1,721,016 research outputs found
A Statistical Approach for Modeling the Aging Effects in Li-Ion Energy Storage Systems
Full text linkThis paper presents a novel approach for the technical and economic assessment of Li-ion battery energy storage systems (BESS) in smart grids supported by renewable energy sources. The approach is based on the definition of a statistical battery degradation cost model (SBDCM), able to estimate the expected costs related to BESS aging, according to the statistical properties of its expected cycling patterns. This new approach can improve the assessment of the economical sustainability of BESSs in this kind of applications, helping in this way the planning processes in electricity infrastructures in presence of high penetration of intermittent renewable energy sources. The SBDCM proposed in this paper is a statistical generalization of a battery degradation model presented in the literature. The proposed approach has been validated numerically comparing the results with those of the deterministic model considering for the BESS a stochastic dataset of input signals. In order to test the usefulness of the proposed model in a real world application, the proposed SBDCM has been applied to the evaluation of the economic benefit associated to the development of distributed energy storage system scenarios in the Italian power system, aimed to provide ancillary services for supporting electricity market
A multistage design procedure for planning and implementing public charging infrastructures for electric vehicles
Full text linkPresented in this paper is a Multistage Design Procedure (MSDP) for planning and implementing Public Charging Infrastructures (PCIs) to satisfy intracity charging demand of Electric Vehicles (EVs). The proposed MSDP splits planning and design processes into multiple stages, from macroscale to fine-scale levels. Consequently, the preliminary results achieved at each stage can be refined at the subsequent stages, leading to determine the accurate number and precise geographical location of each charging point. The main advantage of the proposed approach is that it splits a very complicated procedure into multiple and simpler stages, at each of which appropriate goals, targets and constraints can be included. As a result, the iterative interactions among all the stakeholders involved in the PCI design process are significantly simplified. The proposed MSDP has been employed in the planning and design of the PCI of the Italian island of Sardinia, accordingly to all the public bodies
A Complex Network Approach for the Estimation of the Energy Demand of Electric Mobility
Full text linkWe study how renewable energy impacts regional infrastructures considering the full deployment of electric mobility at that scale. We use the Sardinia Island in Italy as a paradigmatic case study of a semi-closed system both by energy and mobility point of view. Human mobility patterns are estimated by means of census data listing the mobility dynamics of about 700,000 vehicles, the energy demand is estimated by modeling the charging behavior of electric vehicle owners. Here we show that current renewable energy production of Sardinia is able to sustain the commuter mobility even in the theoretical case of a full switch from internal combustion vehicles to electric ones. Centrality measures from network theory on the reconstructed network of commuter trips allows to identify the most important areas (hubs) involved in regional mobility. The analysis of the expected energy flows reveals long-range effects on infrastructures outside metropolitan areas and points out that the most relevant unbalances are caused by spatial segregation between production and consumption areas. Finally, results suggest the adoption of planning actions supporting the installation of renewable energy plants in areas mostly involved by the commuting mobility, avoiding spatial segregation between consumption and generation areas
Distributed generation and resilience in power grids
No full textWe study the effects of the allocation of distributed generation on the resilience of power grids. We find that an unconstrained allocation and growth of the distributed generation can drive a power grid beyond its design parameters. In order to overcome such a problem, we propose a topological algorithm derived from the field of Complex Networks to allocate distributed generation sources in an existing power grid. © 2013 Springer-Verlag
Green power grids: How energy from renewable sources affects networks and markets
