Showing papers on "Electric power published in 2020"

Electric vehicles standards, charging infrastructure, and impact on grid integration: A technological review

Abstract: Transportation electrification is one of the main research areas for the past decade. Electric vehicles (EVs) are taking over the market share of conventional internal combustion engine vehicles. The increasing popularity of EVs results in higher number of charging stations, which have significant effects on the electricity grid. Different charging strat2egies, as well as grid integration methods, are being developed to minimize the adverse effects of EV charging and to strengthen the benefits of EV grid integration. In this paper, a comprehensive review of the current situation of the EV market, standards, charging infrastructure, and the impact of EV charging on the grid is presented. The paper introduces the current EV status, and provides a comprehensive review on important international EV charging and grid interconnection standards. Different infrastructure configurations in terms of control and communication architectures for EV charging are studied and evaluated. The electric power market is studied by considering the participation roles of EV aggregators and individual EV owners, and different optimization and game based algorithms for EV grid integration management are reviewed. The paper specially presents an evaluation on how the future EV development, such as connected vehicles, autonomous driving, and shared mobility, would affect EV grid integration as well as the development of the power grid moves toward future energy Internet and how EVs would affect and benefit the development of the future energy Internet. Finally, the challenges and suggestions for the future development of the EV charging and grid integration infrastructure are evaluated and summarized.

Power generation from ambient humidity using protein nanowires.

Abstract: Harvesting energy from the environment offers the promise of clean power for self-sustained systems1,2. Known technologies—such as solar cells, thermoelectric devices and mechanical generators—have specific environmental requirements that restrict where they can be deployed and limit their potential for continuous energy production3–5. The ubiquity of atmospheric moisture offers an alternative. However, existing moisture-based energy-harvesting technologies can produce only intermittent, brief (shorter than 50 seconds) bursts of power in the ambient environment, owing to the lack of a sustained conversion mechanism6–12. Here we show that thin-film devices made from nanometre-scale protein wires harvested from the microbe Geobacter sulfurreducens can generate continuous electric power in the ambient environment. The devices produce a sustained voltage of around 0.5 volts across a 7-micrometre-thick film, with a current density of around 17 microamperes per square centimetre. We find the driving force behind this energy generation to be a self-maintained moisture gradient that forms within the film when the film is exposed to the humidity that is naturally present in air. Connecting several devices linearly scales up the voltage and current to power electronics. Our results demonstrate the feasibility of a continuous energy-harvesting strategy that is less restricted by location or environmental conditions than other sustainable approaches. A new type of energy-harvesting device, based on protein nanowires from the microbe Geobacter sulforreducens, can generate a sustained power output by producing a moisture gradient across the nanowire film using natural humidity.

Photo-Rechargeable Fabrics as Sustainable and Robust Power Sources for Wearable Bioelectronics

Abstract: Summary Smart textiles for electricity generation are a superior energy solution with greatly improved convenience and comfort for wearable bioelectronics. However, maintaining the sustainability and stability of the power supply, though highly desirable, remains a great challenge. Here, we present a photo-rechargeable fabric with economically viable materials and scalable fabrication technologies. The fabric was able to constantly deliver electric power for 10 min at 0.1 mA after being charged for 1 min under the standard 1-sun condition. It can also work normally under twisted and watery circumstances and hold the stored energy for over 60 days without significant voltage loss. The photo-rechargeable fabric was demonstrated to power a body area sensor network for personalized healthcare.

