Small Hydroelectric Plants Research Articles

Influence of the Pandeiros Small Hydroelectric Plant reservoir on the concentration and composition of solids transported by the Pandeiros River, Brazil

Influence of the Pandeiros Small Hydroelectric Plant reservoir on the concentration and composition of solids transported by the Pandeiros River, Brazil

Hydrological uncertainty analysis using Monte Carlo simulations to determine power purchasing agreements for small hydroelectric powerplants

The energy generated by Small Hydroelectric Plants (SHPs) is sold in Brazil using a Physical Energy Guarantee, also known as a Power Purchase Agreement (PPA), the maximum amount of energy that a generator can sell. The PPA is calculated based on monthly average flow series data, however, studies have shown that this can overestimate the PPA and that daily average flow series data are more accurate in reflecting the amount of generated electric energy. Unlike other hydrological evaluations, the uncertainty levels associated with the data used to calculate the PPA at SHPs are neither considered nor quantified. This study investigates the impact of hydrological uncertainties on SHP PPAs. The Monte Carlo method was used to analyze the uncertainty levels for an SHP case study. It has been elaborated 2 models, where the results show that the models have on average an upper deviation of 1.30 MW from current PPA and a lower deviation of 1.19 MW from the current PPA. Dispersion analysis revealed that SHPs with smaller installed capacities and lower PPAs faced more business risks than SHPs with higher PPAs, which are generally more thoroughly evaluated by investors.

Impacts of small dams on the phytoplankton and invertebrates in an Amazonian river

AbstractThe construction of small hydroelectric plants (SHPs) has increased greatly worldwide, and the impacts of these impoundments can cause changes in the aquatic biota. Here, we investigated the ecological attributes (abundance, richness, and species diversity) of three communities (phytoplankton, invertebrates in the water column, and benthos) and the functional groups of phytoplankton, before and after the construction of five SHPs in an Amazonian river. The communities were sampled at two sites, one upstream and another downstream of each dam or construction site, before the dam closure. The dam did not change the limnological factors, and the acid waters and low electrical conductivity, typical of “cerrado” rivers, were characteristic of both the pre‐ and post‐dam phases. For aquatic communities, the phytoplankton abundance increased and the diversity of groups decreased in the post‐dam phase. Regarding the morphology‐based functional groups (MBFG), there was an increase in groups I (small algae with a high surface/volume ratio) and V (phytoflagellates), with a reduction in groups VI (diatoms) and VII (large mucilaginous colonies) in the post‐dam phase. The relative abundance of zooplankton species increased in the post‐dam phase, and the opposite was observed for the benthic community, with reductions in abundance, richness, and group diversity in the post‐dam phase. The structure of the three communities differed between the pre‐ and post‐dam phases, but no difference in communities' similarity was observed between the upstream and downstream sites in both phases. The results show that the change in hydrodynamics, from lotic to semi‐lentic, in the reservoirs of the SHPs, was the main driving force for the alterations in the three communities. For phytoplankton, SHPs are favorable in the sense of decreasing the incidence of algal blooms, particularly of cyanobacteria.

A Data-Driven Framework for Small Hydroelectric Plant Prognosis Using Tsfresh and Machine Learning Survival Models.

Maintenance in small hydroelectric plants (SHPs) is essential for securing the expansion of clean energy sources and supplying the energy estimated to be required for the coming years. Identifying failures in SHPs before they happen is crucial for allowing better management of asset maintenance, lowering operating costs, and enabling the expansion of renewable energy sources. Most fault prognosis models proposed thus far for hydroelectric generating units are based on signal decomposition and regression models. In the specific case of SHPs, there is a high occurrence of data being censored, since the operation is not consistently steady and can be repeatedly interrupted due to transmission problems or scarcity of water resources. To overcome this, we propose a two-step, data-driven framework for SHP prognosis based on time series feature engineering and survival modeling. We compared two different strategies for feature engineering: one using higher-order statistics and the other using the Tsfresh algorithm. We adjusted three machine learning survival models-CoxNet, survival random forests, and gradient boosting survival analysis-for estimating the concordance index of these approaches. The best model presented a significant concordance index of 77.44%. We further investigated and discussed the importance of the monitored sensors and the feature extraction aggregations. The kurtosis and variance were the most relevant aggregations in the higher-order statistics domain, while the fast Fourier transform and continuous wavelet transform were the most frequent transformations when using Tsfresh. The most important sensors were related to the temperature at several points, such as the bearing generator, oil hydraulic unit, and turbine radial bushing.

