Tactical and operational management of wind energy systems with storage using a probabilistic forecast of the energy resource

The storage of energy facilitates the management of renewable energy systems by reducing the mismatch between the supplied energy and the forecasted production due to forecasting errors. The storage increases the reliability of the renewable energy system and enables participation in the electricity market by committing to the sale of electricity for the following day. Nevertheless, the inclusion of the energy storage capacity requires the development of new management policies. In this paper, we propose a management strategy for a renewable energy system with storage capacity that integrates tactical and operational decisions in a single mathematical model that makes use of an updated probabilistic wind speed forecast. Management policies are obtained by solving a sequence of rolling-horizon stochastic optimization problems whose formulation is inspired by the Stochastic Approximation Average technique. The management policies are illustrated by their application to wind-farms using hydrogen as the energy storage medium

More for less: Sampling strategies of plant functional traits across local environmental gradients

This is the peer reviewed version of the following article: Functional Ecology 29.4 (2015): 579-588, which has been published in final form at http://dx.doi.org/10.1111/1365-2435.12366. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingEcologists use approaches based on plant functional traits to tackle several fundamental and applied questions. Although a perfect characterization of functional trait structure requires the measurement of all the individuals in communities, this is prohibitively resource-consuming. Consequently, the general practice is to average the trait values of a reduced number of individuals per species. However, there are different alternatives regarding the number, identity and spatial location of the individuals chosen to calculate species-averaged trait values. In this study, we compared different strategies for sampling functional traits, using community-weighted mean trait values (CWM) and the Rao index of functional diversity (FD). We intensively sampled the functional trait structure along a topographical gradient in a Mediterranean grassland, obtaining accurate estimations of the 'real' values of these indices (CWMI and FDI) for three traits (height, leaf area and specific leaf area). We simulated three different sampling strategies differing in the spatial location of the individuals used to estimate species-mean trait: (i) average of the whole gradient (GLO), (ii) average of the sampling unit in which the abundances of species maximize (MAX) and (iii) average of a reduced number of individuals per species and sampling unit (LOC). For each strategy, we simulated different sampling intensities (number of individuals sampled). For each trait, we examined the ability of each strategy and sampling intensity to accurately estimate CWMI and FDI, as well as their ability to detect changes in functional trait structure along the topographical gradient. LOC outperformed the other strategies in terms of accuracy and bias, and was much more efficient to describe changes along the gradient, regardless of the traits and indicators considered. Furthermore, LOC was the only strategy that improved consistently as sampling intensity increased, especially at low levels of intensity. Our results indicate that the impact of considering intraspecific variability in trait values can be greater than commonly assumed. Strategies that neglect this source of variability can result in inaccurate or biased estimations of the functional trait structure of plant communities. Most importantly, we show that intraspecific variability can be taken into consideration without any increases in the total number of individuals measuredFinancial support was received from the Spanish Ministry of Science (Project CGL2011-24871), the Madrid Regional Government (Project REMEDINAL3), and the Spanish Ministry of Education (FPU AP2012-2849 for CR). CPC was supported by a Marie Curie Intra-European Fellowship within the 7th European Community Framework Programme (TANDEM; project id. 626392

Diverging facets of grassland ant diversity along a Mediterranean elevational gradient

1. We address associations of taxonomic diversity (TD), functional diversity (FD), and phylogenetic diversity (PD) of ant assemblages with gradients of elevation to assess whether energetic limitations or deterministic or stochastic niche-building processes are more relevant to the assembly of communities. 2. We sampled ant assemblages using pitfall traps in grassland habitats along an elevational gradient of 1712 m in the Guadarrama Mountains of Central Spain. The relationships of alpha and beta diversity metrics with soil temperature, productivity, elevation, and geographical distances were examined with generalised additive (mixed) models. 3. The facets of diversity showed strong and partially coincident responses to the gradients, but the responses and the similarities among them weakened or disappeared when the effects of species richness were factored out. TD and FD changed roughly in a similar manner with elevation and productivity, but PD did not show clear responses to those factors. Taxonomic and functional richness increased with productivity and decreased with elevation. Mean pairwise functional and phylogenetic dissimilarities did not change along the gradients. Elevation and productivity gradients accounted for much of the beta TD among assemblages but only explained a moderate variation of functional traits and phylogenetic relationships, while geographical distances were more explanatory of beta PD. 4. The partial redundancies among facets of diversity suggest that the spatial variation of diversity is mainly related to the sheer number of species. However, both environmental filtering and limiting similarity could be acting in concordance to reduce the number of species present in communitiesAdministrative and financial support was received from the Spanish Ministry of Economy and Competitiveness (Project CGL2014‐53789‐R) and Sierra de Guadarrama Park, which provided the permits for the sampling (ref 10/101642.9/16). Mariola Silvestre, Javier Seoane, and Francisco M. Azcárate work within the Madrid's Government research group network REMEDINAL3‐CM (S‐2013/MAE‐2719). Carlos P. Carmona was supported by the Estonian Research Council (PSG293) and the European Union through the European Regional Development Fund (Centre of Excellence EcolChange). Mariola Silvestre was supported by an FPI grant from MINECO. Special thanks to Héctor Miranda, Laura Morgado, and Miguel Blázquez for laboratory assistance and Violeta Hevia, Joaquin Calatayud, and Anders Forsman for your tips. Alberto González helped us to make the map and Xavier Espadaler to identify some species. We appreciate the use of data from Instituto Geográfico Nacional and Nuria Plaza for provided access with the satellite imager

Improving the coastal record of tsunamis in the ESI-07 Scale : Tsunami Environmental Effects Scale (TEE-16 Scale)

