The understanding of hydraulic behavior in the hydro turbine requires the detailed study of fluid flow in the turbine. Previous methods of analyzing the numerical simulation results on the fluid machinery are short of...The understanding of hydraulic behavior in the hydro turbine requires the detailed study of fluid flow in the turbine. Previous methods of analyzing the numerical simulation results on the fluid machinery are short of intuitiveness on energy dissipation.In this paper, the energy dissipation was analyzed based on the entropy production theory. 3-D steady flow simulations and entropy production calculations of the reduced hydro turbine were carried out. The results indicated that the entropy production theory was suitable for evaluating the performance of the hydro turbine. The energy dissipation in the guide vanes area weighted nearly 25% of the whole flow passage, and mainly happened at the head and tail areas of the vanes. However, more than half the energy dissipation occurred in the runner, mostly at the leading edge of runner blade and the trailing edge of run-ner blade. Meanwhile, close to 20% of the energy dissipation occurred in the elbow. And it can be concluded that the method of entropy production analysis has the advantages of determining the quantity of energy dissipation and where the dissipation happens.展开更多
The low electricity supply rate is a major cause of underdevelopment in Cameroon. To address this issue, Cameroon outlined a strategy in 2003 aiming for a production capacity of 3000 MW by 2020. However, by 2020, prod...The low electricity supply rate is a major cause of underdevelopment in Cameroon. To address this issue, Cameroon outlined a strategy in 2003 aiming for a production capacity of 3000 MW by 2020. However, by 2020, production had only reached 1040 MW, leading Cameroon to devise a new national energy sector development strategy targeting 5000 MW by 2035. This paper provides an overview of the current state of energy production and projects future output by 2035. Scientific articles and investigative reports on energy production in Cameroon have enabled an assessment of the current electrical energy production. The 2035 production estimate is based on the Energy Sector Development Projects (PDSEN) report in Cameroon. The current production is estimated at around 1600 MW. Considering the ongoing construction of power plants, future projects, and financing delays, achieving the 5000 MW goal by 2035 appears challenging. Nonetheless, diversifying energy production sources could bring Cameroon closer to this target.展开更多
Hydrothermal carbonization(HTC)of biomass is a promising method to produce carbonaceous materials.The work presented in this article addresses the application of hydrothermal carbonization(HTC)to produce a solid fuel...Hydrothermal carbonization(HTC)of biomass is a promising method to produce carbonaceous materials.The work presented in this article addresses the application of hydrothermal carbonization(HTC)to produce a solid fuel named HTC-Biochar,whose characteristics are comparable to lignite coal.Biogas sludge(SD),maize silage(MS),and barley silage(BS)as a substrates were hydrothermally carbonized in a 1.5 L batch reactor at 200C for 6 h.The effect of mixing ratios of different substrates on HTC was investigated.Chemical compositions and combustion characteristics of hydro-chars obtained from mono-and co-carbonization were evaluated.Result showed that HTC increased carbon contents and higher heating values(HHV)by 1.4–14.4%and 13–36%,respectively.The evolution of the H/C and O/C atomic ratios indicated that dehydration and decarboxylation occurred during hydrothermal carbonization for all samples.Furthermore,a significant synergistic enhancement was observed for HHV and carbon content.A mixing ratio of 1:1 for BS and SD showed the best performance for co-HTC.In summary,hydrothermal co-carbonization is a promising strategy to tailor high-performance hydro-char for energy applications.展开更多
Recently,renewable energy resources and their impacts have sparked a heated debate to resolve the Australian energy crisis.There are many projects launched throughout the country to improve network security and reliab...Recently,renewable energy resources and their impacts have sparked a heated debate to resolve the Australian energy crisis.There are many projects launched throughout the country to improve network security and reliability.This paper aims to review the current status of different renewable energy resources along with their impacts on society and the environment.Besides,it provides for the first time the statistics of the documents published in the field of renewable energy in Australia.The statistics include information such as the rate of papers published,possible journals for finding relative paper,types of documents published,top authors,and the most prevalent keywords in the field of renewable energy in Australia.It will focus on solar,wind,biomass,geothermal and hydropower technologies and will investigate the social and environmental impacts of these technologies.展开更多
