The world is undergoing profound changes in energy and technology.Countries are vigorously developing new sustainable energy sources and technologies.Renewable energy sources encompass various technologies such as win...The world is undergoing profound changes in energy and technology.Countries are vigorously developing new sustainable energy sources and technologies.Renewable energy sources encompass various technologies such as wind turbines,solar energy,nuclear energy,and bioenergy.Additionally,emerging technology fields include new energy vehicles,robots,and artificial intelligence devices,among others.The renewable energy industries and implementation of new technologies necessitate the development and adoption of new equipment and components.Austempered ductile iron(ADI)is renowned for its unique microstructure and superior properties.By utilizing ADI,lightweight and innovative castings can be designed to not only reduce weight but also save energy and decrease emissions.More importantly,these castings enhance the efficiency and reliability of new energy equipment and emerging technology installations.This paper describes the development,applications,and future prospects of lightweight and innovative ADI castings within sectors such as solar photovoltaic(PV),wind power generation,industry robots,and trucks in China.展开更多
In the contemporary era,the global expansion of electrical grids is propelled by various renewable energy sources(RESs).Efficient integration of stochastic RESs and optimal power flow(OPF)management are critical for n...In the contemporary era,the global expansion of electrical grids is propelled by various renewable energy sources(RESs).Efficient integration of stochastic RESs and optimal power flow(OPF)management are critical for network optimization.This study introduces an innovative solution,the Gaussian Bare-Bones Levy Cheetah Optimizer(GBBLCO),addressing OPF challenges in power generation systems with stochastic RESs.The primary objective is to minimize the total operating costs of RESs,considering four functions:overall operating costs,voltage deviation management,emissions reduction,voltage stability index(VSI)and power loss mitigation.Additionally,a carbon tax is included in the objective function to reduce carbon emissions.Thorough scrutiny,using modified IEEE 30-bus and IEEE 118-bus systems,validates GBBLCO’s superior performance in achieving optimal solutions.Simulation results demonstrate GBBLCO’s efficacy in six optimization scenarios:total cost with valve point effects,total cost with emission and carbon tax,total cost with prohibited operating zones,active power loss optimization,voltage deviation optimization and enhancing voltage stability index(VSI).GBBLCO outperforms conventional techniques in each scenario,showcasing rapid convergence and superior solution quality.Notably,GBBLCO navigates complexities introduced by valve point effects,adapts to environmental constraints,optimizes costs while considering prohibited operating zones,minimizes active power losses,and optimizes voltage deviation by enhancing the voltage stability index(VSI)effectively.This research significantly contributes to advancing OPF,emphasizing GBBLCO’s improved global search capabilities and ability to address challenges related to local minima.GBBLCO emerges as a versatile and robust optimization tool for diverse challenges in power systems,offering a promising solution for the evolving needs of renewable energy-integrated power grids.展开更多
Polymers from renewable resources have been used for a long time in biomedical applications and found an irreplaceable role in some of them.Their uses have been increasing because of their attractive properties,contri...Polymers from renewable resources have been used for a long time in biomedical applications and found an irreplaceable role in some of them.Their uses have been increasing because of their attractive properties,contributing to the improvement of life quality,mainly in drug release systems and in regenerative medicine.Formulations using natural polymer,nano and microscale particles preparation,composites,blends and chemical modification strategies have been used to improve their properties for clinical application.Although many studies have been carried out with these natural polymers,the way to reach the market is long and only very few of them become commercially available.Vegetable cellulose,bacterial cellulose,chitosan,poly(lactic acid)and starch can be found among the most studied polymers for biological applications,some with several derivatives already established in the market,and others with potential for such.In this scenario this work aims to describe the properties and potential of these renewable polymers for biomedical applications,the routes from the bench to the market,and the perspectives for future developments.展开更多
The increased valorization of renewable and cost-effective lignocellulosic feedstocks represents a viable,sustainable,and eco-friendly approach toward the production of biopellets as alternative energy sources.The aim...The increased valorization of renewable and cost-effective lignocellulosic feedstocks represents a viable,sustainable,and eco-friendly approach toward the production of biopellets as alternative energy sources.The aim of this research work was to investigate and evaluate the feasibility of using various lignocellulosic raw materials,i.e.,raru(Cotylelobium melanoxylon),mangrove(Rhizophora spp.),sengon(Paraserianthes falcataria),kemenyan toba(Styrax sumatrana),oil palm(Elaeis guineensis),manau rattan(Calamus manan),and belangke bamboo(Gigantochloa pruriens)for manufacturing biopellets with different particle sizes.The raw materials used were tested for their moisture content,specific gravity,ash,cellulose,and lignin content.In addition,thermal analyses,i.e.,calorific values,thermogravimetric analysis(TGA),and differential scanning calorimetry(DSC),were performed.The following properties of the biopellets produced were investigated:moisture content,volatile matter,ash content,fixed carbon,density,and thermal analyses.Based on an analysis of the raw materials,raru had the lowest moisture content(12%)and ash content(1.5%)and the highest specific gravity(1.2).Markedly,palm oil stem had the highestα-cellulose(55%)and lignin(37%)content.In accordance with the SNI 8675:2018 standard requirements,biopellets with optimal properties(moisture content of 1.4%,ash content of 0.79%,density of 1.09 g/m^(3),calorific value of 4672 cal/g,and TGA residue of 13.9%),were manufactured from raru wood.展开更多
