The present study is a contribution to the study of hybrid electric power conversion systems in rural areas.The approach adopted uses a methodology for analyzing the complementarity that exists between the two renewab...The present study is a contribution to the study of hybrid electric power conversion systems in rural areas.The approach adopted uses a methodology for analyzing the complementarity that exists between the two renewable energy potentials(solar and hydraulic)based on their daily,monthly and annual variations.The different analytical formulas for sizing a PV(photovoltaic)field and a small hydroelectric power station are recalled in this work.The HOMER software served as a tool for optimal sizing and simulation of the system.This work focuses on the analysis of the behavior and control of the performances of a hybrid system made up of two renewable energy sources,hydroelectricity/PV with a storage system and a converter.The main results obtained relate to:monitoring of the variation in temperature variation,solar irradiation of the site,as well as the flow of the watercourse.The profile of the village’s annual charges is known.The annual production of electrical energy is 527.936 kWh/year.The hydroelectric plant will provide 155.316 kWh/year,or 29%,and for the PV field(372.620 kWh/year),or 71%.The monthly energy average is 43.995 kWh/month.The average daily consumption is 731 kWh/d with a maximum power of 163 kW.The completion of this project makes it possible to cover all electrical loads in the Tamagaly district,with an annual energy production of 206.783 kWh.This would make it possible to locally limit greenhouse gas emissions in the area.展开更多
The energy transition,validated by 194 countries at the end of CoP21 in Paris,requires new development design methods.This requirement,for the sub-Saharan African countries(SAC),could be an opportunity to finance thei...The energy transition,validated by 194 countries at the end of CoP21 in Paris,requires new development design methods.This requirement,for the sub-Saharan African countries(SAC),could be an opportunity to finance their development.Following the mixed results of the Clean Development Mechanism(CDM),partly due to its rather restrictive selection criterion,the desire to implement carbon asset transfer mechanisms is proposed by many countries including Cameroon.However,the success of such a mechanism would be guaranteed by encouraging policies to regulate emissions.It is in this perspective that our work falls.It aims at proposing a regulation approach for major projects.We have dwelt on hydroelectric projects.To do this,we ordered considering their quantitative feature,113 projects or visions proposed by 37 countries.Subsequently,a classification of projects according to compartments and trends was made.We finally pointed out 6 visions,including the mitigation in production,mitigation in distribution or service,adaptation in production,mitigation in transport,adaptation in distribution or service,and the adaptation in transport.The regulation methodology proposed for mitigation projects in the hydroelectric sector on a variable threshold hypothesis has led us to three trends in regulation.展开更多
The lack of synergy between infrastructure financing mechanisms and mechanisms for combating climate change does not favor the definition of sustainable infrastructure in Cameroon. The definition of a sustainable infr...The lack of synergy between infrastructure financing mechanisms and mechanisms for combating climate change does not favor the definition of sustainable infrastructure in Cameroon. The definition of a sustainable infrastructure could meet the requirements of these mechanisms, thanks to the control of Greenhouse Gas (GHG) emissions during its installation, in relation to a predefined value. However, the promotion of efforts to reduce emissions from new infrastructures is not subject to a local market. This situation is a limit in the implementation of the policies defined in the Nationally Determined Contribution (NDC). This article proposes a framework for promoting reduction efforts for a national carbon market, in favor of hydroelectric infrastructures. Thanks to the Life Cycle Assessment (LCA) environmental assessment tool, we are going to determine the carbon quota for a specific power. The study carried out on the hydroelectric power station of Mekin (HydroMekin) leads us to a reduction effort of 68.2% compared to the threshold defined at 14.057 gCO<sub>2eq</sub>/kWh<sub>e</sub>. The framework, developed, contributes to defining the environmental parameters in the decarbonation strategy during the implementation of new hydroelectric infrastructures and the market carbon design elements special to the construction phase of these infrastructures.展开更多
Problems due to underground cavities at the level of soft and polymorphic sandstones, collapses and infiltration of acid waters through the fracture networks have been observed around the Kakobola hydroelectric develo...Problems due to underground cavities at the level of soft and polymorphic sandstones, collapses and infiltration of acid waters through the fracture networks have been observed around the Kakobola hydroelectric development, constituting potential risks for the stability of the dam. The objective of this article aims to highlight the major cause that can explain the generating processes of these cavities. Indeed, to do this, the exploration of the subsoil was made possible thanks to the eleven (11) boreholes drilled on the site, the determination of cavities by the method of colored tracers and the petrographic characterization using a microscope. The latter, by means of thin sections, reveals the presence of quartz arenites. The mineralogical characterization of rock materials was carried out using X-ray fluorescence and X-ray diffraction methods. X-ray fluorescence revealed the presence of nickel, zinc and iron. Diffraction shows us an abundance of silica, mainly quartz and its metastable phases, in particular tridymite and cristobalite. It also made it possible to question the presence of carbonated minerals. The drillings enabled us to elaborate the logs and to bring out a geological model of the sector of study. These models were produced on the basis of drilling and observations on excavation. These data also reveal the presence of underground cavities which were also confirmed by the colored tracer method. These cavities would be of natural origin due to the presence of carbonate minerals observed in the rocks and which are attacked by acidic waters attested by the pH 5 measurements of the waters of the Lufuku River. The infiltration of water in rocky materials of low density and through the various networks of fractures and cavities leads to instability of the rock and could damage the hydroelectric development.展开更多