Dams Pose a Critical Threat to Rivers in Brazil’s Cerrado Hotspot

Hydropower dams are touted as one of the cleanest forms of energy production, yet they are associated with severe environmental impacts on both the physical structure and functioning of river ecosystems. The threat is particularly acute in the Brazilian Cerrado—a biodiverse savanna region, spanning over 2 million km2, that concentrates the headwaters of several critical South American watersheds. Our study analyzed the current distribution of large and small hydroelectric plants in the Cerrado and focused on understanding their effect on land use changes. We also propose a Dam Saturation Index (DSI) to help spur more integrated planning for this region. Results indicate that the Cerrado river basins contains 116 (30%) of Brazil’s large hydroelectric plants and 352 (36%) of its small hydroelectric plants. Moreover, these plants spurred significant land use changes within a 5-km buffer of the dams, with over 2255 km2 of native vegetation cleared by 2000 and an additional 379 km2 in the ensuing 20 years, could reach ~1000 km2. Based on the historical anthropization process in the Brazilian savannas, we expect new crops, pastures, and urban equipment to be incorporated into this landscape, with different impact loads.

Koskien valjastamisesta patojen purkuun

The latest phase of river restorations is the closure of small hydroelectric plants. The precedent of this stage in Finland is the Hiitolanjoki river, which is a transboundary river crossing the Finnish-Russian border before flowing to Lake Ladoga. This article focuses on the shift in the hydrosocial rhythm of the Hiitolanjoki river from industrial to post-industrial rhythm. In a waterbody with the industrial rhythm, dams regulate the flow and speed of water in line with the demand for electricity. Current dismantling of dams and restoring its original rhythm is a result of the persistent work of local actor-network which has been able to create a wide supporting network including actors from the Hiitolanjoki river to the European Union’s and the Finnish government’s water and fish stock policies. The case of Hiitolanjoki river shows that achieving results requires an active and committed local network of actors.

Digital twin and machine learning for decision support in thermal power plant with combustion engines

The reliability and performance of the generating machines in a thermal power plant are crucial to ensure agility and assertiveness in decision-making, maximize economic results, and ensure meeting the electricity sector demands. In this work, a decision support system (DSM) was developed to predict trends and operational deviations in thermal power plants with combustion engines in an automated and reliable way. It is based on digital twin models for thermoelectric generation engines and their subsystems associated with models of machine learning for predictive maintenance, allowing the classification of failures in the generating units of the plant. The models represent the mechanical, thermal, and electrical conditions and parameters of each piece of equipment under normal operating conditions, and the tool generates alerts when deviations from the base model occur. The benefits from event forecasting range from a reduction in operational issues to the company’s strategic objectives due to the reduction in corrective maintenance downtimes, resulting in reduced operation and maintenance costs. Considering the real-time execution character of the models, it is essential for the tool to meet the operation’s decision-making needs; so an on-premises application is necessary. The proposed architecture can be applied to any industrial sector that uses SCADA supervisors and can be adapted, expanded, and evolved to other generation technologies, such as thermal plants that use different fuels and small hydroelectric, wind, and thermonuclear plants. The techniques used in conjunction with the developed architecture can be replicated in other systems and energy sectors, such as distribution and transmission, and can also be applied to industry in general: chemical, petrochemical, oil and gas, and others.

Reutilização de barragem como armadilha de sedimento e reserva hídrica

ABSTRACT One of the dilemmas that characterizes the end of active service of small hydroelectric plants (SHPs) is regarding the destination of the dams. This is the case of the Pandeiros SHP, located in the state of Minas Gerais, Brazil. Several alternatives are being considered to make its decommissioning feasible, such as opening the bottom discharge gate and removing the reservoir containment dike. However, in a review of recent research in the basin, more than 200 active gullies were found upstream of the dam, contributing to the silting up of the reservoir and of the Pantanal Mineiro, an extensive wetland downstream of the SHP that is vital to the biodiversity of the region. Following a worldwide movement to reuse such structures, periodic dredging of part of the sediment retained in the reservoir is proposed, converting it into a trap to reduce the silting of the wetland by the upstream sediment, in addition to the creation of a reserve volume of water needed for agriculture and human consumption.

A sustentabilidade como perspectiva para repotenciação de pequenas centrais hidrelétricas no Brasil: método para estimativas

Abstract Repowering is a sustainable option for relatively old hydroelectric plants. However, it is still in the process of developing its technical, socio-environmental and regulatory aspects in Brazil. Moreover, there are few papers available in the literature on the subject. A gap in the area is the lack of methodologies that direct the measurement of benefits in suitable enterprises, to prioritize the most opportune ones, reduce risks, and encourage this practice nationally, regionally, and among agents. This paper presents a theoretical discussion of the practices currently employed and proposes an accessible method (simple, fast and low cost) to support decision-making regarding the applicability of repowering in small hydroelectric plants. The results show the environmental sustainability of the practice given the limitations and challenges that currently involve the construction of large hydroelectric plants.

