Electric Power Energy Research Articles

Dynamic Input Output Analysis: Carbon, Water and Ecological Hierarchy

As the main component of greenhouse gases, excessive carbon emissions are responsible for global climate change and anomalies. Carbon emission metabolism is essential for alleviating climate changes globally. Here, a dynamic input-output model is developed for analyzing carbon emission metabolism and ecological hierarchy. Direct and indirect carbon emissions are evaluated, and mutual relationships between various sectors are explored. The innovation of this research is summarized as follows: firstly, for carbon emission, the competition relationships reveal good interactions in terms of emission reduction while mutualism relationship provides effective pathways to mitigate carbon emissions between pairwise sectors simultaneously. Moreover, analysis of direct and indirect carbon emissions could help to extract embodied sectors with large emissions and identify whether the sectors should adjust their production structure or upgrade the clean combustion technology. In addition, ecological hierarchy analysis would help to identify key sectors lacking driving or pulling force during study period. It provides a new insight into the potential sectors which play an important role in the emission reduction. Results show that carbon emissions mainly concentrated in electricity-generation, manufacturing, and transportation sectors. In Guangdong province, upgrading the clean combustion technology in electric power generation and energy extraction sectors would drive other sectors to cut emissions and adjusting the production structure of the construction sector also contribute to achieve this goal. Tertiary industry is not sufficiently promoting Guangdong’s economic development, and therefore plays a restrictive role in the current economy. Results could help decision makers to develop emission mitigation policies.

Multi Energy System With an Associated Energy Hub: A Review

The increasing penetration of renewable resources causes some challenges like the electric power demand prediction uncertainty and energy surplus. Energy storage systems (ESS) are promising solutions for these challenges. However, considering the marginal capacity of ESSs according to the installation area and the economic portion of ESSs according to the installation capacity, the use of battery ESSs to reduce surplus energy is not efficient and has practical limitations. To efficiently resolve the challenges, a multi-energy system (MES) that is capable of operating different energy sources, such as natural gas storage (NGS), thermal energy storage (TES), ice energy storage (IES), and hydrogen energy storage (HES) has been proposed. The centerpiece of converting and managing multiple energy sources associated with the MES is the energy hub (EH). In this paper, we reviewed and compared the performance of existing ESSs and the MES, and the results have demonstrated the superiority of the MES. In addition, EHs that include power-to-gas, combined heat power, and combined cooling heat power, have been examined based on their structural characteristics. A review of the methods and the primary purpose of MES is also highlighted in this paper.

Optimization of the energy system of the Taimyr coal basin through energy storage

This article examines the influence of energy storage on the possibility of increasing the efficiency of a power plant on the example of the model of the power system of the Taimyr coal basin. The main elements of the power system calculated in this paper included: household consumers (township of Dixon), industrial consumers (coal mining enterprises), sources of thermal and electric energy (coal-fired combined heat and power plant). Storage equipment was selected for the storage of thermal and electrical energy in the power system, such as energy storage systems based on lithium-ion batteries and hot water storage tanks. The changes in the operation modes of the combined heat and power plant during the introduction of battery systems in the power system were evaluated, and the efficiency of the combined heat and power plant was calculated for various modes of energy storage.

Amelioration of Hybrid Power System Using IOT

Today the whole world is facing one of the important crises that inadequate of natural resources like fossil fuels for energy production. In order to overcome this the use of renewable energy resources is encouraged. This paper describes about the electrical energy power generation with the interface of solar photovoltaic and wind energy. Solar Energy and wind energy are non conventional energy resources. This will provide an uninterrupted power supply without damaging the natural balance. Now a day’s maintenance of power production station becomes a little difficult process. In order to overcome this drawback IoT (Internet of Things) used. IoT manages the power production data’s in each PV module and wind turbines. Hence it is further used to identify the defective panels and turbines for the site management purposes.

An overview of the research work of Prof. Oyama, including verification of the applicability of the survivability function for public policy analysis of social systems

Professor Emeritus Tatsuo Oyama of the National Graduate Institute for Policy Studies, Tokyo, Japan, is an expert in the field of operations research (OR) analysis. Oyama has focused his career on bringing OR to novel systems and social infrastructures. He has made its application to various social and public problems over the last 30 years and also he is a key member of both national and international efforts to take a mathematical approach to defining decision-making and public policies. Oyama's OR research is focused on electrical power supply, energy and environmental problems, city traffic management analyses, natural disaster mitigation policy, higher education and research funding policy and the apportionment problem in democratic systems.