The analysis of the risk of flooding upstream from the Imboulou hydroelectric dam on the Léfini River in the Republic of Congo-Brazzaville, focused on the evolution of annual rainfall and flow in the study area d...The analysis of the risk of flooding upstream from the Imboulou hydroelectric dam on the Léfini River in the Republic of Congo-Brazzaville, focused on the evolution of annual rainfall and flow in the study area during the period from 1970 to 2020 before and after the building of the dam in 2005, by applying statistical methods. These methods were used to analyse the spatial and temporal evolution of rainfall and flow at the unique hydrometric station located at the RN2 (National Road N°2) bridge in the village of Mbouambé in the Pool region. This work has shown that rainfall is not the cause of flooding in the Léfini catchment area. The monthly flow coefficient (MFC) showed exceptional flooding from November and December onwards after the dam was built, resulting in a variability of flows, with periods of high and low water. In addition, the annual average flow (AAF) and the maximum average flow (MAF) increased after the dam was built. Maximum average flows (MAF) were higher than annual average flows (AAF) throughout the period of study (1970-2020). The annual and monthly rainfall-runoff relationship showed changes after the dam was built, particularly from 2009 and during the months of November and December. .展开更多
The Yangtze River has been subject to heavy flooding throughout history, and in recent times severe floods such as those in 1998 have resulted in heavy loss of life and livelihoods. Dams along the river help to manage...The Yangtze River has been subject to heavy flooding throughout history, and in recent times severe floods such as those in 1998 have resulted in heavy loss of life and livelihoods. Dams along the river help to manage flood waters, and are important sources of electricity for the region. Being able to forecast high-impact events at long lead times therefore has enormous potential benefit. Recent improvements in seasonal forecasting mean that dynamical climate models can start to be used directly for operational services. The teleconnection from E1 Nifio to Yangtze River basin rainfall meant that the strong E1 Nifio in winter 2015/16 provided a valuable opportunity to test the application of a dynamical forecast system. This paper therefore presents a case study of a real-time seasonal forecast for the Yangtze River basin, building on previous work demonstrating the retrospective skill of such a forecast. A simple forecasting methodology is presented, in which the forecast probabilities are derived from the historical relationship between hindcast and observations. Its performance for 2016 is discussed. The heavy rainfall in the May-June-July period was correctly forecast well in advance. August saw anomalously low rainfall, and the forecasts for the June-July-August period correctly showed closer to average levels. The forecasts contributed to the confidence of decision-makers across the Yangtze River basin. Trials of climate services such as this help to promote appropriate use of seasonal forecasts, and highlight areas for future improvements.展开更多
Background: Ecosystem representation is one key component in assessing the biodiversity impacts of land-use changes that will irrevocably alter natural ecosystems. We show how detailed vegetation plot data can be use...Background: Ecosystem representation is one key component in assessing the biodiversity impacts of land-use changes that will irrevocably alter natural ecosystems. We show how detailed vegetation plot data can be used to assess the potential impact of inundation by a proposed hydroelectricity dam in the Mokihinui gorge, New Zealand, on representation of natural forests. Specifically we ask: 1) How well are the types of forest represented Locally, regionally, and nationally; and 2) How does the number of distinct communities (i.e. beta diversity) in the target catchment compare with other catchments nationally? Methods: For local and regional comparisons plant species composition was recorded on 45 objectively located 400 m2 vegetation plots established in each of three gorges, with one being the proposed inundation area of the Mokihinui lower gorge. The fuzzy classification framework of noise clustering was used to assign these plots to a specific alliance and association of a pre-existing national-scale classification. NationaLly, we examined the relationship between the number of alliances and associations in a catchment and either catchment size or the number of plots per catchment by fitting Generalised Additive Models. Results: The four alliances and five associations that were observed in the Mokihinui lower gorge arepresent in the region but limited locally. One association was narrowly distributed nationally, but is the mostfrequent association in the Mokihinui lower gorge; inundation may have consequences of national importance to its long-term persistence. That the Mokihinui lower gorge area