Energy Management Strategies in hydrogen Smart-Grids: A laboratory experience

As microgrids gain reputation, nations are making decisions towards a new energetic paradigm where the centralized model is being abandoned in favor of a more sophisticated, reliable, environmentally friendly and decentralized one. The implementation of such sophisticated systems drive to find out new control techniques that make the system “smart”, bringing the Smart-Grid concept. This paper studies the role of Energy Management Strategies (EMSs) in hydrogen microgrids, covering both theoretical and experimental sides. It first describes the commissioning of a new labscale microgrid system to analyze a set of different EMS performance in real-life. This is followed by a summary of the approach used towards obtaining dynamic models to study and refine the different controllers implemented within this work. Then the implementation and validation of the developed EMSs using the new labscale microgrid are discussed. Experimental results are shown comparing the response of simple strategies (hysteresis band) against complex on-line optimization techniques, such as the Model Predictive Control. The difference between both approaches is extensively discussed. Results evidence how different control techniques can greatly influence the plant performance and finally we provide a set of guidelines for designing and operating Smart Grids.Ministerio de Economía y Competitividad DPI2013-46912-C2-1-

La gestión de la liquidez del Banco Central Europeo durante la crisis financiera: 2008-2009

Después de la quiebra de Lehman Brothers, en septiembre de 2008, hubo gran tensión en los mercados financieros. En los mercados de dinero, el Eurosistema tuvo que adoptar medidas que ofrezcan liquidez a los bancos a fin de evitar el colapso del mercado interbancario. En este trabajo se analizan los cambios en las formas de inyectar liquidez en el sistema, en un contexto de grave crisis económica y financiera. Con la disminución de las tasas de interés, se había producido una transformación radical entre octubre de 2008 y mediados de 2009. Las operaciones de financiación a más largo plazo alcanzaron la primera posición, la eliminación de las operaciones principales de financiación, mientras que se amplió la lista de valores como garantía, y un número cada vez mayor de bancos recurrieron a las subastas de liquidez. Si el BCE decide limitar las subastas de financiación a más largo plazo, adaptándolas a su procedimiento habitual de la política monetaria, que será de gran interés el análisis de la deuda actual de los bancos con respecto al BCE.After the bankruptcy of Lehman Brothers, in September 2008, there was huge stress in the financial markets. In the money markets, the Eurosystem had to adopt measures providing liquidity to banks in order to avoid the collapse of the interbank market. In this work we analyze the changes in the ways of injecting liquidity in the system, within a context of serious economic and financial crisis. With decreasing interest rates, there had been a radical transformation between October 2008 and mid 2009. The longer-term refinancing operations reached the first position, removing the main refinancing operations, while was enlarged the list of securities as collateral, and an increasing number of banks resorted to liquidity auctions. If the ECB decides to limit longer-term financing auctions, adapting them to its usual monetary policy procedure, it will be of great interest the analysis of the current debt of the banks with respect to the ECB.notPeerReviewe

Integration of Fuel Cell Technologies in Renewable-Energy-Based Microgrids Optimizing Operational Costs and Durability

In this paper, a Model Predictive Control (MPC) approach is proposed to manage a grid-tied hydrogen microgrid (μG) . The μG testbed is equipped with a 1-kW polymer electrolyte membrane (PEM) electrolyzer and a 1.5-kW PEM fuel cell as main equipment. In particular, we present a formulation that includes the cost of the electricity exported/imported, the aging of the components, and the operational constraints. The control objective is to satisfy user demand, as well as extend the lifespan of expensive equipment, as is the case of the fuel cell or the electrolyzer. μG performance is investigated under realistic scenarios in three experiments. The experimental results illustrate how the proposed control system is able to manage the fuel cell and the electrolyzer through smooth power references, as well as to satisfy the power demanded. Finally, benchmarking is carried out between hysteresis band (HB) control and the proposed MPC in regard to efficiency and cost of the operation. The results obtained show that the MPC approach is more effective than HB for this type of μG , with a reduction in operation cost of up to 30%

Physiotherapy for freezing of gait in Parkinson's disease: a systematic review and meta-analysis

Introduction. Freezing of gait (FOG) is one of the most severe symptoms associated with Parkinson's disease (PD). Physiotherapy treatment could be an effective strategy for treating FOG, but no systematic review has been carried out in this regard. Aim. To identify the characteristics, methodological quality, and main outcomes of the studies that have analyzed the effects of physiotherapy interventions in FOG up to date, by performing a systematic review and a meta-analysis. Patients and methods. Four electronic databases were searched in order to find randomized controlled trials that provided information regarding the effects of any kind of physiotherapy treatment on FOG. The methodological quality of the included investigations was assessed by means of the PEDro scale. Results. Twelve studies were identified for inclusion into the qualitative analysis, with four randomized controlled trials included in the final meta-analysis. The quality of the trials was generally good. Those physiotherapy modalities including cues were more effective for treating FOG than traditional physiotherapy approaches. The meta-analysis indicated that physiotherapy interventions had a significantly greater impact on FOG than control comparisons. Conclusions. Physiotherapy treatment, especially those modalities including visual and auditory cueing, should be prescribed to PD patients with FOG. Future studies including PD patients with cognitive impairment and FOG objective measurement tools are need to complete the existing scientific evidence

Sobre el papel del saldo presupuestario en las decisiones del Banco Central Europeo

