Power Energy Sources Research Articles

Increasing the Environmental Efficiency of the Fleet of Boiler Plants in Modern Conditions

Mankind has created a multi-industry production. Its facilities have a harmful effect on the environment. And it resulted in a global environmental problem that has currently arisen. Among the branches of world production, energy is the most environmentally aggressive, and among its facilities the most aggressive are boiler plants. The purpose of this research is to study the effect of energy facilities on the state of natural environment and analyze the methods to reduce its intensity. Boiler plants are the most important element in modern power engineering. Hence, there is a need for a joint solution of the problem of reducing the harmful effect of boiler plants on the environment and the problem of their useful effect on global energy. The purpose of this research is to analyze methods to solve the problem of environmental interaction of boiler plants with the natural environment in modern conditions resorting to their partial renewal and using alternative energy sources in the future. It is necessary to broaden the requirements to the development of the world fleet of boiler plants that should be based on the use of innovative design, technological and operational solutions to provide reliable environmental efficiency of the equipment. Since domestic boiler plants have worked out a significant part of their service life and create greenhouse gas emissions and pollutant emissions into the atmosphere polluting thus water runoff and producing solid waste, it is advisable to continue to operate them in the mode of partial renewal. The partial renewal results in the reduction of the harmful effect of boiler plants on the environment due to the ecological improvement of the combustion process. Low-power worn-out boiler plants should be stopped and electricity should be supplied to consumers instead of steam. The problem of replacing obsolete boiler plants should be solved by using new energy sources of equivalent power, by creating and commissioning new highly efficient power plants that convert the energy of water, wind, geothermal sources, and solar energy. Understanding the important role of the global fleet of boiler plants in the global environmental situation on the part of international authorities has a positive effect on the state and development of energy and industry. The current involvement of our country in the war has complicated the processes that take place in the energy sector. The quality and reliability of the power plants have acquired particular importance. When using the domestic fleet of boiler plants, it is necessary to do our best to increase its environmental efficiency.

Energy: An Overview of Type, Form, Storage, Advantages, Efficiency, and Their Impact

ABSTRACTRecently, energy has been a research area due to increasing awareness of its advantages. Energy is essential for all daily activities and helps the mind and body grows; it has the ability to determine the growth of an economy and the development of a country. However, energy has its disadvantages. Nonrenewable energy is energy such as fossil fuel, which is the main cause of air pollutant emissions, such as carbon dioxide, synthetic fluorinated gases, water vapor, and methane gases; and nuclear energy, its wastes are the main cause of air pollutant. They are also the main cause of global warming, human health, climate change, and environmental degradation from the extraction up to use. Nowadays, fossil fuel energy is used in production and use of energy in all sectors of the world. Nuclear energy is the most powerful energy source. Renewable energy, such as solar, wind, hydropower, geothermal, tidal, wave, and hydrogen energy, produces zero greenhouse gas emissions compared to fossil fuels, reducing air pollution and combating climate change, improving public health, mitigating smog and acid rain, and long‐term sustainability. The production and use of this renewable energy has been increasing, but it is not sufficient to meet the demand of all sectors in the world. Hydrogen energy is the future of fossil fuels and nuclear energy, free of CO2 emissions, and radioactive waste. The hydrogen economy envisions using hydrogen as a clean, versatile, and sustainable energy carrier to replace fossil fuels and reduce greenhouse gas emissions. We must control the impacts of energy first by knowing the types of energy and their impact, and then totally replace nonrenewable energy with renewable energy in the future by increasing the efficiency of renewable energy. To increase the efficiency of energy production, energy storage (storing high amount of energy in a small space) uses nanomaterials and green nanomaterial technologies. International cooperation and policy alignment will be essential for driving global transition to a sustainable energy future. By leveraging Artificial Intelligence (AI) and machine learning (ML), the energy sector becomes more sustainable, efficient, and resilient, supporting the transition toward a low‐carbon future. Harmonizing energy policies, sharing best practices, and aligning climate commitments can facilitate the development of a coordinated approach to addressing energy challenges on a global scale. By incorporating these considerations into energy planning and decision‐making, stakeholders can work toward building a future energy system that is sustainable, resilient, and capable of meeting the energy needs of a rapidly changing world. In this study, a critical review of the type, form, storage, advantages, efficiency, respective, and their impact are reviewed. The amounts of energy produced by each type in different years are discussed.