Methane generation in landfills and its inadequate management represent the major avoidable source of anthropogenic methane today. This paper models methane production and the potential resources expected (electrical ...Methane generation in landfills and its inadequate management represent the major avoidable source of anthropogenic methane today. This paper models methane production and the potential resources expected (electrical energy production and potential carbon credits from avoided CH4 emissions) from its proper management in a municipal solid waste landfill located in Ouagadougou, Burkina Faso. The modeling was carried out using two first-order decay (FOD) models (LandGEM V3.02 and SWANA) using parameters evaluated on the basis of the characteristics of the waste admitted to the landfill and weather data for the site. At the same time, production data have been collected since 2016 in order to compare them with the model results. The results obtained from these models were compared to experimental one. For the simulation of methane production, the SWANA model showed better consistency with experimental data, with a coefficient of determination (R²) of 0.59 compared with the LandGEM model, which obtained a coefficient of 0.006. Thus, despite the low correlation values linked to the poor consistency of experimental data, the SWANA model models methane production much better than the LandGEM model. Thus, despite the low correlation values linked to the poor consistency of the experimental data, the SWANA model models methane production much better than the LandGEM V3.02 model. It was noted that the poor consistency of the experimental data justifies these low coefficients, and that they can be improved in the future thanks to ongoing in situ measurements. According to the SWANA model prediction, in 27 years of operation a biogas plant with 33% electrical efficiency using biogas from the Polesgo landfill would avoid 1,340 GgCO2e. Also, the evaluation of revenues due to electricity and carbon credit gave a total revenue derived from methane production of US$27.38 million at a cost of US$10.5/tonne CO2e.展开更多
Among expert scientists and politicians, there is increasing agreement that it is absolutely necessary to reduce the emission of greenhouse gas (GHG) to lessen the severity of climate change. Although little, renewabl...Among expert scientists and politicians, there is increasing agreement that it is absolutely necessary to reduce the emission of greenhouse gas (GHG) to lessen the severity of climate change. Although little, renewable energy sources currently reduce GHG that are being emitted from the energy industries. According to the majority of long-term energy estimates, renewable energy will be a substantial addition to the supply of energy worldwide by the end of this century, as capacity of renewable energy is gradually increasing in the early decades. However, developing nations like Bangladesh are largely reliant on pricey imported energy supplies (coal, gas, and oil) that lay a heavy weight on the country’s economy. Also, air pollution growing in importance as a national and international environmental issue. Regarding the development of clean and sustainable energy, renewable energy sources seem to be among the most practical and efficient alternatives, in both Bangladesh and globally. The geographic advantages of Bangladesh allow for widespread usage of the majority of such renewable energy sources. The comparative potential and use of fossil fuels against renewable energy sources globally and in Bangladesh is explored in this review.展开更多
Renewable energy sources are essential formitigating the greenhouse effect and supplying energy to resource-scarce regions.However,their intermittent nature necessitates efficient storage solutions to enhance system e...Renewable energy sources are essential formitigating the greenhouse effect and supplying energy to resource-scarce regions.However,their intermittent nature necessitates efficient storage solutions to enhance system efficiency and manage energy costs.This paper investigates renewable and clean storage systems,specifically examining the storage of electricity generated from renewable sources using hydropower plants and hydrogen,both of which are highly efficient and promising for future energy production and storage.The study utilizes extensive literature data to analyze the impact of various parameters on the cost per kWh of electricity production in hybrid renewable systems incorporating hydropower and hydrogen storage plants.Results indicate that these hybrid systems can store electricity efficiently and cost-effectively,with production costs ranging from 0.126 to 0.3$/kWh for renewablehydropower systems and 0.118 to 0.42$/kWh for renewable-hydrogen systems,with expected cost reductions over the next decade due to technological advancements and increased market adoption.The novelty of this study lies in its comprehensive comparison of hybrid renewable systems integrating hydropower and hydrogen storage,providing detailed cost analysis and future projections.It identifies key parameters influencing the cost and efficiency of these systems,offering insights into optimizing storage solutions for renewable energy.Moreover,this research underscores the potential of hybrid systems to reduce dependency on fossil fuels,particularly during peak demand periods,and emphasizes the importance of seasonal and geographic considerations in selecting energy sources.The study highlights the importance of policy support and investment in hybrid renewable systems and calls for further research into optimizing these systems for different seasonal and geographic conditions.Overall,the integration of renewable energy sources with hydropower and hydrogen storage offers a promising pathway to a sustainable,economical,and resilient energy future.展开更多
Naturalfibre(NFR)reinforced functional polymer composites are quickly becoming an indispensable sustainable material in the transportation industry because of their lightweight,lower cost in manufacture,and adaptabilit...Naturalfibre(NFR)reinforced functional polymer composites are quickly becoming an indispensable sustainable material in the transportation industry because of their lightweight,lower cost in manufacture,and adaptability to a wide variety of goods.However,the major difficulties of using thesefibres are their existing poor dimensional stability and the extreme hydrophilicity.In assessing the mechanical properties(MP)of composites,the interfacial bonding(IB)happening between the NFR and the polymer matrix(PM)plays an incredibly significant role.When compared to NFR/syntheticfibre hybrid composites,hybrid composites(HC)made up of two separate NFR are less prevalent;yet,these hybrid composites also have the potential to be valuable materials in terms of environmental issues.A new dimension to theflexibility of composites reinforced with NFR is added by the cost-effective manufacture of hybrid composites utilising NFR.The purpose of this study is to offer an over-view of the keyfindings that were presented on hybrid composites.The emphasis was focused on the factors that influence the performance of the naturalfiber composites,diverse approaches to enhancing MP,physical,electri-cal,and thermal characteristics of the HC.HC study in polymer science gains interest for applications in con-struction and automotive industries.展开更多
An autonomous microgrid that runs on renewable energy sources is presented in this article.It has a supercon-ducting magnetic energy storage(SMES)device,wind energy-producing devices,and an energy storage battery.Howe...An autonomous microgrid that runs on renewable energy sources is presented in this article.It has a supercon-ducting magnetic energy storage(SMES)device,wind energy-producing devices,and an energy storage battery.However,because such microgrids are nonlinear and the energy they create varies with time,controlling and managing the energy inside them is a difficult issue.Fractional-order proportional integral(FOPI)controller is recommended for the current research to enhance a standalone microgrid’s energy management and performance.The suggested dedicated control for the SMES comprises two loops:the outer loop,which uses the FOPI to regulate the DC-link voltage,and the inner loop,responsible for regulating the SMES current,is constructed using the intelligent FOPI(iFOPI).The FOPI+iFOPI parameters are best developed using the dandelion optimizer(DO)approach to achieve the optimum performance.The suggested FOPI+iFOPI controller’s performance is contrasted with a conventional PI controller for variations in wind speed and microgrid load.The optimal FOPI+iFOPI controller manages the voltage and frequency of the load.The behavior of the microgrid as a reaction to step changes in load and wind speed was measured using the proposed controller.MATLAB simulations were used to evaluate the recommended system’s performance.The results of the simulations showed that throughout all interruptions,the recommended microgrid provided the load with AC power with a constant amplitude and frequency.In addition,the required load demand was accurately reduced.Furthermore,the microgrid functioned incredibly well despite SMES and varying wind speeds.Results obtained under identical conditions were compared with and without the best FOPI+iFOPI controller.When utilizing the optimal FOPI+iFOPI controller with SMES,it was found that the microgrid performed better than the microgrid without SMES.展开更多
