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In 2017, a new family of in-plane, chemically-ordered quaternary MAX phases, coined i-MAX, has been reported since 2017. The first i-MAX phase, (Mo2/3Sc1/3)(2)AlC, garnered significant research attention due to the presence of chemically ordered Sc within the Mo-dominated M layer, and the facilitated removal of both Al and Sc upon etching, resulting in 2D i-MXene, Mo1.33C, with ordered divacancies. The i-MXene renders an exceptionally low resistivity of 33.2 mu omega m(-1) and a high volumetric capacitance of approximate to 1150 F cm(-3). This discovery has been followed by the synthesis of, to date, 32 i-MAX phases and 5 i-MXenes, where the latter have shown potential for applications including, but not limited to, energy storage and catalysis. Herein, fundamental investigations of i-MAX phases and i-MXenes, along with their applicability in supercapacitive and catalytic applications, are reviewed. Moreover, recent results on ion intercalation and post-etching treatment of Mo1.33C are presented. The charge storage performance can also be tuned by forming MXene hydrogel and through inert atmosphere annealing, where the latter renders a superior volumetric capacitance of approximate to 1635 F cm(-3). This report demonstrates the potential of the i-MXene family for catalytic and energy storage applications, and highlights novel research directions for further development and successful employment in practical applications. ; Funding Agencies|Wenner-Gren Stiftelserna [UPD2017-0171]; Knut and Alice Wallenbergs FoundationKnut & Alice Wallenberg Foundation; Swedish Foundation for Strategic ResearchSwedish Foundation for Strategic Research; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Vinnova; Swedish Strategy Group for EU-Coordination [2018-02677]

This study was carried out within the HYBUILD project, as part of the task aimed at developing novel evaporators for compact and direct integration of phase-change materials (PCM) into air-conditioning systems for efficient utilization of solar energy. To achieve this, novel evaporators were designed to contain PCM between refrigerant and heat transfer fluid (HTF) channels, allowing a three-media heat exchange mechanism. This paper experimentally assesses the influence of the configuration/arrangement of the channels on the performance of the evaporators, using three different lab-scale prototypes. Key performance indicators (KPI) relevant for thermal energy storage (TES) and heat exchangers (HEX) were used to study the influence of the design on the performance of the different designs of the novel evaporators. The results show that the change in the PCM, refrigerant, and HTF channel configuration affects the performance of the novel evaporators independently. The coefficient of performance (COP) of the refrigeration system and the energy storage density of the modules are the least affected KPIs (less than 16%), whereas the state of charge (SOC) at thermal equilibrium is the most affected KPI (about 44%). A discussion on how these effects provide unique strength for specific applications is included. ; The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. Boniface Dominick Mselle would like to thank Programa Santander Predoc UdL for his research fellowship.

Currently, there is an increasing interest in concentrated solar power (CSP) plants as alternative to produce renewable electricity at large scale by using mirrors to concentrate the solar energy and to convert it into high temperature heat. These facilities can be combined with thermal energy storage (TES) systems, which are, nowadays, one of the most feasible solutions in facing the challenge of the intermittent energy supply and demand. However, they are still in research process and, for that, there is a lack of environmental impact studies of these TES systems complementing solar plants. This paper accounts the environmental impact of three TES systems used nowadays in high temperature applications for CSP plants: first, a system which stores sensible heat in high temperature concrete; second, a system storing sensible heat in molten salts; and third, another system with molten salts but storing latent heat. All the systems are normalised in order to be comparable between them due to its initial storage capacity difference. The environmental impact is accounted by calculating the amount of embodied energy in the components of the different TES systems. Notice that embodied energy refers to the total energy inputs required to make a component. Between the three systems, the sensible heat system using concrete as storage material is the one with less environmental impact while the molten salts and PCM have a higher value of embodied energy, mainly due to the nitrate mixture used as storage material. Finally, advantages and disadvantages of the method proposed used are discussed ; The work was partially funded by the Spanish government (project ENE2011-22722). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA (2009 SGR 534). The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under Grant agreement n PIRSES-GA-2013-610692 (INNOSTORAGE). Eduard Oró would like to thank the University of Lleida for his research fellowship. Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861).

