Load Hours Research Articles

Slovenian Translation, Cross-Cultural Adaptation, and Content Validation of the Updated Oslo Sports Trauma Research Center Questionnaire on Health Problems (OSTRC-H2).

The updated Oslo Sports Trauma Research Questionnaire on Health Problems (OSTRC-H2) has been translated into a limited set of languages and lacks full validation of its new measures. To (1) translate, cross-culturally adapt, and evaluate the measurement properties of the OSTRC-H2 for the Slovenian population and (2) investigate the construct validity for the severity score and time lost due to a health problem. Cohort study (diagnosis); Level of evidence, 3. The OSTRC-H2 was translated from English to Slovenian (OSTRC-H2-SLO) according to international guidelines. A 15-week study was conducted among 188 elite athletes, with a test-retest performed in the 10th week. Internal consistency, reliability, content validity, feasibility, and potential ceiling effects were investigated. Internal consistency was measured using the Cronbach alpha coefficient, while reliability was measured with the intraclass correlation coefficient (ICC). Construct validity was measured with the Spearman rank correlation coefficient (r S). There was a 95% response rate and an 18% mean weekly prevalence of health problems. The OSTRC-H2-SLO showed excellent test-retest reliability (ICC, 0.94 [95% CI, 0.67-0.99]), with a Cronbach α of .93. A strong positive correlation was found between the OSTRC-H2-SLO severity score and days lost due to an acute injury (r S = 0.754), overuse injury (r S = 0.785), and illness (r S = 0.894) (P < .001 for all). Moderate to strong negative correlations were observed between severity score and total load (training and competition load in hours) as well as between days lost and total load (P < .001 for all). The OSTRC-H2-SLO was found to be valid, reliable, and well accepted among Slovenian athletes. The authors confirmed the questionnaire's construct validity and identified total load as an indicator of an increase in the severity score. NCT05471297 (ClinicalTrials.gov identifier).

Renewable energy in sustainable cities: Challenges and opportunities by the case study of Nusantara Capital City (IKN)

Indonesia's future IKN capital might be sustainable, low-carbon, and climate-resilient. The Low Emissions Analysis Platform (LEAP) simulates energy efficiency in various demand sectors, renewable energy, and sustainable transportation solutions. Sustainable cars, such as renewable-energy-powered electric and green hydrogen-powered vehicles, can reduce energy consumption by 43% in 2045 and 33% in 2060, respectively, compared to BAU. GHG emissions per capita will drop 70% in 2045 and 63% in 2060. In the net-zero emission (NZE) scenario, IKN can reach 100% green energy by 2045 with a 4.4 GW solar power plant, a 0.92 GWh BESS, and a full load hour capability of 4 hours. We will use 1.1 GW of hydropower and 143 MW of wind power by 2045. In 2060, hydropower will be 2.8 GW, wind power will be 184 MW, and solar power will be 8 GW with 1.6 GWh of BESS. Lack of legislation, technical expertise, high prices, inadequate grid infrastructure, and insufficient renewable electricity restrict BESS use in Indonesia. Solar energy installation requirements, subsidies, and off-grid project incentives can all help ease BESS use. Forecasts predict 0.53 GW of rooftop solar PV capacity by 2045 and 3.35 GW by 2060. Net metering and solar tariffs boost rooftop solar system profitability. One ton of green hydrogen production requires 55.7 MWh from a solar power plant. Solar power plant capacity will rise to 0.49 GW by 2045, producing 19,359 tons of green hydrogen, and almost quintuple to 89,594 tons by 2060. Hydrogen generation, storage, transit, and distribution require specific infrastructure due to high capital costs and a lack of networks, yet interest in them is growing.