Optimal Solar‐Biomass‐Diesel‐Generator Hybrid Energy for Water Pumping System Considering Demand Response

ABSTRACTThe water pumping system is a vital daily operation for a sustainable society. The demand for this essential commodity is progressively growing around the world. Incorporating renewable energy sources (RES) into its operation mitigates adverse environmental effects stemming from greenhouse gas (GHG) emissions and reduces associated costs linked to fossil fuel energy sources. Hence, the optimal sizing of a hybrid mix of RES and non‐RES energy sources to power water pumping is essential. This study employs a generalized reduced gradient (GRG) optimization method to ascertain the most effective energy mix for water pumping system (WPS) application by integrating time of use demand response. This is achieved through four scenarios: Scenario 1 (S1) utilizes grid power and Diesel generator (DG) energy sources, Scenario 2 (S2) incorporates grid power, DG, and solar PV, Scenario 3 (S3) integrates grid power, DG, solar PV, and biomass energy sources, while Scenario 4 (S4) incorporates Time of Use (TOU) with the three aforementioned energy sources. The key findings reveal an ideal solution comprising of a mix of renewable PV and biomass along with non‐renewable grid energy source embedded with Time of Use demand response (S4) with optimal energy capacities of 4007 kW of PV, 4228 kW of grid, 234 kW of biomass, and 1085 of DG owing to the least cost energy and cost of water pumped of 0.75$/kW and 1.74$/kL, respectively, most volume of water pumped of 270.50 kL. These findings prove that the integration TOU demand response program with a hybrid mix of grid‐biomass‐DG‐solar PV is best suited for water pumping applications as it gives a cost‐competitive value.

Concept and Advantages of Carbon/Air Secondary Battery System as a Fixed Compact Power Storage with Large Capacity

Introduction One of the critical technological isuues to constract carbon neutral society is the suppression of the impact of the volatility in power generation from inexpensive variable renewable energy power sources, such as solar cells and wind powers. It is necessary to maintain a balance between power generation, transmission, and consumption, and to maintain three types of stability in the power system: frequency stability, synchronization stability, and voltage stability. For this reason, energy storage technology is one of the most important issues for making up carbon neutral energy system. Among energy storage technologies, lithium-ion secondary batteries are superior in terms of both output density and energy density, but they present a cost challenge for large-capacity energy storage. Pumped storage power generation is the mainstay of long-term large-capacity energy storage in the current power system, but significant pumped storage expansion is subject to geopolitical constraints. Therefore, a compact, large-capacity energy storage system that can be installed in the power grid is required to expand the introduction of variable renewable energy power sources.In this research, we first describe the operating mechanism and advantages of the "Carbon/Air Secondary Battery (CASB) system" [1,2], a compact power storage system that integrates the functions of a solid oxide fuel cell that generates electricity by producing CO2 through the oxidation reaction of carbon and a solid oxide electrolytic cell that produces carbon through the electrolysis of CO2. The operating mechanism and features of the CASB system are introduced. In addition, we report the calculation results of feasible system efficiency based on thermodynamic considerations compared to power storage system using H2/H2O-solid oxide fuel cells/electrolysis cells. In addition, the advantages/disadvantages of the two types of CASBs, integrated type of CASB between carbon deposition /electrochemical reaction, and the separated type of CASBs, as well as their representative charge/discharge characteristics will be presented. Theoreticl advantage of CASB as a fixed compact power storage with large capacity The theoretical charge/discharge efficiency of CASB, which is the ΔG/ΔH of reaction “C+O2→CO2” is 100%. This means that there is no heat input and output ideally in both carbon generation and CO2 electrolysis (in charge/discharge). Therefore, temperature control is simple and a heat exchanger can be minimized, which may allow the system to be compact. The feasible charge/discharge system efficiency of CASB including possible heat exchange were estimated as 92% based on thermodynamics, which is much higher than that of power storage system using H2/H2O-solid oxide fuel cells/electrolysis cells (63%). In addition, since CO2 can be liquefied at about 6.4 MPa at 25°C, its volumetric energy density to 1.62 × 103 Wh L-1, about four times higher than the volumetric energy density of hydrogen compressed at 20 MPa at 25°C, 3.79 × 102 Wh L-1. A key technological point of CASB at its discharging , which is combination between electrochemical reaction (CO2→ CO+O2-) and thermochemical reaction (2CO→ C+CO2) by achiving at closed system The discharge reaction of the CASB is the same as that of the Rechargeable Direct Carbon Fuel Cell [3,4,5]. The reason for the first successful demonstration of the CASB is that the combining electrochemical reaction with low overpotential (CO2 →CO+O2-) with the thermochemical reaction, the Boudouard equilibrium reaction (2CO → C+CO2) were achieved at the charging by making the system a closed system. Two types of CASBs, (1) Integrated type of CASB between carbon deposition /electrochemical reaction, and (2) the separated type of CASBs Since generally, the carbon deposition on the electrode cause its degradation [6], two type of CASBs can be designed and demonstrated (as shown in Fig.1). Both types of CASBs could be demonstrated.

