 2020, the first Italian law concerning collective self-consumption and renewable energy communities came into force. This study focuses on the possible applications and limits of the law in the Valle d’Aosta region. In this area, energy communities are stimulating a great interest, also thanks
to the century-long history of the area as a producer of renewable energy through hydroelectric power plants. Analyzing the context of Valle d’Aosta, some issues appear to be prominent with respect to the energy communities. The paper focuses on two crucial aspects that needs to be defined in the next energy policy on energy communities: aggregation criteria and incentive scheme
Energy planning approach for an efficient distribution grid
No full textThe work proposes a novel planning procedure to design the portfolio of Dispersed Generation in a given area in order to exploit optimally the locally available RES. The objective of the work is to provide suitable indications to Policy Makers useful to develop more effective regional energy plans. The developed approach is applied on a real life study case: the electric distribution network supplying the urban area and the neighbourhood of the Italian city of Aosta
To Join or Not to Join? The Energy Community Dilemma: An Italian Case Study
Full text linkEnergy Communities (EC) are becoming a major driver to foster the energy transition in Europe and the regulatory framework adopted by each Member State (MS) plays a key role for a prosperous deployment of ECs. This paper is thus divided into two layers. The first layer of this paper addresses the current regulations introduced by MSs regarding ECs, providing a critical comparison of each solution used. The second layer of research concerns the introduction of a Mixed Integer Linear Programming (MILP) optimization algorithm early studied by some of the authors furtherly developed to assess the conditions that favour prosumers’ participation to ECs. Both these models have been tested on a case study located in the city of Magliano Alpi, in the north of Italy. The results demonstrate that the proposed methodology correctly evaluates the key parameters influencing participation of citizens in ECs and indicate that for the Italian EC under study, there is the possibility to further expand the capacity installed without undermining the profitability of investment
Microgrid design: sensitivity on models and parameters
Full text linkDesigning off-grid systems in developing countries
is not a trivial task; unpredictable energy sources and uncertain
load demands have to match in a seamless solution, providing
the most favourable conditions in terms of adequacy with respect
to the energy needs and costs. The challenge is to define which
parameters/assumptions could have a strong impact on the results
in order to properly model them.
This paper is based on a peculiar study case: a microgrid
deployed by the Politecnico di Milano team in Tanzania, load
and generator power profiles have been sampled each second over
many months. Given such a large amount of data, it is proposed
a sensitivity analysis devoted to quantifying the impact that
different assumptions could have in the design of a theoretical
new microgrid that could optimally feed the loads. Numerical
analysis is based on a tool, named PoliNRG, developed by a
research team of Politecnico di Milano
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