With the large-scale development and utilization of renewable energy,industrial flexible loads,as a kind of loadside resource with strong regulation ability,provide new opportunities for the research on renewable ener...With the large-scale development and utilization of renewable energy,industrial flexible loads,as a kind of loadside resource with strong regulation ability,provide new opportunities for the research on renewable energy consumption problem in power systems.This paper proposes a two-layer active power optimization model based on industrial flexible loads for power grid partitioning,aiming at improving the line over-limit problem caused by renewable energy consumption in power grids with high proportion of renewable energy,and achieving the safe,stable and economical operation of power grids.Firstly,according to the evaluation index of renewable energy consumption characteristics of line active power,the power grid is divided into several partitions,and the interzone tie lines are taken as the optimization objects.Then,on the basis of partitioning,a two-layer active power optimization model considering the power constraints of industrial flexible loads is established.The upper-layer model optimizes the planned power of the inter-zone tie lines under the constraint of the minimum peak-valley difference within a day;the lower-layer model optimizes the regional source-load dispatching plan of each resource in each partition under the constraint of theminimumoperation cost of the partition,so as to reduce the line overlimit phenomenon caused by renewable energy consumption and save the electricity cost of industrial flexible loads.Finally,through simulation experiments,it is verified that the proposed model can effectively mobilize industrial flexible loads to participate in power grid operation and improve the economic stability of power grid.展开更多
In recent years,switched inductor(SL)technology,switched capacitor(SC)technology,and switched inductor-capacitor(SL-SC)technology have been widely applied to optimize and improve DC-DC boost converters,which can effec...In recent years,switched inductor(SL)technology,switched capacitor(SC)technology,and switched inductor-capacitor(SL-SC)technology have been widely applied to optimize and improve DC-DC boost converters,which can effectively enhance voltage gain and reduce device stress.To address the issue of low output voltage in current renewable energy power generation systems,this study proposes a novel non-isolated cubic high-gain DC-DC converter based on the traditional quadratic DC-DC boost converter by incorporating a SC and a SL-SC unit.Firstly,the proposed converter’s details are elaborated,including its topology structure,operating mode,voltage gain,device stress,and power loss.Subsequently,a comparative analysis is conducted on the voltage gain and device stress between the proposed converter and other high-gain converters.Then,a closed-loop simulation system is constructed to obtain simulation waveforms of various devices and explore the dynamic performance.Finally,an experimental prototype is built,experimental waveforms are obtained,and the experimental dynamic performance and conversion efficiency are analyzed.The theoretical analysis’s correctness is verified through simulation and experimental results.The proposed converter has advantages such as high voltage gain,low device stress,high conversion efficiency,simple control,and wide input voltage range,achieving a good balance between voltage gain,device stress,and power loss.The proposed converter is well-suited for renewable energy systems and holds theoretical significance and practical value in renewable energy applications.It provides an effective solution to the issue of low output voltage in renewable energy power generation systems.展开更多
The renewable energy industry has grown its contribution to the global energy mix, particularly in terms of electricity generation. This study investigates the implications of an increasing renewable energy share on O...The renewable energy industry has grown its contribution to the global energy mix, particularly in terms of electricity generation. This study investigates the implications of an increasing renewable energy share on OAPEC countries and proposes a comprehensible policy strategy for the region. Four main topics are discussed: scientific and engineering principles of renewable energy utilization, current strategies for electricity generation in each OAPEC member country, economic and environmental implications of the energy transition under two future scenarios, as well as political interactions between oil-consuming and oil-producing countries. Based on this study, realistic and cost-effective strategies are proposed for OAPEC countries to better leverage their significant renewable energy resources while stabilizing fossil fuel supplies and strengthening their position in the global energy market. To mitigate the negative impacts of the energy transition, OAPEC countries are encouraged to take the following steps: 1) Developing renewable energy in conjunction with fossil fuel resources to reduce local demand for fossil fuel and increase the supply for exportation;2) Reviewing economic policies, environmental regulations, and carbon taxes imposed by oil-consuming countries;3) Increasing investment in renewable energy infrastructure;4) Cooperating to achieve a balance between economic development and environmental protection.展开更多
Against the backdrop of global energy shortages and increasingly severe environmental pollution,renewable energy is gradually becoming a significant direction for future energy development.Power electronics converters...Against the backdrop of global energy shortages and increasingly severe environmental pollution,renewable energy is gradually becoming a significant direction for future energy development.Power electronics converters,as the core technology for energy conversion and control,play a crucial role in enhancing the efficiency and stability of renewable energy systems.This paper explores the basic principles and functions of power electronics converters and their specific applications in photovoltaic power generation,wind power generation,and energy storage systems.Additionally,it analyzes the current innovations in high-efficiency energy conversion,multilevel conversion technology,and the application of new materials and devices.By studying these technologies,the aim is to promote the widespread application of power electronics converters in renewable energy systems and provide theoretical and technical support for achieving sustainable energy development.展开更多
