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Inorganic systems based upon polyoxometalate (POM) clusters provide an experimental approach to develop artificial life. These artificial symmetric anionic macromolecules with oxidometalate polyhedra as building blocks were shown to be well suited as inorganic frameworks for complex self-assembling and organizing systems with emergent properties. Analogously to mineral cells based on iron sulfides, POMs are considered as inorganic cells in facilitating prelife chemical processes and displaying “life-like” characteristics. However, the relevance of POMs to life-sustaining processes (e.g., microbial respiration) has not yet been addressed, while iron sulfides are very well known as ubiquitous mineral precursors and energy sources for chemolithotrophic metabolism. Metallosphaera sedula is an extreme metallophilic and thermoacidophilic archaeon, which flourishes in hot acid and respires by metal oxidation. In the present study we provide our observations on M. sedula cultivated on tungsten polyoxometalate (W-POM). The decomposition of W-POM macromolecular clusters and the appearance of low molecular weight W species (e.g., WO) in the presence of M. sedula have been detected by electrospray ionization mass spectrometry (ESI-MS) analysis. Here, we document the presence of metalloorganic assemblages at the interface between M. sedula and W-POM resolved down to the nanometer scale using scanning and transmission electron microscopy (SEM and TEM) coupled to electron energy loss spectroscopy (EELS). High-resolution TEM (HR-TEM) and selected-area electron diffraction (SAED) patterns indicated the deposition of redox heterogeneous tungsten species on the S-layer of M. sedula along with the accumulation of intracellular tungsten-bearing nanoparticles, i.e., clusters of tungsten atoms. These results reveal the effectiveness of the analytical spectroscopy coupled to the wet chemistry approach as a tool in the analysis of metal–microbial interactions and microbial cultivation on supramolecular self-assemblages based on inorganic metal clusters. We discuss the possible mechanism of W-POM decomposition by M. sedula in light of unique electrochemical properties of POMs. The findings presented herein highlight unique metallophilicity in hostile environments, extending our knowledge of the relevance of POMs to life-sustaining processes, understanding of the transition of POMs as inorganic prebiotic model to life-sustainable material precursors and revealing biogenic signatures obtained after the decomposition of an artificial inorganic compound, which previously was not associated with any living matter.

Since 2014, the European Union’s strategy is clearly formulated: we need to drive a clean, secure and efficient energy transition to face climate and energy challenges. It is reinforced by the strong commitment of the European Union to the 2015 Paris Agreement. Therefore, in November 2016, the Commission proposed an ambitious “Clean Energy for All Europeans” package. Therein, all relevant meetings, summits and measures started from a simple observation: “It is in everyone’s long-term interest to have a rapid and orderly transition towards a cleaner, more sustainable and less carbon intensive energy future.” However, this apparently simple observation requires us to consider numerous challenges: i) Moving towards a low carbon energy sector; ii) Creating a pan European integrated energy system and iii) Mobilizing public and private sectors by iv) Maintaining and extending Europe’s industrial leadership. The European Commission is working on the long-term vision where all these multidimensional challenges would be addressed by a single coherent plan.This paper describes the Vision 2050, as elaborated by the European Technology and Innovation Platform of Smart Networks for Energy Transition (ETIP SNET), which gathered research and industry experts, European and National public authorities, European associations and other relevant actors from the energy sector to tackle the key aspects of this very complex challenge.

Solid State Transformers (SST) may become, in the near future, key technological enablers for decentralized energy supply systems. They have the potential to unleash new technologies and operation strategies of microgrids and prosumers to move faster towards a low carbon-based economy. This work proposes a paradigm change in the hierarchically and distributed operated power systems where SSTs are used to asynchronously connect the many small low voltage (LV) distribution networks, such as clusters of prosumers or LV microgrids, to the bulk power system. The need for asynchronously coupled microgrids requires a design that allows the LV system to operate independently from the bulk grid and to rely on its own control systems. The purpose of this new approach is to achieve immune and resilient by design configurations that allow maximizing the integration of Local Renewable Energy Resources (L-RES). The paper analyses from the stability point of view, through simplified numerical simulations, the way in which SST-interconnected microgrids can become immune to disturbances that occur in the bulk power system and how sudden changes in the microgrid can damp out at the Point of Common Coupling (PCC), thus achieving better reliability and predictability in both systems and enabling strong and healthy distributed energy storage systems (DESSs). Moreover, it is shown that in a fully inverter-based microgrid there is no need for mechanical or synthetic inertia to stabilize the microgrid during power unbalances. This happens because the electrostatic energy stored in the capacitors connected behind the SST inverter can be used for a brief time interval, until automation is activated to address the power unbalance for a longer term.