Two-Stage Locating and Capacity Optimization Model for the Ultra-High-Voltage DC Receiving End Considering Carbon Emission Trading and Renewable Energy Time-Series Output Reconstruction

With the load center’s continuous expansion and development of the AC power grid’s scale and construction, the recipient grid under the multi-feed DC environment is facing severe challenges of DC commutation failure and bipolar blocking due to the high strength of AC-DC coupling and the low level of system inertia, which brings many complexities and uncertainties to economic scheduling. In addition, the large-scale grid integration of wind power, photovoltaic, and other intermittent energy sources makes the ultra-high-voltage (UHV) DC channel operation state randomized. The deterministic scenario-based timing power simulation is no longer suitable for the current complex and changeable grid operation state. In this paper, we first start with the description and analysis of the uncertainty in renewable energy (RE) sources, such as wind and solar, and reconstruct the time-sequence power model by using the stochastic differential equation model. Then, a carbon emission trading cost (CET) model is constructed based on the CET mechanism, and the two-stage locating and capacity optimization model for the UHV DC receiving end is proposed under the constraint of dispatch safety and stability. Among them, the first stage starts with the objective of maximizing the carrying capacity of the UHV DC receiving end grid; the second stage checks its dynamic safety under the basic and fault modes according to the results of the first stage and corrects the drop point and capacity of the UHV DC line with the objective of achieving safe and stable UHV DC operation at the lowest economic investment. In addition, the two-stage model innovatively proposes UHV DC relative inertia constraints, peak adjustment margin constraints, transient voltage support constraints under commutation failure conditions, and frequency support constraints under a DC blocking state. In addition, to address the problem that the probabilistic constraints of the scheduling model are difficult to solve, the discrete step-size transformation and convolution sequence operation methods are proposed to transform the chance-constrained planning into mixed-integer linear planning for solving. Finally, the proposed model is validated with a UHV DC channel in 2023, and the results confirm the feasibility and effectiveness of the model.

Improved fuzzy energy management strategy for fuel cell vehicles based on IPIO

In the energy management of fuel cell vehicles (FCEV), the traditional fuzzy logic strategy has the problems of strong subjectivity and average vehicle economy. This paper proposes a composite fuzzy energy management strategy with the goal of improving the life of the auxiliary energy source power battery, using an improved pigeon swarm optimization algorithm (IPIO) to update the fuzzy membership function, while ensuring that the power battery works in a suitable range for a long time and reducing equivalent hydrogen consumption quantity. This paper conducts secondary development on the existing ADVISOR model to establish a simulation model of the FCEV hybrid system, and conducts simulation experiments under NEDC and CLTC-P operating conditions. The results show that IPIO's improved energy management strategy can charge more than twice as fast as the power following strategy when the initial SOC is low, and can reach the appropriate SOC range faster, which can extend the life of the power battery; when the initial SOC is high, the charging speed is more than twice that of the power following strategy. In this case, the equivalent hydrogen consumption of IPIO's improved composite fuzzy energy management strategy was reduced by 9.09% and 9.09% respectively in the two working conditions compared with the before improvement 11.8%, which significantly reduced the hydrogen consumption and improved the economy of hydrogen fuel cell vehicles.

