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Water conduits have a large untapped potential to recapture energy for small hydroelectric generation, which can substantially reduce grid electricity consumption and/or provide renewable energy to water agencies. Over the past decade, there has been a recent technological renaissance in off-the-shelf “water-to-wire” turbine technologies including reaction, impulse, and hydrokinetic turbines that target the sub 1-MW in-conduit hydroelectric market. However, adoption of small hydropower technologies remain limited in water and wastewater utility sector, possibly due to the lack of market penetration and exposure. Moreover, information about newly developed small hydropower technologies in the last 5–10 years for in-conduit applications are highly dispersed in the literature. As such, this paper is a comprehensive review on recent technological innovations and trends in hydropower generation from water conduits. Sixteen turbine technologies (eight conventional turbines and eight emerging turbines) are assessed and compared based on their potential benefits and challenges, technology readiness levels, as well as potential sites for installations in diversion structures, potable and irrigation water distribution systems, and wastewater outfalls. Although conventional turbines are considered to be more robust, the modular design of the newer turbines potentially offers a more cost effective solution and better scaling-up capability. Selected case studies on the application of conventional and new turbines for pipelines are also are also reviewed and discussed.

Although environmental rehabilitation projects that did not succeed are not uncommon, there are few research papers that deal with the subject. Works on the rehabilitation of borrow pits are even more rare. In an attempt to fulfill some gaps, the present study sought to evaluate the effectiveness of a program for the restoration of a clay borrow pit used for the construction of a hydroelectric plant, twenty years after its execution. In order to assess the current degradation stage and to identify the possible errors of this intervention, the area was mapped using an unmanned aerial vehicle, which allowed the identification of the remaining physical structures, dimensioning of the actual degraded area and characterization of vegetation cover and types of exposed soil. Physical and chemical parameters of the degraded area soils were compared to those of a contiguous preserved area, which was used as a control. Soils of the degraded area are significantly more compacted (with significant reduction in macroporosity) and depleted in organic matter and nutrients. The results showed that the methodologies used in the rehabilitation project were not sufficient to recover the resilience of a deeply degraded ecosystem. The long-term success of a rehabilitation project is only possible with the guarantee of the ecological sustainability of the area, which is largely related to the restoration of soil ecological processes. Most of the time, this cannot be achieved with the simple use of classical erosion control and revegetation techniques and without the addition of sediment material to aid the process.

The primary objective of this paper is to investigate the isolated impacts of hydroelectricity consumption on the environment in Malaysia as an emerging economy. We use four different measures of environmental degradation including ecological footprint, carbon footprint, water footprint and CO2 emission as target variables, while controlling for GDP, GDP square and urbanization for the period 1971 to 2016. A recently introduced unit root test with breaks is utilized to examine the stationarity of the series and the bounds testing approach to cointegration is used to probe the long run relationships between the variables. VECM Granger causality technique is employed to examine the long-run causal dynamics between the variables. Sensitivity analysis is conducted by further including fossil fuels in the equations. The results show evidence of an inverted U-shaped relationship between environmental degradation and real GDP. Hydroelectricity is found to significantly reduce environmental degradation while urbanization is also not particularly harmful on the environment apart from its effect on air pollution. The VECM Granger causality results show evidence of unidirectional causality running from hydroelectricity and fossil fuels consumption to all measures of environmental degradation and real GDP per capita. There is evidence of feedback hypothesis between real GDP to all environmental degradation indices. The inclusion of fossil fuel did not change the behavior of hydroelectricity on the environment but fossil fuels significantly increase water footprint.

Over the past few years, many sectors such as energy generation, industry, domestic supply, and agriculture have encountered serious environmental problems due to the lack of rainfall. Thus, the purpose of this paper is to review the current methodology of royalties distribution from Itaipu hydroelectric plant. In the proposed approach, two criteria were considered to establish the division of Itaipu royalties: (1) the relative percentage of the water flow in the generation of electricity and, (2) the relative percentage of the drop in the height of water. 62 hydroelectric plants were evaluated in this study. In 52 plants the water flow was the factor that most contributed to the generation of electricity. In 2013, 346 municipalities benefited the Itaipu royalties. With the proposed methodology, 1,327 municipalities will receive the resource, what would increase the revenue of each of these municipalities by, on average, US$ 87,436.91 per year. The methodology presented herein proposes a reduction in the environmental disparity that now exists in Brazil, through improvement to Government instruments and environmental policies. The distribution of royalties throughout the watershed can provide additional resources to support payment programs for environmental services at the state and municipality levels.