Thermal energy storage technologies need to be further developed and need to become an integral component in the future energy system infrastructure to meet variations in both the availability and demand of energy. The main objectives of project HEATSTORE are to lower the cost, reduce risks, improve the performance of high temperature (~25°C to ~90°C) underground thermal energy storage (HT-UTES) technologies and to optimize heat network demand side management (DSM). This is primarily achieved by 6 new demonstration pilots and 8 case studies of existing systems with distinct configurations of heat sources, heat storage and heat utilization. It will advance the commercial viability of HT-UTES technologies and, through an optimized balance between supply, transport, storage and demand, enable geothermal energy production to reach its maximum deployment potential in the European energy transition. HEATSTORE is a project under the GEOTHERMICA – ERA NET Cofund and contributes to achieving the several objectives of accelerating the uptake of geothermal energy by 1) advancing and integrating different types of underground thermal energy storage (UTES) in the energy system, 2) providing a means to maximize geothermal heat production and optimize the business case of geothermal heat production doublets, 3) addressing technical, economic, market, environmental, regulatory and policy aspects that are necessary to support efficient and cost-effective deployment of UTES technologies in Europe. The 3-year project started in 2018 will stimulate a fast-track market uptake in Europe, promoting development from demonstration phase to commercial deployment within 2 to 5 years, and provide an outlook for utilization potential towards 2030 and 2050. The HEATSTORE consortium brings together 23 contributing partners (mix of scientific research institutes and private companies) from 9 countries. ; HEATSTORE (170153-4401) is one of nine projects under the GEOTHERMICA – ERA NET Cofund aimed at accelerating the uptake of geothermal energy. The GEOTHERMICA project is supported by the European Union's HORIZON 2020 programme for research, technological development and demonstration under grant agreement No 731117. ; Postprint (published version)

Faster market integration of new energy technologies can be achieved by use of proper support mechanisms that will create favourable market conditions for such technologies. The best examples of support mechanisms presented in the last two decades have been the various schemes for the promotion of renewable energy sources (RES). In the EU, the most successful supporting schemes are feed-in tariffs which have significantly increased utilisation of renewable energy sources in Germany, Spain, Portugal, Denmark and many other EU countries. Despite the successful feed-in tariffs for RES promotion, in many cases RES penetration is limited by power system requirements linked to the intermittency of RES sources and technical capabilities of grids. These problems can be solved by implementation of energy storage technologies like reversible or pumped hydro, hydrogen, batteries or any other technology that can be used for balancing or dump load. In this paper, feed-in tariffs for various energy storage technologies are discussed along with a proposal for their application in more appropriate regions. After successful application on islands and outermost regions, energy storage tariffs should be also applied in mainland power systems. Increased use of energy storage could optimise existing assets on the market. (C) 2010 Elsevier Ltd. All rights reserved.

A bstract. — The Poynting vector and the electric and magnetic energy densities of waves propagating in media exhibiting dispersion are calculated explicitly. It is shown that slight extensions of the conventional formulas are sufficient to take into account the modifications introduced by dispersion.

In this work, a strategy for scheduling a battery energy storage system (BESS) in a renewable energy community (REC) is proposed. RECs have been defined at EU level by the 2018/2001 Directive; some Member States transposition into national legislation defined RECs as virtual microgrids since they still use the existing low voltage local feeder and share the same low-medium voltage transformer. This work analyzes a REC which assets include PV generators, BESS and non-controllable loads, operating under the Italian legislative framework. A methodology is defined to optimize REC economic revenues and minimize the operation costs during the year. The proposed BESS control strategy is composed by three different modules: (i) a machine learning-based forecast algorithm that provides a 1-day-ahead projection for microgrid loads and PV generation, using historical dataset and weather forecasts; (ii) a mixed integer linear programming (MILP) algorithm that optimizes the BESS scheduling for minimal REC operating costs, taking into account electricity price, variable feed-in tariffs for PV generators, BESS costs and maximization of the self-consumption; (iii) a decision tree algorithm that works at the intra-hour level, with 1 min timestep and with real load and PV generation measurements adjusting the BESS scheduling in real time. Validation of the proposed strategy is performed on data acquired from a real small-scale REC set up with an Italian energy provider. A 10% average revenue increase could be obtained for the prosumer alone when compared to the non-optimized BESS usage scenario; such revenue increase is obtained by reducing the BESS usage by around 30% when compared to the unmanaged baseline scenario.