Exploring the Feasibility of Solar Inverters for Wastewater Pumping Using Mathematical Modelling at Wood Drive Sewage Pump Station

Solar photovoltaic systems could be an alternative for the pumping of wastewater as opposed to that of electric power or diesel energy systems currently being utilized in the urban environment. Wastewater pumping stations (WWPS) are an integral part of the wastewater treatment (WWT) process or what is referred to as the pumping or collection stage. A basic WWPS is designed according to what flows (m³/time) into the facility and the amount of head (m) that the pump should overcome, however the design, construction, maintenance and input energy costs is what makes these facilities costly and the motivation behind this research would be to look at ways to enable WWPSs to be more efficient through the use of solar photovoltaic (SPV) as an alternative input energy or a renewable energy source (RES). This paper uses the dynamic modelling of solar photovoltaic towards the application and feasibility of wastewater pumping at the Wood Drive pumping station in Parklands, Cape Town. This paper also demonstrates how data pertaining to pumping flow and energy consumption was collected over a study period of several weeks. These variables are collated; benchmarked and ultimately compared against other countries specific energy intensity for wastewater pumping. Energy simulations are also carried out using Hybrid Optimization Model of Electric Renewables (HOMER), where different renewable energy systems and configurations will be modelled and analysed based on the historic energy load profile of the wastewater pumping station.

Measurement of embodied carbon and energy of HVAC facilities in healthcare centers

Abstract The design of a sustainable building should include a reduction of its energy consumption, by considering the embodied energy and CO2 emissions generated during material manufacturing, transport and construction processes. A Heating, Ventilation and Air Conditioning (HVAC) facility in buildings consumes large amounts of energy. The aim of this work is to quantify the embodied carbon and energy of HVAC systems installed in healthcare centers. For this purpose, 6 healthcare centers in the region of Extremadura (Spain) -projected between 2006 and 2009 and built between 2007 and 2010- were analyzed. The results show that the embodied carbon -considering HVAC installations lifetime estimated at 15 years-is equivalent to the CO2 emitted for 2.3 years in the operation phase, and that the embodied energy is approximately 2.65 times the amount used in one year during that phase. Particularly, the average embodied carbon and energy is 48.95 kg of CO2 and 587.32 MJ per m2, respectively, discarding the environmental impact of refrigerant gases. Additionally, different reference indicators are proposed to calculate both parameters according to different structural variables of a given healthcare center, including number of users, number of staff, HVAC installation costs, electrical power and average annual energy consumption.

ECONOMIC IMPACTS OF POLICY ADOPTED BY CHINA FOR ITS AGING POPULATION

With China’s rapidly aging population, this paper constructs a policy model using overlapping generation (OLG) model and the computable general equilibrium (CGE) modeling to analyze the second-child policy and delaying retirement policy. Our research findings suggest that considering the short-term effects, delaying the retirement age imposes a greater impact on the economy than the second-child policy. Its economic impact increases initially, but then decreases to a stable level showing a diminishing influence. In the long term, the second-child policy has greater ability to boost the economy than the delaying retirement age policy and its economic impact gets stronger. From an industrial output perspective, the two policies exert greater influence on agriculture, light industry, finance and service sector than on construction and heavy industries. From an industrial import and export perspective, the two policies have great influence on finance, electric power, and fossil energy more than they do on the agricultural sector. From a monetary perspective, the impacts are greater on household income followed by the government income and corporate income, respectively. The policies also make a bigger difference to fixed capital than to changes in deposits and loans.

Multicarrier Energy System Management as Mixed Integer Linear Programming

This paper presents the problem model of multicarrier energy system management. The proposed problem includes three types of energy that is as electrical, natural and heating. Electrical and gas energies are as hub input, and hub output is as electrical and heating. The electricity energy provides using (1) renewable energy sources (RESs), electrical energy storage system, combined heat and power (CHP) system that are managed by hub operator and are not to play at market and (2) electricity market with PoolCo and bilateral contracts models. Therefore, the proposed problem is as optimization problem that its objective function is minimizing energy cost of hub. The constraints are electrical, natural and district heating networks power flow, RES, storage system, CHP and market constraints, and limitation of all networks indexes. This problem is modeled as mixed integer nonlinear programming. But, this paper uses the equivalent mixed integer linear programming model for accessing to optimal solution with low calculation time and error. Finally, this problem applied to standard test network with GAMS software, and thus, the capability of proposed problem investigates.