Spike load smoothing strategy considering behavioral decision under vehicle-road-network convergence

To reduce the impact of large-scale electric vehicles on traffic and electric load peaks, we propose a "vehicle-road-network" integration strategy that takes into account behavioral decisions. To reduce the impact of large-scale electric vehicles on traffic and electric load, we propose a peak load suppression strategy that takes into account behavioral decisions under "vehicle-road-network" integration. Firstly, a "vehicle-road-network" fusion model is constructed based on the large-scale access of EVs; then, a load model is built considering the large-scale access of EVs; finally, based on the third-generation foreground theory, the behavioral decision of EV users is analyzed based on the operation state of the fusion system, and a decision model is built by the foreground value to minimize the operation cost. The spike load smoothing strategy scheme is established with minimum operation cost. By using the fusion of Sioux Falls urban road network system and IEEE33 node grid system as the simulation example, the simulation results show that the proposed peak load smoothing strategy can coordinate the distribution of charging load and relieve traffic pressure during peak load hours, and reduce the travel and charging costs of EV users.

Global optimization of capacity ratios between electrolyser and renewable electricity source to minimize levelized cost of green hydrogen

This paper presents a novel and effective approach for calculating Levelized Cost of Hydrogen production across the globe, without requiring timely resolved modelling or data. We select characteristic production patterns of photovoltaic and wind turbine power generation based on location qualities indicated by full load hours. These representative patterns are applied worldwide on similar locations to evaluate the proportion of electricity that electrolyzers can use if they have a smaller capacity than the renewable electricity source. Hence, the ratio of capacities is optimized to minimize hydrogen cost. The findings from various worldwide locations reveal that decreasing electrolyzer capacity is economically beneficial across all locations for boosting full load hours and curbing investments, particularly in locations with lower electricity generation. Validation using precise electricity production timeseries in specific locations revealed minimal errors in the methodology, though the quality of the results is impacted by the seasonality index differences between representative and exact location.

Renewable-battery hybrid power plants in congested electricity markets: Implications for plant configuration

Examining coupled renewable-battery power plants (“hybrids”) in congested areas provides insights into a future of increased wind and solar penetration. Our study focuses on two types of congested regions, Variable Renewable Energy (VRE)-rich Areas and Load Centers, and explores likely plant configuration choices for developers and transmission network planners. This paper examines how hybrid value, comprising energy and capacity value, varies by plant configuration and congested region type considering factors such as storage duration, battery degradation, and ability to charge from the grid. We select plant locations from across the seven main U.S. independent system operators (ISOs). Hybrid value for each configuration is computed based on profit-maximizing plant operation given perfect foresight, according to observed wholesale power market real time prices from 2018 to 2021. In VRE-rich Areas, the median increase in energy value from extending storage duration from one to 4 h is 29.4 % for solar and 26.8 % for wind, assuming low battery degradation costs and storage sized to 100 % of the plant's nameplate generation capacity. Increasing storage duration beyond 4 h does not substantially increase its value from energy markets, even in VRE-rich Areas. We find that solar hybrids reach a 90 % capacity credit with 4 h of storage, while wind hybrids require 8 h of storage, based on the capacity factor of each hybrid during the top 100 net load hours.

Assessing Voltage and Frequency Instability in Renah Kemumu's Micro Hydro Power Plant

The increasing demand for energy and the need for environmental sustainability have led to the adoption of renewable energy sources, such as micro-hydropower plants (PLTMH), in isolated communities in Indonesia. However, voltage and frequency instability issues are commonly encountered in PLTMH systems, which undermine their performance. In 2009, a micro-hydropower plant with a capacity of 30 KW was built in Renah Kemumu village. Ranah Kemumu village is located in Jangkat sub-district, Merangin district, Jambi province. In this study, the voltage and frequency instability of PLTMH in Renah Kemumu Village were investigated. The methodology employed in this study was observational. The voltage and frequency data were measured and recorded during peak load hours from 18.00 to 21.00 over one month. The percentage increase relative to the standard voltage and frequency was calculated. Boxplots were generated to visualize the distributions. The voltage measurements showed maximum and minimum values of 270 V and 264 V, representing increases of 22.72 % and 20.45% from the 220 V (standard set by the power utility (PLN)). The frequency ranged from 66.32 Hz to 57.46 Hz, corresponding to 30.92% and 14.92% deviations from the 50 Hz (standard set by the power utility (PLN)). These values exceeded the tolerance limits of the State Electricity Company of Indonesia. The analysis indicates that the voltage and frequency levels at the PLTMH in Renah Kemumu Village are unstable during peak loads, with fluctuations stemming from changing water flows, load currents, and weather conditions