had nearly twice as many plots that could not be assigned to pre- existing alliances and associations than either the Mokihinui upper or the Karamea lower gorges and proportionally more than the national dataset emphasises the compositional distinctiveness of this gorge. These outlier plots in the Mokihinui lower gorge may be unsorted assemblages of species or reflect sampling bias or that native- dominated woody riparian vegetation is rare on the landscape. At a national scale, the Mokihinui catchment has a higher diversity of forest alliances and associations (i.e. beta-diversity) than predicted based on catchment size and sampling intensity. Conclusions: Our analytical approach demonstrates one transparent solution to a common conservation planning problem: assessing how well ecosystems that will be destroyed by a proposed land-use change are represented using a multi-scale spatial and compositional framework. We provide a useful tool for assessing potential consequences of land-use change that can help guide decision making.展开更多
This paper presents a computational method to model and evaluate if Pumped Storage Plants (PSP) have the potential to reduce the intermittency of wind generation from different sites in Brazil and to improve the opera...This paper presents a computational method to model and evaluate if Pumped Storage Plants (PSP) have the potential to reduce the intermittency of wind generation from different sites in Brazil and to improve the operation efficiency of hydroelectric plants when operating in cascade. Since the problem to be solved does not have a defined analytic solution, a Stochastic Optimization Algorithm was implemented to reach an optimal solution to the set of equations, inputs and proposed scenarios. A case study was developed based on the Paraná River Basin and the results shows that the model can operate in a variety of different operational patterns, making feasible the evaluation of different hydrological and wind scenarios. Given the Model support, it is easy to assume different PSP storage and generation capacities, allowing the comparison between the efficiency improvement of a conventional Pumped-Storage and a Season-al-Pumped-Storage in the same scenario. The study concludes that a PSP can effectively reduce the intermittency of wind and solar sources and contribute to the optimization of the Brazilian electricity sector.展开更多
This research is based on the detailed design and study of a plant power generation system for green building roofs based on the combination of bionics and design science.The selection of power generation plants is ca...This research is based on the detailed design and study of a plant power generation system for green building roofs based on the combination of bionics and design science.The selection of power generation plants is carried out through experiments and research,and based on which the connection between the plant power generation unit and the internal circuit of the building is studied to generate a complete building roof plant power generation system.展开更多
In this paper, a hybrid improved particle swarm optimization (IPSO) algorithm is proposed for the optimization of hydroelectric power scheduling in multi-reservoir systems. The conventional particle swarm optimizati...In this paper, a hybrid improved particle swarm optimization (IPSO) algorithm is proposed for the optimization of hydroelectric power scheduling in multi-reservoir systems. The conventional particle swarm optimization (PSO) algorithm is improved in two ways: (1) The linearly decreasing inertia weight coefficient (LDIWC) is replaced by a self-adaptive exponential inertia weight coefficient (SEIWC), which could make the PSO algorithm more balanceable and more effective in both global and local searches. (2) The crossover and mutation idea inspired by the genetic algorithm (GA) is imported into the particle updating method to enhance the diversity of populations. The potential ability of IPSO in nonlinear numerical function optimization was first tested with three classical benchmark functions. Then, a long-term multi-reservoir system operation model based on IPSO was designed and a case study was carried out in the Minjiang Basin in China, where there is a power system consisting of 26 hydroelectric power plants. The scheduling results of the IPSO algorithm were found to outperform PSO and to be comparable with the results of the dynamic programming successive approximation (DPSA) algorithm.展开更多
Objective:To compare perceived ill-health and health seeking behavior between two communities affected by the large Nam Theun 2 hydroelectric project in central Lao People’s Democratic Republic(PDR).Methods: Two diff...Objective:To compare perceived ill-health and health seeking behavior between two communities affected by the large Nam Theun 2 hydroelectric project in central Lao People’s Democratic Republic(PDR).Methods: Two different affected areas;Nakai plateaubeing remote,sparcely populated and mountainous,and Xe Bang Fai lowland plains,more densely populated and comparatively affluent were included.Data were obtained from two cross-sectional household-based health and socio-economic surveys.Results:We found pronounced differences in the frequency of self-reported fever,cough,headache and myalgia according to location.On the Nakai plateau,45.1%of the individuals with ill-health report(recall period;2 weeks) went to a local health volunteer compared to only 7.2%in the Xe Bang Fai area(P 【 0.001 ).In Nakai,there were disproportionately more illiterates seeking help from local health volunteers when compared to those who attended at least primary schooling(49.2%versus 17.5%,P 【0.01 ).Self-medication with antimalarials was more common in Xe Bang Fai than on Nakai(32.3%versus 7.0%,P 【 0.001).The mean amount of money spent per health consultation was US $ 1.7 in Nakai and US $ 7.2 in Xe Bang Fai.Conclusion:The observed differences in self-reported ill-health and health seeking behavior among these two Lao communities need to be considered when implementing setting-specific mitigation measures as part of the public health action plan of the Nam Theun 2 hydroelectric project.展开更多