Realising the potential of thermoelectric technology: a Roadmap

Abstract: All machines from jet engines to microprocessors generate heat, as do manufacturing processes ranging from steel to food production. Thermoelectric generators (TEGs) are solid-state devices able to convert the resulting heat flux directly into electrical power. TEGs therefore have the potential to offer a simple, compact route to power generation in almost every industrial sector. Here, in a Roadmap developed with wide-ranging contributions from the UK Thermoelectric Network and international partners, we present the science and technology that underpins TEGs. We outline how thermoelectric (TE) technology capable of generating power outputs from microwatts to tens/hundreds kW, and potentially to MW, can have an impact across a wide range of applications in powering devices, ranging from medical to building monitoring, the internet of things, transportation and industrial sectors. The complementary application of TE technology in cooling affords additional opportunities in refrigeration and thermal management. Improved waste-heat harvesting and recovery and more efficient cooling offer significant opportunities to reduce energy usage and CO2 emissions. We provide an overview of the key challenges associated with the development of new materials and devices that offer higher power output, while matching TE solutions to the wide range of applications that would benefit from energy harvesting. There is an existing supply chain to develop, manufacture and integrate thermoelectric devices into a broad range of end-user sectors all with global market potential: the full realisation of which will require new state-of-the-art manufacturing techniques to be embraced in order to drive down costs through high-volume manufacturing to widen the application base.

A P2P-Dominant Distribution System Architecture

Abstract: Peer-to-peer interactions between small-scale energy resources exploit distribution network infrastructure as an electricity carrier, but remain financially unaccountable to electric power utilities. This status-quo raises multiple challenges. First, peer-to-peer energy trading reduces the portion of electricity supplied to end-customers by utilities and their revenue streams. Second, utilities must ensure that peer-to-peer transactions comply with distribution network limits. This article proposes a peer-to-peer energy trading architecture, in two configurations, that couples peer-to-peer interactions and distribution network operations. The first configuration assumes that these interactions are settled by the utility in a centralized manner, while the second one is peer-centric and does not involve the utility. Both configurations use distribution locational marginal prices to compute network usage charges that peers must pay to the utility for using the distribution network.

An Innovative synthesis of deep learning techniques (DCapsNet & DCOM) for generation electrical renewable energy from wind energy

Abstract: Renewable energy becomes one of the main resources that help the world to safety the environment from pollution and provide the people of new type of energy; therefore, this paper presents model called multi-objectives renewable energy-generation (MORE-G) for generating electrical energy from the wind. In general, this model consists of five basic phases: in a first phase collecting and preparing the data, so to make it in format suitable for the decision-making stage, this phase split into multi-steps (i.e., handle missing values and normalization dataset), and the second phase focuses on building constraints for each dataset and develops one of the optimization algorithms called cuckoo based on horizontal combination and multi-objective optimization used in third phase to generate the energy. Another model is developed as multi-layer neural network called (DCapsNet) based on linear combination and multi-objective functions used in the fourth phase to generate the energy. Final phase is related to evaluation of both models (DCOM and DCapsNet) to determine the best. The MORE-G is characterized by addressing one of the real problems, saving on material costs (i.e., reducing the need for manpower and reducing dependence on other countries in importing electric power) and upgrading the scope of the ministry of electricity.

Self-operating transpiration-driven electrokinetic power generator with an artificial hydrological cycle

Abstract: Autonomous energy scavenging from the ambient environment, or self-energy management, has attracted increasing attention because it could solve the energy problem of abundant Internet of things (IoT) devices. In recent years, several energy harvesters that generate electricity using water have been invented due to their simplicity, sustainability, and eco-friendliness. Until now, the devices have required periodic supplementation of water for continuous electricity generation, which hinders their practical use. Here, we built an artificial hydrological cycle in a transpiration-driven electrokinetic power generator (TEPG) to continuously and autonomously generate electric power. The TEPG, composed of carbon-coated cotton fabric, generates electricity by using a few drops of water (0.2 mL); the electric power originates from the potential difference in the asymmetrically wetted device and the pseudostreaming current. However, after only one hour, the TEPG stops generating electricity, as water inevitably evaporates from the device. For continuous self-operation, we utilized calcium chloride (CaCl2), a typical deliquescent chemical, to collect water vapor from the surrounding environment and continuously supply water to the TEPG. In the range of 15–60% relative humidity (RH), CaCl2 successfully compensates for the water loss by evaporation and maintains the electrical power generation in the closed system. In addition, CaCl2 enhances the generated voltage (0.74 V) and current (22.5 μA) by supplying additional Ca2+ ions to the carbon surface and reducing the resistance of the device, respectively. The developed self-operating transpiration-driven electrokinetic power generator (STEPG) is stable enough to light a light-emitting diode (LED) for a week and charge a commercialized supercapacitor (5 F) to 1.6 V for 8 days.

