Showing papers on "Electric power published in 2019"

Power-to-Gas: Electrolysis and methanation status review

Abstract: This review gives a worldwide overview on Power-to-Gas projects producing hydrogen or renewable substitute natural gas focusing projects in central Europe. It deepens and completes the content of previous reviews by including hitherto unreviewed projects and by combining project names with details such as plant location. It is based on data from 153 completed, recent and planned projects since 1988 which were evaluated with regards to plant allocation, installed power development, plant size, shares and amounts of hydrogen or substitute natural gas producing examinations and product utilization phases. Cost development for electrolysis and carbon dioxide methanation was analyzed and a projection until 2030 is given with an outlook to 2050. The results show substantial cost reductions for electrolysis as well as for methanation during the recent years and a further price decline to less than 500 euro per kilowatt electric power input for both technologies until 2050 is estimated if cost projection follows the current trend. Most of the projects examined are located in Germany, Denmark, the United States of America and Canada. Following an exponential global trend to increase installed power, today's Power-to-Gas applications are operated at about 39 megawatt. Hydrogen and substitute natural gas were investigated on equal terms concerning the number of projects.

Development and applications of photovoltaic–thermal systems: A review

Abstract: The commercial solar cells are currently less efficient in converting solar radiation into electricity. During electric power convention, most of the absorbed energy is dissipated to the surroundings. In order to improve energy efficiency, many efforts have been made to investigate and develop hybrid photovoltaic and thermal collector systems. A photovoltaic–thermal (PV/T) system does both the generation of electric power and collection of thermal energy at the same time. Thus, the overall efficiency of the photovoltaic–thermal (PV/T) system can increase accordingly. In this work, we attempt to summarize various research works on technologies like flat–plate PV/T systems and concentrator type PV/T systems, using different kinds of working fluids under a variety of environmental conditions. The purpose of this review is to define the appropriate environmental conditions and applications for different kinds of PV/T systems. Besides, it is also presented that the applications and developments of the PV/T systems. In order to develop novel PV/T systems, more effort is needed in accurate modeling, exploration of novel materials, enhancement of PV/T system stability and the design of a supporting energy storage system.

Improving electric energy consumption prediction using CNN and Bi-LSTM

Abstract: The electric energy consumption prediction (EECP) is an essential and complex task in intelligent power management system. EECP plays a significant role in drawing up a national energy development policy. Therefore, this study proposes an Electric Energy Consumption Prediction model utilizing the combination of Convolutional Neural Network (CNN) and Bi-directional Long Short-Term Memory (Bi-LSTM) that is named EECP-CBL model to predict electric energy consumption. In this framework, two CNNs in the first module extract the important information from several variables in the individual household electric power consumption (IHEPC) dataset. Then, Bi-LSTM module with two Bi-LSTM layers uses the above information as well as the trends of time series in two directions including the forward and backward states to make predictions. The obtained values in the Bi-LSTM module will be passed to the last module that consists of two fully connected layers for finally predicting the electric energy consumption in the future. The experiments were conducted to compare the prediction performances of the proposed model and the state-of-the-art models for the IHEPC dataset with several variants. The experimental results indicate that EECP-CBL framework outperforms the state-of-the-art approaches in terms of several performance metrics for electric energy consumption prediction on several variations of IHEPC dataset in real-time, short-term, medium-term and long-term timespans.

An efficient polymer moist-electric generator

Abstract: The depletion of fossil fuels and the corresponding environmental concerns require the development of new kinds of green energy. We herein present a new type of highly efficient electric generation by the traditional polyelectrolyte membrane of poly(4-styrensulfonic acid) (PSSA) with moisture. This polymer moist-electric generator (PMEG) with a piece of 1 cm2 PSSA membrane can offer an open-circuit-voltage of up to ∼0.8 V and a short-circuit-current density of ∼0.1 mA cm−2, which is sufficient to power up many electronic devices. Flexible power supply devices made of PSSA membranes are designed and fabricated for harvesting the energy from human breath and some other real-life conditions. The experimental demonstration and theoretical modeling reveal that the moisture-induced directional movement of protons within the PSSA membrane led to the generation of electric power. This work opens a novel perspective for the traditional polyelectrolyte membrane and offers an extremely simple method for energy conversion of practical importance.

Development of a wide range-operable, rich-lean low-NOx combustor for NH3 fuel gas-turbine power generation

Abstract: Low-NOx NH3-air combustion power generation technology was developed by using a 50-kWe class micro gas-turbine system at the National Institute of Advanced Industrial Science and Technology (AIST), Japan, for the first time. Based on the global demand for carbon-free power generation as well as recent advances involving gas-turbine technologies, such as heat-regenerative cycles, rapid fuel mixing using strong swirling flows, and two-stage combustion with equivalence ratio control, we developed a low-NOx NH3-air non-premixed combustor for the gas-turbine system. Considering a previously performed numerical analysis, which proved that the NO reduction level depends on the equivalence ratio of the primary combustion zone in a NH3-air swirl burner, an experimental study using a combustor test rig was carried out. Results showed that eliminating air flow through primary dilution holes moves the point of the lowest NO emissions to the lesser fuel flow rate. Based on findings derived by using a test rig, a rich-lean low NOx combustor was newly manufactured for actual gas-turbine operations. As a result, the NH3 single fueled low-NOx combustion gas-turbine power generation using the rich-lean combustion concept succeeded over a wide range of power and rotational speeds, i.e., below 10–40 kWe and 75,000–80,000 rpm, respectively. The NO emissions were reduced to 337 ppm (16% O2), which was about one-third of that of the base system. Simultaneously, unburnt NH3 was reduced significantly, especially at the low electrical power output, which was indicative of the wider operating range with high combustion efficiency. In addition, N2O emissions, which have a large Global Warming Potential (GWP) of 298, were reduced significantly, thus demonstrating the potential of NH3 gas-turbine power generation with low environmental impacts.

