Hydropeaking,which refers to rising or falling discharges caused by the turning on or off of hydro-turbines to generate electricity,is a topic of growing interest due to its impact on fluvial ecosystems.To date,most h...Hydropeaking,which refers to rising or falling discharges caused by the turning on or off of hydro-turbines to generate electricity,is a topic of growing interest due to its impact on fluvial ecosystems.To date,most hydropeaking studies have focused on the impact of peak fluctuations on invertebrate and fish communities,but little attention has been paid to its impact on riverine plants and how functional traits may make them resistant to hydropeaking.We performed a review to assess how a set of 32 plant functional traits can be expressed in riverine plant species,and found evidence of how such expression affects their capacity to cope with common sources of hydropeaking disturbance(i.e.,inundation,fast water drawdown,and rapid water fluctuations linked to up-ramping and down-ramping hydropeaking operations).The information here presented can simplify the evaluation of impacts on riverine plant communities worldwide,as well as to detect suitable species to successfully restore rivers affected by hydropower production.展开更多
Many hydropower plants are operated as peak generators or frequency controllers, because they can change their output quickly to follow the fluctuating power demand. When meeting peak load requirements, a power statio...Many hydropower plants are operated as peak generators or frequency controllers, because they can change their output quickly to follow the fluctuating power demand. When meeting peak load requirements, a power station is turned on at a particular time during the day, generates power at a constant load for a certain number of hours, and is then turned off or set to a different load for another time period, resulting in a high variability inflow discharges. Where reservoir hydro schemes are operated primarily to provide peak load services, there are particular environmental risks that should be considered in any environmental impact assessment. At a minimum these should focus on water quality, fluvial geomorphology, riparian vegetation, macro-invertebrate and fish communities underpinned by a sound hydrological analysis. Frequent temperature changes may occur downstream of a peaking power station; increased seepage-induced erosion of riverbanks due to frequent water level drawdowns; and impacts to macro-invertebrate and fish communities due to rapid and frequent in channel habitat conditions. With a sound understanding of the potential environmental issues, there are strategies that can be employed at the siting and design stage to minimize or mitigate these risks, including but not limited to minimum environmental flows, ramping rules, utilization of a re-regulation storage and localized treatment works.展开更多
An effect of hydropower and hydropeaking regulation in rivers is stranding of fish. Those fishes that survive stranding may experience stranding as a stressful situation. In four experimental stranding experiments (ea...An effect of hydropower and hydropeaking regulation in rivers is stranding of fish. Those fishes that survive stranding may experience stranding as a stressful situation. In four experimental stranding experiments (each with 6 individuals in 10 control and 10 treatment replicates), the energetic consequences of two forms of stranding (i.e. trapping and beaching) of juvenile Atlantic salmon (Salmo salar) were investigated in summer and winter. Restricted food access in the experimental channels ensured that effects of hydropeaking could be revealed. Mean fish length ranged between 60 mm and 110 mm among experiments. Both during the winter and summer experiments fish did not grow in length, neither in the control nor in the treatment channels and fish lost body mass as well as body fat in all experiments (body fat in summer trapping experiment not determined). The four experiments revealed similar results: stranding did not affect growth or energy content. Despite the severity of the stranding and the resulting mortality, which was especially high during summer, no stranding related effects on fish performance could be detected.展开更多
To avoid negative consequences to freshwater biota from climate change,society must complete the transition from fossil to renewable electricity sources.However,temporal patterns in hydropower generation(and flow rele...To avoid negative consequences to freshwater biota from climate change,society must complete the transition from fossil to renewable electricity sources.However,temporal patterns in hydropower generation(and flow releases that affect aquatic biota)may change with increased wind and solar penetration.We used power cost modeling to characterize current and future within-day and seasonal patterns in hydropower generation across the Eastern Interconnection in a wet and a dry year.Compared to the baseline,future hydropower generation across the grid decreased during the day and increased before dawn and after dusk.At a project level,such a pattern would suggest‘double peaking’operation(up-and down-ramping before dawn and after dusk,with lower releases midday).Variation in generation was higher in wet years than dry years,foreshadowing possible flow constraints on hydropower flexibility.At the grid scale,projected ramping rates were higher in all seasons.A review of the ecological literature suggests that these changes would shift the timing of invertebrate drift and elevate the risk of nest scouring during up-ramping and the risk of stranding or dewatering during down ramping.Thermal conditions may be moderated by increased ramping.Strategies for adapting to future shifts in the renewable portfolio range from re-regulation in reservoir cascades to providing flow refuge(structures and vegetation)below individual projects.Coordinated basin-scale operation can distribute peaking operation to maintain grid support while restricting local ramping at critical ecological times.In addition,research to design hybrid renewable systems that add battery storage is needed to understand how we can mitigate future risks to aquatic communities while promoting the use of renewable energy.This study,which is among the first to examine ecological side-effects of the shift to renewable energy in freshwater ecosystems,lays out a path toward understanding and navigating changes to flow regimes under the energy transition.展开更多
基金supported by the Fundação para a Ciência e a Tecnologia(FCT)[scholarship reference number:PD/BD/143020/2018]The authors are also grateful to FCT for its support through funding UIDB/04625/2020 from the research unit CERISThis study has been also supported by the Spanish Ministry of Science and Innovation(Programa Estatal de Proyectos de I+D+i,Ref.PID2019-111252RA-I00 CTA).