Este trabajo analiza si el saldo presupuestario del conjunto de los países que integran la Unión Monetaria Europea ha influido en la determinación de los tipos de interés a corto plazo por parte del Banco Central Europeo (BCE). El análisis empírico es llevado a cabo con el método de los momentos generalizados, estimando una función de reacción de política monetaria que incluye esa variable fiscal. Se ha encontrado que, para el periodo que va desde 1999:1 hasta 2007:4, el saldo presupuestario fue una variable significativa en la función de reacción del BCE.This study inquires into whether the budgetary balance of the set of countries constituting the European Monetary Union has influenced the European Central Bank's (ECB's) determination of short term interest rates. The empirical analysis is performed using the generalized method of moments to estimate a monetary policy reaction function that includes the aforementioned fiscal variable. It was found that for the period 1999:1 to 2007:4, the budget balance was a significant variable in the ECB's reaction function.peerReviewe

Switching costs in the European postal service. Are there any solutions?

This article examines the costs of switching that may exist in the European postal sector, where it is carried out an ambitious process of opening to competition since 1997. Inadequate regulation of the access to some elements of postal infrastructure or services within the scope of the universal postal service exists. This article proposes adaptations to ensure transparent and non-discriminatory access conditions to elements of postal infrastructure in line with the sectorial directives aimed at strengthening competition in the long term in the postal market. The proposed adaptations focus on services such as postcode systems, address databases, post office boxes, delivery boxes, re-direction and return to sender services. All of them can help reduce the switching cost and thus strengthen competition

Building penetration losses at 3.5 GHz: dependence on polarization and incidence angle

We measured and analyzed the building penetration losses for four different kinds of facades as a function of the incidence angle and polarization at 3.5 GHz, which is a frequency of interest for fifth generation (5G) communication systems. Results show that the attenuation may vary up to 8 dB with the incidence angle, which justifies the need for an angular characterization of the penetration losses, going beyond the simpler characterization used for normal incidence. We also found that there is a relevant polarization dependence of this attenuation, as electromagnetic theory predicts for wave transmission across flat discontinuities and even across flat dielectric slabs. Results would be of interest for the network design of future 5G base stations using orthogonal polarizations.Xunta de Galicia | Ref. ED431C 2019/26Ministerio de Ciencia e Innovación | Ref. PID2020-112545RB-C52Fundação para a Ciência e a Tecnologia | Ref. UIDB/EEA/50008/202

Management systems in the EU fisheries

In the different proposals about fishing resources management systems there is a trend to consider that some incompatibilities exist between forms of management (public intervention or co-management) and the use of instruments based in creating market of fishing rights. In this paper, we will try to leave behind this incompatibility by means of a new concept of management system, which distinguishes accurately the instrument from the institutional framework under which the former is applied. We can see the usefulness of our concept in the European Union fisheries management. Although there is a common policy for all Member States, the way some countries have implemented the Community Regulations has changed the institutional framework which determines the fishermen's activity. The results of our analysis become more outstanding since The Green Paper on the Future of the Common Fisheries Policy emphasises the need to share with the fishermen the drawing-up of the fisheries policy.Xunta de GaliciaMinisterio de Ciencia y Tecnologı́a | Ref. SEC2001-370

Spain's North Atlantic swordfish fishery

The great growth of the Spanish swordfish fleet at the beginning of the 1990s has consolidated its position as the main northern stock swordfish producer, followed far behind by the USA, Canada and other EU countries. The aim of this paper is to analyse the determining institutional and economic factors in said fishery. We study the management instruments, placing special emphasis on the pertinent Spanish regulations and describe in detail the technical characteristics of the fleet, the fishing effort and the landings. We also carry out estimations of the revenues, costs and total income generated by the fleet. The results show the economic profitability of the fishery, with incomes which have increased, on average, by 7% in the last 15 years.Ministerio de Ciencia y Tecnología | Ref. SEC2001-3700Fundación CaixaGalici

¿Son asimétricas las reacciones de política monetaria de un banco central? El caso del BCE

Una gran parte de los bancos centrales adopta sus decisiones conforme a determinados objetivos, fundamentalmente de inflación y crecimiento económico. La pregunta que nos hacemos es si son igual de intensas las reacciones de esos institutos centrales cuando las desviaciones respecto a los objetivos señalados son positivas, en comparación con el caso en que sean negativas, o si, por el contrario, las reacciones son asimétricas. Para responder a esta cuestión, con base en los planteamientos taylorianos de la función de reacción de política monetaria, analizamos las posibles causas de comportamientos asimétricos y establecemos una metodología para determinar si las decisiones de un banco central han sido asimétricas, o no. Empíricamente, analizamos el caso del Banco Central Europeo (BCE), para concluir que en el caso de éste no es posible afirmar que haya reaccionado asimétricamente en el periodo 1999-2008.A large part of the central bank's decisions are subject to certain objectives, mainly inflation and economic growth. The question we ask is whether they are equally intense reactions when these central institutes deviations to the above objectives are positive, compared to the case in which they are negative, or if, on the contrary, the reactions are asymmetric. To answer this question, based on Taylorist approaches the reaction function of monetary policy, analyze the possible causes of asymmetric behavior and establish a methodology for determining whether the decisions of a central bank are asymmetric or not. Empirically, we analyze the case of the European Central Bank (ECB), to conclude that if this is not possible to say that has reacted asymmetrically periodo 1999 in 2008.peerReviewe