CSS/Italy

Italian Chapter of Complex Systems Society

research

research

Keeping global climate change within 1.5 ºC through net negative electric cities

By Chris Kennedy, Iain D Stewart, Michael I Westphal, Angelo Facchini, and Renata Mele, Current Opinon in Environmental sustainability, 2018, 30:18-25, https://doi.org/10.1016/j.cosust.2018.02.009

The development of net negative electric cities encompasses the three strategies of decarbonizing power supply, energy efficiency and electrification. There is potential to pursue these combined strategies rapidly to hold climate change to within 1.5  ºC. Recent work has identified many cities in developing countries that are ideal for electrification today based on carbon intensity and high access to electricity. Net negative electric cities could be achieved by following a comprehensive policy framework for low carbon investment. 

 

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A Statistical Approach for Modeling the Aging Effects in Li-Ion Energy Storage Systems

By Mario Mureddu, Angelo Facchini, Alfonso Damiano

Published in IEEE Access, vol 6, 2018, 42196

 

 This 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 approachis based on the denition 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 generalisation 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.

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Changes to Gate Closure and its impact on wholesale electricity prices: The case of the UK

Angelo Facchini, Alessandro Rubino, Guido Caldarelli, Giuseppe di Liddo

Published in Energy Policy, 125 (2019) 110-121

The electricity supply industry in the United Kingdom underwent a number of regulatory reforms since late 80’s that have transformed the trading and pricing of the energy market. Herein we provide empirical evidence that the Modification Proposal P12 (Mod P12) – that took place in 7/2/2002 – moving the Gate Closure (GC) interval from 3.5 h to 1 h before real time has caused a permanent alteration in the UK spot price volatility.

Using a combination of Recurrence Plot (RP) and Recurrence Quantification Analysis (RQA) we find that, after the the change in the GC time, short term price volatility significantly decreased between 2001 and 2008 while long term price volatility is not affected by CG change. Similar results are obtained by means of spectral analysis on the price series, showing a significant reduction in its variability. The results of our analysis suggest that a dynamical regime shift of the price occurred, and such shift is linked to the GC change whereby shorter GC intervals facilitate short-term forecasting on electricity demand and better reliability on the supply side. Therefore, GC closer to real time is associated to reduced price fluctuations in the wholesale market.

 

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Portfolio analysis and geographical allocation of renewable sources: A stochastic approach

Antonio Scala, Angelo Facchini, Umberto Perna, Riccardo Basosi

Published in Energy Policy, 125 (2019), 154-159

We take inspiration from the Modern Portfolio Theory introduced by Markowitz to propose a simplified strategy for the portfolio management of renewable energy sources based on Gaussian fluctuations with tunable correlations.

By analysing the impact of production fluctuations, we show how – depending on the sources’ temporal correlation patterns – a careful geographical allocation of different types of renewal energy sources can reduce both the energy needs for balancing the power system and its uncertainty. The proposed strategy can be easilyintegrated in a decision support system for the planning of renewable energy sources. Therefore, providing  policy/decision makers with an additional tool. We test our strategy on a set of case studies including a real-case based on literature data for solar and wind sources, and discuss how to extend the computation to non-Gaussian sources.

The paper shows that in the Markowitz framework an efficient trade-off between production and  fluctuations can be easily achieved, and that such framework also leads to important considerations on energy security. In perspective, analysis of time series together with such enriched frameworks would allow for the analysis of multiple realistic renewable generation scenarios helping decisions on the optimal size and spatial allocation of future energy storage facilities.

 

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Adaptive metabolic strategies explain diauxic shifts and promote species coexistence

Authors: Leonardo Pacciani, Samir Suweis, Amos Maritan

 

Competitive systems are most commonly described mathematically using MacArthur’s consumer-resource model, leading to the “competitive exclusion principle” which limits the number of coexisting competing species to the number of available resources. Nevertheless, several empirical evidences – in particular bacterial community cultures – show that this principle is violated in real ecosystems. Another experimental evidence that cannot be explained in this framework is the existence of diauxic (or polyauxic) shifts in microbial growth curves: bacteria consume resources sequentially, using first the one that ensures the highest growth rate and then, after a lag phase, they start growing slower using the second one. By introducing adaptive metabolic strategies whose dynamics tends to maximize species’ relative fitness, we are able to explain both these empirical evidences, thus setting the paradigm for adaptive consumer-resource models.

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Ecology in financial markets

Our work on Long Term Ecology of Investors in a Financial Markets providing empirical evidence of the existence of an ecology of investors adapting their trading strategies over a long period of time is out on Palgrave Communications – Nature https://lnkd.in/evedBSs

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Network Structural Vulnerability: A Multiobjective Attacker Perspective

L. Faramondi, R. Setola S. Panzieri, F. Pascucci, M. Schlueter, M. Munetomo and G. Oliva, IEEE Transactions on Systems, Man, and Cybernetics: Systems (Early Access Paper) doi:10.1109/TSMC.2018.2790438

 

Criticality of the airports within the U.S. Airline Network as it was in 1997 (node size is proportional to its degree and node color is proportional to criticality). The criticality is calculated by considering an attacker that aims at destroying some nodes, dealing the largest possible damage while keeping the cost of the attack to a minimum; the criticality is the frequency of attack of a node considering the solutions in the Pareto front. Panel (a): criticality for equal attack costs (b) criticality assuming the nodes are protected in a way proportional to the criticality indices shown in Panel (a).