Analysis of Metal Fused Filament Fabrication process chain for 316L stainless steel

Metal Fused Filament Fabrication (MFFF) has emerged as a prominent technology in Additive Manufacturing (AM), characterized by its cost-effectiveness, versatility in creating intricate geometries using diverse materials, and widespread availability of AM machines. However, the intricate processes of making filament, printing, debinding, and sintering in MFFF pose unique challenges, with a vast number of parameters influencing each stage. Specialized companies handle these stages for research purposes, yet detailed information on the processes remains limited. The objective of this research is to conduct a meticulous examination of the parameters governing the printing, debinding, and sintering of 316L stainless steel—a material widely employed in various industries. The goal is to provide researchers and manufacturers with a comprehensive understanding, enabling them to achieve high-density metal parts that rival those produced through Selective Laser Melting (SLM). This research employs a systematic approach in producing flawless metal parts through fine-tuning parameters such as printing speed, nozzle diameter, extruder and construction table temperatures, heating rate, nitric acid injection during debinding, and sintering atmosphere and temperature. Despite advancements in MFFF parameters in this study, a comparative analysis with SLM reveals superior mechanical properties and density in SLM-produced parts. Because, the robust bonding facilitated by a powerful energy source (laser) in SLM minimizes porosities, whereas MFFF relies solely on molten filament adherence, potentially leading to small gaps between layers. This research contributes valuable insights for achieving dense, defect-free metal parts through Metal Fused Filament Fabrication (MFFF). It sheds light on the persistent advantages of Selective Laser Melting (SLM) in terms of mechanical performance and density. The comprehensive understanding of parameters provided in this study empowers researchers and manufacturers to optimize MFFF processes for 316L stainless steel, narrowing the gap between the two technologies (MFFF and SLM) and enhancing the competitiveness of MFFF in producing high-quality metal parts.

Critical lines dynamic identification for grid-connected wind power system under N-k contingency based on Oscillating equations

Abstract As the penetration rate of wind power and other renewable energy sources increases, power systems are more prone to experiencing multiple component failures, known as N-k contingency Identifying and then closely monitoring and protecting critical components during N-k contingency can effectively prevent widespread cascading failures. The primary task in identifying critical components is to model the power system; A refined model better captures the time-varying characteristics of electrical components. Therefore, a dynamic model of line power flow decay and oscillation based on swing equations is established; it introduces time-varying saturated cut-set and transfer margin indices to identify critical lines. Simulations on the IEEE-118 nodes system, along with MATCASC cascading failure simulations, demonstrate that targeting identified critical lines as deliberate attack points in the grid results in a normalized remaining load demand decrease to 50% of the original.

Enhancement of photovoltaic parameters of thermally stable graphene/LaVO3 semitransparent solar cell by employing interfacial graphene quantum dots

Semitransparent solar cells are attracting attention not only for their visual effects but also for their ability to effectively utilize solar energy. Here, we demonstrate a translucent solar cell composed of bis(trifluoromethane sulfonyl)-amide (TFSA)-doped graphene (Gr), graphene quantum dots (GQDs), and LaVO3. By introducing a GQDs intermediate layer at the TFSA-Gr/LaVO3interface, we can improve efficiency by preventing carrier recombination and promoting charge collection/separation in the device. As a result, the efficiency of the GQDs-based solar cell was 4.35%, which was higher than the 3.52% of the device without GQDs. Furthermore, the average visible transmittance of the device is 28%, making it suitable for translucent solar cells. The Al reflective mirror-based system improved the power conversion efficiency by approximately 7% compared to a device without a mirror. Additionally, the thermal stability of the device remains at 90% even after 2000 h under an environment with a temperature of 60 °C and 40% relative humidity. These results suggest that TFSA-Gr/GQDs/LaVO3-based cells have a high potential for practical use as a next-generation translucent solar energy power source.

