The Urban Metabolism of Lima: Perspectives and Policy Indications for GHG Emission Reductions

The urban metabolism of Metropolitan Lima, the largest urban agglomeration in Peru, which has recently surpassed 10 million inhabitants, was analyzed in this study. This coastal megacity, located within the Rimac, Chillón, and Lurin watersheds constitutes the socioeconomic center of the country and is the hub of the main import and export routes. A multi-layer approach was used to explore material and energy flows in the Peruvian capital for a 10-year timeframe. Results show that in 2006 the GDP of the 49 districts that shape the metropolitan area of Lima was 105.2 billion USD-PPP, while in 2014 it reached about 200 billion USD-PPP. Based on this growth, we highlight that energy, electricity and water flows experienced a linear increase with respect to GDP, being the electricity consumption in years 2006, 2011 and 2014, 7295, 10,112, and 11,465 GWh, respectively. Regarding demographics, population growth ratios of GDP (650%), electricity consumption (400%), solid waste production (250%), and water (100%) confirm the results of super linear scaling found by Kennedy et al. (2015) for the other megacities. Finally, the increase in greenhouse gas (GHG) emissions was computed following an important shift in the primary energy sources to produce electricity. The most important change was linked to the shift from hydropower to natural gas, a trend that initiated in 2006. For instance, in 2001 79% of the total electricity production came from hydropower, whereas in 2014 69% was linked to natural gas. This shift produced an increase of GHG emissions of more than 200% in 2014 when compared to the electricity generation mix of 2001. Following these results, we strongly encourage policies for the decarbonization of the electricity production sector, as well as for mobility infrastructures, e.g., electric public and transport sector, with a progressive shift toward electric mobility

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

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 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 network simplification approach to ease topological studies about the food-web architecture

Food webs studies are intrinsically complex and time-consuming. Network data about trophic interaction across different large locations and ecosystems are scarce in comparison with general ecological data, especially if we consider terrestrial habitats. Here we present a complex network strategy to ease the gathering of the information by simplifying the collection of data with a taxonomic key. We test how well the topology of three different food webs retain their structure at the resolution of the nodes across distinct levels of simplification, and we estimate how community detection could be impacted by this strategy. The first level of simplification retains most of the general topological indices; betweenness and trophic levels seem to be consistent and robust even at the higher levels of simplification. This result suggests that generalisation and standardisation, as a good practice in food webs science, could benefit the community, both increasing the amount of open data available and the comparison among them, thus providing support especially for scientists that are new in this field and for exploratory analysis

A genetic algorithm approach for the identification of microgrids partitioning into distribution networks

In this paper a Genetic Algorithm (GA) is used to partition a distribution network with the aim to minimize the energy exchange among the microgrids (i.e. maximize self-consumption) in presence of distributed generation. The proposed GA is tested on the IEEE prototypical network PG & E 69-bus. The microgrid partitioning is tested over a period of one year with hourly sampled data of real household consumption and real distributed generation data. The proposed GA approach is compared with a Tabu Search (TS) method already presented in the scientific literature. Results show that both GA and TS lead to the identification of equivalent microgrids. However, the GA based approach achieves better convergence results allowing for a reliable network partitioning with less CPU effort. Moreover, the histograms of the power unbalances of the microgrids show unimodal and skewed distributions offering an interesting starting point for the appropriate deployment of storage and control systems

Tracing two decades of carbon emissions using a network approach

Carbon emissions are currently attributed to producers although a consumption-aware accounting is advocated. After constructing the Carbon Trade Network, we trace the flow of emissions over the past two decades. Our analysis reveals the presence of an unexpected, positive feedback: despite individual exchanges have become less carbon-intensive, the increase in trading activity has ultimately risen the amount of emissions directed from `net exporters' towards `net importers'. Adopting a consumption-aware accounting would re-distribute responsibility between the two groups, possibly reducing disparities

Energy and material flows of megacities

Understanding the drivers of energy and material flows of cities is important for addressing global environmental challenges. Accessing, sharing, and managing energy and material resources is particularly critical for megacities, which face enormous social stresses because of their sheer size and complexity. Here we quantify the energy and material flows through the world’s 27 megacities with populations greater than 10 million people as of 2010. Collectively the resource flows through megacities are largely consistent with scaling laws established in the emerging science of cities. Correlations are established for electricity consumption,heating and industrial fuel use, ground transportation energy use, water consumption, waste generation, and steel production in terms of heating-degree-days, urban form, economic activity, and population growth. The results help identify megacities exhibiting high and low levels of consumption and those making efficient use of resources. The correlation between per capita electricity use and urbanized area per capita is shown to bea consequence of gross building floor area per capita, which is found to increase for lower-density cities. Many of the megacities are growing rapidly in population but are growing even faster in terms of gross domestic product (GDP) and energy use. In the decade from 2001–2011, electricity use and ground transportation fuel use in megacities grew at approximately half the rate of GDP growthPostprint (published version

