Cost Of Electrical Energy Research Articles

Study of the kinetics of the extraction of zinc ions from wastewater by ferritization

Given the relevance of the problem of wastewater treatment from heavy metal ions, and in particular from zinc ions, it is necessary to study the regularities of the process. One of the key aspects is the kinetics of the process and the dependence of the ion extraction efficiency on the duration of the purification process. Reducing the time of the process makes it possible to reduce the cost of electrical energy for technological processes, in particular for the activation of the reaction mixture by heating or electromagnetic pulses.
 Based on the obtained results of the experiment, a mathematical model of the kinetics of the process of extracting zinc ions from wastewater by ferritization with thermal and electromagnetic pulse activation was built. A regression model was used for data processing and an algorithm for calculating the dependence of the degree of purification on the time of the process was proposed. Determined the degree of purification of wastewater from heavy metal ions at different values ​​of the process duration. The expediency of carrying out the process of ferritization cleaning with a duration of 10-15 minutes has been substantiated.

Economic Viability of a 6.5kW Off-grid Solar PV with Various Sun-Tracking Systems in Northern Cyprus: A Case Study

In this paper, an in-depth analysis of small-scale PV in Northern Cyprus is conducted for the first time at 37 locations in Northern Cyprus. No previous study has investigated the viability of off-grid PV systems with various sun-tracking systems in Northern Cyprus. In order to achieve this, NASA POWER data were used for the evaluation of the solar resource in the selected locations. The results showed that the selected locations are suitable for the installation of various scales of PV systems due to the high global horizontal solar radiation. The mathematical modeling method was utilized for the design and analysis of PV systems with various sun-tracking systems and for the assessment of their economic viability and feasibility. Energy production, capacity factor, payback period, and cost of energy production were calculated. The results indicate that the proposed systems are very promising for all the selected locations. The PV projects with a 2-axis sun-tracking system produce a large amount of energy and have a low electricity cost. It was found that the electrical energy cost of the developed systems was within the range of 0.4851-0.6641TL/kWh. The payback periods varied from 4.57 years to 8.49 years, depending on the type of solar PV panel and sun-tracking system. This study provides some useful recommendations for decision-makers regarding the development and deployment of PV energy technology in the country in order to achieve sustainable development goals.

Економічний аналіз технологій акумулювання електричної енергії

The use of cost-effective large-scale electrical energy storage systems is necessary for the reliability of the power system due to the rapid growth of its production by powerful renewable energy sources. The article examines stationary electric energy storage devices, namely: sodium-sulfur; lead-acid; lithium-ion; nickel-cadmium; vanadium reduction, polysulfide-bromine and zinc-bromine flow batteries; supercapacitors; superconducting magnetic energy. Information from open sources on technologies of electric energy storage has been analyzed. As a criterion of optimality in world practice, the weighted average cost of electric energy for the life cycle is used, which ensures the self-sufficiency of the source of its production or accumulation for the entire cycle of its existence. A comparison of modern technical and economic indicators of various electrical energy storage technologies is made. Calculated average cost of electrical energy storage over the life cycle (LCOS) of various storage devices. It was determined that supercapacitors and superconductors of magnetic energy have the lowest cost of storage, and lithium-ion ones have the highest. Therefore, to minimize short-term power fluctuations in power systems, superconducting magnetic and supercapacitor storage devices are preferable. They have a lower cost of electric energy storage, short response time and high specific power.

Optimize electrical energy cost of air conditioning considering to different wall characteristics

The purpose of this study is to optimize the electrical energy cost (EC) of air conditioning (AC) with consideration of different wall characteristics. The type of wall characteristics is based on the varying composition of the wall. For example: Styrofoam, soil, calcium carbonate and iron. There are three kinds of wall that have been evaluated to design an economical building. To fulfill the goal of this research, a cooling model of building has been designed to optimize the electrical EC of the AC considering to temperature room. Under numerical optimization the electrical EC can be computed by considering thermal conductivity (K) and outside temperature (Tout). Consequently, the electrical EC for Building-1, Building-2, and Building-3 can be reduced to IDR 25,000, IDR 23,000, and IDR 20,000, respectively. In addition, this model is tested considering the value of Tout in Barru South Sulawesi-Indonesia during the entire day of July 17th, 2021 in dry session with geographical coordinates are 4° 24′ 20″ South, 119° 36’ 23” East and Latitude −4.436417.