Cloud-fog architecture-based control of smart island microgrid in master-slave organization using disturbance observer-based hybrid backstepping sliding mode controller

Distributed control is an effective method to coordinate the microgrid with various components, and also in a smart microgrid, communication graph layouts are essential since changing the topology unexpectedly could disrupt the operation of the distributed controllers, and also an imbalance may occur between the production and load. Hence, reducing the exchanged data between units and system operator is essential in order to reduce the transmitted data volume and computational burden. For this purpose, an islanded microgrid with multiple agents which is using cloud-fog computing is proposed here, in order to reduce the computing burden on the central control unit as well as reducing data exchange among units. To balance the production power and loads in a smart island with a stable voltage/frequency, a hybrid backstepping sliding mode controller (BSMC) with disturbance observer (DO) is suggested to control voltage/frequency and current in the MG-based master-slave organization. Therefore, this paper proposes a DO-driven BSMC for controlling voltage/frequency, and power of energy sources within a Master-Slave organization; in addition, the study proposes a clod-fog computing for enhancing performance, reducing transferred data volume, and processing information on time. In the extensive simulations, the suggested controller shows a reduction in steady-state error, a fast response, and a lower total harmonic distortion (THD) for nonlinear and linear loads less than 0.33 %. The fog layer serves as a local processing level, so it reduces the exchanged data between cloud and fog nodes.

Doubling Power Conversion Efficiency of Si Solar Cells.

Improving solar cells' power conversion efficiency (PCE) is crucial to further the deployment of renewable electricity. In addition, solar cells cannot function at exceedingly low temperatures owing to the carrier freeze-out phenomenon. This report demonstrates that through temperature regulation, the PCE of monocrystalline single-junction silicon solar cells can be doubled to 50-60% under monochromatic lasers and the full spectrum of AM 1.5 light at low temperatures of 30-50 K by inhibiting the lattice atoms' thermal oscillations for suppressing thermal loss, an inherent feature of monocrystalline Si cells. Moreover, the light penetration, determined by its wavelength, plays a critical role in alleviating the carrier freeze-out effect and broadening the operational temperature range of silicon cells to temperatures as low as 10 K. Understanding these new observations opens tremendous opportunities for designing solar cells with even higher PCE to provide efficient and powerful energy sources for cryogenic devices and outer and deep space explorations.

Transient Synchronous Stability Modeling and Comparative Analysis of Grid-Following and Grid-Forming New Energy Power Sources

New energy power sources can be categorized into grid-following and grid-forming types based on their synchronization characteristics with the grid. Due to the different basic control operation principles of these two types of new energy power sources, they can lead to the instability of the grid-connected system through different paths. A mathematical model is established to describe the dynamic characteristics of the grid-following and the grid-forming new energy power resources, and the control block diagram of the nonlinear dynamic characteristic equation is compared and analyzed. The similarity between grid-following and grid-forming new energy power supply is revealed, and we preliminarily discuss the influencing factors of the stability of new energy sources. Using a single-machine infinite system model, the influence of key control parameters on transient stability is separately investigated for grid-following and grid-forming types. The influence of the converter synchronous loop control parameters on the system is verified, and the factors affecting the stability are discussed in combination with current limiting and frequency limiting. The research will provide reference for the design of a new energy power grid connection system.