Comprehensive Review of Distributed FACTS Control Algorithms for Power Quality Enhancement in Utility Grid With Renewable Energy Penetration

Abstract: Rapid industrialization and its automation on the globe demands increased generation of electrical energy with more reliability and quality. Renewable energy (RE) sources are considered as a green form of energy and extensively used as an alternative source of energy for conventional energy sources to meet the increased demand for electrical power. However, these sources, when integrated to the utility grid, pose challenges in maintaining the power quality (PQ) and stability of the power system network. This is due to the unpredictable and variable nature of generation by these sources. The distributed flexible AC transmission system (DFACTS) devices such as distributed static compensator (DSTATCOM) and dynamic voltage restorer (DVR) play an active role in mitigating PQ issues associated with RE penetration. The performance of DFACTS devices is mostly dependent on the type of control algorithms employed for switching of these devices. This paper presents a comprehensive review of various conventional and adaptive algorithms used to control DFACTS devices for improvement of power quality in utility grids with RE penetration. This review intends to provide a summary of the design, experimental hardware, performance and feasibility aspects of these algorithms reported in the literature. More than 170 research publications are critically reviewed, classified, and listed for quick reference for the advantage of engineers and academician working in this area.

Sweat-activated biocompatible batteries for epidermal electronic and microfluidic systems

Abstract: Recent advances in materials, mechanics and design have led to the development of ultrathin, lightweight electronic devices that can conformally interface with human skin. With few exceptions, these devices rely on electrical power to support sensing, wireless communication and signal conditioning. Unfortunately, most sources of such power consist of batteries constructed using hazardous materials, often with form factors that frustrate incorporation into skin-like, or epidermal, electronic devices. Here we report a biocompatible, sweat-activated battery technology that can be embedded within a soft, microfluidic platform. The battery can be used in a detachable electronic module that contains wireless communication and power management systems, and is capable of continuous on-skin recording of physiological signals. To illustrate the practical utility of our approach, we show using human trials that the sweat-activated batteries can operate hybrid microfluidic/microelectronic systems that simultaneously monitor heart rate, sweat chloride and sweat pH. Sweat-activated, biocompatible batteries can be used to power flexible on-skin electronic systems that monitor and wirelessly transmit physiological signals.

Aluminum-air batteries: A viability review

Abstract: Aluminum–air (Al–air) batteries, both primary and secondary, are promising candidates for their use as electric batteries to power electric and electronic devices, utility and commercial vehicles and other usages at a relatively lower cost. This paper provides an analysis of the performance of these batteries with a component by component comparison with other technologies. It also aims to identify the major impediments that must be overcome for the battery. Al alloys are inexpensive and provide better electrochemical performances as compared to pure Al. The oxygen reduction reaction (ORR) at the cathode is traditionally controlled by platinum and other noble catalysts, but several carbonaceous materials, transitional metal oxides, and polymer-based systems may be satisfactory alternatives. The aqueous alkali electrolytes, though widely used at present, may be suitably replaced by non-aqueous electrolytes, aprotic and ionic liquids for both primary and secondary batteries. The different types of design and assembly for greater performance and economic viability are also described. This review may serve as a scientific tool for the progression of research on Al–air battery system.