A just and sustainable future requires green renewable power. Net-zero by 2050 is the international goal to limit global warming to 1.5 degrees Celsius and sustain the biosphere. Green renewable energy, including wind...A just and sustainable future requires green renewable power. Net-zero by 2050 is the international goal to limit global warming to 1.5 degrees Celsius and sustain the biosphere. Green renewable energy, including wind, solar, biomass and small hydro is abundant in Canada, with potential to satisfy demand with 100% green renewables. This paper compares the renewable power landscape across Canada’s provinces considering four factors—electricity energy mix, renewable energy targets (RETs), renewable energy standard offer programs (RESOPs), feed-in tariff (FITs) or community FITs (comFITs). The provinces with green renewable energy sources typically have enabling policies of RESOP, RETs and FITS, as Prince Edward Island, Nova Scotia, Ontario and New Brunswick do. In contrast, provinces with abundant oil and gas or large-scale hydro are without pro-renewable energy policies, nor community power options, excepting green renewables in Indigenous communities due to federal funding programs. Community green renewable power projects, such as the “Indigenous off-diesel initiative”, are creating jobs, community revenue and energy sovereignty, towards just and inclusive energy in off-grid Indigenous communities. To reduce climate change, fast-tracking net-zero electricity by 2035 is recommended with the prioritization of community renewable energy by RESOPs, FITs and comFITs. For the transportation and other sectors, banning of all fossil fuels before 2040 is needed. Finally, a long-term plan to reduce the negative impacts of hydroelectricity water fluctuation is needed, considering decommissioning some dams.展开更多
Mathematically simulated energy transfers from the energy source to the chassis through hydro transmissions and hydro differential. The developed unified mathematical model of a dynamic system allows, at the design st...Mathematically simulated energy transfers from the energy source to the chassis through hydro transmissions and hydro differential. The developed unified mathematical model of a dynamic system allows, at the design stage, of many branched drive mechanisms, including transmission hydraulic and hydraulic differential actuators, to explore dynamic processes and select rational parameters.展开更多
In order to cut greenhouse-gas emissions and increase energy security,the European Commission stimulates the deployment of intermittent renewable energy sources(IRES) towards 2050.In an electricity system with high sh...In order to cut greenhouse-gas emissions and increase energy security,the European Commission stimulates the deployment of intermittent renewable energy sources(IRES) towards 2050.In an electricity system with high shares of IRES implemented in the network,energy balancing like storage is needed to secure grid stability and smooth demand satisfaction.Pumped hydro storage(PHS) is at this moment the best option for large scale storage.Switzerland has strong ambitions to further develop their PHS sector and become the battery of Europe.In this research,the potential of the Swiss PSH plants is explored,whilst taking inflow into the upper reservoirs of the PHS plants into consideration.To simulate electricity imbalance,Germany is used as a case study.Germany already has a high penetration of IRES and has plans to increase installed IRES capacity.By using an energy planning model(Power Plan),three future scenarios of the German electricity system were designed,each with a different set of IRES installed(solar,mixed and wind).Results show that the Swiss battery ambition offers most benefits to a wind-oriented scenario,reducing both shortages as well as surpluses.Water inflow in Swiss PHS-reservoirs is of minor importance when looking at security of supply,although it was shown that the solarscenario profits more from inflow in terms of system stability.However,a potential conflict was observed in the solar-scenario between the need for electricity storage and the storage of natural inflow,resulting in more surpluses in the system when inflow was taken into account.展开更多