Impact of the Double-Reduction Policy on Middle School Students Study

This study explores the impact of the Double-Reduction Policy on middle school students' study habits, academic performance, and overall wellbeing. The policy aims to reduce academic stress by decreasing homework load and classroom hours. Through this research, we examine the diverse effects that this policy has on students' perceptions and experiences. The majority of students see the policy favourably; they report lower levels of stress, better sleep habits, and more free time for extracurricular activities. However, concerns about a perceived lack of readiness for future academic activities as well as a decreased academic challenge and falling enthusiasm are voiced, especially among high achievers. With an emphasis on the function of observational learning, self-efficacy beliefs, modeling actions, and the dynamic interaction of personal and environmental elements, social cognitive theory provides a theoretical framework to comprehend the observed behaviors and results. This research highlights the necessity for balanced policies that promote well-being while retaining academic rigor as well as the need of taking into account individual variances in students' reactions to policy changes. These findings hold significant implications for teachers and policymakers. It highlights the need of educational policy that takes into account the varied life experiences of students in order to improve their health and success in school. More study is required to figure out how these policies will play out in the long run and what elements will have the most impact on individual outlooks and experiences.

Variable renewable energy modeling system to study challenges that impact electrical load at different penetration levels: A case study on Kuwait's load profile

The transitioning from conventional power systems to variable renewable energy (VRE) could impose significant challenges on transmission, short-term balancing requirements, and more cycling to ramp conventional plants. Kuwait's government has set a target of 15% of electricity generation from renewable resources by 2030 and more in the following years. This ambitious target requires close collaboration between researchers and decision-makers to overcome the upcoming challenges. The current study comes in the context of this objective to support decision-makers technically during planning and deploying VRE plats in various parts of the country. An in-house simulation modeling system for solar photovoltaic (PV) and wind power based on high-quality weather data has been developed. The system can model centralized or decentralized VRE scenarios. Several load characteristics have been used to examine the output of the scenario, such as the residual load, impact on the peak, and baseload due to changes in VRE penetration level. Other parameters, including capacity credit, full load hours, ramping power magnitude and rate, and overproduction of resources, are also outputs of the system. The output results of the modeling system have been validated against two years of operational solar PV and wind Shagaya power plants data. The results show combining solar PV with wind could dramatically increase the capacity credit, reduce overproduction, and reduce ramping power. The authors will continue evolve and improve this in-house modeling system to support research in this field and for the upcoming future RE projects instead of relying on commercial software.

Assessing worldwide future potentials of renewable electricity generation: Installable capacity, full load hours and costs

Several studies calculate the potential of renewable energies throughout the world. However, these studies vary in the underlying assumptions and do not consider several technologies within a uniform methodology, which affects comparability. In this paper, we calculate the worldwide potentials of ground-mounted photovoltaic (PV), concentrated solar power (CSP), and wind onshore and offshore on a 6.5 by 6.5 km grid. The results consist of installable capacity, generated electricity, and specific cost of electricity generation. Our methodology combines high-resolution data for land uses, slope, and hourly weather data with a thorough analysis of different factors for wind power, like hub heights and rotor diameters, and solar power plants, like tilt angle, and temperature-related loss of efficiency. The results show that the summed-up potential capacity of ground-mounted PV surpasses the amount of CSP, wind onshore and offshore combined with 450 TW. Given the cost-potential curve, ground-mounted PV reaches 560,000 TWh at costs below 20 €/MWh, which is twice the projected worldwide primary energy supply of the World Energy Outlook 2022 for the year 2050 with 205,557 TWh. The calculated results can function as input factors for energy system models, which are an important tool to analyse the energy transition.