A new optimized fuzzy FOPI-FOPD controller for automatic generation control of electric power systems

Abstract: In the rapidly expanding size and complexity of the electricity network, automatic generation control (AGC) is contemplated to be the most remarkable option for offering good quality electric power supply to the end users. An AGC system entails highly vigorous, competent and intelligent control technique to deliver a healthy power under stochastic nature of consumers’ power demand. Hence, in this paper, a hybrid fuzzy fractional order proportional integral-fractional order proportional derivative (FFOPI-FOPD) controller is proposed as a new expert control technique to tackle AGC profitably in isolated and interconnected multi-area power systems. A recently developed imperialist competitive algorithm (ICA) is utilized for the optimization of the output gains (KP/KP1/KI/KD) and other parameters such as order of integrator (λ) and differentiator (μ) of FFOPI-FOPD controller exercising integral of squared error criterion. The proposed technique is firstly implemented on 1-area thermal system, then to express its potential and extensibility, the work is extended to 2-area hydro-thermal and 3-area thermal power systems widespread in the literature. The eminence of the method is betokened by comparing the results with the various newly published control methodologies and FPI/FFOPI controller designed in the study via ICA in terms of minimum values of various error criteria and undershoots/overshoots/settling times of frequency and tie-line power deviations following a sudden load demand in an area. The sensitivity analysis substantiates that the suggested controller is robust and performs staunchly under the wide variations in the system parameters, random load pattern and in the company of physical constraints to produce more clean electricity.

Understanding the Giant Gap between Single-Pore- and Membrane-Based Nanofluidic Osmotic Power Generators

Abstract: Nanofluidic blue energy harvesting attracts great interest due to its high power density and easy-to-implement nature. Proof-of-concept studies on single-pore platforms show that the power density approaches up to 103 to 106 W m-2 . However, to translate the estimated high power density into real high power becomes a challenge in membrane-scale applications. The actual power density from existing membrane materials is merely several watts per square meter. Understanding the origin and thereby bridging the giant gap between the single-pore demonstration and the membrane-scale application is therefore highly demanded. In this work, an intuitive resistance paradigm is adopted to show that this giant gap originates from the different ion transport property in porous membrane, which is dominated by both the constant reservoir resistance and the reservoir/nanopore interfacial resistance. In this case, the generated electric power becomes saturated despite the increasing pore number. The theoretical predictions are further compared with existing experimental results in literature. For both single nanopore and multipore membrane, the simulation results excellently cover the range of the experimental results. Importantly, by suppressing the reservoir and interfacial resistances, kW m-2 to MW m-2 power density can be achieved with multipore membranes, approaching the level of a single-pore system.

Stability and Reliability of Lateral GaN Power Field-Effect Transistors

Abstract: GaN electronics constitutes a revolutionary technology with power handling capabilities that amply exceed those of Si and other semiconductors in many applications. RF, microwave, and millimeter-wave GaN-based power amplifiers are now deployed in commercial communications, radar, and sensing systems. GaN power transistors for electrical power management are also starting to reach the marketplace. From the dawn of this technology, inadequate transistor stability and reliability have represented stumbling blocks preventing widespread commercial use of GaN electronics. Intense research has been devoted to addressing these issues, and great progress has taken place recently. This article reviews some of the most interesting and significant stability and reliability issues that have plagued GaN power field-effect transistors for RF and power management applications.

Impact of the Electric Mobility Implementation on the Greenhouse Gases Production in Central European Countries

Abstract: The preference and the development of electromobility are included among the priorities of transport policies in many European countries. This article deals with the issue of electric vehicle operation from the point of view of the environmental impact of electric power production, specifically the energy effectiveness of its production by utilizing primary power production sources. Differences in the effectiveness of the conversion of mixed forms of energy into electricity and their share in the process directly affect the final level of greenhouse gases (GHG) production, and thus the ecological footprint of electric vehicle operations. The specification of energy consumption and GHG production is based on the principles of the EN 16 258: 2012 standard, which considers legislative-regulated power plant effectiveness values, statistical values of GHG emissions from electricity production, and real energy consumption values of an electric vehicle fleet. The calculation takes into account the share of primary sources and the efficiency of electricity production and effectiveness of electricity distribution in each of the evaluated countries. The specific research study is performed by comparing measured parameters for individual countries chosen from the Central Europe region. The results of the study show that the quantification of the positive environmental consequences of increasing electromobility varies greatly in different countries, which means full-scale deployment of electromobility does necessarily deliver the sustainability of transport that was expected from it.