The impact of hydro energy production,economic complexity,urbanization,technological innovation and financial development on environmental sustainability between 1995 and 2017 is examined for a panel of thirteen Asian...The impact of hydro energy production,economic complexity,urbanization,technological innovation and financial development on environmental sustainability between 1995 and 2017 is examined for a panel of thirteen Asian economies using two environmental proxies—their ecological footprint and CO_(2)emissions.The non-parametric Driscoll-Kraay standard error method and the Dumitrescu-Hurlin panel causality test are applied to the data.Our findings show that hydro energy production and technological innovation have a significant negative impact on the environment,thus promoting environmental sustainability.Economic complexity significantly lowers environmental sustainability while the non-linear effect of economic complexity favors environmental sustainability;this confirms the existence of an economic-complexity-based inverted-U-shaped environmental Kuznets curve hypothesis.Moreover,urbanization and financial development significantly decrease environmental sustainability.The results of our study confirm the feedback causality between hydro energy production and carbon dioxide emissions.We recommend expansionary policies regarding hydro energy production that are beneficial for substituting fossil fuel energy.This paves a path towards environmental sustainability in this era of global boiling.展开更多
Indonesia’s vast maritime territory offers a unique opportunity for harnessing the potential Energy of seawater currents.This study explores the effectiveness of a combined Savonius and propeller-type turbine system....Indonesia’s vast maritime territory offers a unique opportunity for harnessing the potential Energy of seawater currents.This study explores the effectiveness of a combined Savonius and propeller-type turbine system.The Savonius turbine,known for its efficiency in capturing ocean currents due to its large sweep area,is combined with a propeller-type turbine to enhance rotational speed and power generation.A novel approach is employed to induce turbulence and optimize energy extraction,first channeling water through the propeller turbine and then into the Savonius turbine.A comprehensive investigation is conducted through simulations and experimental tests within a controlled tunnel environment.The study explores the performance of two-bladed and three-bladed Propeller-Savonius configurations at varying inlet water velocities(0.1,0.3,0.6 and 1.0 m/s).The simulation incorporates a turbulence model with 5%intensity and a hydraulic diameter of 0.216 m.Results indicate that the proposed configuration achieves a maximum power output of 2.0293 W with an impressive efficiency of 63.339%in simulation.Concurrently,experimental testing yields a peak efficiency of 61.335%and turbine power of 0.3951 W.The findings demonstrate the feasibility of the combined turbine system and highlight the importance of turbulence in optimizing energy extraction from seawater currents.This research contributes valuable insights into the design and performance of hybrid turbines for harnessing oceanic Energy,emphasizing the potential for sustainable power generation in maritime regions.The methodology and results presented herein offer a foundation for further exploration and refinement of seawater current energy conversion technologies.展开更多
This article offers a demonstration of a novel technology that uses hydro and solar power combined with battery storage to generate electricity for deployment off coastal regions.Called the coastal power plant(CPP),su...This article offers a demonstration of a novel technology that uses hydro and solar power combined with battery storage to generate electricity for deployment off coastal regions.Called the coastal power plant(CPP),such an installation has a multistorey water reservoir that draws in seawater that is then pumped up in vertical stages by geyser pumps into an overhead tank,from which it is released into a hydropower plant to generate electricity.The ocean surface is utilized to install a floating solar plant for photovoltaic energy generation.The intermittent renewable source is combined with a battery energy storage system to meet peak demands.Offshore oil industry technologies are utilized in fabricating the structures on shore and towing them to the site.The potential and cost effectiveness of a 201-MW CPP are also analyzed.Results demonstrate the effectiveness of the new design in terms of investment and operation/maintenance costs.These compare favorably with other renewable energy technologies.展开更多