Based on the significance of renewable resources in relieving energy crisis,application of renewable resources for reducing energy consumption of rural housings and carbon emission of traditional energies are believed...Based on the significance of renewable resources in relieving energy crisis,application of renewable resources for reducing energy consumption of rural housings and carbon emission of traditional energies are believed as an inevitable choice for the construction of a conservation-minded society.Taking easily-acquired and low-cost solar energy,biomass energy and rainwater for example,strategies of applying renewable resources in rural housings are discussed.And the research focuses on the application of solar energy PV Power System and solar energy photo-thermal power system in rural residence,significance of power system such as methane and waste reusing for the integrated utilization of biomass energy and residence,and also recycling and cooling effects of intermediate water.展开更多
This paper briefs the basic objective of pursuing Renewable Portfolio Standard (RPS), puts forward a thinking about the scope and three modes of RPS-implementation in China and enumerates other possible measures, such...This paper briefs the basic objective of pursuing Renewable Portfolio Standard (RPS), puts forward a thinking about the scope and three modes of RPS-implementation in China and enumerates other possible measures, such as public bidding on concession, exemption from value-added tax, to promote wind power exploitation and development.展开更多
In this review,we primarily analyze the hydrogen production technologies based on water and biomass,including the economic,technological,and environmental impacts of different types of hydrogen production technologies...In this review,we primarily analyze the hydrogen production technologies based on water and biomass,including the economic,technological,and environmental impacts of different types of hydrogen production technologies based on these materials,and comprehensively compare them.Our analyses indicate that all renewable energy-based approaches for hydrogen production are more environmentally friendly than fossil-based hydrogen generation approaches.However,the technical ease and economic efficiency of hydrogen production from renewable sources of energy needs to be further improved in order to be applied on a large scale.Compared with other renewable energy-based methods,hydrogen production via biomass electrolysis has several advantages,including the ease of directly using raw biomass.Furthermore,its environmental impact is smaller than other approaches.Moreover,using a noble metal,catalyst-free anode for this approach can ensure a considerably low power consumption,which makes it a promising candidate for clean and efficient hydrogen production in the future.展开更多
The renewable hydrogen generation through ethanol steam reforming is one of the anticipated areas for sustainable hydrogen generation. To elucidate the role of Ni and Co with ZSM-5 support, catalysts were prepared by ...The renewable hydrogen generation through ethanol steam reforming is one of the anticipated areas for sustainable hydrogen generation. To elucidate the role of Ni and Co with ZSM-5 support, catalysts were prepared by wet impregnation method and ethanol steam reforming(ESR) was performed. The catalysts were characterized by HR-XRD, ATR–FTIR, HR-SEM, TEM with SAED, EDAX, surface area analyzer and TPR. It had shown complete ethanol conversion at 773 K, but the selectivity in hydrogen generation was found higher for 10% Ni/ZSM-5 catalyst as compared to 10% Co/ZSM-5. The 10% Ni/ZSM-5 catalyst has about 72% hydrogen selectivity at temperature 873 K. It indicates that Ni is a more sustainable catalyst as compared to Co with ZSM-5 support for ESR. The C_2H_4 was found major undesirable products up to 823 K temperature. Nevertheless, the 10% Ni/ZSM-5 catalyst had shown its stability for high temperature(873 K) ESR performance.展开更多
Based on a general review of marine renewable energy in China, an assessment of the development status and amount of various marine renewable energy resources, including tidal energy, tidal current energy, wave energy...Based on a general review of marine renewable energy in China, an assessment of the development status and amount of various marine renewable energy resources, including tidal energy, tidal current energy, wave energy, ocean thermal energy, and salinity gradient energy in China's coastal seas, such as the Bohai Sea, the Yellow Sea, the East China Sea, and the South China Sea, is presented. We have found that these kinds of marine renewable energy resources will play an important role in meeting China's future energy needs. Additionally, considering the uneven distribution of China's marine renewable energy and the influences of its exploitation on the environment, we have suggested several sites with great potential for each kind of marine energy. Furthermore, perspectives on and challenges related with marine renewable energy in China are addressed.展开更多
Over the past decade, the Chinese government has developed several plans regulations and policy measures related to the development of renewable energy technologies and has implemented a series of pilot projects. Chin...Over the past decade, the Chinese government has developed several plans regulations and policy measures related to the development of renewable energy technologies and has implemented a series of pilot projects. Chinese policymakers have spent several years studying how renewable energy policy models that have been used internationally could be implemented in China. Programs are currently underway to implement pilot renewable portfolio standards, or mandatory market shares (MMS) for renewable energy, in several provinces. This paper examines the primary institutions that are involved in promoting renewable policies in China, the structure of the policies that currently are being drafted, and the status of the complementary, national-level renewable energy law being drafted to provide a legal basis for ongoing local and national-level policies. It then examines the legal requirements for promoting renewable energy legislation under the Chinese law-making system. Finally, it provides recommendations展开更多
文摘The world is undergoing profound changes in energy and technology.Countries are vigorously developing new sustainable energy sources and technologies.Renewable energy sources encompass various technologies such as wind turbines,solar energy,nuclear energy,and bioenergy.Additionally,emerging technology fields include new energy vehicles,robots,and artificial intelligence devices,among others.The renewable energy industries and implementation of new technologies necessitate the development and adoption of new equipment and components.Austempered ductile iron(ADI)is renowned for its unique microstructure and superior properties.By utilizing ADI,lightweight and innovative castings can be designed to not only reduce weight but also save energy and decrease emissions.More importantly,these castings enhance the efficiency and reliability of new energy equipment and emerging technology installations.This paper describes the development,applications,and future prospects of lightweight and innovative ADI castings within sectors such as solar photovoltaic(PV),wind power generation,industry robots,and trucks in China.