Variable capacity polymer based energy harvesters with integrated macroporous elastomer springs

We introduce a manufacturing concept of variable capacity energy harvesters consisting of macroporous springs integrated within a conducting silicone rubber and dielectric. Printing and polymerising emulsion templates resulted in macroporous spring elements, which were coated with conducting silicone rubber to maintain the active contact surface. By increasing size and number of these springs, the capacitance change of the energy harvesters during compression and recovery increased from 0.4 nF/cm2 to 0.8 nF/cm2. During cyclic loading with 30 N at 2 Hz, the energy harvesters with macroporous springs delivered a power density of 0.58 µW/cm2 at a bias voltage of 50 V, which was 25 times higher than the control without springs. The energy harvesters provided a constant power output over three hours of cyclic loading (21,600 cycles), indicating their structural stability and the durability of the macroporous springs.

Role of Renewables in Energy Storage Economic Viability in the Western Balkans

Given the growing shares of renewable energy sources in the grids, the interest in energy storage systems has increased. The role of pumped hydro energy storage systems as flexible solutions for managing peak and off-peak prices from nuclear and fossil power plants in previous systems is now revitalized in the liberalized systems, with a volatile generation of wind and solar energy. Thus, understanding of the patterns behind the economics of energy storage is crucial for the further integration of energy storage in the grids. In this paper, the factors that impact the economic viability of energy storage in electricity markets are analyzed. The method of approach used in this study considers the electricity market price distribution, full load hours, the total costs of energy storage, and linear regression analysis. Using revenues from arbitraging a 10-megawatt (MW) pumped hydro storage system in the Western Balkans, resulting from the electricity market price distribution and the analysis of the total costs of storage, an econometric model is created. This model shows the impacting factors of energy storage development in the context of the rising renewables sector. Research shows that the previous hypothesis about the integration of energy storage systems in proportion to the increase in shares of renewables in the grids is incorrect. There is a significant correlation between energy storage revenues, the dependent variable, and the independent variables of hydro, wind, and solar generation. The conducted analysis indicates the future arbitraging opportunities of pumped hydro energy storage systems and provides useful insights for energy storage investors and policymakers. During the transitional period, until the deployment of renewables changes the effects of fossil power plants, energy storage price arbitrage is profitable and desirable for 500, 1000, and 2000 full load hours in the Western Balkan region. Despite the need for flexibility, with more renewables in the grids, large-scale energy storage systems will not be economically viable in the long run because of “revenue cannibalization”.

Profitability Model of Green Hydrogen Production on an Existing Wind Power Plant Location

This paper presents a new economic profitability model for a power-to-gas plant producing green hydrogen at the site of an existing wind power plant injected into the gas grid. The model is based on a 42 MW wind power plant, for which an optimal electrolyzer of 10 MW was calculated based on the 2500 equivalent full load hours per year and the projection of electricity prices. The model is calculated on an hourly level for all variables of the 25 years of the model. With the calculated breakeven electricity price of 74.23 EUR/MWh and the price of green hydrogen production of 99.44 EUR/MWh in 2045, the wind power plant would produce 22,410 MWh of green hydrogen from 31% of its total electricity production. Green hydrogen injected into the gas system would reduce the level of CO2 emissions by 4482 tons. However, with the projected prices of natural gas and electricity, the wind power plant would cover only 20% of the income generated by the electricity delivered to the grid by producing green hydrogen. By calculating different scenarios in the model, the authors concluded that the introduction of a premium subsidy model is necessary to accelerate deployment of electrolyzers at the site of an existing wind power plant in order to increase the wind farm profitability.

