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In this paper, we address the problem of determining the optimal day-ahead generation profile for a wind power producer by exploiting wind speed forecasts provided by a meteorological service. In the considered framework, the wind power producer is called to take part in the responsibility of system operation by providing day-ahead generation profiles and undergoing penalties in case of deviations from the schedule. Penalties are applied only if the delivered hourly energy deviates from the schedule more than a given relative tolerance. The optimal solution is obtained analytically by formulating and solving a stochastic optimization problem aiming at maximizing the expected profit. The proposed approach consists in exploiting wind speed forecasts to classify the next day into one of several predetermined classes, and then selecting the optimal solution derived for each class. The performance of the bidding strategy is demonstrated using real data from an Italian wind plant and weather forecasts provided by a commercial meteorological service.

Why are small islands more vulnerable to the global and major ordeal of climate change? How do they face this huge challenge and what can we learn from their experience? These are among the crucial questions examined by Carola Klöck and Michael Fink in their recently coedited volume entitled Dealing with Climate Change on Small Islands: Toward Effective and Sustainable Adaptation, published by Universitätsverlag Göttingen. Interview by Miriam Périer, CERI.

Fil: Bavio, Marcela Alejandra. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Fisica e Ingenieria del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Tandil. Centro de Investigaciones en Fisica e Ingenieria del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernacion. Comision de Investigaciones Cientificas. Centro de Investigaciones en Fisica e Ingenieria del Centro de la Provincia de Buenos Aires; Argentina

Artículos en revistas Liberalization policies, the challenges of integrating distributed generation resources, and the recent flattening of electricity demand due to the economic crisis and technological change have led to lower returns for European electricity suppliers. Innovative and sustainable business models are needed to serve electricity customers while reflecting the operational needs of the system and maintaining supplier financial viability. This paper describes a novel model of Integrated Energy Services that encompasses distributed generation (DG) and demand response (DR) resources for industrial customers. We further reflect on some of the market opportunities and regulatory drivers for the development of similar schemes across Europe. info:eu-repo/semantics/publishedVersion

Abstract The aerodynamic design of small wind turbines for the urban setting attracts increasing interest within the scientific community, but the adoption of a proper control strategy may be just as important, especially in high turbulent winds, where such energy conversion devices should ideally operate. As a matter of fact, the mere rotor efficiency is meaningless unless the system has also the capability of rapidly changing its angular speed in case of a sudden variation of the wind velocity, to reach a new optimal operating condition. This work will attempt neither to develop dynamic simulation models nor to examine possible turbine control strategies, being the focus much broader, namely, the investigation of operational contexts where the peculiar inertial characteristics of wind turbines would compromise any form of robust control. Inertial and operational data of commercially available turbines (characterized by both horizontal and vertical-axis architectures), as well as the results disseminated in various literature sources, operational experiences and design best practices, are here collected under one cover and compared, thus deriving some basic and fundamental relations between rotor inertia and angular acceleration, highlighting how, in several cases, a control strategy based on the continuous tracking of the optimal operating condition is most unlikely. Such considerations raise the question of whether the problem of inertia renders futile many prevailing theories about small wind turbine operation and plans for implementing new control strategies, especially as far as vertical axis architectures are concerned. On the other hand, some constructive advice is also presented, in the form of a means to compare the effective performances of different turbines, in a given installation site, with respect to their nominal (i.e. steady state, or wind tunnel) behaviour. As a final result, a new bound for a reliable estimation of the amount of energy a wind turbine will generate in a specific site is suggested, based on the comparison between a representative time scale of the installation site and the response time of the candidate wind turbine.

The development of heat transfer fluids (HTF) and heat storage materials (HSM) is crucial to design concentrating solar plant (CSP). Binary alkaline nitrate mixtures are currently used as sensible thermal energy storage materials. However, multi-component nitrate/nitrite systems were proposed as possible better candidates. In particular, ternaries mixtures containing sodium, potassium, and calcium are extremely promising as thermal fluids, given their reduced toxicity and greater cost-effectiveness. Nevertheless, very few data are present in the scientific literature regarding the correspondent phase diagram, and only the properties of specific compositions are reported. For this reason, a regular solution model was developed and employed in this work, and validated by comparing the simulation results with experimentally obtained phase change values. In particular, given that the common calorimetric techniques are impracticable for detecting the transition temperatures of calcium containing nitrate mixtur...

Industry is a fundamental sector that allows mass production to support a large population. As population grows, many industries produce large amounts of industrial effluents with different pollutants, that must be removed at the industrial wastewater treatment plants, with the consequent production of large amounts of sludge. The present study was conducted to identify and evaluate different sludge treatment/valorisation methodologies, being given priority to the valorisation in detriment of the elimination operations, like incineration or landfill. Therefore, sludges from the wastewater treatment plant of a resin industry, after dehydration operation by a press, were submitted to several valorisation methodologies, such as: application in anaerobic digestion aiming the production of biogas and allowing energy recovery, use in the preparation of adsorbents for the treatment of industrial wastewater, use as cement replacement in mortar production, and application of heterogeneous catalysts to produce biodiesel. The results revealed that all methodologies can be applied as sludge recovery. However, it is possible to conclude that the most promising industrial sludge treatment/recovery hypothesis is anaerobic co-digestion followed by the production of heterogeneous catalysts for biodiesel production.

Water is necessary for the survival of all life forms on Earth. The consequences of climate change on water resources can be seen in two dimensions: water availability and water quality. Factors on which water quality depends include population growth, urbanization, and land use change. Climate change encourages changes in the hydrological cycle as water is included in all components of the climate system, including the atmosphere, hydrosphere, lithosphere, and biosphere. Therefore, the link between climate change and water resources is essential for survival. Since the beginning of the Earth, the climate has been constantly changing and this is a normal event, but this otherwise slow process is extremely accelerated. Knowledge of the different hydrological and biochemical processes occurring in different waters is crucial for understanding climate change and water quality. Voda je nužna za opstanak svih oblika života na Zemlji. Posljedice klimatskih promjena na vodne resurse mogu se vidjeti u dvije dimenzije: dostupnost vode i kvaliteta vode. Čimbenici o kojima ovisi kvaliteta vode uključuju rast stanovništva, urbanizacija i promjene u načinu korištenja zemljišta. Klimatske promjene potiču izmjene u hidrološkom ciklusu budući da je voda uključena u sve komponente klimatskog sustava, uključujući atmosferu, hidrosferu, litosferu i biosferu. Stoga je veza između klimatskih promjena i vodnih resursa bitna za opstanak. Od početka Zemlje, klima se stalno mijenjala i to je normalan događaj, ali je taj inače spori proces izuzetno ubrzan. Poznavanje različitih hidroloških i biokemijskih procesa koji se događaju u različitim vodama ključno je za razumijevanje klimatskih promjena i kvalitete vode.