Isolated energy systems in archipelagos are characterized for having a great dependence on fossil sources due to isolation and territorial fragmentation.The island of La Palma is situated on the northwest of the Canar...Isolated energy systems in archipelagos are characterized for having a great dependence on fossil sources due to isolation and territorial fragmentation.The island of La Palma is situated on the northwest of the Canary Islands,and its electric system is very small.Sustainability policies planned by local authorities are aimed to increase the share of renewable energies and the reduction of fossil energies.However,intermittence and the concentration of unmanageable renewable energies in few locations may hinder the operation of the system.In order to solve these problems,energy storage plays an essential role.The aim of this paper is to analyse the effects of the introduction of two possible alternatives as a way of energy storage:pumped hydro storage and electric vehicles.For this,we use a simulation model adapted to the features of La Palma,considering different scenarios.Results show that,in the most favourable scenario,the installation of an additional 25 MW from renewables(more than double the current power),supported by 20 MW of pumped hydro storage and a fleet of 3361 electric vehicles,would allow the current share of renewables to increase from11%(in 2015)to 49%.Furthermore,this would mean a 26%reduction in CO2 emissions,10%in costs of generated k Wh and 19%in energy dependence.展开更多
基金supported by the National Key Technology R&D Program of China(Grant No.2007BAA05B07)the National Natural Science Foundation of China(Grant No.51006026)the Fundamental Research Funds for the Central Universities(Grant No.HIT.NSRIF.2012.072)
文摘The understanding of hydraulic behavior in the hydro turbine requires the detailed study of fluid flow in the turbine. Previous methods of analyzing the numerical simulation results on the fluid machinery are short of intuitiveness on energy dissipation.In this paper, the energy dissipation was analyzed based on the entropy production theory. 3-D steady flow simulations and entropy production calculations of the reduced hydro turbine were carried out. The results indicated that the entropy production theory was suitable for evaluating the performance of the hydro turbine. The energy dissipation in the guide vanes area weighted nearly 25% of the whole flow passage, and mainly happened at the head and tail areas of the vanes. However, more than half the energy dissipation occurred in the runner, mostly at the leading edge of runner blade and the trailing edge of run-ner blade. Meanwhile, close to 20% of the energy dissipation occurred in the elbow. And it can be concluded that the method of entropy production analysis has the advantages of determining the quantity of energy dissipation and where the dissipation happens.
文摘The low electricity supply rate is a major cause of underdevelopment in Cameroon. To address this issue, Cameroon outlined a strategy in 2003 aiming for a production capacity of 3000 MW by 2020. However, by 2020, production had only reached 1040 MW, leading Cameroon to devise a new national energy sector development strategy targeting 5000 MW by 2035. This paper provides an overview of the current state of energy production and projects future output by 2035. Scientific articles and investigative reports on energy production in Cameroon have enabled an assessment of the current electrical energy production. The 2035 production estimate is based on the Energy Sector Development Projects (PDSEN) report in Cameroon. The current production is estimated at around 1600 MW. Considering the ongoing construction of power plants, future projects, and financing delays, achieving the 5000 MW goal by 2035 appears challenging. Nonetheless, diversifying energy production sources could bring Cameroon closer to this target.
文摘Hydrothermal carbonization(HTC)of biomass is a promising method to produce carbonaceous materials.The work presented in this article addresses the application of hydrothermal carbonization(HTC)to produce a solid fuel named HTC-Biochar,whose characteristics are comparable to lignite coal.Biogas sludge(SD),maize silage(MS),and barley silage(BS)as a substrates were hydrothermally carbonized in a 1.5 L batch reactor at 200C for 6 h.The effect of mixing ratios of different substrates on HTC was investigated.Chemical compositions and combustion characteristics of hydro-chars obtained from mono-and co-carbonization were evaluated.Result showed that HTC increased carbon contents and higher heating values(HHV)by 1.4–14.4%and 13–36%,respectively.The evolution of the H/C and O/C atomic ratios indicated that dehydration and decarboxylation occurred during hydrothermal carbonization for all samples.Furthermore,a significant synergistic enhancement was observed for HHV and carbon content.A mixing ratio of 1:1 for BS and SD showed the best performance for co-HTC.In summary,hydrothermal co-carbonization is a promising strategy to tailor high-performance hydro-char for energy applications.