Hybrid system based on a multi-objective optimization and kernel approximation for multi-scale wind speed forecasting

Researching wind speed forecasting is increasingly important given the growing importance of wind energy in power system operation. Precise and reliable wind speed forecasting methods can effectively enhance the operational stability of power grids and improve their economic and environmental benefits. In recent decades, numerous methods have been proposed to reduce the forecasting errors caused by the non-stationary and non-linear properties of wind speed data. However, some traditional forecasting methods are restricted by the limitations of single prediction methods and do not consider the necessity of applying data processing technology and optimization algorithms, which leads to poor prediction accuracy. To overcome the limitations of traditional forecasting methods and provide more precise and stable wind speed prediction results, an advanced hybrid prediction system based on data reconstruction and kernel approximation (random Fourier mapping) is proposed in this paper. The proposed system successfully maximizes the forecasting capabilities of the component methods and effectively improves the wind speed prediction performance. Based on 10-min and 30-min data collected from Shandong province, China, the simulation results indicate that the forecasted values obtained using the proposed strategy are considerably better than those obtained using the compared strategies, which is beneficial for electrical energy conversion and power grid security.

Modeling and scheduling of residential electric loads for energy self‐sufficiency

AbstractThe utility company enforces a limit on the amount of energy injected into the utility grid from residential renewable plants due to the stability/protection concerns caused by the reverse power flow. Under this scenario, a proper load scheduling at the consumer end is necessary to ensure maximum renewable energy utilization during the surplus generation. This article proposes a novel objective function to impart energy self‐sufficiency for residential consumers who own electric vehicles and renewable energy power plants. The proposed objective function aims to promote the consumers to utilize the local sources such as the battery of an electric vehicle, solar PV, wind, etc., effectively through load scheduling. A dedicated program in MATLAB platform is developed for load scheduling, and an experimental case study is conducted using the forecasted demand and generation profiles collected from 10 typical residential consumers. Three new techno‐economic parameters namely, aggregate daily exchanged energy, daily average discharged energy, and daily average self‐sufficiency hours are proposed to conduct the comparative study. An Average Rank ranking method is introduced to evaluate the effectiveness of the proposed and conventional objective functions statistically. The result analysis proves that load scheduling using the proposed objective function secure the best Average Rank of 2.02 compared to the conventional objective functions.

Influence of supply voltage and frequency variations on the electrical equipment and power consumption in LV and MV distribution networks

This paper is focused on the analysis of supply voltage and frequency quality in low voltage and medium voltage distribution power systems. The influence of supply voltage and frequency variations, within the limits defined in the valid standards, on the power network’s parameters has been evaluated using the stochastic theory and the statistical analysis methods. The circuit of RLC-load was considered for numerical evaluation. The probability distribution of supply voltage and frequency was defined and the suggestions on optimum voltage and frequency quality parameters regarding electric energy consumption, power losses and electrical equipment lifespan were given.

Thermodynamic analysis and optimization of supercritical carbon dioxide Brayton cycles for use with low-grade geothermal heat sources

The transcritical carbon dioxide Rankine cycle has emerged as an alternative for power generation in low-grade heat applications. However, the low heat rejection temperatures required for condensing the carbon dioxide is almost prohibitive for many locations. A simple solution is the adoption of a supercritical carbon dioxide Brayton cycle which does not need such low temperature heat sinks. This power cycle has been poorly studied previously in low-grade heat applications. Therefore, with the aim of determining the performance and feasibility of the supercritical carbon dioxide Brayton cycle from thermodynamic viewpoint, using a low-grade geothermal heat source, this paper presents a comparative thermodynamic analysis between four different supercritical carbon dioxide Brayton cycles. For this purpose, detailed models were developed and solved by coupling the thermodynamic model with the thermal-hydraulic model of a Printed Circuit Heat Exchanger. Subsequently, simulations of a base case, a parametric analysis, and an optimization using Genetic Algorithms, were carried out. Results show that there is a combination of operating conditions that maximizes the electrical output of the system. Besides, some values of the minimum pressure of the cycles can increase substantially the precooler cooling water pumping power. At the optimum design point, using a 20 kg/s geothermal brine stream at 150 °C as heat source with a minimum allowable reinjection temperature of 70 °C, the Intercooled Recuperated Brayton Cycle achieved the highest electric power output, energy and exergy efficiencies, obtaining values of 779.99 kW, 11.51%, and 52.49%, respectively. The other feasible alternatives were the Recuperated Brayton Cycle, the Simple Brayton Cycle and the Intercooled Brayton Cycle, ranked, in that order.

