Grid-scale pumped hydro energy storage for the low countries

Penetration of intermittent renewable energy sources into the power grid requires large-scale energy storage to ensure grid stability. Pumped Hydro Energy Storage (PHES) is among the most mature, environmentally friendly, and economical energy storage technologies, but has traditionally only been feasible at sites with large natural topographic gradients. ALPHEUS addresses this by developing reversible pump-turbines efficient at low heads, that operate between an enclosed inner basin (that functions as the upper or lower reservoir) and a shallow sea or lake

Low-head pumped hydro storage: A review of applicable technologies for design, grid integration, control and modelling

To counteract a potential reduction in grid stability caused by a rapidly growing share of intermittent renewable energy sources within our electrical grids, large scale deployment of energy storage will become indispensable. Pumped hydro storage is widely regarded as the most cost-effective option for this. However, its application is traditionally limited to certain topographic features. Expanding its operating range to lowhead scenarios could unlock the potential of widespread deployment in regions where so far it has not yet been feasible. This review aims at giving a multi-disciplinary insight on technologies that are applicable for low-head (2-30 m) pumped hydro storage, in terms of design, grid integration, control, and modelling. A general overview and the historical development of pumped hydro storage are presented and trends for further innovation and a shift towards application in low-head scenarios are identified. Key drivers for future deployment and the technological and economic challenges to do so are discussed. Based on these challenges, technologies in the field of pumped hydro storage are reviewed and specifically analysed regarding their fitness for low-head application. This is done for pump and turbine design and configuration, electric machines and control, as well as modelling. Further aspects regarding grid integration are discussed. Among conventional machines, it is found that, for high-flow low-head application, axial flow pump-turbines with variable speed drives are the most suitable. Machines such as Archimedes screws, counter-rotating and rotary positive displacement reversible pump-turbines have potential to emerge as innovative solutions. Coupled axial flux permanent magnet synchronous motor-generators are the most promising electric machines. To ensure grid stability, grid-forming control alongside bulk energy storage with capabilities of providing synthetic inertia next to other ancillary services are required

An extension of the momentum transfer model to time-dependent pipe turbulence

We analyze a possible extension of Gioia and Chakraborty's momentum transfer model of friction in steady turbulent pipe flows (Phys. Rev. Lett. 96, 044502 (2006)) to the case of time and/or space dependent turbulent flows. The end result is an expression for the stress at the wall as the sum of an steady and a dynamic component. The steady part is obtained by using the instantaneous velocity in the expression for the stress at the wall of a stationary flow. The unsteady part is a weighted average over the history of the flow acceleration, with a weighting function similar to that proposed by Vardy and Brown (Journal of Sound and Vibration 259, 1011 (2003); ibid. 270, 233 (2004)), but naturally including the effect of spatial derivatives of the mean flow, as in the Brunone model (B. Brunone et al., J. of Water Resources Planning and Management 236 (2000)).Comment: 15 pages. 2 figures (included) arXiv admin note: text overlap with arXiv:1005.040

The bodily presence of significant others: Intensive care patients' experiences in a situation of critical illness

This study is about intensive care patients and the bodily presence of significant others. The aim of the study is to inquire and understand the patients experience of the body in relation to their significant others during critical illness. Open, unstructured, in-depth interviews with six former intensive care patients provide the data for the study. The phenomenological–hermeneutical analysis points to a theme among ICU patients' experience of conflict between proximity and distance during the bodily presence of their relations. Patients experience different and conflicting forms of responses to the presence of their significant others. Patients experience significant positive confirmation but also negation through this presence. In the ICU situation, the reactions of significant others appear difficult to deal with, yet the physical presence is significant for establishing a sense of affinity. Patients seek to take some responsibility for themselves as well as for their relatives, and are met with a whole spectrum of reactions. Intensive care patients experience the need to be actively, physically present, which often creates sharp opposition between their personal needs and the needs of their significant others for active participation

Gender balance in ECEC : why is there s little progres?

Social attitudes about male participation in the upbringing of children have changed considerably over the past few decades. Men are now seen as important for children’s development and learning. Research from many countries worldwide shows that in early childhood care and education (ECEC), male workers are welcomed by female colleagues and parents. In the last two decades there have been initiatives for more men in ECEC in several European countries. Nevertheless the proportion of male workers ECEC remains low worldwide. This article questions the persisting gender imbalance in ECEC and analyzes ambivalences regarding more men in the field. Based on recent gender theory, efforts and limits of strategies for more male students and workers in ECEC in Belgium, Norway and Germany are discussed. It is concluded that deeply held gendered attitudes and practices in the field of care and educational work with young children have to be put into question. More space in ECEC for embodied subjectivities is needed to overcome essentialist conceptions of differences between body and mind, women and men

Young children’s perspectives regarding rough and tumble play:a systematic review

Abstract Play types and play environments often are influenced by adults, with children having little agency in organizing their own play. This is particularly illustrated in the context of rough and tumble play (RT), which is a type of play pursued by children, but often discouraged by adults. When adults prohibit RT play, they limit opportunities for children to benefit from the outcomes associated with this form of play. A systematic review of literature was conducted toward understanding children’s perspectives regarding RT play and how children have been included in RT research. The results suggest, despite having several roles in RT research, thereis a noticeable absence of children’s perspectives on RT play. This absence points to a need for research that captures children’s perspectives on specifically RTplay in ways that involve children not just as the subjects of observations, but as active participants with voices, preferences, ideas, and agency

Contributions to sustainability through young children’s nature play:a systematic review

Abstract Nature play with young children has been criticized for lacking the transformative power necessary for meaningfully contributing to sustainability issues. The purpose of this systematic review was to identify outcomes associated with young children’s nature play that align with Education for Sustainability outcomes, toward addressing the question of its contribution to a more sustainable future. A total of 272 citation records were screened using eligibility and quality appraisal criteria, resulting in 32 studies that were reviewed. These studies’ outcomes were coded and then mapped to an education for sustainability framework. Results suggest that nature play supports education for sustainability benchmarks of applied knowledge, dispositions, skills, and applications. The multiple and varied relevant outcomes associated with nature play suggest practitioners should not abandon nature play in the pursuit of sustainability. Implications for practice and further research are discussed