Techno-economic modelling of water electrolysers in the range of several mw to provide grid services while generating hydrogen for different applications: a case study in spain applied to mobility with fcevs

The use of hydrogen as energy carrier is a promising option to decarbonize both energy and transport sectors. This paper presents an advanced techno-economic model for calculation of optimal dispatch of large-scale multi MW electrolysis plants in order to obtain a more accurate evaluation of the feasibility of business cases related to the supply of this fuel for different end uses combined with grid services' provision. The model is applied to the Spanish case using different scenarios to determine the minimum demand required from the FCEV market so that electrolysis facilities featuring several MW result in profitable business cases. The results show that grid services contribute to the profitability of hydrogen production for mobility, given a minimum but considerable demand from FCEV fleets

Multi-state techno-economic model for optimal dispatch of grid connected hydrogen electrolysis systems operating under dynamic conditions

The production of hydrogen through water electrolysis is a promising pathway to decarbonize the energy sector. This paper presents a techno-economic model of electrolysis plants based on multiple states of operation: production, hot standby and idle. The model enables the calculation of the optimal hourly dispatch of electrolyzers to produce hydrogen for different end uses. This model has been tested with real data from an existing installation and compared with a simpler electrolyzer model that is based on two states. The results indicate that an operational strategy that considers the multi-state model leads to a decrease in final hydrogen production costs. These reduced costs will benefit businesses, especially while electrolysis plants grow in size to accommodate further increases in demand

Optimal dispatch model for PV-electrolysis plants in self-consumption regime to produce green hydrogen: a Spanish case study

The production of green hydrogen from renewable energy by means of water electrolysis is a promising approach to support energy sector decarbonization. This paper presents a techno-economic model of plants with PV sources connected to electrolysis in self-consumption regime that considers the dynamics of electrolysis systems. The model calculates the optimal hourly dispatch of the electrolysis system including the operational states (production, standby, and idle), the load factor in production, and the energy imports and exports to the electricity grid. Results indicate that the model is a useful decision support tool to operate electrolysis plants connected to PV plants in self-consumption regimes with the target of reducing hydrogen production costs

AGN counts at 15um. XMM observations of the ELAIS-S1-5 sample

Context: The counts of galaxies and AGN in the mid infra-red (MIR) bands are important instruments for studying their cosmological evolution. However, the classic spectral line ratios techniques can become misleading when trying to properly separate AGN from starbursts or even from apparently normal galaxies. Aims: We use X-ray band observations to discriminate AGN activity in previously classified MIR-selected starburst galaxies and to derive updated AGN1 and (Compton thin) AGN2 counts at 15 um. Methods: XMM observations of the ELAIS-S1 15um sample down to flux limits ~2x10^-15 erg cm^-2 s^-1 (2-10 keV band) were used. We classified as AGN all those MIR sources with a unabsorbed 2-10 keV X-ray luminosity higher that ~10^42 erg/s. Results: We find that at least about 13(+/-6) per cent of the previously classified starburst galaxies harbor an AGN. According to these figures, we provide an updated estimate of the counts of AGN1 and (Compton thin) AGN2 at 15 um. It turns out that at least 24% of the extragalactic sources brighter than 0.6 my at 15 um are AGN (~13% contribution to the extragalactic background produced at fluxes brighter than 0.6 mJy).Comment: Accepted for publication on A&

Multi-state optimal power dispatch model for power-to-power systems in off-grid hybrid energy systems: A case study in Spain

The electricity production from Renewable Energy (RE) in isolated locations requires long-term energy storage systems. To that end, Hybrid Energy Storage Systems (HESS), through a combination of hydrogen and batteries, can benefit from the different advantages of both technologies. This paper presents a hybrid Power-to-Power (PtP) Optimal Power Dispatch (OPD) model for isolated systems with no electric grid access. Currently, the electricity supply in such cases is usually based on a mix of RE as the primary energy source sustained by a diesel genset acting as a backup generator. In this context, the model delivers the hourly energy flows between renewable production sources, energy storage devices and the electrical load, which minimises costs and Green House Gases (GHG) emissions. For validation purposes, the model was tested through its application to a case study in an isolated area in the Canary Islands, Spain. The results show that the algorithm calculates the hourly OPD successfully for a given plant sizing, considering the defined operational states of the different assets. These operational constraints showed a decrease in the PtP round-trip efficiency of 5.4% and a reduction of the hydrogen production of 9.7%. Finally, the techno-economic analysis of the results proves that the combination of hydrogen and batteries with RE production is a feasible alternative to phasing out fossil fuels for the selected case study – reducing the diesel generator usage down to 1.2% of the yearly energy supply