Hydropower if scientifically developed is considered to be one of the clean and non-polluted renewable energy sources.But its impacts always exist on physical and social environment of the area.The present study was c...Hydropower if scientifically developed is considered to be one of the clean and non-polluted renewable energy sources.But its impacts always exist on physical and social environment of the area.The present study was conducted in the River Satluj basin which is well known for its hydropower potential.The main objective of the study was to understand the vulnerability of the Satluj basin and to develop a strategy for the development of hydropower projects.This basin has been facing many problems relating to construction of haphazard development of hydropower projects.This has led multi-hazards like landslides,floods,earthquakes,etc.Here,vulnerability assessment index was assessed quantitatively and qualitatively.Geographical Information System and people’s perception were used to study these aspects in the basin.The parameters considered for vulnerability assessment were slope,slope profile,relative relief,curvature,slope aspect,soil texture,lithology,river morphometry,precipitation,hydroelectric projects,land use and land cover,mass-movement,flood,geological elements and earthquake occurrences.The highest vulnerability was found in the middle zone,and finally on the basis of parameters analyzed;the hydropower’s development strategy was developed.展开更多
This paper, the first in a series provides the background of the project, reports on the early phases of construction with the descriptions of the pre and post flooded conditions related to vegetation and land cover t...This paper, the first in a series provides the background of the project, reports on the early phases of construction with the descriptions of the pre and post flooded conditions related to vegetation and land cover types surrounding the reservoir. Currently there are plans to develop the so called “Lower Churchill Area” by establishing new power plants at Gull Island and at Muskrat Falls with associated reservoirs. These new plants would use the discharged water of the plant from Churchill Falls and the additional water collected from some of the Churchill River Basin. The information provided by these papers could have relevance to the environmental evaluation of these new developments. The Churchill Falls Hydro Project (called the “Upper Churchill Development”) in Labrador, Canada, was initiated in the late 1960s and the 5428-MW hydro generating plant constructed was then among the largest in the world. At that time, in general, not much attention was paid to the impact of such development on the flooding of vegetation especially forest stands. Both forested and un-forested terrestrial vegetation types were flooded (244 915 ha). Some islands were created and in addition portions of existing areas were flooded to form islands (74 075 ha) in the Main (Smallwood) Reservoir area. The flooded area of forest and un-forested land in the reservoir is 77% while the islands is 23 percent. The percentages of forested and un-forested areas lost to flooding are 64% and 36% respectively. The percent of commercial forests lost to flooding is approximately 1% and the non-commerci- al forests is 99% (with a total volume of approximately 10 million cubic meters of wood).展开更多
The paper discusses harvesting the Congo River for bulk hydroelectric generation based on run of river, low head generation technology, as employed at the existing Inga 2 power station in the Democratic Republic of Co...The paper discusses harvesting the Congo River for bulk hydroelectric generation based on run of river, low head generation technology, as employed at the existing Inga 2 power station in the Democratic Republic of Congo. The evolutionary approach builds on existing infrastructure.The results show that the footprint is much smaller than that which employs a conventional dam. The environmental impact is minimized. These collectively will contribute to lower capital costs. In summary, 10,000 cm3/sec of constant river flow will produce 5,000 MW of base power. On average, the constant recorded flow of the river is 30,000 cm3/sec and a total of 15,000 MW of base power generation is possible.展开更多
In this article, the primal-dual interior-point methods are used to minimize costs and losses in a predispatch model for the generation and transmission of direct current (DC) power flow in a hydroelectric system with...In this article, the primal-dual interior-point methods are used to minimize costs and losses in a predispatch model for the generation and transmission of direct current (DC) power flow in a hydroelectric system with pre-programmed manipulations;i.e., in cases of preventive maintenance, within a period of twenty-four hours. From the computational standpoint, the effort required to solve a problem with and without manipulations is similar, and the reasons why will be also discussed in this study. Computational results prove these findings.展开更多