For countries dependent on hydroelectricity, water scarcity poses a real risk. Hydroelectric plants are among the most vulnerable enterprises to climate change. Investing in the conservation of the hydrographic basin is a solution found by the hydropower sector. Given the importance of the Itaipu plant to the energy matrix of Brazil and Paraguay, the aim of this study is to review the current distribution of royalties from Itaipu, using the hydrographic basin as a of criterion of analysis. Approximately 98.73% of the Itaipu basin is in Brazil. The flow contributes 99% of the total electricity generated there, while the drop height of the water contributes only 1%. Under the current policy, royalties are shared equally between Brazil and Paraguay. In the proposed approach, each country would receive a percentage for their participation in the drop height and water flow in the output of the turbines, which are intrinsic factors for electricity generation. Thus, Brazil would receive 98.35% of the royalties and Paraguay, 1.65%. The inclusion of the hydrographic basin as a criterion for the distribution of royalties will promote more efficient water resource management, since the payment will be distributed throughout the basin of the plant. The methodology can be applied to hydroelectric projects worldwide.

Rare earth elements (REE), including neodymium, praseodymium, and dysprosium are used in a range of low-carbon technologies, such as electric vehicles and wind turbines, and demand for these REE is forecast to grow. This study demonstrates that a process simulation-based life cycle assessment (LCA) carried out at the early stages of a REE project, such as at the pre-feasibility stage, can inform subsequent decision making during the development of the project and help reduce its environmental impacts. As new REE supply chains are established and new mines are opened. It is important that the environmental consequences of different production options are examined in a life cycle context in order that the environment footprint of these raw materials is kept as low as possible. Here, we present a cradle-to-gate and process simulation-based life cycle assessment (LCA) for a potential new supply of REE at Songwe Hill in Malawi. We examine different project options including energy selection and a comparison of on-site acid regeneration versus virgin acid consumption which were being considered for the project. The LCA results show that the global warming potential of producing 1 kg of rare earth oxide (REO) from Songwe Hill is between 17 and 87 kg CO2-eq. A scenario that combines on-site acid regeneration with off-peak hydroelectric and photovoltaic energy gives the lowest global warming potential and performs well in other impact categories. This approach can equally well be applied to all other types of ore deposits and should be considered as a routine addition to all pre-feasibility studies.

The past two decades have witnessed growing global concern about excessive greenhouse gas (GHG) emissions by reservoirs and the development of hydropower. Literature review showed that life cycle GHG emissions per energy production of collected global dataset ranged from 0.04 to 237.0 gCO2eq/kW⋅h, with a mean of 25.8 ± 3.0 gCO2eq/kW⋅h. Synthesis from the China's five largest hydro-projects and other publications estimated that the large- and mid-scale hydro-projects in China had a carbon footprint between 6.2 gCO2eq/kWh and 34.6 gCO2eq/kWh, with a mean value of 19.2 ± 6.8 gCO2eq/kWh (mean ± sd.). Over 80% of the carbon footprint of the hydro-projects could be conservatively allocated to hydroelectricity generation, while the rest could then be allocated to flood control services. In the Three Gorges Dam Project, the allocated life cycle GHG emissions per energy production of its hydroelectricity production was estimated to be 17.8 gCO2eq/kW⋅h. GHG emissions from reservoir sediments and in the phase of operation and maintenance were still uncertain. There is still a need of in-depth research on reservoir carbon cycling to quantify net reservoir GHG emissions.

International audience; The sustained development of hydropower energy in the last century has caused important ecological impacts, promoting recent advances in efficient mitigation measures to be implemented in existing and future hydropower plants. Although upstream fish migration has been largely addressed with the development of fish-pass infrastructures, downstream passage solutions are often missing or inefficient, strengthening the need for their improvement and efficiency assessment. The efficiency of horizontally inclined (26°) low bar spacing racks associated to a bypass was assessed using salmon smolts radiotelemetry along three successive hydropower plants (HPP) in the Ariège River (southern France). In average, nearly 90% of the smolts were successfully protected by the racks and rapidly guided to the bypass, within few minutes in most cases. Furthermore, we detected a significant positive influence of the bypass discharge (Qbp% expressed as the proportion of concurrent HPP discharge) on the probability of successful bypass passage, reaching 85% of successful passage with a Qbp% of only 3%, and more than 92% when the Qbp% exceeded 5%. The probability of bypass passage without hesitation (e.g. passage within the first 5 min) also increased with Qbp%, and reached 90% with 5% of Qbp%. Passage without hesitation was especially detected on the site having larger bypass entrances and transversal currents, providing better guidance into the bypass. High-efficiency results of inclined racks yielded with reduced Qbp% confirmed their relevance to mitigate some of the HPP ecological impacts, re-establishing safe downstream salmon migration with lower impact on energy production than older less efficient solutions.

Few studies have examined the influence of reservoir hydrodynamics on the water quality of its limnological zones. In this study, the relationships between the operational phases and the water quality of the limnological zones were assessed for the Amazonian reservoir Tucuruí. Limnological zones were clustered by means of an artificial neural network technique, and inputs used were water quality variables, measured at twelve stations between 2006 and 2016. Generalized Linear Models (GLMs) were then used to identify the influence of the operational phases of the reservoir on the water quality of its limnological zones. The GLM with a gamma-distributed response variable indicated that Chlorophyll-a concentrations in the riverine and transitional zones differed notably from those observed in the lacustrine zone. Chlorophyll-a concentrations were significantly lower during the operational falling water phase than in the low water phase (p < 0.05). The GLM with an inverse Gaussian-distributed response variable indicated that Secchi depth was significantly lower in the riverine than in the lacustrine limnological zone (p < 0.05). Our results suggest that more eutrophic conditions occur during the operational rising water phase, and that the area most vulnerable to eutrophication is the transitional zone. We demonstrate that the use of GLMs is suitable for determining areas and operational phases most vulnerable to eutrophication. We envisage that this information will be useful to decision-makers when monitoring the water quality of hydroelectric reservoirs with dendritic patterns and dynamic operational phases.