The roles (of culture) of yesterday

Asistimos a una inesperada reivindicación de la llamada prensa cultural marginal española, surgida durante el franquismo en forma sobre todo de revistas y fanzines de diversa índole, con un marcado acento contracultural en sus propuestas, dotadas a su vez de un innegable atractivo estético desde el punto de vista del diseño. A través de exposiciones, retrospectivas y monografías estas publicaciones están reconstruyendo el relato cultural de España, provocando a su vez encendidos debates en la prensa cultural actual. Se da así la aparente paradoja de que la prensa cultural oficial de ahora se está viendo obligada a hablar de la marginal de antaño. Nos planteamos en consecuencia qué publicaciones culturales actuales podrán el día de mañana tener un valor y una funcionalidad similar a la de aquella prensa marginal.We attended an unexpected notification of the socalled marginal Spanish cultural press, emerged during the Franco regime in the form of magazines and fanzines of various kinds, with a strong accent from a point of view of countercultural design in their proposals, endowed with an undeniable aesthetic appeal from the point of view of design. Through exhibitions, retrospectives and monographs these publications are reconstructing the cultural story of Spain, causing in turn fired debates in the current cultural press. There is thus the apparent paradox that the official cultural press is now being forced to talk about the marginal cultural press of yesteryear. We consider accordingly what cultural publications may have tomorrow have a value and functionality like the marginal press

Hand span influences optimal grip span in adolescents with Down syndrome

Introduction: The hand grip strength test provides useful and reliable information about overall health. Different studies have investigated the optimal grip span for determining maximal hand grip strength in different populations such as adults, adolescents and children without disabilities. Objective: To ascertain whether there is an optimal grip span for determining maximal hand grip strength in adolescents with Down syndrome (DS). Methods: Twenty-seven right-handed youths with DS (seven females) aged 15.5 ± 3.6 years were evaluated in this methodological study. Each hand was randomly tested on ten times using five different grip spans, allowing one-minute rest between attempts. The hand span was measured from the tip of the thumb to the tip of the small finger with the hand widely opened. To confirm the usefulness of the optimal grip span, a new group of 15 adolescents with DS were recruited. Results: An optimal grip span was identified for the dominant hand in adolescents with DS. The equation relating grip span as a function of dominant hand span in this group is formulated as follows: y = 0.342x - 1.161 cm (r = 0.63, p < 0.05). In the case of non-dominant hand, a tendency towards a linear association (p = 0.058) was found; the equation is formulated as follows: y = 0, 210x + 1.324 cm. Conclusion: It is important to standardize the procedure and increase reliability when measuring hand grip strength in DS population. The values stated in this study are recommended to assess hand grip strength in adolescents with Down syndrome

Phasing out steam methane reformers with water electrolysis in producing renewable hydrogen and ammonia: A case study based on the Spanish energy markets

Deploying renewable hydrogen presents a significant challenge in accessing off-takers who are willing to make long-term investments. To address this challenge, current projects focus on large-scale deployment to replace the demand for non-renewable hydrogen, particularly in ammonia synthesis for fertiliser production plants. The traditional process, involving Steam Methane Reformers (SMR) connected to Haber-Bosch synthesis, could potentially transition towards decarbonisation by gradually integrating water electrolysis. However, the coexistence of these processes poses limitations in accommodating the integration of renewable hydrogen, thereby creating operational challenges for industrial hubs. To tackle this issue, this paper proposes an optimal dispatch model for producing green hydrogen and ammonia while considering the coexistence of different processes. Furthermore, the objective is to analyse external factors that could determine the appropriate regulatory and pricing framework to facilitate the phase-out of SMR in favour of renewable hydrogen production. The paper presents a case study based in Spain, utilising data from 2018, 2022 and 2030 perspectives on the country's renewable resources, gas and electricity wholesale markets, pricing ranges, and regulatory constraints to validate the model. The findings indicate that carbon emissions taxation and the availability and pricing of Power Purchase Agreements (PPAs) will play crucial roles in this transition - the carbon emission price required for total phasing out SMR with water electrolysis would be around 550 EUR/ton CO2

Is Playing Soccer More Osteogenic for Females Before the Pubertal Spurt?

The aims of this study were to assess bone mass in children and adolescent soccer players and to evaluate the influence of both gender and pubertal status on bone mass. A total of 110 soccer players (75 males / 35 females; 12.73 ± 0.65 / 12.76 ± 0.59 years) participated in this cross-sectional study. They were divided into two groups according to their pubertal status. Bone and lean masses were measured with Dual-energy X-ray Absorptiometry. An independent t-test and an adjusted by subtotal lean and training experience multivariate analysis of covariance were used to analyse the differences in bone mass values between genders and maturity status. Female soccer players presented higher bone mass values than their male counterparts in most of the measured weight-bearing sites. Moreover, when stratifying by pubertal status, peripubertal and postpubertal females had higher subtotal body and lumbar spine bone mass than males. Comparing between pubertal status groups before adjustment, both male and female postpubertal players showed higher bone mass than their pubertal counterparts. After adjusting, these differences disappeared and, in fact results were inverted as bone mass at the femoral neck was higher in both male and female peripubertal soccer players than in postpubertal players. Bone mass seems to be more intensely stimulated by playing soccer in female than male players, particularly in the lumbar spine. The results of peripubertal players showing higher bone mass at the femoral neck after adjusting suggest that playing soccer during the peripubertal stage could be an effective activity to achieve optimal bone mass values