Mathematical Model with Pressure Constraints to Minimize Electric Energy Costs in the Operation of Hydraulic Pumps

Water supply systems are responsible for providing quality water to the population in sufficient quantity. As sanitation companies are major energy consumers of electrical power, they have a contract of power in which the cost of electricity varies according to the period of the day. Thus, for these companies, at peak times the price of electricity is much higher. Most of the expenditure on electricity in water supply systems is due to hydraulic pumps, which are activated when the level of the tanks reaches the minimum level and remain on until the maximum levels are reached, without taking into account the time where this operation is performed. This work proposes a mathematical model for the optimization of electricity costs in water supply systems through the planning of the operation of hydraulic pumps. Numerical tests were performed through the implementation of the proposed model in GAMS software and solved by the CPLEX optimization package for different demand scenarios, in order to validate the proposed model. A model that simulates the operation performed in the practice of water supply systems is also presented, and its results are compared to the proposed optimization model. The obtained results proof of the efficiency of hydraulic pumps operation planning provided by the proposed model in relation to the operation performed in practice in water supply systems.

Experimental validation of a state-of-the-art model predictive control approach for demand side management with a hot water heat pump

Hot water heat pumps are well suited for demand side management, as the heat pump market faced a rapid growth in the past years with the trend to decentralized domestic hot water use. Sales were accelerated through wants and needs of energy conservation, energy efficiency, and less restrictive rules regarding Legionella. While in literature the model predictive control potential for heat pumps is commonly shown in simulations, the share of experimental studies is relatively low. To this day, experimental studies considering solely domestic hot water use are not available. In this paper, the realistic achievable model predictive control potential of a hot water heat pump is compared to the standard hysteresis control, to provide an experimental proof. We show for the first time, how state-of-the-art approaches (model predictive control, system identification, live state estimation, and demand prediction) can be transferred from electric hot water heaters to hot water heat pumps, combined, and implemented into a real-world hot water heat pump setup. The optimization approach, embedded in a realistic experimental setting, leads to a decrease in electric energy demand and cost per unit electricity by approximately 12% and 14%, respectively. Further, an increase in efficiency by approximately 13% has been achieved.

Justification of the feasibility of use of frequency converters in control stations of submersible centrifugal pumps

The article considers the problem of determining the conditions under which the use of a frequency converter in a submersible pump control station leads to a reduction in electrical energy costs and becomes efficient from an energy point of view. Analytical expressions are given that allow calculating the specific costs of electrical energy during artificial lift oil production for the case when the operating mode and well flow rate are provided by wellhead choke throttling. At the same time, special attention is paid to determining the rotation speed of the submersible asynchronous motor, which ensures the required location of the operating point on the pump pressure characteristic. Formulas are also given that make it possible to calculate the specific costs of electrical energy during artificial lift oil production for the case when the operating mode and well flow rate are set by the frequency converter of the control station. An analytical expression has been found to determine the rotation speed and frequency of the supply voltage, which provide the required operating point of the pump with frequency regulation of the submersible motor. It is proposed, using the above analytical expressions, to use the iterative method to calculate the pump performance, at which the specific energy costs for the production of a cubic meter of liquid will be equal both in the case of using a frequency converter in the control station and without it. An example of calculating such a boundary value of pump performance for a hypothetical well is given. It is shown that a decrease in the required flow rate relative to the limiting value of the pump performance leads to a decrease in the specific consumption of electrical energy during artificial lift oil production in the case of using a frequency converter in the submersible pump control station.