基金supported by the Deanship of Postgraduate Studies and Scientific Research at Majmaah University in Saudi Arabia under Project Number(ICR-2024-1002).
文摘In the contemporary era,the global expansion of electrical grids is propelled by various renewable energy sources(RESs).Efficient integration of stochastic RESs and optimal power flow(OPF)management are critical for network optimization.This study introduces an innovative solution,the Gaussian Bare-Bones Levy Cheetah Optimizer(GBBLCO),addressing OPF challenges in power generation systems with stochastic RESs.The primary objective is to minimize the total operating costs of RESs,considering four functions:overall operating costs,voltage deviation management,emissions reduction,voltage stability index(VSI)and power loss mitigation.Additionally,a carbon tax is included in the objective function to reduce carbon emissions.Thorough scrutiny,using modified IEEE 30-bus and IEEE 118-bus systems,validates GBBLCO’s superior performance in achieving optimal solutions.Simulation results demonstrate GBBLCO’s efficacy in six optimization scenarios:total cost with valve point effects,total cost with emission and carbon tax,total cost with prohibited operating zones,active power loss optimization,voltage deviation optimization and enhancing voltage stability index(VSI).GBBLCO outperforms conventional techniques in each scenario,showcasing rapid convergence and superior solution quality.Notably,GBBLCO navigates complexities introduced by valve point effects,adapts to environmental constraints,optimizes costs while considering prohibited operating zones,minimizes active power losses,and optimizes voltage deviation by enhancing the voltage stability index(VSI)effectively.This research significantly contributes to advancing OPF,emphasizing GBBLCO’s improved global search capabilities and ability to address challenges related to local minima.GBBLCO emerges as a versatile and robust optimization tool for diverse challenges in power systems,offering a promising solution for the evolving needs of renewable energy-integrated power grids.
基金The authors acknowledge FAPESP for funding the Research Project Number 2017-18-782-6 and the Grant 2021/07458-9.
文摘Polymers from renewable resources have been used for a long time in biomedical applications and found an irreplaceable role in some of them.Their uses have been increasing because of their attractive properties,contributing to the improvement of life quality,mainly in drug release systems and in regenerative medicine.Formulations using natural polymer,nano and microscale particles preparation,composites,blends and chemical modification strategies have been used to improve their properties for clinical application.Although many studies have been carried out with these natural polymers,the way to reach the market is long and only very few of them become commercially available.Vegetable cellulose,bacterial cellulose,chitosan,poly(lactic acid)and starch can be found among the most studied polymers for biological applications,some with several derivatives already established in the market,and others with potential for such.In this scenario this work aims to describe the properties and potential of these renewable polymers for biomedical applications,the routes from the bench to the market,and the perspectives for future developments.
基金supporting the research fund through to Grant of Penelitian Tesis Magister(PTM)year 2022(Number 14/UN5.2.3.1/PPM/KP-DRTPM/TI/2022)supported by the project“Development,Exploitation Properties and Application of Eco-Friendly Wood-Based Composites from Alternative Lignocellulosic Raw Materials”,Project No.НИС-Б-1290/19.10.2023,carried out at the University of Forestry,Sofia,Bulgaria.
文摘The increased valorization of renewable and cost-effective lignocellulosic feedstocks represents a viable,sustainable,and eco-friendly approach toward the production of biopellets as alternative energy sources.The aim of this research work was to investigate and evaluate the feasibility of using various lignocellulosic raw materials,i.e.,raru(Cotylelobium melanoxylon),mangrove(Rhizophora spp.),sengon(Paraserianthes falcataria),kemenyan toba(Styrax sumatrana),oil palm(Elaeis guineensis),manau rattan(Calamus manan),and belangke bamboo(Gigantochloa pruriens)for manufacturing biopellets with different particle sizes.The raw materials used were tested for their moisture content,specific gravity,ash,cellulose,and lignin content.In addition,thermal analyses,i.e.,calorific values,thermogravimetric analysis(TGA),and differential scanning calorimetry(DSC),were performed.The following properties of the biopellets produced were investigated:moisture content,volatile matter,ash content,fixed carbon,density,and thermal analyses.Based on an analysis of the raw materials,raru had the lowest moisture content(12%)and ash content(1.5%)and the highest specific gravity(1.2).Markedly,palm oil stem had the highestα-cellulose(55%)and lignin(37%)content.In accordance with the SNI 8675:2018 standard requirements,biopellets with optimal properties(moisture content of 1.4%,ash content of 0.79%,density of 1.09 g/m^(3),calorific value of 4672 cal/g,and TGA residue of 13.9%),were manufactured from raru wood.