文摘Recently,renewable energy resources and their impacts have sparked a heated debate to resolve the Australian energy crisis.There are many projects launched throughout the country to improve network security and reliability.This paper aims to review the current status of different renewable energy resources along with their impacts on society and the environment.Besides,it provides for the first time the statistics of the documents published in the field of renewable energy in Australia.The statistics include information such as the rate of papers published,possible journals for finding relative paper,types of documents published,top authors,and the most prevalent keywords in the field of renewable energy in Australia.It will focus on solar,wind,biomass,geothermal and hydropower technologies and will investigate the social and environmental impacts of these technologies.
文摘A just and sustainable future requires green renewable power. Net-zero by 2050 is the international goal to limit global warming to 1.5 degrees Celsius and sustain the biosphere. Green renewable energy, including wind, solar, biomass and small hydro is abundant in Canada, with potential to satisfy demand with 100% green renewables. This paper compares the renewable power landscape across Canada’s provinces considering four factors—electricity energy mix, renewable energy targets (RETs), renewable energy standard offer programs (RESOPs), feed-in tariff (FITs) or community FITs (comFITs). The provinces with green renewable energy sources typically have enabling policies of RESOP, RETs and FITS, as Prince Edward Island, Nova Scotia, Ontario and New Brunswick do. In contrast, provinces with abundant oil and gas or large-scale hydro are without pro-renewable energy policies, nor community power options, excepting green renewables in Indigenous communities due to federal funding programs. Community green renewable power projects, such as the “Indigenous off-diesel initiative”, are creating jobs, community revenue and energy sovereignty, towards just and inclusive energy in off-grid Indigenous communities. To reduce climate change, fast-tracking net-zero electricity by 2035 is recommended with the prioritization of community renewable energy by RESOPs, FITs and comFITs. For the transportation and other sectors, banning of all fossil fuels before 2040 is needed. Finally, a long-term plan to reduce the negative impacts of hydroelectricity water fluctuation is needed, considering decommissioning some dams.
文摘Mathematically simulated energy transfers from the energy source to the chassis through hydro transmissions and hydro differential. The developed unified mathematical model of a dynamic system allows, at the design stage, of many branched drive mechanisms, including transmission hydraulic and hydraulic differential actuators, to explore dynamic processes and select rational parameters.
文摘In order to cut greenhouse-gas emissions and increase energy security,the European Commission stimulates the deployment of intermittent renewable energy sources(IRES) towards 2050.In an electricity system with high shares of IRES implemented in the network,energy balancing like storage is needed to secure grid stability and smooth demand satisfaction.Pumped hydro storage(PHS) is at this moment the best option for large scale storage.Switzerland has strong ambitions to further develop their PHS sector and become the battery of Europe.In this research,the potential of the Swiss PSH plants is explored,whilst taking inflow into the upper reservoirs of the PHS plants into consideration.To simulate electricity imbalance,Germany is used as a case study.Germany already has a high penetration of IRES and has plans to increase installed IRES capacity.By using an energy planning model(Power Plan),three future scenarios of the German electricity system were designed,each with a different set of IRES installed(solar,mixed and wind).Results show that the Swiss battery ambition offers most benefits to a wind-oriented scenario,reducing both shortages as well as surpluses.Water inflow in Swiss PHS-reservoirs is of minor importance when looking at security of supply,although it was shown that the solarscenario profits more from inflow in terms of system stability.However,a potential conflict was observed in the solar-scenario between the need for electricity storage and the storage of natural inflow,resulting in more surpluses in the system when inflow was taken into account.
基金Researchers Supporting Project number(RSP2024R87),King Saud University,Riyadh,Saudi Arabia.
文摘The impact of hydro energy production,economic complexity,urbanization,technological innovation and financial development on environmental sustainability between 1995 and 2017 is examined for a panel of thirteen Asian economies using two environmental proxies—their ecological footprint and CO_(2)emissions.The non-parametric Driscoll-Kraay standard error method and the Dumitrescu-Hurlin panel causality test are applied to the data.Our findings show that hydro energy production and technological innovation have a significant negative impact on the environment,thus promoting environmental sustainability.Economic complexity significantly lowers environmental sustainability while the non-linear effect of economic complexity favors environmental sustainability;this confirms the existence of an economic-complexity-based inverted-U-shaped environmental Kuznets curve hypothesis.Moreover,urbanization and financial development significantly decrease environmental sustainability.The results of our study confirm the feedback causality between hydro energy production and carbon dioxide emissions.We recommend expansionary policies regarding hydro energy production that are beneficial for substituting fossil fuel energy.This paves a path towards environmental sustainability in this era of global boiling.