The Danube River basin was home to some of the world’s earliest human cultures such as the Danubian Neolithic cultures including the Linear Pottery culture. The Vucedol culture was famous for ceramics during the thir...The Danube River basin was home to some of the world’s earliest human cultures such as the Danubian Neolithic cultures including the Linear Pottery culture. The Vucedol culture was famous for ceramics during the third millennium BC. Early settlement required fortresses and castles to be built on the Danube River to defend the settlements from invading forces. These included the Persia, Roman and Ottoman empires. Cities included Vienna, Budapest, Belgrade and Ruse. The risks include stream capture, settlement, invasions, navigation, trade, pollution, industrial and urban wastewater, over fishing, food insecurity, locks and dams, shoreline erosion and flooding. The primary objective was to document the settlement history on the Danube River which became Eastern Europe’s pathway for settlement, invasions, navigation and trade in the Danube basin has put the river at risk for more than 2500 years. River capturing of the Danube by the Rhine River has reduced the length and flow of the Danube. The Danube River has had a huge economic, social and environmental impact on 10 European countries. However, with 10 countries sharing the river it has been difficult to manage and mitigate the risks and threats to the Danube River and its water quality.展开更多
The karst immersion and waterlogging is one of the typical and the m os t harmful natural disasters in southern karst areas of China. It is threat to th e local production and life for a long time. In recent years, du...The karst immersion and waterlogging is one of the typical and the m os t harmful natural disasters in southern karst areas of China. It is threat to th e local production and life for a long time. In recent years, due to the constru ction of more reservoirs, the disaster became serious. This article takes immers ion and waterlogging of Banwen's subterranean rivers in Yantan reservoir area as an example, researches the daily rainfall's reflection to the water level of re servoir depression, discusses characteristics of immersion and waterlogging of t he valley, analyzes the disaster index in detail, such as water level process, t he highest water level, sensitive rainfall, original waterlogged rainfall and de layed day numbers etc., and provides the reference as a basis to the disaster an alysis.展开更多
文摘The present study is a contribution to the study of hybrid electric power conversion systems in rural areas.The approach adopted uses a methodology for analyzing the complementarity that exists between the two renewable energy potentials(solar and hydraulic)based on their daily,monthly and annual variations.The different analytical formulas for sizing a PV(photovoltaic)field and a small hydroelectric power station are recalled in this work.The HOMER software served as a tool for optimal sizing and simulation of the system.This work focuses on the analysis of the behavior and control of the performances of a hybrid system made up of two renewable energy sources,hydroelectricity/PV with a storage system and a converter.The main results obtained relate to:monitoring of the variation in temperature variation,solar irradiation of the site,as well as the flow of the watercourse.The profile of the village’s annual charges is known.The annual production of electrical energy is 527.936 kWh/year.The hydroelectric plant will provide 155.316 kWh/year,or 29%,and for the PV field(372.620 kWh/year),or 71%.The monthly energy average is 43.995 kWh/month.The average daily consumption is 731 kWh/d with a maximum power of 163 kW.The completion of this project makes it possible to cover all electrical loads in the Tamagaly district,with an annual energy production of 206.783 kWh.This would make it possible to locally limit greenhouse gas emissions in the area.
文摘The energy transition,validated by 194 countries at the end of CoP21 in Paris,requires new development design methods.This requirement,for the sub-Saharan African countries(SAC),could be an opportunity to finance their development.Following the mixed results of the Clean Development Mechanism(CDM),partly due to its rather restrictive selection criterion,the desire to implement carbon asset transfer mechanisms is proposed by many countries including Cameroon.However,the success of such a mechanism would be guaranteed by encouraging policies to regulate emissions.It is in this perspective that our work falls.It aims at proposing a regulation approach for major projects.We have dwelt on hydroelectric projects.To do this,we ordered considering their quantitative feature,113 projects or visions proposed by 37 countries.Subsequently,a classification of projects according to compartments and trends was made.We finally pointed out 6 visions,including the mitigation in production,mitigation in distribution or service,adaptation in production,mitigation in transport,adaptation in distribution or service,and the adaptation in transport.The regulation methodology proposed for mitigation projects in the hydroelectric sector on a variable threshold hypothesis has led us to three trends in regulation.
文摘The lack of synergy between infrastructure financing mechanisms and mechanisms for combating climate change does not favor the definition of sustainable infrastructure in Cameroon. The definition of a sustainable infrastructure could meet the requirements of these mechanisms, thanks to the control of Greenhouse Gas (GHG) emissions during its installation, in relation to a predefined value. However, the promotion of efforts to reduce emissions from new infrastructures is not subject to a local market. This situation is a limit in the implementation of the policies defined in the Nationally Determined Contribution (NDC). This article proposes a framework for promoting reduction efforts for a national carbon market, in favor of hydroelectric infrastructures. Thanks to the Life Cycle Assessment (LCA) environmental assessment tool, we are going to determine the carbon quota for a specific power. The study carried out on the hydroelectric power station of Mekin (HydroMekin) leads us to a reduction effort of 68.2% compared to the threshold defined at 14.057 gCO<sub>2eq</sub>/kWh<sub>e</sub>. The framework, developed, contributes to defining the environmental parameters in the decarbonation strategy during the implementation of new hydroelectric infrastructures and the market carbon design elements special to the construction phase of these infrastructures.