Microgrids present tremendous advantages when it comes to resilience of the distribution sector inpower systems. The DC supply of such small power networks is also appealing due to more and more site based energy harvesting (e.g. RES generation) and electricity storage that is present at building level, as well as more and more domestic and office appliances are DC native loads or DC compatible. There are increasing number of studies with respect to possible architectures and control schemes of such systems, however there is very little work when it comes to power quality (PQ) aspects. The objective of this work is to make useful qualitative and quantitative appreciations into the possible distortions that might appear on the DC bus supplying the loads in a DC microgrid. &nbsp

This work analyzes a number of business models that are exemplified for a lab/campus-scale demonstrator for DC-resilient communities in Bucharest, Romania. The aim of this study is to pave the path that could unlock some of the above mentioned challenges and barriers, and help such networks to flourish in the near future. The analysis is carried out using the Business Model Generation Framework (BMGF), one of the most popular and systematized industry’s state of the art (SoA) tools for developing and creating innovative business models and tools. &nbsp

This work presents the architecture and operational features of a demonstrator developed at the premises of MicroDERLab Research Group at UPB that consists of two interconnected DC low voltage microgrids aiming to serve several research projects that focus on resilient DC LV communities. The architecture of the demonstrator uses a case-driven approach to validate and demonstrate the toolkits to be developed. Concretely, the demonstrator aims to facilitate the experimental assessments of several applications from monitoring and active power management of energy consumption in prosumers’ world, to aggregation of measurement data for modelling, planning, integration, operation and evaluation of distributed Energy Storage Systems. One of the major innovation of the proposed architecture consists in the extension of the functionality of the Unbundled Smart Meter (USM), the so called SMX side that processes all the information coming from the micro-controller of the energy router (ER). Simulated results of a distributed and adaptive energy management system to be tested on this demonstrator are also presented, while briefing a number of use-cases in line with several business models that led us to this design.

Technological developments are pushing for new solutions towards massive integration of renewable-based electricity generation in networks already facing many challenges. The paper presents a new approach for managing the energy transfer towards prosumers making use of a smart management of the local energy storage. The proposed grid design (including storage dimensioning procedure) is based on several operation scenarios in which the prosumer is operating as a “load only” entity (from grid perspective) exhibiting self-resilience and higher energy efficiency. One of the major advantages of this restriction in prosumer operation is the preservation of resilience against changing regulatory environment. This can be realized within a newly proposed Uni-directional Resilient Consumer (UniRCon) architecture. For the proof of concept three use-cases are detailed: (i) PV installations connected behind the meter, (ii) PV and storage available and controllable behind the meter and (iii) the UniRCon architecture. The three use-cases are then compared and assessed for four near-future timelines as starting points for the investment. The numerical simulations show the attractiveness of the UniRCon solution in what concerns both system operation costs and self-resilience. Savings are expressed as opportunity savings arising from difference in tariffs while charging and discharging the storage unit and due to avoidance of curtailment as well as special taxes for connection of PV (depending of regulatory environment). An extension of UniRCon concept is presented also at community scale, with neighbourhood energy exchange inside a cluster envisions energy supply resilience at community scale.

Power quality aspects related to DC stationary microgrids are still on virgin grounds of research. However, they may play an important role both in the design stage and on the microgrid control scheme to be adopted. Currently there is no comprehensive, quantitative and qualitative analysis on which of the power quality parameters are the most stringent constraints to be taken into account. This work is one of the first attempts in defining and quantifying a set of power quality indices for DC stationary microgrids. We relate our analysis on the design aspects of DC/DC power converters that are the most critical elements interfacing sources and loads in a stand-alone low voltage DC microgrid., © 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. I. Ciornei, M. Albu, M. Sanduleac, L. Hadjidemetriou, and E. Kyriakides, "Analytical derivation of PQ indicators compatible with control strategies for DC microgrids," in Proc. IEEE POWERTECH, Manchester, UK, 2017, pp. 1-6. DOI: 10.1109/PTC.2017.7981179 https://www.ieee.org/publications_standards/publications/rights/rights_policies.html

The last decade marked an exponential increase in photovoltaic (PV) systems installed on the rooftop of domestic residences within Europe and in other developed countries around the world. This situation was basically favored by generous financial schemes such as Feed-in-Tariff. However, such governmental incentives drastically reduced recently or they were already replaced with net-metering schemes which favor a different scenario: increase of self-consumption and decrease of grid back injection. This unstable regulatory environment puts both new and old owners of PV systems under a regulatory financial risk. Battery energy storage systems (BESS) are seen as viable options to overcome such barriers as well as increasing the self-consumption from locally produced energy. Furthermore, formation of resilient communities arranged as clusters of residential microgrids within a small territory is also appealing due to the potential of buying and selling locally produced renewable energy (favored by the smoothing effect load aggregation), reduced power losses within the distribution grid where each prosumer within the cluster is connected, and potential of sharing static or mobile electricity storage installed individually or at community level. We focus this study on the use of storage for increasing self-consumption of PV local production at community level microgrids and develop an optimal scheduling strategy of storage facilities within the cluster over a 24 hour period and one year, respectively. The optimization problem has been framed as a stochastic program with probability weights derived form a k-mean clustering method applied on real PV measured data over one year

Todays technological developments are drivers for new solutions towards massive renewables deployments resulting in increased network challenges. The paper presents a new approach for prosumers having such a local PV production and storage devices which allows, with adequate design, the user to change from classic prosumer to consumer-only from grid perspective, with enhanced efficiency and resilience based on a hybrid (AC and DC) architecture. Three use-cases are presented: PV behind the meter, PV and storage behind the meter and a newly proposed UniRCon (Unidirectional Resilient Consumer) architecture. This use-cases analysis considers four timeline horizons (2018, 2020, 2022, and 2025). It is shown for the selected profiles of consumption and production that PV plus storage behind the meter bring savings, as recognized and expected by today trend of business-cases, and that the complete UniRCon architecture steps in even with more savings together with higher resilience against the grid outages. The UniRCon solution gives also better ramp behaviour during the evening period, compared with the duck curve expected to challenge power systems with high PV penetration.