The Johan Cruijff ArenA (JC ArenA) is a big events location in Amsterdam, where national and international football matches, concerts and music festivals take place for up to 68,000 visitors. The JC ArenA is already one of the most sustainable, multi-functional stadia in the world and is realizing even more inspiring smart energy solutions for the venue, it’s visitors and neighbourhood. The JC ArenA presents a complex testbed for innovative energy services, with a consumption of electricity comparable to a district of 2700 households. Thanks to the 1 MWp solar installation on the roof of the venue, the JC ArenA already produces around 8% of the electricity it needs, the rest is by certified regional wind energy.Within the Seev4-City project the JC ArenA has invested in a 3 MW/2.8 MWh battery energy storage system, 14 EV charging stations and one V2G charging unit. The plan was to construct the 2.8 MWh battery with 148 2nd life electric car batteries, but at the moment of realisation there were not enough 2nd life EV batteries available, so 40% is 2nd life. The JC ArenA experienced compatibility issues installing a mix of new and second-life batteries. Balancing the second-life batteries with the new batteries proved far more difficult than expected because an older battery is acting different compared to new batteries.The EV-based battery energy storage system is unique in that it combines for the first time several applications and services in parallel. Main use is for grid services like Frequency Containment Reserve, along with peak shaving, back-up services, V2G support and optimization of PV integration. By integrating the solar panels, the energy storage system and the (bi-directional) EV chargers electric vehicles can power events and be charged with clean energy through the JC ArenA’s Energy Services. These and other experiences and results can serve as a development model for other stadiums worldwide and for use of 2nd life EV batteries.The results of the Seev4-City project are also given in three Key Performance Indicators (KPI): reduction of CO2-emission, increase of energy autonomy and reduction in peak demand. The results for the JC ArenA are summarised in the table below. The year 2017 is taken as reference, as most data is available for this year. The CO2 reductions are far above target thanks to the use of the battery energy storage system for FCR services, as this saves on the use of fossil energy by fossil power plants. Some smaller savings are by replacement of ICEby EV. Energy autonomy is increased by better spreading of the PV generated, over 6 instead of 4 of the 10 transformers of the JC ArenA, so less PV is going to the public grid. A peak reduction of 0.3 MW (10%) is possible by optimal use of the battery energy storage system during the main events with the highest electricity demand.
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Background: Both the Short Physical Performance Battery (SPPB) and daily life gait quality and quantity obtained from wearable sensors are used to measure functional status in older adults. It is generally assumed that they are interrelated and exchangeable, but this has not yet been established. Interchangeability of these measures would pave the way for remote monitoring of functional status.Research Question: Are the SPPB and daily life gait quality and quantity measures correlated in community-dwelling older adults?Methods: The SPPB and gait quality and quantity data of 229 community-dwelling adults of 65 years or older were collected. The SPPB is a combined score of the Three Stage Balance test, Four Meter Walk test, and Five Times Sit to Stand test and ranges from 0 to 12. Participants wore a tri-axial inertial sensor for one week to assess gait quality (e.g. gait stability and smoothness) and quantity (e.g. number of strides). Correlation coefficients between SPPB scores and gait quality and quantity measures were assessed using Spearman's correlation.Results: The median age of the study population was 76.2 years (IQR 72.6-81.0), and 76 % were women (n=175). The median SPPB score was 10 (IQR 8-11). Spearman's correlation coefficients between the SPPB and gait quality and quantity measures were all below 0.3.Significance: A possible explanation for the observed weak correlations is that the SPPB reflects one's maximal capacity, while gait quality and quantity reflect the submaximal performance in daily life. The SPPB and gait quality and quantity seem therefore distinct constructs with complementary value, rather than interchangeable. A more comprehensive understanding of functional status might be achieved by combining the SPPB assessment of standardized activities with the evaluation of inertial sensor measurements obtained during daily life activities.
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Several studies have shown that flying electric between the so-called ABC-islands in the Caribbean (i.e., Aruba, Bonaire and Curaçao) is feasible with the upcoming first generation of battery-electric aircraft. This paper presents a real-world case study that deals with the technical and operational characteristics of electric flight in that region. With that purpose, the Aruba Airport Authority (AAA) commissioned this investigation, which involved numerous local stakeholders, such as airlines, energy providers and navigation services. This study involves two commuter electric aircraft under development, aiming to investigate how they fit in the current operational scheme of three local airlines and three conventional aircraft types in terms of technology, capacity, schedule, performance, CO2 emissions and fuel costs. Conclusions indicate that a transition to batter-electric aircraft is feasible with regards to the aforementioned criteria and with the current technology and energy density of batteries.
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In de komende decennia zullen batterijen (vooral Li-ion) veelvuldig ingezet worden voor de opslag van elektrische energie. De belangrijkste toepassing zal die in elektrische voertuigen zijn. Batterijen verouderen en daarom is het van belang om de gezondheidstoestand van een batterij te kunnen schatten. Met deze schatting wordt bepaald of deze batterij in de eerste toepassing bruikbaar blijft of dat deze beter geschikt is om in een second-life toepassing geplaatst te worden. Uiteindelijk zullen de batterijen gerecycled worden. Tijdens gesprekken met bedrijven, waarvan de meeste in het consortium deelnemen, werd het duidelijk dat er veel praktijkvragen zijn rondom batterijen en hun hergebruik. In het bijzonder is er nood aan praktisch inzetbare methoden om de gezondheidstoestand en restlevensduur van gebruikte batterijen te bepalen. Uitgangspunt is om hiervoor rekenmodellen in te zetten. Bestaande modellen zullen doorontwikkeld worden zodat ze de gezondheidstoestand van batterijpakketten kunnen inschatten. Voor de validatie van deze modelen zijn geschikte meetdata nodig. Hiervoor wordt een (nieuwe) meetopstelling gebouwd die mogelijk de basis kan worden van een merk-onafhankelijke batterijtest. Tegelijkertijd worden methoden vastgelegd voor validatie met meetdata uit het veld. Ook de vraag hoe een batterijpakket, op een veilige manier, gerepareerd kan worden is onderdeel van het project. Eenmaal de gezondheidstoestand van een batterij bepaald is, is de vervolg vraag hoe de restlevensduur van ervan bepaald kan worden aan de hand van de soort data die beschikbaar zijn. Deze restlevensduur is verder afhankelijk van de typische inzet in de second-life toepassing. Het vaststellen en bepalen van de bepalende kenmerken van deze inzet is eveneens onderdeel van het onderzoek. Tot slot wordt de economische haalbaarheid bepaald om het gebruik van batterijen te verlengen in eerste of second-life toepassingen. De uitkomsten van dit onderzoek zullen bijdrage om de consortiumleden inzicht te geven in de gebruiksmogelijkheden van batterijen in de verschillende duurzame toepassingen.