Effect of Weather Factors on Severity of Early Blight Incited by Alternaria solani (Ellis and Martin) Jones and Grout in Potato

A study was conducted to find out the influence of weather factors, temperature, relative humidity, bright sunshine hour, rainfall, evaporation and wind speed and spore load on the incidence of Alternaria solani (Ellis and Martin) Jones and Grout induced early blight of potato (Solanum tuberosum L.) during 2019 to 2022. Eight weather factors taken from the agrometeorological observatory located at Anand Agricultural University, Anand, Gujarat, India, and were subjected to correlation analysis. The relationship between early blight and concerned weather parameters during Rabi 2020-21 revealed a highly significant positive correlation with evaporation (0.87) and maximum temperature (0.84) at the 0.01 level. PDI was significantly positively correlated with spore load (0.71) and bright sunshine hour (0.64) at the 0.05 level. Whereas Per cent Disease Intensity was negatively correlated with evening humidity (-0.78) at a 0.01 level. During the year Rabi (winter) 2021-22, a substantial negative correlation with evening humidity at the 0.05 level. PDI was positively correlated with spore load (0.79), bright sunshine (0.73) and evaporation (0.68).

Optimizing energy consumption in smart homes: Load scheduling approaches

AbstractRising fuel prices, global warming, and environmental damage are leading to increased demand for rooftop solar energy systems connected to the power grid. The development of smart grids, modern metering systems, and energy management could promote energy conservation in households. In this study, two different meta‐heuristic optimization techniques were employed to schedule the shiftable load in suitable hours for decreasing electricity costs and minimizing peak to average ratio in a smart home while maintaining optimum user comfort. For power generation and storing energy, a grid‐connected residential load with rooftop solar panels, a battery, and an inverter is considered. First, the problem is theoretically described using a load model and an objective function, with the primary goal of reducing power costs by moving the time of usage for certain home appliances. Simulations validate the proposed strategies, which effectively reduce power costs by 4.5% by shifting the time of use, with both optimization algorithms showing similar output. The residential electricity cost before optimization was 507.12 BDT/day, which decreased to 484.33 BDT/day after optimization without compromising load turn‐off.

Droop parameter-based economic dispatch for islanded microgrid considering demand response

The droop parameter setting of the distributed generator (DG) has an essential role in islanded microgrid (MG) systems. This paper presents droop-based economic load dispatch (ELD) in an islanded MG. In this approach, the Power–frequency (P–f) droop characteristic of DG is integrated into its incremental cost, which is the derivative of the cost function of DG. The optimisation problem is formulated by considering the standard deviations of the incremental costs of DGs. Under steady-state conditions, DGs operate at a single frequency and the P–f droop-based ELD ensures that the incremental costs of DGs are equal, minimising the overall cost of active power generation, following the equal incremental cost principle. Furthermore, an incentive-based demand response (DR) programme is integrated into the system to maximise the utility benefit function by incentivising customers for power curtailment. The results exhibit significant power curtailment during peak load hours, indicating the effectiveness of the DR programme. The proposed combined mathematical model is applied to the modified 33-bus islanded MG and solved using basic particle swarm optimisation. It calculates optimal droop parameters for a day-ahead scenario and emphasises the efficiency benefits of optimised droop settings and the integration of DR in islanded MGs.

Life Cycle Assessment of a 5 MW Polymer Exchange Membrane Water Electrolysis Plant

This study performs a cradle‐to‐grave life cycle assessment of a 5 MW proton exchange membrane water electrolysis plant. The analysis follows a thorough engineering‐based bottom‐up design based on the electrochemical model of the system. Three scenarios are analyzed comprising a state‐of‐the‐art (SoA) plant operated with the German electricity grid‐mix, a SoA plant operated with a completely decarbonized energy system, and a future development plant electrolyzer with reduced energy and material demand, operated in a completely decarbonized energy system. The results display a global warming potential of 34 kg CO2‐eq. kg‐H2−1 and indicate a reduction potential of 89% when the plant is operated in a decarbonized energy system. A further reduction of 9% can be achieved by the technological development of the plant. Due to the reduced impacts of operation in a completely decarbonized energy system, the operation at locations with large offshore wind electricity capacity is recommended. In the construction phase, the stacks, especially the anode catalyst iridium, bipolar plates, and porous transport layers, are identified as dominant sources of the environmental impact. A sensitivity analysis shows that the environmental impact of the construction phase increases with a decreasing amount of operational full load hours of the plant.