文摘Methane generation in landfills and its inadequate management represent the major avoidable source of anthropogenic methane today. This paper models methane production and the potential resources expected (electrical energy production and potential carbon credits from avoided CH4 emissions) from its proper management in a municipal solid waste landfill located in Ouagadougou, Burkina Faso. The modeling was carried out using two first-order decay (FOD) models (LandGEM V3.02 and SWANA) using parameters evaluated on the basis of the characteristics of the waste admitted to the landfill and weather data for the site. At the same time, production data have been collected since 2016 in order to compare them with the model results. The results obtained from these models were compared to experimental one. For the simulation of methane production, the SWANA model showed better consistency with experimental data, with a coefficient of determination (R²) of 0.59 compared with the LandGEM model, which obtained a coefficient of 0.006. Thus, despite the low correlation values linked to the poor consistency of experimental data, the SWANA model models methane production much better than the LandGEM model. Thus, despite the low correlation values linked to the poor consistency of the experimental data, the SWANA model models methane production much better than the LandGEM V3.02 model. It was noted that the poor consistency of the experimental data justifies these low coefficients, and that they can be improved in the future thanks to ongoing in situ measurements. According to the SWANA model prediction, in 27 years of operation a biogas plant with 33% electrical efficiency using biogas from the Polesgo landfill would avoid 1,340 GgCO2e. Also, the evaluation of revenues due to electricity and carbon credit gave a total revenue derived from methane production of US$27.38 million at a cost of US$10.5/tonne CO2e.
文摘Among expert scientists and politicians, there is increasing agreement that it is absolutely necessary to reduce the emission of greenhouse gas (GHG) to lessen the severity of climate change. Although little, renewable energy sources currently reduce GHG that are being emitted from the energy industries. According to the majority of long-term energy estimates, renewable energy will be a substantial addition to the supply of energy worldwide by the end of this century, as capacity of renewable energy is gradually increasing in the early decades. However, developing nations like Bangladesh are largely reliant on pricey imported energy supplies (coal, gas, and oil) that lay a heavy weight on the country’s economy. Also, air pollution growing in importance as a national and international environmental issue. Regarding the development of clean and sustainable energy, renewable energy sources seem to be among the most practical and efficient alternatives, in both Bangladesh and globally. The geographic advantages of Bangladesh allow for widespread usage of the majority of such renewable energy sources. The comparative potential and use of fossil fuels against renewable energy sources globally and in Bangladesh is explored in this review.
文摘Renewable energy sources are essential formitigating the greenhouse effect and supplying energy to resource-scarce regions.However,their intermittent nature necessitates efficient storage solutions to enhance system efficiency and manage energy costs.This paper investigates renewable and clean storage systems,specifically examining the storage of electricity generated from renewable sources using hydropower plants and hydrogen,both of which are highly efficient and promising for future energy production and storage.The study utilizes extensive literature data to analyze the impact of various parameters on the cost per kWh of electricity production in hybrid renewable systems incorporating hydropower and hydrogen storage plants.Results indicate that these hybrid systems can store electricity efficiently and cost-effectively,with production costs ranging from 0.126 to 0.3$/kWh for renewablehydropower systems and 0.118 to 0.42$/kWh for renewable-hydrogen systems,with expected cost reductions over the next decade due to technological advancements and increased market adoption.The novelty of this study lies in its comprehensive comparison of hybrid renewable systems integrating hydropower and hydrogen storage,providing detailed cost analysis and future projections.It identifies key parameters influencing the cost and efficiency of these systems,offering insights into optimizing storage solutions for renewable energy.Moreover,this research underscores the potential of hybrid systems to reduce dependency on fossil fuels,particularly during peak demand periods,and emphasizes the importance of seasonal and geographic considerations in selecting energy sources.The study highlights the importance of policy support and investment in hybrid renewable systems and calls for further research into optimizing these systems for different seasonal and geographic conditions.Overall,the integration of renewable energy sources with hydropower and hydrogen storage offers a promising pathway to a sustainable,economical,and resilient energy future.
文摘Naturalfibre(NFR)reinforced functional polymer composites are quickly becoming an indispensable sustainable material in the transportation industry because of their lightweight,lower cost in manufacture,and adaptability to a wide variety of goods.However,the major difficulties of using thesefibres are their existing poor dimensional stability and the extreme hydrophilicity.In assessing the mechanical properties(MP)of composites,the interfacial bonding(IB)happening between the NFR and the polymer matrix(PM)plays an incredibly significant role.When compared to NFR/syntheticfibre hybrid composites,hybrid composites(HC)made up of two separate NFR are less prevalent;yet,these hybrid composites also have the potential to be valuable materials in terms of environmental issues.A new dimension to theflexibility of composites reinforced with NFR is added by the cost-effective manufacture of hybrid composites utilising NFR.The purpose of this study is to offer an over-view of the keyfindings that were presented on hybrid composites.The emphasis was focused on the factors that influence the performance of the naturalfiber composites,diverse approaches to enhancing MP,physical,electri-cal,and thermal characteristics of the HC.HC study in polymer science gains interest for applications in con-struction and automotive industries.