Flexible Aluminum-Air Batteries

Wearable and flexible electronics have a wide range of applications. Making a flexible power source for them is essential. Aluminum-air batteries are attractive for powering portable, lightweight devices due to their inexpensive, light, and powerful energy source. In this project, the Al-air battery was made using activated carbon and aluminum electrodes, chloride-based electrolytes with ionic liquid additives. Various mixtures of 1-ethyl-3-methylimidazolium chloride, aluminum chloride, sodium hydroxide, and sodium chloride were studied. Fundamental properties of room-temperature ionic liquids, such as lower conductivity and density, improved the performance of aluminum-air batteries. Cell capacity, cyclic voltammetry behavior, and cell interfacial impedance with various electrolytes were optimized using the design of experiments. The battery's electrical power output and cell capacity were lower than those obtained using an activated carbon air cathode. The cell capacity over repeated electrochemical reactions was stable. The Al-air battery had regular cyclic voltammetry behavior. Aluminum hydroxide was not found on the anode electrode when an ionic liquid electrolyte was used. The interfacial cell impedance did not decrease after electrochemical reactions over a long time.

Distinguishing Electrochemical Processes in PEM Electrolysis By Impedance Modeling – Distribution of Relaxation Times

Proton exchange membrane (PEM) water electrolysis is a key technology in hydrogen production to provide capacity and flexibility for renewable energy power sources. Various research topics for electrolyzer development focus on cost reduction, performance optimization and lifetime extension with minimum platinum group metal (PGM) loading required [1]. Understanding degradation mechanisms in PEM electrolysis cells becomes necessary for developing mitigation strategies in dynamic durability tests, which facilitates the importance of advanced electrochemical characterization methods.Electrochemical impedance spectroscopy (EIS) is a commonly used diagnostic technique in electrochemical systems. For impedance interpretation, equivalent circuit model (ECM) can be an option with prior knowledge about the system and appropriate circuit elements to prevent overfitting. Alternatively, distribution of relaxation times (DRT) provides a model-free pathway to address electrochemical mechanisms with different time constants and it has been applied to fuel cells, batteries and capacitors in the past years [2, 3]. Impedance deconvolution by DRT, however, has not been well adapted for PEMECs. In this study, electrochemical processes are successfully identified from the DRT profile by varying membrane electrode assembly (MEA) compositions and different operational conditions. In a single cell testing, four main peaks in DRT results associated with (1) mass transport losses (2) reaction kinetic (3) ionic conductivity within the catalyst layer and (4) ohmic properties at the interface of membrane and catalyst layers can be separated and quantified. Examination of electron microscopy provides further explanation of different MEA characteristics in performance analysis. This study verifies DRT is a promising tool to better understand PEM electrolysis processes and will be applied to degradation mitigation in the future.

Lifetime (Bx) improvement of PV inverter using Si-SiC H-IGBT/Diode: a reliability approach

Technological advancements have made it possible to harness the power of renewable energy sources. The efficiency of power electronic devices has increased to almost 98%. In order to reduce the risks of failure and maintain the operation of photovoltaic (PV)-based energy converters, reliable devices are needed. Due to the increasing number of wide-bandgap silicon in electronic converters, the need for more efficient and reliable devices has become more prevalent. However, the cost of these devices is a major issue. Hence, in this work extensive analysis of hybrid silicon (Si)-IGBT and silicon carbide (SiC) antiparallel Diode (H-IGBT/Diode) based PV inverter is proposed to improve the lifetime (Bx). A reliability oriented lifetime assessment is performed on a test case of single stage three kilowatt photovoltaic inverter with 600 V/30 A hybrid switch. Long term mission profile for one year is considered for evaluation at B. V. Raju Institute of Technology (BVRIT), Telangana, India. Finally, B10 lifetime is calculated, comparison analysis is presented between conventional Si-IGBT and proposed Si-SiC H-IGBT/Diode. The results of the study revealed that the H-IGBT exhibited a significant increase in PV inverter reliability.

Machine Learning Models for Solar Power Generation Forecasting in Microgrid Application Implications for Smart Cities