External Electrode Temperature Monitoring of Lithium Iron Phosphate Batteries Based on Fiber Bragg Grating Sensors

Lithium-ion (Li-ion) batteries have become a promising candidate for the electrical energy storage and power delivery solutions. Thermal management is a key tool to improve performance and safety of Lithium-ion batteries. Currently, the common method is using electric sensors to monitor the thermal behaviour of batteries. In this work, an optical fiber sensor was proposed for temperature measurement of cells. The proposed sensor consists of a metal ring and a fiber Bragg grating (FBG). The FBG sensor calibration test shows a good linearity and high sensitivity. The FBG sensors were gloved on the external electrodes to monitor the temperature variation during charge/discharge cycles, and the PT100 sensors were attached on the electrodes as a comparison. Comparison test illustrates the response of proposed FBG sensors has a good agreement with PT100 sensors. It provides that the proposed FBG sensor can be used to monitor the temperature variation of cells, which provides a promising tool to improve the thermal management and safety of Li-ion batteries.

Effect of a New Absorber Design on the Performance of PV/T Collector: Numerical Comparative Study

The solar energy applications can be roughly divided into two main groups. A photovoltaic is an energy system that transforms solar energy into electric power and thermal energy system called solar collector that transforms solar energy into thermal energy. The photovoltaics performance affected by the high temperature of it is surface that absorbs the solar irradiance and the efficiency drop due to these higher temperatures. Therefore, the two systems associated with each other in the combined system called PV/T to enhance photovoltaic efficiency. The term PV/T (photovoltaic thermal) refers to a solar collector that uses a photovoltaic cell as an integral component of the absorption plate. The high temperature of solar photovoltaic will be decreased and transmitted to the circulated fluid inside the collector tubes. This system produces electrical and thermal at the same time. The solar collector is the vital part of PV/T. Many absorber designs have been developed in the solar collector to enhance the overall performance of the PV/T system. In the present work, a new photovoltaic thermal collector named serpen-direct is designed. Modeling for the new absorber design has been developed and validated. Numerically, PV/T performance for the serpent-direct design is analyzed and compared with the conventional serpentine design by using MATLAB Simulink. The PV and thermal efficiencies were determined under various parameters condition; mass flow rates range from 0.01 kg/s to 0.1 kg/s and solar irradiance values 700 W/m2 and 900 W/m2. Results indicate that the serpen-direct flow absorber design achieved a better system overall performance than serpentine design under similar operating conditions. The higher electrical and thermal efficiencies were 14.52%, 55%, respectively, for the PV/T serpen-direct absorber design and 14.43 %, 56.1%, correspondingly, for the serpentine absorber design.

Energy analysis of a proposed hybrid solar–biomass coffee bean drying system

A hybrid solar-biomass system for drying coffee beans was developed, combining the combustion of coffee husk pellets with a PV/T system. The energy contribution and efficiency of the combined use of coffee husk pellets and solar energy was analyzed in detail, evaluated at two locations, and compared with the conventional system. The proposed prototype reduced the moisture content of the coffee beans to 12% w. b. with 80% lower operating costs. Over 24-h operation, solar electrical energy and thermal power contributed an average of 9.5% of need and 0.6 kW continuous, respectively, to combustion air preheating. Finally, the use of coffee husk resulted in net zero CO2 emissions from combustion. Further study, evaluating the thermal and electrical performance at higher dryer outputs, using the system at full capacity, is recommended in order to optimize the hybrid system.

Exploring the link between vulnerability of energy systems and social acceptance of renewable energy in two selected districts of Uganda