基金This research was funded by the Deputyship for Research and Innovation,Ministry of Education,Saudi Arabia,through the University of Tabuk,Grant Number S-1443-0123.
文摘An autonomous microgrid that runs on renewable energy sources is presented in this article.It has a supercon-ducting magnetic energy storage(SMES)device,wind energy-producing devices,and an energy storage battery.However,because such microgrids are nonlinear and the energy they create varies with time,controlling and managing the energy inside them is a difficult issue.Fractional-order proportional integral(FOPI)controller is recommended for the current research to enhance a standalone microgrid’s energy management and performance.The suggested dedicated control for the SMES comprises two loops:the outer loop,which uses the FOPI to regulate the DC-link voltage,and the inner loop,responsible for regulating the SMES current,is constructed using the intelligent FOPI(iFOPI).The FOPI+iFOPI parameters are best developed using the dandelion optimizer(DO)approach to achieve the optimum performance.The suggested FOPI+iFOPI controller’s performance is contrasted with a conventional PI controller for variations in wind speed and microgrid load.The optimal FOPI+iFOPI controller manages the voltage and frequency of the load.The behavior of the microgrid as a reaction to step changes in load and wind speed was measured using the proposed controller.MATLAB simulations were used to evaluate the recommended system’s performance.The results of the simulations showed that throughout all interruptions,the recommended microgrid provided the load with AC power with a constant amplitude and frequency.In addition,the required load demand was accurately reduced.Furthermore,the microgrid functioned incredibly well despite SMES and varying wind speeds.Results obtained under identical conditions were compared with and without the best FOPI+iFOPI controller.When utilizing the optimal FOPI+iFOPI controller with SMES,it was found that the microgrid performed better than the microgrid without SMES.
基金supported by State Grid Corporation of China Project“Research and Application of Key Technologies for Active Power Control in Regional Power Grid with High Penetration of Distributed Renewable Generation”(5108-202316044A-1-1-ZN).
文摘With the large-scale development and utilization of renewable energy,industrial flexible loads,as a kind of loadside resource with strong regulation ability,provide new opportunities for the research on renewable energy consumption problem in power systems.This paper proposes a two-layer active power optimization model based on industrial flexible loads for power grid partitioning,aiming at improving the line over-limit problem caused by renewable energy consumption in power grids with high proportion of renewable energy,and achieving the safe,stable and economical operation of power grids.Firstly,according to the evaluation index of renewable energy consumption characteristics of line active power,the power grid is divided into several partitions,and the interzone tie lines are taken as the optimization objects.Then,on the basis of partitioning,a two-layer active power optimization model considering the power constraints of industrial flexible loads is established.The upper-layer model optimizes the planned power of the inter-zone tie lines under the constraint of the minimum peak-valley difference within a day;the lower-layer model optimizes the regional source-load dispatching plan of each resource in each partition under the constraint of theminimumoperation cost of the partition,so as to reduce the line overlimit phenomenon caused by renewable energy consumption and save the electricity cost of industrial flexible loads.Finally,through simulation experiments,it is verified that the proposed model can effectively mobilize industrial flexible loads to participate in power grid operation and improve the economic stability of power grid.
基金This work was supported by China Railway Corporation Science and Technology Research and Development Project(P2021J038).
文摘In recent years,switched inductor(SL)technology,switched capacitor(SC)technology,and switched inductor-capacitor(SL-SC)technology have been widely applied to optimize and improve DC-DC boost converters,which can effectively enhance voltage gain and reduce device stress.To address the issue of low output voltage in current renewable energy power generation systems,this study proposes a novel non-isolated cubic high-gain DC-DC converter based on the traditional quadratic DC-DC boost converter by incorporating a SC and a SL-SC unit.Firstly,the proposed converter’s details are elaborated,including its topology structure,operating mode,voltage gain,device stress,and power loss.Subsequently,a comparative analysis is conducted on the voltage gain and device stress between the proposed converter and other high-gain converters.Then,a closed-loop simulation system is constructed to obtain simulation waveforms of various devices and explore the dynamic performance.Finally,an experimental prototype is built,experimental waveforms are obtained,and the experimental dynamic performance and conversion efficiency are analyzed.The theoretical analysis’s correctness is verified through simulation and experimental results.The proposed converter has advantages such as high voltage gain,low device stress,high conversion efficiency,simple control,and wide input voltage range,achieving a good balance between voltage gain,device stress,and power loss.The proposed converter is well-suited for renewable energy systems and holds theoretical significance and practical value in renewable energy applications.It provides an effective solution to the issue of low output voltage in renewable energy power generation systems.
文摘The renewable energy industry has grown its contribution to the global energy mix, particularly in terms of electricity generation. This study investigates the implications of an increasing renewable energy share on OAPEC countries and proposes a comprehensible policy strategy for the region. Four main topics are discussed: scientific and engineering principles of renewable energy utilization, current strategies for electricity generation in each OAPEC member country, economic and environmental implications of the energy transition under two future scenarios, as well as political interactions between oil-consuming and oil-producing countries. Based on this study, realistic and cost-effective strategies are proposed for OAPEC countries to better leverage their significant renewable energy resources while stabilizing fossil fuel supplies and strengthening their position in the global energy market. To mitigate the negative impacts of the energy transition, OAPEC countries are encouraged to take the following steps: 1) Developing renewable energy in conjunction with fossil fuel resources to reduce local demand for fossil fuel and increase the supply for exportation;2) Reviewing economic policies, environmental regulations, and carbon taxes imposed by oil-consuming countries;3) Increasing investment in renewable energy infrastructure;4) Cooperating to achieve a balance between economic development and environmental protection.