Aggregated Use of Energy Flexibility in Office Buildings

Due to climate change consequences, all Member States of the European Union signed an agreement with the goal of becoming the first society and economy with a neutral impact on the planet by 2050. The building sector is one of the highest energy consumers, using 33% of global energy production. Given the global increase for energy demand, implementing energy flexibility strategies is crucial for a better integration of renewable energy sources and a reduction of consumption peaks arising from the electrification of energy demand. The work described in this paper aims to develop an optimization algorithm to use the existing aggregated energy flexibility in office buildings to reduce both the electric energy costs of each office, considering the tariffs applied at each moment and the total power peak, aiming to reduce the entire building’s cost of the contracted power, considering the Portuguese context. The obtained results conclude that it is possible to reduce both the costs associated with electric energy consumption and contracted power. Nevertheless, since the cost of contracted power has a lower impact on the overall energy bill, it is more beneficial to focus only on the reduction of costs associated with electric energy consumption in the considered case study.

Levelised cost of storage comparison of energy storage systems for use in primary response application

The intermittent nature of renewable energy sources brings about fluctuations in both voltage and frequency on the power network. Energy storage systems have been utilised to mitigate these disturbances hence ensuring system flexibility and stability. Amongst others, a novel linear electric machine-based gravity energy storage system (LEM-GESS) has recently been proposed. This paper presents an economic analysis of the LEM-GESS and existing energy storage systems used in primary response. A 10MWh storage capacity is analysed for all systems. The levelised cost of storage (LCOS) method has been used to evaluate the cost of stored electrical energy. The LCOS of the LEM-GESS was compared to that of the flywheel, lead–acid battery, lithium-ion battery and vanadium-redox flow battery. The results show that the LEM-GESS has great potential as a cost-competitive technology for primary response grid support, with several distinct advantages. The LEM-GESS is about 26% more cost-effective than the currently competitive flywheel energy storage technology. Further, a sensitivity analysis highlights that the LCOS of the LEM-GESS is sensitive to capital expenditure, efficiency, discount rate and discharge duration.

Newton-Raphson Method Based Power Flow Analysis and Dynamic Security Assessment

China will accelerate the construction of a new power system under the goal of "carbon neutrality and emission peak". With the change of energy structure and system characteristics, the uncertainty on both the supply and demand sides of the power system has increased significantly, and the problem of small disturbance stability has gradually emerged. In this paper, by performing power flow calculation for the power system, the nodes requiring voltage regulation and the lines with the highest active power losses are identified, and adjustment measures are provided according to their location. In that way, the terminal voltage of each power-using device can be maintained within the specified fluctuation range, reducing the active power losses in the network while satisfying customer demand, which lowers the cost of electrical energy and reduces the waste of energy resources. This paper first introduces the basic mathematical model of the power system and the principle of the Newton-Raphson method for solving power flow. Then simulates the IEEE standard node system and proposes grid operation optimization recommendations such as adjusting the output of generating units or reactive power compensation in conjunction with the simulation results of the calculation example. It enables efficient and targeted measures to be taken to improve system safety and economy in real-time monitoring of power systems, ensuring safe and economic operation.

Strategic Participation of Active Citizen Energy Communities in Spot Electricity Markets Using Hybrid Forecast Methodologies

The increasing penetrations of distributed renewable generation lead to the need for Citizen Energy Communities. Citizen Energy Communities may be able to be active market players and solve local imbalances. The liberalization of the electricity sector brought wholesale and retail competition as a natural evolution of electricity markets. In retail competition, retailers and communities compete to sign bilateral contracts with consumers. In wholesale competition, producers, retailers and communities can submit bids to spot markets, where the prices are volatile or sign bilateral contracts, to hedge against spot price volatility. To participate in those markets, communities have to rely on risky consumption forecasts, hours ahead of real-time operation. So, as Balance Responsible Parties they may pay penalties for their real-time imbalances. This paper proposes and tests a new strategic bidding process in spot markets for communities of consumers. The strategic bidding process is composed of a forced forecast methodology for day-ahead and short-run trends for intraday forecasts of consumption. This paper also presents a case study where energy communities submit bids to spot markets to satisfy their members using the strategic bidding process. The results show that bidding at short-term markets leads to lower forecast errors than to long and medium-term markets. Better forecast accuracy leads to higher fulfillment of the community programmed dispatch, resulting in lower imbalances and control reserve needs for the power system balance. Furthermore, by being active market players, energy communities may save around 35% in their electrical energy costs when comparing with retail tariffs.