Iran’s Participatory Power Market Regarding Distributed Generation from Renewable Sources: A Case Study

To study initial conditions for participatory power market formation based on renewable energy sources (RES) in Iran after complete accomplishment of the economic evolutionary plan, a case study for a residential building has been conducted to consider the effects of the most important parameters. So, a model of power market including three parts: consumption, production and regulations, has been optimized to achieve to a micro cost effective system of participatory power market regarding distributed generation from RES. The results indicate that the power tariff structure and rates, RES technology capital cost and economic conditions are prominent parameters. As well, to initiate the power market, a revised power tariff structure and rates are suggested; namely, a plan for shifting peak load hours from evening to day hours is essential. Also, it is demonstrated that the policy of establishing a participatory power market included photovoltaic distributed generation systems must be pursued in the economic evolutionary plan with emphasis on development of zero energy cost buildings.

Entrained flow gasification-based biomass-to-X processes: A techno-economic assessment

In the pursuit of a successful energy transition, synthetic basic chemicals and fuels, alongside renewable energies, play pivotal roles. This study focuses on the utilization of biomass as a carbon source to replace conventional fossil feedstocks, conducting detailed process simulations and techno-economic analyses for various biomass-to-x pathways. Six key products—Methanol, Dimethyl Ether, Methane (SNG), Fischer-Tropsch syncrude, Hydrogen, and Ammonia—derived from entrained flow gasification of a representative biomass are systematically compared. The uniformity of simulation detail and economic methodology enables a direct and comprehensive comparison of these products. Notably, carbon-based products exhibit up to 34% lower average investment costs compared to their hydrogen-based counterparts, namely ammonia and hydrogen. This cost discrepancy is reflected in the levelized costs of manufacturing, with hydrogen-based products emerging as the most energy-expensive. The analysis identifies variable costs as the primary contributor to overall costs with around 50%, followed by fixed investment. The study underscores the critical impact of full load hours, plant lifetime, and feedstock costs on results. This emphasise the importance of detailed planning if alternative feedstock is used to balance fuel costs and enhance plant availability. Among the evaluated products, methanol emerges as the most promising across the evaluated KPIs with costs of 283.48 € MWh−1. However, regarding hydrogen-based products, it is suggested that, especially in the context of CO2 abatement costs, a comprehensive consideration of the long-term system effects is essential to prevent misinvestments during the early stages of the energy transition. This emphasizes the need for strategic planning to ensure a sustainable and economically viable shift towards biomass-derived synthetic fuels.

Off-grid vs. grid-based: Techno-economic assessment of a power-to-liquid plant combining solid-oxide electrolysis and Fischer-Tropsch synthesis

The economic performance of Power-to-Liquid processes depends substantially on the power source’s features, i.e., electricity costs and full load hours. Off-grid solutions can ensure cheap, green electricity without being exposed to fluctuating electricity markets. A techno-economic assessment of a Power-to-Liquid plant combining solid-oxide electrolysis and Fischer-Tropsch synthesis has been conducted. Off-grid and grid-based scenarios of three process configurations at plant scales from 1 to 1000 MWel. rated electrolyzer power were evaluated. Net production costs of Fischer-Tropsch products ranging from 2.42 to 4.56 €2022/kg were obtained for the grid-based scenarios. In contrast, values of 1.28 to 2.40 €2022/kg were determined for the evaluated off-grid scenarios. Scaling up the plant showed a weakened decrease in net production costs after surpassing a threshold of 100 MWel. due to substantial relative electricity costs of up to 88 %. Thus, future Power-to-Liquid projects should be designed at a scale of 100MWel. rated electrolyzer power. In addition, an availability exceeding 4000 h/a is recommended for off-grid plants, e.g., by implementing hybrid renewable power plants as well as electricity and syngas storage technologies.

Radiology Loading and Coverage Hours in Kazakhstan.

Radiology Loading and Coverage Hours in Kazakhstan.