In the context of escalating concerns about environmental sustainability in smart cities, solar power and other renewable energy sources have emerged as pivotal players in the global effort to curtail greenhouse gas emissions and combat climate change. The precise prediction of solar power generation holds a critical role in the seamless integration and effective management of renewable energy systems within microgrids. This research delves into a comparative analysis of two machine learning models, specifically the Light Gradient Boosting Machine (LGBM) and K Nearest Neighbors (KNN), with the objective of forecasting solar power generation in microgrid applications. The study meticulously evaluates these models’ accuracy, reliability, training times, and memory usage, providing detailed experimental insights into optimizing solar energy utilization and driving environmental sustainability forward. The comparison between the LGBM and KNN models reveals significant performance differences. The LGBM model demonstrates superior accuracy with an R-squared of 0.84 compared to KNN’s 0.77, along with lower Root Mean Squared Error (RMSE: 5.77 vs. 6.93) and Mean Absolute Error (MAE: 3.93 vs. 4.34). However, the LGBM model requires longer training times (120 s vs. 90 s) and higher memory usage (500 MB vs. 300 MB). Despite these computational differences, the LGBM model exhibits stability across diverse time frames and seasons, showing robustness in handling outliers. These findings underscore its suitability for microgrid applications, offering enhanced energy management strategies crucial for advancing environmental sustainability. This research provides essential insights into sustainable practices and lays the foundation for a cleaner energy future, emphasizing the importance of accurate solar power forecasting in microgrid planning and operation.

The ankle dorsiflexion kinetics demand to increase swing phase foot-ground clearance: implications for assistive device design and energy demands

BackgroundThe ankle is usually highly effective in modulating the swing foot’s trajectory to ensure safe ground clearance but there are few reports of ankle kinetics and mechanical energy exchange during the gait cycle swing phase. Previous work has investigated ankle swing mechanics during normal walking but with developments in devices providing dorsiflexion assistance, it is now essential to understand the minimal kinetic requirements for increasing ankle dorsiflexion, particularly for devices employing energy harvesting or utilizing lighter and lower power energy sources or actuators.MethodsUsing a real-time treadmill-walking biofeedback technique, swing phase ankle dorsiflexion was experimentally controlled to increase foot-ground clearance by 4 cm achieved via increased ankle dorsiflexion. Swing phase ankle moments and dorsiflexor muscle forces were estimated using AnyBody modeling system. It was hypothesized that increasing foot-ground clearance by 4 cm, employing only the ankle joint, would require significantly higher dorsiflexion moments and muscle forces than a normal walking control condition.ResultsResults did not confirm significantly increased ankle moments with augmented dorsiflexion, with 0.02 N.m/kg at toe-off reducing to zero by the end of swing. Tibialis Anterior muscle force incremented significantly from 2 to 4 N/kg after toe-off, due to coactivation with the Soleus. To ensure an additional 4 cm mid swing foot-ground clearance, an estimated additional 0.003 Joules/kg is required to be released immediately after toe-off.ConclusionThis study highlights the interplay between ankle moments, muscle forces, and energy demands during swing phase ankle dorsiflexion, offering insights for the design of ankle assistive technologies. External devices do not need to deliver significantly greater ankle moments to increase ankle dorsiflexion but, they should offer higher mechanical power to provide rapid bursts of energy to facilitate quick dorsiflexion transitions before reaching Minimum Foot Clearance event. Additionally, for ankle-related bio-inspired devices incorporating artificial muscles or humanoid robots that aim to replicate natural ankle biomechanics, the inclusion of supplementary Tibialis Anterior forces is crucial due to Tibialis Anterior and Soleus co-activation. These design strategies ensures that ankle assistive technologies are both effective and aligned with the biomechanical realities of human movement.

Modelling and Assessing the Advantages of Integrating Wind, Solar, and Coal Systems within an Annual Bilateral Trading Setting

The integration and co-location of new energy sources and thermal power generation within the same grid connection point, under the management of a single market operator, provide noteworthy potential for exploration in the northern part of our nation. This method is based on the premise of allocating new energy resources primarily for generating contracted electricity, while using thermal power to offer ancillary services. This strategy aims to integrate and use the distinct benefits of both thermal power and new energy sources. The yearly bilateral trade market has significant potential for growth and development. In order to model and evaluate the income generated by the interconnected system’s involvement in the yearly bilateral trading market, this study first establishes the definition of the interconnected system and examines its research significance in engaging in annual bilateral trading. This study utilizes the theoretical framework of master-slave games to analyze the involvement of a coupled system in yearly bilateral trade. The specific case examined in this research is a wind-solar-thermal coupling system located in a particular location of Liaoning Province. This study examines the economic advantages of engaging in the electricity market by considering the marginal cost and LCOE (Levelized Cost of Electricity) perspectives. The findings suggest a notable enhancement in the advantages of the integrated system inside the yearly bilateral trade market, in contrast to conventional power sources present in the market, as well as instances when these sources function autonomously without integration.