Преимущества систем цифрового мониторинга электроснабжения

In this paper, the technological situation in the world was analyzed, which contributes to a change in the production process of various organizations, the key role of the electric power industry was established in many industries. The article indicates the main problems that need to be solved in order to provide high-quality and reliable power supply to consumers. As a solution to these situations, it is proposed to put into operation a digital monitoring system of electric power parameters. In the presented article, a plan is laid for the development of a methodology for organizing digital monitoring systems in the electric power industry, positive effects are noted from the application of this approach. In addition, the advantages of digital monitoring systems are indicated, which will affect the cost of electrical energy for industrial enterprises, as well as ordinary consumers. The presented work indicates the current situation in the market of electric power companies that are interested in developing a digital monitoring system and are ready to invest in this direction. The performed analysis proves the relevance of developing such a system and allows us to outline possible ways for its implementation.

Energy Saving Implementation in Hydraulic Press Using Industrial Internet of Things (IIoT)

With the growing cost of electrical energy, the necessity of energy-saving implementation in industries based on energy audits has become a major focus area. Energy audit results indicate energy-saving potential in an application and require the physical presence of the auditor’s team for monitoring and analyzing the energy consumption data. The use of Industrial Internet of Things (IIoT) for remote data monitoring and analysis is growing and new industrial applications based on IIoT are being developed and used by various industrial sectors. Possibilities of a mixed method of physical and remote energy audit using IIoT in industrial applications and its advantages as proposed in this research work needs to be explored. Existing hydraulic press machines running with direct online starter (DOL) can be run with variable speed drive (VSD) for energy saving but this requires an extensive energy audit. Key electrical and operational parameters of the hydraulic pump motor were monitored and analyzed remotely using IIoT in this research work by operating the hydraulic press with DOL and VSD motor control methods one by one. The input power factor of the hydraulic pump motor showed an improvement from 0.79 in DOL control to 0.9 in VSD control at different motor loads. The hydraulic pump motor starting current showed a reduction of 84% with VSD control. The hydraulic pump motor’s continuous current was reduced by 40% and 65% during the loading and unloading cycle, respectively, with VSD control. Electrical consumption was reduced by 24% as a result of operating the hydraulic pump motor at 35 Hz with VSD control without impacting the performance of the hydraulic press. These results indicated more efficient control by changing to VSD control in comparison with DOL control. A combination of physical and remote energy audits as performed in this research work using the proposed IIoT framework can be utilized for implementing energy saving in hydraulic presses thus motivating industries to adopt available more energy-efficient technologies at a faster pace.

OPTIMIZATION OF THE OPERATION OF PUMPING SYSTEMS AND RESERVOIRS OF WATER DISTRIBUTION SYSTEMS WITH EMPHASIS IN ENERGY EFFICIENCY

Electricity costs for pumping account for the majority of operating expenses for water distribution systems. Therefore, researchers and technicians in the water sector have sought to develop techniques that minimize the consumption of electricity in these systems. The large number of elements, which can change state at any time, generates a range of possibilities that makes it difficult to determine which operational scheme is most efficient. Defining the best operating rules for pumping systems is often a complex activity. In this context, the present work presents an optimization model for water distribution systems that combines the efficient use of reservoirs with the best operational rule for activating pumping systems. Using a genetic algorithm, the developed model aims to minimize the operating costs of electrical energy in the systems. The results obtained indicated that, with a better use of the water storage infrastructure, it is possible to reduce the electricity costs of the system as a whole.