Optimal integration of DGs into radial distribution network in the presence of plug-in electric vehicles to minimize daily active power losses and to improve the voltage profile of the system using bio-inspired optimization algorithms

Abstract: The increase in plug-in electric vehicles (PEVs) is likely to see a noteworthy impact on the distribution system due to high electric power consumption during charging and uncertainty in charging behavior. To address this problem, the present work mainly focuses on optimal integration of distributed generators (DG) into radial distribution systems in the presence of PEV loads with their charging behavior under daily load pattern including load models by considering the daily (24 h) power loss and voltage improvement of the system as objectives for better system performance. To achieve the desired outcomes, an efficient weighted factor multi-objective function is modeled. Particle Swarm Optimization (PSO) and Butterfly Optimization (BO) algorithms are selected and implemented to minimize the objectives of the system. A repetitive backward-forward sweep-based load flow has been introduced to calculate the daily power loss and bus voltages of the radial distribution system. The simulations are carried out using MATLAB software. The simulation outcomes reveal that the proposed approach definitely improved the system performance in all aspects. Among PSO and BO, BO is comparatively successful in achieving the desired objectives. The main contribution of this paper is the formulation of the multi-objective function that can address daily active power loss and voltage deviation under 24-h load pattern including grouping of residential, industrial and commercial loads. Introduction of repetitive backward-forward sweep-based load flow and the modeling of PEV load with two different charging scenarios.

Enhanced Coordinated Operations of Electric Power and Transportation Networks via EV Charging Services

Abstract: Electric power and transportation networks become increasingly coupled through electric vehicles (EV) charging station (EVCS) as the penetration of EVs continues to grow. In this paper, we propose a holistic framework to enhance the operation of coordinated electric power distribution network (PDN) and urban transportation network (UTN) via EV charging services. Under this framework, a bi-level model is formulated to optimally determine EVCS charging service fees (CSF) for guiding EV charging behaviors and minimizing the total social cost. At the upper level, PDN with wind power generation is formulated as a second-order cone problem (SOCP) where CSF is determined. Given the settings calculated at the upper level, the lower level problem is described as a traffic assignment problem (TAP) which is subject to the user equilibrium (UE) principle and captures the individual rationality of single EV owners in UTN. The uncertainties in wind power output and origin-destination (O-D) traffic demands are considered in the proposed model and a deep reinforcement learning (DRL)-based solution framework is developed to decouple and approximately solve the stochastic bi-level problem. Both gradient-based and gradient-free training algorithms are implemented in this paper and the respective results are compared. The case studies on a 5-node system, 24-node Sioux-Falls system and real-world Xi’an city in China are conducted to verify the effectiveness of the proposed model, which demonstrates the enhanced operation of coordinated PDN and UTN networks by reducing the traffic congestion and improving the integration of renewable energy.

Can Green Hydrogen Production Be Economically Viable under Current Market Conditions

Abstract: This paper discusses the potential of green hydrogen production in a case study of a Slovenian hydro power plant. To assess the feasibility and eligibility of hydrogen production at the power plant, we present an overview of current hydrogen prices and the costs of the power-to-gas system for green hydrogen production. After defining the production cost for hydrogen at the case study hydro power plant, we elaborate on the profitability of hydrogen production over electricity. As hydrogen can be used as a sustainable energy vector in industry, heating, mobility, and the electro energetic sectors, we discuss the current competitiveness of hydrogen in the heating and transport sectors. Considering the current prices of different fuels, it is shown that hydrogen can be competitive in the transport sector if it is unencumbered by various environmental taxes. The second part of the paper deals with hydrogen production in the context of secondary control ancillary service provided by a case study power plant. Namely, hydrogen can be produced during the time period when there is no demand for extra electric power within a secondary control ancillary service, and thus the economics of power plant operation can be improved.