文摘Problems due to underground cavities at the level of soft and polymorphic sandstones, collapses and infiltration of acid waters through the fracture networks have been observed around the Kakobola hydroelectric development, constituting potential risks for the stability of the dam. The objective of this article aims to highlight the major cause that can explain the generating processes of these cavities. Indeed, to do this, the exploration of the subsoil was made possible thanks to the eleven (11) boreholes drilled on the site, the determination of cavities by the method of colored tracers and the petrographic characterization using a microscope. The latter, by means of thin sections, reveals the presence of quartz arenites. The mineralogical characterization of rock materials was carried out using X-ray fluorescence and X-ray diffraction methods. X-ray fluorescence revealed the presence of nickel, zinc and iron. Diffraction shows us an abundance of silica, mainly quartz and its metastable phases, in particular tridymite and cristobalite. It also made it possible to question the presence of carbonated minerals. The drillings enabled us to elaborate the logs and to bring out a geological model of the sector of study. These models were produced on the basis of drilling and observations on excavation. These data also reveal the presence of underground cavities which were also confirmed by the colored tracer method. These cavities would be of natural origin due to the presence of carbonate minerals observed in the rocks and which are attacked by acidic waters attested by the pH 5 measurements of the waters of the Lufuku River. The infiltration of water in rocky materials of low density and through the various networks of fractures and cavities leads to instability of the rock and could damage the hydroelectric development.
文摘The analysis of the risk of flooding upstream from the Imboulou hydroelectric dam on the Léfini River in the Republic of Congo-Brazzaville, focused on the evolution of annual rainfall and flow in the study area during the period from 1970 to 2020 before and after the building of the dam in 2005, by applying statistical methods. These methods were used to analyse the spatial and temporal evolution of rainfall and flow at the unique hydrometric station located at the RN2 (National Road N°2) bridge in the village of Mbouambé in the Pool region. This work has shown that rainfall is not the cause of flooding in the Léfini catchment area. The monthly flow coefficient (MFC) showed exceptional flooding from November and December onwards after the dam was built, resulting in a variability of flows, with periods of high and low water. In addition, the annual average flow (AAF) and the maximum average flow (MAF) increased after the dam was built. Maximum average flows (MAF) were higher than annual average flows (AAF) throughout the period of study (1970-2020). The annual and monthly rainfall-runoff relationship showed changes after the dam was built, particularly from 2009 and during the months of November and December. .
基金supported by the UK-China Research & Innovation Partnership Fund through the Met Office Climate Science for Service Partnership China as part of the Newton Fundsupported by the National Natural Science Foundation of China(Grant No.41320104007)supported by the Project for Development of Key Techniques in Meteorological Operation Forecasting(Grant No.YBGJXM201705)
文摘The Yangtze River has been subject to heavy flooding throughout history, and in recent times severe floods such as those in 1998 have resulted in heavy loss of life and livelihoods. Dams along the river help to manage flood waters, and are important sources of electricity for the region. Being able to forecast high-impact events at long lead times therefore has enormous potential benefit. Recent improvements in seasonal forecasting mean that dynamical climate models can start to be used directly for operational services. The teleconnection from E1 Nifio to Yangtze River basin rainfall meant that the strong E1 Nifio in winter 2015/16 provided a valuable opportunity to test the application of a dynamical forecast system. This paper therefore presents a case study of a real-time seasonal forecast for the Yangtze River basin, building on previous work demonstrating the retrospective skill of such a forecast. A simple forecasting methodology is presented, in which the forecast probabilities are derived from the historical relationship between hindcast and observations. Its performance for 2016 is discussed. The heavy rainfall in the May-June-July period was correctly forecast well in advance. August saw anomalously low rainfall, and the forecasts for the June-July-August period correctly showed closer to average levels. The forecasts contributed to the confidence of decision-makers across the Yangtze River basin. Trials of climate services such as this help to promote appropriate use of seasonal forecasts, and highlight areas for future improvements.
基金funded by Meridian Energy Limited,New Zealandby Core funding for Crown Research Institutes from the New Zealand Ministry of Business,Innovation and Employment’s Science and Innovation Group
文摘Background: Ecosystem representation is one key component in assessing the biodiversity impacts of land-use changes that will irrevocably alter natural ecosystems. We show how detailed vegetation plot data can be used to assess the potential impact of inundation by a proposed hydroelectricity dam in the Mokihinui gorge, New Zealand, on representation of natural forests. Specifically we ask: 1) How well are the types of forest represented Locally, regionally, and nationally; and 2) How does the number of distinct communities (i.e. beta diversity) in the target catchment compare with other catchments nationally? Methods: For local and regional comparisons plant species composition was recorded on 45 objectively located 400 m2 vegetation plots established in each of three gorges, with one being the proposed inundation area of the Mokihinui lower gorge. The fuzzy classification framework of noise clustering was used to assign these plots to a specific alliance and association of a pre-existing national-scale classification. NationaLly, we examined the relationship between the number of alliances and associations in a catchment and either catchment size or the number of plots per catchment by fitting Generalised Additive Models. Results: The four alliances and five associations that were observed in the Mokihinui lower gorge arepresent in the region but limited locally. One association was narrowly distributed nationally, but is the mostfrequent association in the Mokihinui lower gorge; inundation may have consequences of national importance to its long-term persistence. That the Mokihinui lower gorge area had nearly twice as many plots that could not be assigned to pre- existing alliances and associations than either the Mokihinui upper or the Karamea lower gorges and proportionally more than the national dataset emphasises the compositional distinctiveness of this gorge. These outlier plots in the Mokihinui lower gorge may be unsorted assemblages of species or reflect sampling bias or that native- dominated woody riparian vegetation is rare on the landscape. At a national scale, the Mokihinui catchment has a higher diversity of forest alliances and associations (i.e. beta-diversity) than predicted based on catchment size and sampling intensity. Conclusions: Our analytical approach demonstrates one transparent solution to a common conservation planning problem: assessing how well ecosystems that will be destroyed by a proposed land-use change are represented using a multi-scale spatial and compositional framework. We provide a useful tool for assessing potential consequences of land-use change that can help guide decision making.