Relating pain intensity of newborns to onset of nonlinear phenomena in cry recordings

The cries of several full term newborns, recorded during blood sampling, were analyzed. Spectrograms showed the appearance of irregular patterns related to the pain assessed using the method of the DAN scale. In particular, the appearance of Noise concentration Patterns (NP) in spectrograms was related to the increase of the pain suffered by the newborns. In this scenario, pain constitutes a bifurcation parameter for the vocal folds dynamic, inducing a Ruelle-Takens-Newhouse chaotic transition.Comment: 15 pages, 4 figures, 1 table. Accepted for publication in Phys. Lett.

Tendencias y dinámicas de los flujos de materiales y energía en un contexto urbano: un estudio de caso de una ciudad con una economía emergente

Antecedentes: Actualmente, la mayor parte de la población mundial vive en ciudades, y la rápida urbanización de la población está impulsando aumentos en la demanda de productos, bienes y servicios. Para diseñar eficazmente políticas de sostenibilidad urbana, es importante comprender las tendencias de los flujos de energía y materiales a medida que entran y salen de una ciudad. Este El conocimiento es fundamental para determinar los elementos clave que caracterizarán el futuro crecimiento urbano y abordarán el futuro. desafíos de suministro. Métodos: Este trabajo presenta un análisis de los flujos de energía y materia en la ciudad de Bogotá a lo largo del tiempo. de 2001 a 2017. Los flujos urbanos también se caracterizan en función de su evolución temporal con respecto a la población crecimiento para comparar e identificar cambios en los principales flujos de insumos, producción de riqueza, emisiones y residuos en el ciudad. Resultados: Los resultados del análisis se comparan luego con los de otras grandes aglomeraciones urbanas seleccionadas en América Latina y el mundo para resaltar similitudes y hacer inferencias. Los resultados muestran que en Bogotá había disminución de algunos de los flujos de materiales, como el consumo de agua y la generación de vertidos, en los últimos años, mientras que hubo un incremento en el consumo de energía y cemento y en la producción de emisiones de CO2 y materiales de construcción. La producción de residuos sólidos se mantuvo relativamente estable. En comparación con las otras grandes ciudades. considerado, observamos que las tasas de crecimiento de 10 años de los flujos en relación con el crecimiento de la población son más bajas en Bogotá, particularmente si se compara con otras aglomeraciones urbanas de América Latina. Conclusiones: Los hallazgos de este estudio son importantes para avanzar en las caracterizaciones de las tendencias de materiales y los flujos de energía en las ciudades, y contribuir al establecimiento de un referente que permita definir y evaluar los diferentes impactos de las políticas públicas y promover la sostenibilidad de Bogotá en las próximas décadas.Background: Currently, most of the world’s population lives in cities, and the rapid urbanization of the population is driving increases in the demand for products, goods and services. To efectively design policies for urban sustainability, it is important to understand the trends of fows in energy and materials as they enter and leave a city. This knowledge is essential for determining the key elements characterizing future urban growth and addressing future supply challenges. Methods: This paper presents an analysis of the energy and material fows in the city of Bogotá over the time span from 2001 to 2017. Urban fows are also characterized in terms of their temporal evolution with respect to population growth to compare and identify the changes in the main input fows, wealth production, emissions and waste in the city. Results: The results of the analysis are then compared with those for other selected large urban agglomerations in Latin America and worldwide to highlight similarities and make inferences. The results show that in Bogotá, there was a decrease in some of the material fows, such as the consumption of water and the generation of discharge, in recent years, while there was an increase in the consumption of energy and cement and in the production of CO2 emissions and construction materials. Solid waste production remained relatively stable. With respect to the other large cities considered, we observe that the 10-year growth rates of the fows with respect to population growth are lower in Bogotá, particularly when compared with the other urban agglomerations in Latin America. Conclusions: The fndings of this study are important for advancing characterizations of the trends of material and energy fows in cities, and they contribute to the establishment of a benchmark that allows for the defnition and evaluation of the diferent impacts of public policy while promoting the sustainability of Bogotá in the coming decades