Full text linkThe increasing attention to environmental issues is forcing the implementation of novel energy models based on renewable sources. This is fundamentally changing the configuration of energy management and is introducing new problems that are only partly understood. In particular, renewable energies introduce fluctuations which cause an increased request for conventional energy sources to balance energy requests at short notice. In order to develop an effective usage of low-carbon sources, such fluctuations must be understood and tamed. In this paper we present a microscopic model for the description and for the forecast of short time fluctuations related to renewable sources in order to estimate their effects on the electricity market. To account for the inter-dependencies in the energy market and the physical power dispatch network, we use a statistical mechanics approach to sample stochastic perturbations in the power system and an agent based approach for the prediction of the market players' behavior. Our model is data-driven; it builds on one-dayahead real market transactions in order to train agents' behaviour and allows us to deduce the market share of different energy sources. We benchmarked our approach on the Italian market, finding a good accordance with real data
Bench-Scale Absorption Testing of Aqueous Potassium Lysinate as a New Solvent for CO2 Capture in Natural Gas-Fired Power Plants
No full textThis work reports the results of an experimental campaign aiming at the characterization of the CO2 absorption performance for different aqueous solutions of potassium lysinate (LysK). The solvent stands out as a promising amino acid for post-combustion CO2 capture from combustion flue gas and it has been selected based on the high values of the overall kinetic constant (kov) and CO2 absorption flow reported in the literature. Three different LysK concentrations (8.9, 17.4 and 32.9 %w/w) have been compared and benchmarked against aqueous MEA solution (30% w/w), via closed-cycle absorption tests conducted on a bench-scale column (D = 80 mm, Packed Height = 900 mm). Liquid to gas ratios (1.39 mol/mol) and synthetic flue gas conditions (4% CO2 concentration on a molar basis, the remainder being N2) target the solvent application of CO2 capture in natural gas combined cycles, and are consistent with previous tests conducted on MEA and Potassium prolinate (ProK) solutions. Results highlight that LysK attains faster loading increase rates compared to ProK and higher CO2 loadings at saturation (between 0.82 and 0.98 molCO2/molAlk depending on the test case) with respect to MEA (0.52 molCO2/molAlk) and ProK. Finally, according to the capacity trend measured in this work, an aqueous solution with 43.7% w/w LysK has been identified as a promising option to be further investigated, verifying potential savings in the absorber packing requirements (i.e. lower packing height in a full-scale application, due to the better kinetics of LysK) while ensuring the same absorption capacity level of 30% MEA
A Combined Planning and Design Approach of a Public Charging Infrastructure for Electric Vehicles
No full textA Combined Planning and Design approach (CPD) for a Public Charging Infrastructure (PCI) for Electric Vehicles (EVs) is presented in this paper. The aim is defining the displacement of charging infrastructures for easing early EV diffusion. The proposed CPD consists in a traffic/parking model that estimates the charging demand of potential EV owners for a given scenario. A coarse distribution of Charging Stations (CSs) over the selected Zones of Interest (ZOIs) is achieved at first, by taking into account the charging demand coverage. Subsequently, PCI structure is further and sequentially refined in order to comply with both urban and power system constraints, by minimizing installation cost at the same time. The proposed CPD is being employed for designing the PCI of the Italian island of Sardinia in order to support the adoption of EVs for commuting; its effectiveness is shown by some preliminary results that refer to a portion of the overall PCI
Optimal positioning of storage systems in microgrids based on complex networks centrality measures
Full text linkWe propose a criterion based on complex networks centrality metrics to identify the optimal position of Energy Storage Systems in power networks. To this aim we study the relation between centrality metrics and voltage fluctuations in power grids in presence of high penetration of renewable energy sources and storage systems. For testing purposes we consider two prototypical IEEE networks and we compute the correlation between node centrality (namely Eigenvector, Closeness, Pagerank, Betweenness) and voltage fluctuations in presence of intermittent renewable energy generators and intermittent loads measured from domestic users. We show that the topological characteristics of the power networks are able to identify the optimal positioning of active and reactive power compensators (such as energy storage systems) used to reduce voltage fluctuations according to the common quality of service standards. Results show that, among the different metrics, eigenvector centrality shows a statistically significant exponential correlation with the reduction of voltage fluctuations. This finding confirms the technical know-how for which storage systems are heuristically positioned far from supply reactive nodes. This also represents an advantage both in terms of computational time, and in terms of planning of wide resilient networks, where a careful positioning of storage systems is needed, especially in a scenario of interconnected microgrids where intermittent distributed energy sources (such as wind or solar) are fully deployed
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