文摘Hydropeaking,which refers to rising or falling discharges caused by the turning on or off of hydro-turbines to generate electricity,is a topic of growing interest due to its impact on fluvial ecosystems.To date,most hydropeaking studies have focused on the impact of peak fluctuations on invertebrate and fish communities,but little attention has been paid to its impact on riverine plants and how functional traits may make them resistant to hydropeaking.We performed a review to assess how a set of 32 plant functional traits can be expressed in riverine plant species,and found evidence of how such expression affects their capacity to cope with common sources of hydropeaking disturbance(i.e.,inundation,fast water drawdown,and rapid water fluctuations linked to up-ramping and down-ramping hydropeaking operations).The information here presented can simplify the evaluation of impacts on riverine plant communities worldwide,as well as to detect suitable species to successfully restore rivers affected by hydropower production.
文摘Many hydropower plants are operated as peak generators or frequency controllers, because they can change their output quickly to follow the fluctuating power demand. When meeting peak load requirements, a power station is turned on at a particular time during the day, generates power at a constant load for a certain number of hours, and is then turned off or set to a different load for another time period, resulting in a high variability inflow discharges. Where reservoir hydro schemes are operated primarily to provide peak load services, there are particular environmental risks that should be considered in any environmental impact assessment. At a minimum these should focus on water quality, fluvial geomorphology, riparian vegetation, macro-invertebrate and fish communities underpinned by a sound hydrological analysis. Frequent temperature changes may occur downstream of a peaking power station; increased seepage-induced erosion of riverbanks due to frequent water level drawdowns; and impacts to macro-invertebrate and fish communities due to rapid and frequent in channel habitat conditions. With a sound understanding of the potential environmental issues, there are strategies that can be employed at the siting and design stage to minimize or mitigate these risks, including but not limited to minimum environmental flows, ramping rules, utilization of a re-regulation storage and localized treatment works.
基金part of the EnviPEAK-project and has been financed by Centre for Environmental Design of Renewable Energy(CEDREN),one of the Norwegian Research Council’s Research Centres for Environmental Friendly Energy(FME contract-number:193818).
文摘An effect of hydropower and hydropeaking regulation in rivers is stranding of fish. Those fishes that survive stranding may experience stranding as a stressful situation. In four experimental stranding experiments (each with 6 individuals in 10 control and 10 treatment replicates), the energetic consequences of two forms of stranding (i.e. trapping and beaching) of juvenile Atlantic salmon (Salmo salar) were investigated in summer and winter. Restricted food access in the experimental channels ensured that effects of hydropeaking could be revealed. Mean fish length ranged between 60 mm and 110 mm among experiments. Both during the winter and summer experiments fish did not grow in length, neither in the control nor in the treatment channels and fish lost body mass as well as body fat in all experiments (body fat in summer trapping experiment not determined). The four experiments revealed similar results: stranding did not affect growth or energy content. Despite the severity of the stranding and the resulting mortality, which was especially high during summer, no stranding related effects on fish performance could be detected.
文摘To avoid negative consequences to freshwater biota from climate change,society must complete the transition from fossil to renewable electricity sources.However,temporal patterns in hydropower generation(and flow releases that affect aquatic biota)may change with increased wind and solar penetration.We used power cost modeling to characterize current and future within-day and seasonal patterns in hydropower generation across the Eastern Interconnection in a wet and a dry year.Compared to the baseline,future hydropower generation across the grid decreased during the day and increased before dawn and after dusk.At a project level,such a pattern would suggest‘double peaking’operation(up-and down-ramping before dawn and after dusk,with lower releases midday).Variation in generation was higher in wet years than dry years,foreshadowing possible flow constraints on hydropower flexibility.At the grid scale,projected ramping rates were higher in all seasons.A review of the ecological literature suggests that these changes would shift the timing of invertebrate drift and elevate the risk of nest scouring during up-ramping and the risk of stranding or dewatering during down ramping.Thermal conditions may be moderated by increased ramping.Strategies for adapting to future shifts in the renewable portfolio range from re-regulation in reservoir cascades to providing flow refuge(structures and vegetation)below individual projects.Coordinated basin-scale operation can distribute peaking operation to maintain grid support while restricting local ramping at critical ecological times.In addition,research to design hybrid renewable systems that add battery storage is needed to understand how we can mitigate future risks to aquatic communities while promoting the use of renewable energy.This study,which is among the first to examine ecological side-effects of the shift to renewable energy in freshwater ecosystems,lays out a path toward understanding and navigating changes to flow regimes under the energy transition.