文摘Against the backdrop of global energy shortages and increasingly severe environmental pollution,renewable energy is gradually becoming a significant direction for future energy development.Power electronics converters,as the core technology for energy conversion and control,play a crucial role in enhancing the efficiency and stability of renewable energy systems.This paper explores the basic principles and functions of power electronics converters and their specific applications in photovoltaic power generation,wind power generation,and energy storage systems.Additionally,it analyzes the current innovations in high-efficiency energy conversion,multilevel conversion technology,and the application of new materials and devices.By studying these technologies,the aim is to promote the widespread application of power electronics converters in renewable energy systems and provide theoretical and technical support for achieving sustainable energy development.
文摘Based on the significance of renewable resources in relieving energy crisis,application of renewable resources for reducing energy consumption of rural housings and carbon emission of traditional energies are believed as an inevitable choice for the construction of a conservation-minded society.Taking easily-acquired and low-cost solar energy,biomass energy and rainwater for example,strategies of applying renewable resources in rural housings are discussed.And the research focuses on the application of solar energy PV Power System and solar energy photo-thermal power system in rural residence,significance of power system such as methane and waste reusing for the integrated utilization of biomass energy and residence,and also recycling and cooling effects of intermediate water.
文摘This paper briefs the basic objective of pursuing Renewable Portfolio Standard (RPS), puts forward a thinking about the scope and three modes of RPS-implementation in China and enumerates other possible measures, such as public bidding on concession, exemption from value-added tax, to promote wind power exploitation and development.
基金supported by the Beijing Science and Technology Major Project (Grant No.Z171100002017021)CHN Energy Science and Technology Innovation Project (2017B1BE00100)
文摘In this review,we primarily analyze the hydrogen production technologies based on water and biomass,including the economic,technological,and environmental impacts of different types of hydrogen production technologies based on these materials,and comprehensively compare them.Our analyses indicate that all renewable energy-based approaches for hydrogen production are more environmentally friendly than fossil-based hydrogen generation approaches.However,the technical ease and economic efficiency of hydrogen production from renewable sources of energy needs to be further improved in order to be applied on a large scale.Compared with other renewable energy-based methods,hydrogen production via biomass electrolysis has several advantages,including the ease of directly using raw biomass.Furthermore,its environmental impact is smaller than other approaches.Moreover,using a noble metal,catalyst-free anode for this approach can ensure a considerably low power consumption,which makes it a promising candidate for clean and efficient hydrogen production in the future.
基金Institute of Technology (BHU) Varanasi and MHRD, Govt. of India for financial assistance (TA) to Mr Ashutosh Kumar
文摘The renewable hydrogen generation through ethanol steam reforming is one of the anticipated areas for sustainable hydrogen generation. To elucidate the role of Ni and Co with ZSM-5 support, catalysts were prepared by wet impregnation method and ethanol steam reforming(ESR) was performed. The catalysts were characterized by HR-XRD, ATR–FTIR, HR-SEM, TEM with SAED, EDAX, surface area analyzer and TPR. It had shown complete ethanol conversion at 773 K, but the selectivity in hydrogen generation was found higher for 10% Ni/ZSM-5 catalyst as compared to 10% Co/ZSM-5. The 10% Ni/ZSM-5 catalyst has about 72% hydrogen selectivity at temperature 873 K. It indicates that Ni is a more sustainable catalyst as compared to Co with ZSM-5 support for ESR. The C_2H_4 was found major undesirable products up to 823 K temperature. Nevertheless, the 10% Ni/ZSM-5 catalyst had shown its stability for high temperature(873 K) ESR performance.
基金supported by the National Natural Science Foundation of China(Grants No.51079072 and 51279088)the National High Technology Research and Development Program of China(Grant No.2012AA052602)the Tsinghua University Initiative Scientific Research Program(Grant No.20101081791)
文摘Based on a general review of marine renewable energy in China, an assessment of the development status and amount of various marine renewable energy resources, including tidal energy, tidal current energy, wave energy, ocean thermal energy, and salinity gradient energy in China's coastal seas, such as the Bohai Sea, the Yellow Sea, the East China Sea, and the South China Sea, is presented. We have found that these kinds of marine renewable energy resources will play an important role in meeting China's future energy needs. Additionally, considering the uneven distribution of China's marine renewable energy and the influences of its exploitation on the environment, we have suggested several sites with great potential for each kind of marine energy. Furthermore, perspectives on and challenges related with marine renewable energy in China are addressed.
文摘Over the past decade, the Chinese government has developed several plans regulations and policy measures related to the development of renewable energy technologies and has implemented a series of pilot projects. Chinese policymakers have spent several years studying how renewable energy policy models that have been used internationally could be implemented in China. Programs are currently underway to implement pilot renewable portfolio standards, or mandatory market shares (MMS) for renewable energy, in several provinces. This paper examines the primary institutions that are involved in promoting renewable policies in China, the structure of the policies that currently are being drafted, and the status of the complementary, national-level renewable energy law being drafted to provide a legal basis for ongoing local and national-level policies. It then examines the legal requirements for promoting renewable energy legislation under the Chinese law-making system. Finally, it provides recommendations