FACTORS ANALYSIS USE ELECTRICAL ENERGY SOURCES IN MICROGRIDS FROM ENERGY MANAGEMENT SYSTEM POSITION

The analysis of the factors of the use of electrical energy sources in microgrids from the point of view of the energy management system is a comprehensive study aimed at studying and evaluating various aspects of the use of electrical energy in small energy systems that can function independently of centralized energy networks. The main purpose of such an analysis is to identify key factors , which affect the efficiency and stability of the microgrid, as well as in the development of strategies to optimize their operation from the point of view of energy management. To achieve this goal, research is conducted covering the following aspects: technical characteristics of electrical sources, economic aspects, environmental consequences, energy management, social aspects. This is an important stage in the development of energy systems, aimed at creating efficient and sustainable energy solutions for the future. The analysis of the efficiency, reliability and power of various energy sources, such as solar batteries, wind turbines, batteries, etc., was considered. The cost of installation and operation of electric energy sources was calculated. , including the costs of maintenance, maintenance and replacement of equipment. The method of analyzing the impact of the use of various energy sources on the environment and the development of strategies for reducing emissions of greenhouse gases and other harmful substances are given. The essence of energy management systems that allow efficient management of production, storage and distribution of electricity in microgrids to ensure maximum efficiency and stability of system operation is considered. The question of the development of alternative energy sources has become particularly relevant, therefore, considering the existing structures of microgrids, it is advisable to notice the peculiarities of the construction of each microgrid, for example, the structure of a microgrid based on a wind generator can be built in several variants, and in a solar power plant, for efficient operation, the MPPT control algorithm is used, which aims to control the step-up converter in that point of the current and voltage characteristics of the photovoltaic battery, where the maximum output power can be obtained. In such microgrid structures, storage batteries are used for reserve, which are charged through step-up converters. Inverters are used to power the AC load. It is advisable to combine the solar power plant and the wind generator system into one microgrid structure, and to ensure the operation of the microgrid in conditions of low generation of one or both generating units, a diesel-generator system is used. In the built hybrid structure of the microgrid, there are operational costs that must be minimized.

Feasibility analysis of virtual clean hydrogen plant platform: A case study on energy policy in S. Korea using stochastic programming

In S. Korea, high-density renewable and high-density load areas are separate. This separation has led to increased transmission constraints. As both Renewable Energy Source (RES) penetration and power demand simultaneously increase, RES saturation occurs. This phenomenon reduces both the benefits of power transactions and the acceptance of RES. Addressing this issue requires actions from Independent Power Producers (IPP) and policymakers. This paper suggests a Virtual Clean Hydrogen Plant (VCHP) platform design that consolidates the Photovoltaic (PV) energy from high-density renewable areas into a single power plant. The platform converts excess energy, generated by PV due to transmission constraints, into hydrogen and supplies it to the high-density load areas. The South Korean government plans to introduce a Clean Hydrogen Portfolio Standard (CHPS), which offers a fixed premium (FP) to private power generators that provide power through clean hydrogen. Consequently, the proposed benefit structure of the VCHP platform includes an FP, settled through CHPS. This paper's design and operation algorithm for the VCHP platform incorporates stochastic programming to analyze PV operation and deterministic optimization for the optimal scheduling of Fuel Cells (FC) that provide power and heat to high-density load areas. The simulation results demonstrate that the minimum subsidy required for CHPS benefits varies depending on how PV-coupled P2G technology is utilized. Specifically, engaging in net metering with VCHP over the course of one month can establish a cost-effective benefit structure, verified to require a subsidy ranging from a minimum of 0.2036 $/kWh to a maximum of 0.2416 $/kWh.