文摘This paper presents a computational method to model and evaluate if Pumped Storage Plants (PSP) have the potential to reduce the intermittency of wind generation from different sites in Brazil and to improve the operation efficiency of hydroelectric plants when operating in cascade. Since the problem to be solved does not have a defined analytic solution, a Stochastic Optimization Algorithm was implemented to reach an optimal solution to the set of equations, inputs and proposed scenarios. A case study was developed based on the Paraná River Basin and the results shows that the model can operate in a variety of different operational patterns, making feasible the evaluation of different hydrological and wind scenarios. Given the Model support, it is easy to assume different PSP storage and generation capacities, allowing the comparison between the efficiency improvement of a conventional Pumped-Storage and a Season-al-Pumped-Storage in the same scenario. The study concludes that a PSP can effectively reduce the intermittency of wind and solar sources and contribute to the optimization of the Brazilian electricity sector.
文摘This research is based on the detailed design and study of a plant power generation system for green building roofs based on the combination of bionics and design science.The selection of power generation plants is carried out through experiments and research,and based on which the connection between the plant power generation unit and the internal circuit of the building is studied to generate a complete building roof plant power generation system.
基金supported by the National Natural Science Foundation of China (Grant No. 50679011)
文摘In this paper, a hybrid improved particle swarm optimization (IPSO) algorithm is proposed for the optimization of hydroelectric power scheduling in multi-reservoir systems. The conventional particle swarm optimization (PSO) algorithm is improved in two ways: (1) The linearly decreasing inertia weight coefficient (LDIWC) is replaced by a self-adaptive exponential inertia weight coefficient (SEIWC), which could make the PSO algorithm more balanceable and more effective in both global and local searches. (2) The crossover and mutation idea inspired by the genetic algorithm (GA) is imported into the particle updating method to enhance the diversity of populations. The potential ability of IPSO in nonlinear numerical function optimization was first tested with three classical benchmark functions. Then, a long-term multi-reservoir system operation model based on IPSO was designed and a case study was carried out in the Minjiang Basin in China, where there is a power system consisting of 26 hydroelectric power plants. The scheduling results of the IPSO algorithm were found to outperform PSO and to be comparable with the results of the dynamic programming successive approximation (DPSA) algorithm.
基金financial support was granted by the Swiss National Science Foundationthe Swiss Agency for Development and Cooperation(projects no.3270B0 - 110020 to SS and PO and no.PPOOB - 102883 to TEE and JU)
文摘Objective:To compare perceived ill-health and health seeking behavior between two communities affected by the large Nam Theun 2 hydroelectric project in central Lao People’s Democratic Republic(PDR).Methods: Two different affected areas;Nakai plateaubeing remote,sparcely populated and mountainous,and Xe Bang Fai lowland plains,more densely populated and comparatively affluent were included.Data were obtained from two cross-sectional household-based health and socio-economic surveys.Results:We found pronounced differences in the frequency of self-reported fever,cough,headache and myalgia according to location.On the Nakai plateau,45.1%of the individuals with ill-health report(recall period;2 weeks) went to a local health volunteer compared to only 7.2%in the Xe Bang Fai area(P 【 0.001 ).In Nakai,there were disproportionately more illiterates seeking help from local health volunteers when compared to those who attended at least primary schooling(49.2%versus 17.5%,P 【0.01 ).Self-medication with antimalarials was more common in Xe Bang Fai than on Nakai(32.3%versus 7.0%,P 【 0.001).The mean amount of money spent per health consultation was US $ 1.7 in Nakai and US $ 7.2 in Xe Bang Fai.Conclusion:The observed differences in self-reported ill-health and health seeking behavior among these two Lao communities need to be considered when implementing setting-specific mitigation measures as part of the public health action plan of the Nam Theun 2 hydroelectric project.