Study of braking energy recovery impact on cost-efficiency and environmental safety of vehicle

Abstract: The article addresses the evaluation of the impact of regenerative braking on fuel consumption and, consequently, on pollutant emissions from vehicles operated under conditions leading to frequent acceleration and deceleration. We assume that the vehicle is equipped with a system of conversion and accumulation of electric energy obtained only from braking. Basic analyzed characteristics are determined by a comparison of gasoline engine operation modes with braking energy recovery and without it. As initial physicomathematical tools, we use relationships of propulsion power and energy analysis and propulsion drive operation, which were previously suggested by one of the authors. As an example of using the mentioned relationships, the article presents the analysis results for a vehicle moving in the low-speed segment of the WLTC driving cycle. Energy passing through the battery and energy reserve in it are calculated. It is assumed that the accumulated braking energy makes it possible to start moving at the next segment not using the gasoline engine; the engine starts its operation only after the energy in the battery is exhausted. Superposition of the curves of gasoline engine operation modes with and without recovery allows us to estimate changes in the energy generated. In order to account for different values of specific fuel consumption, the authors use an adjustment factor, which takes into account pollutant emissions from the vehicle depending on the average speed. Functions of changes in fuel consumption and pollutant emissions when using regenerative braking are obtained by the integration of values. The authors compare the obtained results with the results of road tests of vehicles with the energy recovery system. The materials suggested expand our knowledge of the operational properties of vehicles with electromechanical and electrical power units

A Novel Electric Vehicles Charging/Discharging Management Protocol Based on Queuing Model

Abstract: High electric vehicles (EVs) penetration is expected to increase smart grid solicitation especially with various EV charging demands. As result, the EV charging process at the supply station has to be managed in the way to promote the EV satisfaction level while preserving smart grid stability. In this article, the bidirectional power flow between EV and grid; Grid-to-Vehicle (G2V) and Vehicle-to-Grid (V2G), is exploited. We make a profit from the unused electric power of EVs and we present an EV load management technique based on EV charging and EV discharging coordination. We propose a peak load management model (PLM) used to schedule EVs for charging or discharging service according to the power demand with the timing and location where each EV need to be served. Also, we propose an Electric Vehicle Supply Equipment (EVSE) selection model to guide EVs to the supply station. We develop a mathematical formalism for handling requests for EV charging/discharging at EVSE based on queuing theory. Those models are evaluated while considering the mobility of vehicles in an urban scenario and time-of-use-pricing (TOUP). Finally, extensive matlab simulations are conducted to validate the proposed approach and demonstrate its effectiveness.

Discussion on Electric Power Supply Systems for All Electric Aircraft

Abstract: The electric power supply system is one of the most important research areas within sustainable and energy-efcient aviation for more- and especially all electric aircraft. This paper discusses the history in electrication, current trends with a broad overview of research activities, state of the art of electrication and an initial proposal for a short-range aircraft. It gives an overviewof the mission prole, electrical sources, approaches for the electrical distribution system and the required electrical loads. Current research aspects and questions are discussed, including voltage levels, semiconductor technology, topologies and reliability. Because of the importance for safety possible circuit breakers for the proposed concept are also presented and compared, leading to a initial proposal. Additionally, a very broad review of literature and a state of the art discussion of the wiring harness is given, showing that this topic comes with a high number of aspects and requirements. Finally, the conclusion sums up the most important results and gives an outlook on important future research topics.

High Penetration of Power Electronic Interfaced Power Sources and the Potential Contribution of Grid Forming Converters

Abstract: The traditional electrical power system and electricity markets have been designed to work with SGs, and so these have traditionally provided various 'inherent' capabilities to the system critical to ensure the stable operation of the power systems during severe faults and even basic system survival during rare system splits. Due to the potential total absence of SGs approaches during periods of high penetration (HP) of PEIPS infeed, the wider industry has engaged in a closer examination of the lack of these system capabilities [4], [17], [31], [32]. Traditionally, the focus in the context of PEIPS has been on steady state and a limited number of dynamic (faster) aspects recently expanded to include PEIPS contributing fast fault current during system faults and extended contribution to frequency management (although this latter capability has been required from RES for more than 10 years in some countries). Demand side contributions in these contexts are emerging and have significant potential.