PurposeThis paper aims to show preliminary evidence of the link between the perceived low vulnerability of vital energy systems (LVRE) and social acceptance of renewable energy (SARE) while treating environmental opportunities and threats (EOPT), renewable energy technological innovations (TECH) and business model innovations as possible antecedents.Design/methodology/approachThe objectives are delivered through a survey of 199 households (potential and actual customers/suppliers of electric power and renewable energy gadgets in Kampala and Wakiso districts of Uganda), and the data obtained were analysed using ordinary least squares (OLS) regression.FindingsBoth LVRE and EOPT, on their own, significantly predict SARE. TECH significantly mediate in the relation between EOPT and SARE. The highest form of SARE is market acceptance. Also, the current state of vulnerability of vital energy systems in the two Ugandan districts seems to espouse energy security as the real value of renewable energy. The study further finds that to deliver high SARE, there is a need to encompass potential user performance expectations of renewable energy technologies.Research implications/limitationBecause the current results are from only two cities (districts) of Uganda and also based on a non-probability sample, generalizing them can be considered remote. In other words, it appears that more complex models need developing and testing in the future concerning LVRE and SARE. The present preliminary results are offered as a stimulus to such efforts. Well, it is expected, and, consistent with the diffusion of innovations theory (Rogers, 1995), that the population in Kampala and Wakiso districts are potential change agents (i.e. capable of influencing others in rural areas of Uganda).Originality/valueThe study estimates the direct and indirect effects to show how strongly TECH operate. Basing on OLS regression coefficients, the indirect effects are larger. Using the medgraph, we find probably for the first time, the adoption of technological innovation explains a significant part of the link between EOPT and SARE in the current study setting.

CALCULATION-EXPERIMENTAL DETERMINATION OF THE AVERAGE NUMBER OF QUANTIZED LONGITUDINAL ELECTRON DE BROGLIE HALF WAVES IN A CYLINDRICAL CONDUCTOR WITH PULSED AXIAL CURRENT

Purpose: Implementation of calculation-experimental determination of average number n0m of the quantized longitudinal electron de Broglie half waves of length λezm/2 in the metal cylindrical conductor with the pulsed axial current of high density. Methodology. Scientific bases of theoretical electrophysics and quantum physics, theoretical bases of the electrical engineering, electrophysics bases of technique of high-voltage and high pulsed currents. Results: The results of calculation-experimental estimations of average number n0m of the quantized longitudinal electron de Broglie half waves in the round continuous zincked steel wire of radius 0.8mm and of length 320 mm with aperiodic pulsed axial current i0(t) of temporal shape 9 ms/160 ms of high density (at its amplitude of δ0m=0.37 kA/mm2). It is shown that in examined case the numeral value of the average quantized number from data of calculation and experiment makes n0m=9, and test average length of quantized longitudinal electron de Broglie half waves in the indicated steel wire appears approximately equal to λezm/2≈34 mm. Electrophysical results are confirmed during the high current high temperature experiment conducted by a powerful high-voltage equipment calculation information on the choice of average value of quantized number n0m for longitudinal «hot» areas of the width Δz of the wire, different anomalous enhanceable concentration of drifting lone electrons and accordingly temperature of Joule heating. Originality: On the basis of the known conformities to the law of atomic and quantum physics new quantum-mechanical calculation correlation is obtained for determination in a metallic conductor with axial current of conductivity i0(t) of different type (direct, alternating and pulsed) of average number n0m of the quantized longitudinal electron de Broglie half waves and accordingly longitudinal «hot» areas of the width Δz of periodic localization along the conductor of drifting lone electrons. Practical Value: Obtained results allow to make an evaluation prognosis on finding of possible places of longitudinal periodic localization of drifting lone electrons on narrow areas of the width Δz of current-carrying parts of power wires and cables of objects of electrical power energy, production and dwellings apartments, showing up most strongly (expressed) in malfunctions of operation of cable-conductor products with the currents of short-circuit and high current density.

Biofuels, biodiesel and biohydrogen production using bioprocesses. A review

Energy demands, pollution and global warming induced by globalization are rising, thus calling for alternative sources of energies. In particular, biofuels are increasingly used for transportation, electric power and heat energy generation. Biofuels can mitigate greenhouse gas emissions by up to 50%. Biofuels are produced from organic matter and waste such as dry lignocellulose, algae, yeast, restaurant greases, food grain, non-food grain and animal fats. Biofuel from crop residues can be promoted by government subsidies to reduce the fuel price and meet the requirement of industries, transportation and agricultural sectors.

A Novel Technique of Piezoelectric Energy Harvesting

Energy harvesting is the technology to extract energy from environment with many surrounding sources of energy. From these sources it is used to extract less electrical power energy and boost up tiny electrical systems or amount of energy stored in a battery. Many methods in energy harvesting among one of the method for harvesting energy is piezoelectric transducers. Energy harvesting depends upon so many factors like conducting circuit, number of sensors, and coupling coefficient of piezoelectric sensors with electromechanical. For large scale applications, one of the best suited technique energy harvesting .