基金the ‘Director, G.B. Pant National Institute of Himalayan Environment and Sustainable Development, Kosi-Katarmal, Almora, Uttarakhand- 263 647, India’ for providing fundthe Inhouse funded project by the Institute titled, ‘Strategic Environmental Assessment of Hydropower Projects in the Indian Himalayan region’
文摘Hydropower if scientifically developed is considered to be one of the clean and non-polluted renewable energy sources.But its impacts always exist on physical and social environment of the area.The present study was conducted in the River Satluj basin which is well known for its hydropower potential.The main objective of the study was to understand the vulnerability of the Satluj basin and to develop a strategy for the development of hydropower projects.This basin has been facing many problems relating to construction of haphazard development of hydropower projects.This has led multi-hazards like landslides,floods,earthquakes,etc.Here,vulnerability assessment index was assessed quantitatively and qualitatively.Geographical Information System and people’s perception were used to study these aspects in the basin.The parameters considered for vulnerability assessment were slope,slope profile,relative relief,curvature,slope aspect,soil texture,lithology,river morphometry,precipitation,hydroelectric projects,land use and land cover,mass-movement,flood,geological elements and earthquake occurrences.The highest vulnerability was found in the middle zone,and finally on the basis of parameters analyzed;the hydropower’s development strategy was developed.
文摘This paper, the first in a series provides the background of the project, reports on the early phases of construction with the descriptions of the pre and post flooded conditions related to vegetation and land cover types surrounding the reservoir. Currently there are plans to develop the so called “Lower Churchill Area” by establishing new power plants at Gull Island and at Muskrat Falls with associated reservoirs. These new plants would use the discharged water of the plant from Churchill Falls and the additional water collected from some of the Churchill River Basin. The information provided by these papers could have relevance to the environmental evaluation of these new developments. The Churchill Falls Hydro Project (called the “Upper Churchill Development”) in Labrador, Canada, was initiated in the late 1960s and the 5428-MW hydro generating plant constructed was then among the largest in the world. At that time, in general, not much attention was paid to the impact of such development on the flooding of vegetation especially forest stands. Both forested and un-forested terrestrial vegetation types were flooded (244 915 ha). Some islands were created and in addition portions of existing areas were flooded to form islands (74 075 ha) in the Main (Smallwood) Reservoir area. The flooded area of forest and un-forested land in the reservoir is 77% while the islands is 23 percent. The percentages of forested and un-forested areas lost to flooding are 64% and 36% respectively. The percent of commercial forests lost to flooding is approximately 1% and the non-commerci- al forests is 99% (with a total volume of approximately 10 million cubic meters of wood).
文摘The paper discusses harvesting the Congo River for bulk hydroelectric generation based on run of river, low head generation technology, as employed at the existing Inga 2 power station in the Democratic Republic of Congo. The evolutionary approach builds on existing infrastructure.The results show that the footprint is much smaller than that which employs a conventional dam. The environmental impact is minimized. These collectively will contribute to lower capital costs. In summary, 10,000 cm3/sec of constant river flow will produce 5,000 MW of base power. On average, the constant recorded flow of the river is 30,000 cm3/sec and a total of 15,000 MW of base power generation is possible.
文摘In this article, the primal-dual interior-point methods are used to minimize costs and losses in a predispatch model for the generation and transmission of direct current (DC) power flow in a hydroelectric system with pre-programmed manipulations;i.e., in cases of preventive maintenance, within a period of twenty-four hours. From the computational standpoint, the effort required to solve a problem with and without manipulations is similar, and the reasons why will be also discussed in this study. Computational results prove these findings.
文摘The Danube River basin was home to some of the world’s earliest human cultures such as the Danubian Neolithic cultures including the Linear Pottery culture. The Vucedol culture was famous for ceramics during the third millennium BC. Early settlement required fortresses and castles to be built on the Danube River to defend the settlements from invading forces. These included the Persia, Roman and Ottoman empires. Cities included Vienna, Budapest, Belgrade and Ruse. The risks include stream capture, settlement, invasions, navigation, trade, pollution, industrial and urban wastewater, over fishing, food insecurity, locks and dams, shoreline erosion and flooding. The primary objective was to document the settlement history on the Danube River which became Eastern Europe’s pathway for settlement, invasions, navigation and trade in the Danube basin has put the river at risk for more than 2500 years. River capturing of the Danube by the Rhine River has reduced the length and flow of the Danube. The Danube River has had a huge economic, social and environmental impact on 10 European countries. However, with 10 countries sharing the river it has been difficult to manage and mitigate the risks and threats to the Danube River and its water quality.
文摘The karst immersion and waterlogging is one of the typical and the m os t harmful natural disasters in southern karst areas of China. It is threat to th e local production and life for a long time. In recent years, due to the constru ction of more reservoirs, the disaster became serious. This article takes immers ion and waterlogging of Banwen's subterranean rivers in Yantan reservoir area as an example, researches the daily rainfall's reflection to the water level of re servoir depression, discusses characteristics of immersion and waterlogging of t he valley, analyzes the disaster index in detail, such as water level process, t he highest water level, sensitive rainfall, original waterlogged rainfall and de layed day numbers etc., and provides the reference as a basis to the disaster an alysis.