Simulation of the operation of a gas turbine installation of a thermal power plant with a hydrogen fuel production system

The growth in demand for the production of heat and electricity requires an increase in fuel consumption by power equipment. At the moment, the most demanded thermal equipment for construction and modernization is gas turbine units. Gas turbines can burn a variety of fuels (natural gas, synthesis gas, methane), but the main fuel is natural gas of various compositions. The use of alternative fuels makes it possible to reduce CO2 and NOx emissions during the operation of a gas turbine. Under conditions of operation of thermal power plants at the wholesale power market, it becomes probable that combined cycle power units, designed to carry base load, will start to operate in variable modes. Variable operation modes lead to a decrease in the efficiency of power equipment. One way to minimize or eliminate equipment unloading is to install an electrolysis unit to produce hydrogen.In this article the technology of “Power to gas” production with the necessary pressure at the outlet of 30 kgf/cm2 (this pressure is necessary for stable operation of the fuel preparation system of the gas turbine) is considered. High cost of hydrogen fuel during production affects the final cost of heat and electric energy, therefore it is necessary to burn hydrogen in mixture with natural gas. Burning a mixture of 5% hydrogen fuel and 95% natural gas requires minimal changes in the design of the gas turbine, it is necessary to supplement the fuel preparation system (install a cleaning system, compression for hydrogen fuel). In addition, the produced hydrogen can be stored, transported to the consumer. For the possibility of combustion of a mixture of natural gas and hydrogen fuel in a gas turbine the methodology of calculation of thermodynamic properties of working bodies developed by a team of authors under the guidance of Academician RAS (the Russian Academy of Sciences) V.E. Alemasov has been adapted, resulting in a program that allows to obtain an adequate mathematical model of the gas turbine. The permissible range of the working body temperature is limited to 3000 K. This paper presents the developed all-mode mathematical model of a gas turbine.On the basis of mathematical modeling of a gas turbine, a change in the main energy and environmental characteristics is shown depending on the composition of the fuel gas. Adding 5% hydrogen to natural gas has little effect on the gas turbine air treatment system, the flow rate remains virtually unchanged. CO2 emissions decrease, but there is an increase in the amount of H2O in the turbine exhaust gases.

Bidding strategy for wireless charging roads with energy storage in real-time electricity markets

The combination of wireless charging roads and energy storage systems is a promising option for electric vehicle charging because of their capabilities in mitigating range anxiety of electric vehicle drivers. Wireless charging road operators can purchase electric energy by submitting price-sensitive demand bids in real-time electricity markets. Efficient bidding strategies are crucial to minimizing the energy costs for providing wireless charging services. In this study, we first propose a composite statistical model based on graph signal processing and linear regression to forecast the future locational marginal prices (LMPs) in a power network. Then an estimate of future electric load on each wireless charging road is derived by simulating its traffic flow using a point queue-based traffic flow model. An efficient price-sensitive bidding strategy for each individual wireless charging road is developed based on its LMP forecast, wireless charging load estimate, and a model predictive control framework. Our numerical example shows that the proposed price-sensitive demand bidding strategy reduces the electric energy cost for operating a wireless charging road with an energy storage system by 6% compared to a baseline bidding strategy.

Industrial Cyber Blockchain Physical System for Microgrid in Data Based Predictive Analysis for Automatic Control Analysis

As an efficient distributed renewable energy utilization model, a microgrid is predictable to realize the higher incorporation of the industrial cyber-physical system (CPS) that has gained significant interest in the academia and industry fields. Electric grid is now facing exceptional variations in generation and load as rising number of distributed energy resources (DERs), typically interfaced via power electronics converter, have been positioned, which possess multifaceted technical problems. In the context of electric grid, Blockchain (BC) was primarily developed for peer-to-peer energy trading through cryptocurrency. This paper presents a deep learning based predictive model for automated control analysis (DLBPM-ACS) in BC assisted industrial CPS environment. The presented DLBPM-ACS technique aims to forecast the short-term energy requirement for reducing the delivery cost of electrical energy for consumers. In addition, the presented DLBPM-ACS technique employs BC for effective energy utilization monitoring and trading control. Moreover, the presented DLBPM-ACS technique employs deep belief network (DBN) model for energy prediction process. Furthermore, the artificial ecosystem optimizer (AEO) algorithm is applied for optimal tuning of the hyperparameters related to the DBN approach. A wide range of simulations was conducted and the outcomes demonstrate the better outcomes of the DLBPM-ACS technique.