Environmental Impact Assessment (EIA) is a systematically constructed procedure whereby environmental impacts caused by proposed projects are examined. Geographical Information Systems (GIS) are crucially efficient tools for impact assessment and their use is likely to dramatically increase in the near future. GIS have been applied to a wide range of different impact assessment projects and dams among them have been taken as the case work in this article. EIA Regulation in force in Turkey requires the analysis of steering natural processes that can be adversely affected by the proposed project, particularly in the section of the analysis of the areas with higher landscape value. At this point, the true potential value of GIS lies in its ability to analyze spatial data with accuracy. This study is an attempt to analyze by GIS the areas with higher landscape value in the impact assessment of dam constructions in the case of Seyhan-Kopru Hydroelectric Dam project proposal. A method needs to be defined before the overlapping step by GIS to analyze the areas with higher landscape value. In the case of Seyhan-Kopru Hydroelectric Dam project proposal of the present work, considering the geological conditions and the steep slopes of the area and the type of the project, the most important natural process is erosion. Therefore, the areas of higher erosion risk were considered as the Areas with Higher Landscape Value from the conservation demands points of view.

Evaluating the environmental impacts of electric utilities is crucial for informed electrical system planning. This paper presents an approach to constructing an index of environmental impact for an electric utility, based on multiattribute utility theory (MAUT). The paper begins with an overview of decision analysis, the framework in which MAUT is applied. Next, the underlying assumptions and steps needed in constructing an index based on technical and value judgements are outlined. An example of an index is discussed, drawing on interviews and a MAUT elicitation with planners from BC Hydro, a major Canadian electric utility. Potential uses of the index are illustrated and trade-offs between the environmental index and costs are discussed.

Runs of salmon in the Columbia Basin in the north-western United States have declined dramatically over the past 50 years, due to hydropower development, habitat degradation, over-harvest and other causes. This article describes a suite of models that analyze the biological effectiveness and financial costs of strategies designed to meet harvest and escapement goals for nearly 80 stocks of salmon simultaneously. Results suggest that finding a cost-effective solution requires that all aspects of the salmon life-cycle must be analyzed simultaneously. Policy implications and difficulties in using this modeling approach to inform regional decision-making also are discussed.

The merits of the fauna section of the Olympic Dam Project Environmental Impact Statement (EIS) are discussed. The values of different survey methods and monitoring organisms used in this document are evaluated following 10 years of fauna monitoring and research subsequent to the preparation of the EIS. The pilot fauna reconnaissance was found to be of little value, although the associated literature review formed an integral part of the EIS. Over 95% of all amphibian, reptile and bird species recorded at Olympic Dam were confirmed or predicted to occur in the EIS. Mammal predictions were less accurate because of the sparse populations and irruptive nature of several arid-zone species. Prediction and monitoring of rare species were demonstrably difficult. The Olympic Dam Project EIS was found in general to be an accurate and useful document. However, it is suggested that more emphasis be placed on establishing monitoring programmes for future EISs, particularly for invertebrates.

The generation of electricity through hydropower can, along with other anthropogenic activities, degrade river hydromorphology and ecosystems. In this case, water for power generation is diverted from the River Durance to a canal, which services a chain of 17 power stations, with the lower three being in the catchment of the Etang de Berre. This means that excess water and sediments are discharged into the salt-water lagoon with enormous consequences for ecosystems there. This paper summarizes the impacts of HEP and other human activities on both the river and lagoonal systems. It also considers agency and government attempts to understand and counter the degradation of these systems, both to date and in the future, with the latter catering for the potential impacts of future human development and global warming.

This paper presents a new kind of integrated modeling method for simulating the vulnerability of a critical infrastructure for a hazard and the subsequent interdependencies among the interconnected infrastructures. The developed method has been applied to a case study of a network of hydroelectricity generating infrastructures, e.g., water storage concrete gravity dam, penstock, power plant and transformer substation. The modeling approach is based on the fragility curves development with Monte Carlo simulation based structural-hydraulic modeling, flood frequency analysis, stochastic Petri net (SPN) modeling, and Markov Chain analysis. A certain flood level probability can be predicted from flood frequency analysis, and the most probable damage condition for this hazard can be simulated from the developed fragility curves of the dam. Consequently, the resulting interactions among the adjacent infrastructures can be quantified with SPN analysis; corresponding Markov Chain analysis simulates the long term probability matrix of infrastructure failures. The obtained results are quite convincing to prove the novel contribution of this research to the field of infrastructure interdependency analysis which might serve as a decision making tool for flood related emergency response and management.