基金The research institute of Politeknik Negeri Bandung supported this research.
文摘Indonesia’s vast maritime territory offers a unique opportunity for harnessing the potential Energy of seawater currents.This study explores the effectiveness of a combined Savonius and propeller-type turbine system.The Savonius turbine,known for its efficiency in capturing ocean currents due to its large sweep area,is combined with a propeller-type turbine to enhance rotational speed and power generation.A novel approach is employed to induce turbulence and optimize energy extraction,first channeling water through the propeller turbine and then into the Savonius turbine.A comprehensive investigation is conducted through simulations and experimental tests within a controlled tunnel environment.The study explores the performance of two-bladed and three-bladed Propeller-Savonius configurations at varying inlet water velocities(0.1,0.3,0.6 and 1.0 m/s).The simulation incorporates a turbulence model with 5%intensity and a hydraulic diameter of 0.216 m.Results indicate that the proposed configuration achieves a maximum power output of 2.0293 W with an impressive efficiency of 63.339%in simulation.Concurrently,experimental testing yields a peak efficiency of 61.335%and turbine power of 0.3951 W.The findings demonstrate the feasibility of the combined turbine system and highlight the importance of turbulence in optimizing energy extraction from seawater currents.This research contributes valuable insights into the design and performance of hybrid turbines for harnessing oceanic Energy,emphasizing the potential for sustainable power generation in maritime regions.The methodology and results presented herein offer a foundation for further exploration and refinement of seawater current energy conversion technologies.
文摘This article offers a demonstration of a novel technology that uses hydro and solar power combined with battery storage to generate electricity for deployment off coastal regions.Called the coastal power plant(CPP),such an installation has a multistorey water reservoir that draws in seawater that is then pumped up in vertical stages by geyser pumps into an overhead tank,from which it is released into a hydropower plant to generate electricity.The ocean surface is utilized to install a floating solar plant for photovoltaic energy generation.The intermittent renewable source is combined with a battery energy storage system to meet peak demands.Offshore oil industry technologies are utilized in fabricating the structures on shore and towing them to the site.The potential and cost effectiveness of a 201-MW CPP are also analyzed.Results demonstrate the effectiveness of the new design in terms of investment and operation/maintenance costs.These compare favorably with other renewable energy technologies.
基金the Chaire Armand Peugeot for its financial and logistic support to conduct this researchthe financial support of the Ministerio de Economíay Competitividad of Spain through Project ECO2013-48884-C3-3-Pthe University of La Laguna for its financial support through its young research support program
文摘Isolated energy systems in archipelagos are characterized for having a great dependence on fossil sources due to isolation and territorial fragmentation.The island of La Palma is situated on the northwest of the Canary Islands,and its electric system is very small.Sustainability policies planned by local authorities are aimed to increase the share of renewable energies and the reduction of fossil energies.However,intermittence and the concentration of unmanageable renewable energies in few locations may hinder the operation of the system.In order to solve these problems,energy storage plays an essential role.The aim of this paper is to analyse the effects of the introduction of two possible alternatives as a way of energy storage:pumped hydro storage and electric vehicles.For this,we use a simulation model adapted to the features of La Palma,considering different scenarios.Results show that,in the most favourable scenario,the installation of an additional 25 MW from renewables(more than double the current power),supported by 20 MW of pumped hydro storage and a fleet of 3361 electric vehicles,would allow the current share of renewables to increase from11%(in 2015)to 49%.Furthermore,this would mean a 26%reduction in CO2 emissions,10%in costs of generated k Wh and 19%in energy dependence.