AbstractIn order to achieve global carbon neutrality in the middle of the 21st century, efficient utilization of fossil fuels is highly desired in diverse energy utilization sectors such as industry, transportation, building as well as life science. In the energy utilization infrastructure, about 75% of the fossil fuel consumption is used to provide and maintain heat, leading to more than 60% waste heat of the input energy discharging to the environment. Types of low-grade waste heat recovery technologies are developed to increase the energy efficiency. However, due to the spatial and temporal mismatch between the need and supply of the thermal energy, much of the waste thermal energy is difficult to be recovered. Thermal energy storage (TES) technologies in the forms of sensible, latent and thermochemical heat storage are developed for relieving the mismatched energy supply and demand. Diverse TES systems are developed in recent years with the superior features of large density, long-term, durable and low-cost. These technologies are vital in efficient utilization of low-grade waste heat and expected for building a low or zero carbon emission society. This paper reviews the thermal storage technologies for low carbon power generation, low carbon transportation, low carbon building as well as low carbon life science, in addition, carbon capture, utilization, and storage are also considered for carbon emission reduction. The conclusion and perspective are raised after discussing the specific technologies. This study is expected to provide a reference for the TES technologies in achieving zero-carbon future.

This paper investigates the potential of using gravity energy storage with suspended weights as a new technology for redeveloping abandoned deep mine shafts. The technology has relatively low energy density, but has advantages including a power capacity decoupled from its energy capacity, no cycle-limit and the potential to be combined with compressed air energy storage. It is currently being trialled in the United Kingdom, targeting abandoned coal mines. The paper presents analysis for sizing the suspended weight to maximize the energy storage capacity, given a mine shaft's physical dimensions. In addition, it is shown that the power capacity of the system's motor and power electronics determine the maximum ramp-rate, and therefore the range of power system services that can be provided. A case study is presented, estimating the total energy storage capacity which could be obtained by converting abandoned mines in the United Kingdom Midlands, using geographic information system data from the United Kingdom Government Coal Authority Abandoned Mine Catalogue.

The Federal Energy Regulatory Commission ("FERC" or "the Commission") regulates the rates, terms, and conditions of interstate transmission and interstate wholesale energy transactions. While states regulate local distribution facilities and retail sales, substantially all electricity ultimately delivered to consumers in the United States passes through FERC's jurisdiction. Depending on the circumstance, an energy storage device might behave like any of the traditional grid classifications: generation, transmission, distribution, and even load. These multifaceted operational characteristics, which make energy storage so useful, also confound regulatory rules and categories tailored to the more rigid operational characteristics of legacy technologies. Consequently, storage cannot compete on a level playing field with traditional resources in FERC-jurisdictional markets. This federal regulatory lag impedes the commercialization of technologies that the federal government itself supports with billions of dollars in funding, while obstructing the success of state policies promoting storage and renewable energy resources. Laudably, FERC has proactively addressed some particular barriers to storage, which this Article will discuss, but many significant barriers remain. Part I introduces energy storage, particularly its history, its operational uses, and its benefits. Part II introduces federal electricity regulation, and analyzes various FERC-jurisdictional opportunities and barriers to energy storage. It also highlights recent FERC actions that proactively address or incidentally impact energy storage resources. Finally, Part III proposes actions FERC should take to remedy identified barriers. In particular, it argues that FERC is required under the Federal Power Act ("FPA") to eliminate unjust, unreasonable, and unduly discriminatory barriers to energy storage in organized wholesale markets and resource adequacy planning processes. It then argues that the Commission should clarify its policies for classifying storage devices, without arbitrarily limiting storage resources from maximally benefiting the grid by performing multiple functions. Finally, it argues that energy storage resources should be considered comparably alongside traditional resources in transmission planning processes.