This paper discusses possibilities to improve the Environmental Seismic Intensity Scale (ESI-07 scale), a scale based on the effects of earthquakes in the environment. This scale comprises twelve intensity degrees and considers primary and secondary effects, one of them the occurrence of tsunamis. Terminology and physical tsunami parameters corresponding to different intensity levels are often misleading and confusing. The present work proposes: i) a revised and updated catalogue of environmental and geological effects of tsunamis, gathering all the available information on Tsunami Environmental Effects (TEEs) produced by recent earthquake-tsunamis; ii) a specific intensity scale (TEE-16) for the effects of tsunamis in the natural environment at coastal areas. The proposed scale could be used in future tsunami events and, in historic and paleo-tsunami studies. The new TEE-16 scale incorporates the size specific parameters already considered in the ESI-07 scale, such as wave height, run-up and inland extension of inundation, and a comprehensive and more accurate terminology that covers all the different intensity levels identifiable in the geological record (intensities VI-XII). The TEE-16 scale integrates the description and quantification of the potential sedimentary and erosional features (beach scours, transported boulders and classical tsunamites) derived from different tsunami events at diverse coastal environments (e.g. beaches, estuaries, rocky cliffs,). This new approach represents an innovative advance in relation to the tsunami descriptions provided by the ESI-07 scale, and allows the full application of the proposed scale in paleoseismological studies. The analysis of the revised and updated tsunami environmental damage suggests that local intensities recorded in coastal areas do not correlate well with the TEE-16 intensity (normally higher), but shows a good correlation with the earthquake magnitude (Mw). Tsunamis generated by earthquakes can then be considered efficient processes in the direct transference of the "energy" released by offshore seismogenic sources to the nearest coastal areas, even over distances of hundreds of kilometres (>200km). This scale, as the previous ones, is independent of the earthquake type (i.e. style of faulting) and only focuses on the environmental effects triggered by tsunamis of seismic origin

“Numbers: zona cero” (I): método científico de investigación estadística

Desde la realidad de los currículos españoles sobre la resolución de problemas de matemáticas, se analiza la necesidad de los alumnos ante los métodos de científicos. Este es el punto de partida para la presentación de un modelo de pensamiento estadístico, que se configura como marco teórico para el análisis del contenido del capítulo “Vector” de la serie Numb3rs. Dicha propuesta se enmarca dentro de las acciones formativas del Proyecto titulado EarlyStatistics: improving statistics instruction in European elementary and middle schools though online professional development”. (Acción 1: COMENIUS Project 226573-CP-1-2005).Palabras clave: Método científico; pensamiento estadístico; entornos profesionales de aprendizaje.“Numbers: zero zone" (I): scientific method of statistical investigationFrom the reality of the Spanish curriculum about the mathematical problem solving, we analyse the students’ needs about the statistical scientific methods. This is the depart point for presenting a model of Statistical Thinking, that it becomes a theoretical framework to analyse the content of the Chapter “Vector” of Numb3rs’ Serial. This proposal is framed in the instructional actions of the Project “EarlyStatistics: improving statistics instruction in European elementary and middle schools though online professional development” (Action 1: COMENIUS Project 226573-CP-1-2005).Key words: Scientific method; Statistics thinking; professional learning environments

Algunas interpretaciones sobre el fenómeno de las estaciones en niños, estudiantes y adultos: revisión de la literatura

En este trabajo se lleva a cabo un análisis de la literatura sobre las interpretaciones personales de los alumnos acerca del fenómeno de las estaciones. En primer lugar se describe el procedimiento y los criterios seguidos en la revisión y se analizan las características metodológicas de los estudios revisados. En segundo lugar se pasa a describir e interpretar los modelos explicativos más frecuentes que aparecen en la bibliografía, comentando la incidencia que la edad o la variable enseñanza parecen tener sobre la amplitud y evolución de los mismos. Finalmente se realiza un análisis crítico de los tipos de estudios realizados sobre el tema hasta el momento, manifestando la necesidad de nuevos enfoques y nuevas formas de abordar investigaciones en esta área.Palabras claves: ciclos estacionales, fenómenos de las estacione, interpretaciones de los alumnos, modelos explicativos, revisión bibliográfica

“Numbers: zona cero” (II): entorno de aprendizaje profesional

En este artículo se presenta un entorno de aprendizaje profesional basado en el visionado del capítulo “Vectores” de la serie televisiva “Numb3rs”. Se introduce el significado de entornos de aprendizaje profesional como el marco teórico para las acciones formativas del Proyecto titulado EarlyStatistics: improving statistics instruction in European elementary and middle schools though online professional development”. (Acción 1: COMENIUS Project 226573-CP-1-2005). Además, se incluye el análisis didáctico de las actividades que los alumnos deben realizar antes, durante y después del visionado del capítulo, y las propuestas de contraste de las mismas como tareas profesionales para los docentes.Palabras clave: Entornos de aprendizaje profesionales; método científico; pensamiento estadístico.“Numbers: zero zone" (II). Professional learning environmentIn this paper, we introduce an professional learning environment based in viewing the chapter “Vector” of Numb3rs. We introduce the meaning of environment of professional learning as a theoretical framework for the instructional actions of the project titled EarlyStatistics: improving statistics instruction in European elementary and middle schools though online professional development”. (Action 1: COMENIUS Project 226573-CP-1-2005). We, also, include the didactical analysis of the activities that students should do before, during and after viewing the chapter, and the proposals of its contrast as teachers’ professional tasks.Keywords: Professional learning environments; Scientific method; Statistics thinking