Technical and economic feasibility analysis of a PV grid-connected system installed on a university campus in Iraq.

In this article, a technical-economic study has been displayed to evaluate the productivity of grid-connected photovoltaic (PV) solar system in a campus of University of Zakho, Iraq. The feasibility of this study is based on performance ratio, capacity factor, cost of energy and yield factor. The analysis of the system has been performed using System Advisor Model (SAM) software and real data of Zakho city that is available in national renewable energy laboratory (NREL). Results show that the system produces 5205 AC MWh during the year with a maximum power generated by the arrays equal to 3.15 AC MW. The yield factor from the proposed PV system for first year is 1554 kWh/kW, whereas the capacity factor nearly equal to 17.7%. Findings indicate that the cost of energy generated by the solar system is 6.3¢/kWh. The payback period to restore the cost of the government electrical energy without using the local electrical generators is 7years while the payback period becomes 4years when local electrical generators is used. Finally, results demonstrate that the investment in the technology of PV system is quite favourable in this site and hence, this article has a valuable information for those who wish to invest in PV technology in Iraq.

Electric power (capacity) supply on the wholesale market for industrial consumers operating within the Siberian United Power System: dynamics of price signals changes study

One of the main goals of creating a wholesale electricity market in the Russian Federation was to reduce the prices for circulating electricity. The achievement of this goal was supposed to be due to the development of competitive energy market relations, equal access to electricity supply services to consumers among all participants of the energy market, transparency and structuring of the electricity pricing mechanism. Traditionally, the regions with the lowest prices for supplied electricity in Russia are the territories of the Siberian United Energy System, where the demand for electricity is provided by cheap hydro generation, which ensures the competitiveness of the Siberian economy and high investment potential in the industrial sector. The article presents an empirical analysis of the dynamic changes in the parameters of the total cost of electricity sold in the regions of Russia included various federal districts with a comparison of the cost of electricity in the Siberian Federal District regions with other territories of Russia, with the identification of key trends and features of changes. Analysis of the dynamics of changes in the components of the cost of electricity on various territories for the period January 2021 – March 2022 revealed a significant increase in the cost of electric energy and electric capacity. Their dynamics in some cases exceeds 30 %, and led to a significant increase in prices for electricity sold to all groups of consumers operating in the United Energy System of Siberia regions, and in particular on territories of the Krasnoyarsk Krai and the Republic of Khakassia. The presented article emphasizes the need to study the factors and pricing conditions affecting the change in price parameters for power supplied to consumers operating in the regions of the Siberian United Energy System, with the development of follow-up measures to manage the increase in prices for electricity (capacity) in these regions.

Simultaneous recovery of bio-sulfur and bio-methane from sulfate-rich wastewater by a bioelectrocatalysis coupled two-phase anaerobic reactor

The microbial electrolysis cell coupled the two-phase anaerobic digestion (MEC-TPAD) was developed for simultaneous recovery of bio-sulfur and bio-methane from sulfate-rich wastewater. In acidogenic phase, the produced sulfides were efficiently converted into bio-sulfur via anodic bio-oxidation, with a maximum recovery of 59 ± 5.5 %. The anode coupled acidogenesis produced more volatile fatty acids which were benefit for the subsequent methanogenesis. The cathode in methanogenic phase created a suitable pH condition and enhanced the methanogenesis. Correspondingly, the maximum bio-methane yield in MEC-TPAD was 2 times higher than that in TPAD. Microbial communities revealed that major functional consortia capable of sulfides oxidation (e.g. Alcaligenes) in anode biofilm, hydrogenotrophic methanogenesis (e.g. Methanobacterium) in cathode biofilm, and acetotrophic methanogenesis (e.g. Methanosaeta) in methanogenic sludge were enriched. Economic benefit could totally cover the cost of input electric energy. This work opens an appealing avenue for recovering nutrient and energy from wastewater.