Sustainability as a perspective for the repowering of small hydroelectric plants in Brazil: estimation method

Resumo A repotenciação é uma opção sustentável para hidrelétricas relativamente antigas. Contudo, ainda encontra-se em um processo de desenvolvimento dos seus aspectos técnicos, socioambientais e regulatórios, no Brasil. Além disso, existem poucos trabalhos disponíveis na literatura sobre o tema. Uma lacuna da área é a falta de metodologias que direcionem a mensuração dos benefícios nos empreendimentos aptos, para priorização dos mais oportunos, redução dos riscos e incentivo dessa prática no âmbito nacional, regional e dos agentes. Neste trabalho apresenta-se uma discussão teórica das práticas atualmente empregadas e propõe-se um método acessível (simples, rápido e de baixo custo) para suporte à tomada de decisão quanto à aplicabilidade da repotenciação em pequenas centrais hidrelétricas. Os resultados explicitam a sustentabilidade ambiental da prática frente às limitações e desafios que envolvem a construção de grandes hidrelétricas, atualmente.

МЕТОД СТРУКТУРНОЇ ІДЕНТИФІКАЦІЇ НЕЛІНІЙНИХ ІНТЕРВАЛЬНИХ МОДЕЛЕЙ СТАТИЧНИХ ОБ’ЄКТІВ

The process of building mathematical models of static objects and systems, which includes the solution of two problems: structural and parametric identification, is considered. At the same time, the task of identifying the structure of the model is more difficult and primary. The problem of structural identification of interval models of the characteristic of a static object is the problem of multiple solving of problems of parametric identification of this model, and therefore, from a computational point of view, it is NP complex. The procedure for finding the optimal structure of the model is considered as a directed selection of a defined set of structures in such a way as to minimize the number of iterations of the formation of interval systems of nonlinear algebraic equations. The article formulates the problem of structural identification of interval models of static objects, as a problem of repeatedly searching for solutions of interval systems of nonlinear algebraic equations, in the form of optimization problems with a nonlinear objective function and nonlinear constraints. For the first time, a method of structural identification of interval models of the characteristics of static objects based on the analysis of interval data is proposed and substantiated, which, unlike the existing ones, is based on self-organization and self-adaptation procedures of computing procedures by analogy with artificial bee colony (АBC), which gives the ability to implement model structure identification procedures with lower computational complexity and obtain interval models with simpler structures compared to known methods. The proposed method was tested on the example of building an interval model of the characteristics of a small hydroelectric plant for the purpose of research and ensuring the maximum efficiency of the use of hydropower resources, which demonstrated the effectiveness of using computational procedures based on the artificial bee colony. Accordingly, the proposed method makes it possible to obtain simple, from the point of view of complexity, interval models of complex static objects with a given guaranteed accuracy and with a lower computational complexity of identifying these models. Such features of the method ensure the effective development of the mathematical apparatus, which is used both in decision-making processes and in the processes of preparing decisions in intellectualized data-oriented systems.

Influences of Small Hydroelectric Plants on the genetic differentiation of Neotropical freshwater fish populations: a case study

ABSTRACT In view of the growing global demand for electricity, many countries have been looking for ways to diversify production. However, in countries such as Brazil, hydroelectric power plants still constitute the predominant generating source, occupying important drainage systems, such as the Upper Paraná River. At the same time, hydroelectric dams are among the main sources of impacts on freshwater fish, interfering, for example, in the genetic distribution of populations. Although the same could be expected from Small Hydroelectric Plants, very little genetic information has been obtained along Neotropical drainages. Based on this, the present study analyzed the DNA (microsatellite loci) of non-migratory fish species (seven) upstream and downstream of three Small Hydroelectric Plants in the Upper Paraná River basin, obtaining information about the genetic distribution of fish populations in this scenario. In general, the data suggest that populations have been genetically subdivided by Small Hydroelectric Plants and that other factors, such as the number of Small Hydroelectric Plants along a drainage and connectivity with long free stretches, could also influence genetic differentiation levels, which provides information of great relevance to global discussions about the impacts of hydroelectric power plants, as well as for the implementation and management of projects.

A conceptual approach to public participation in the environmental licensing of small hydroelectric plants: state of the art of research on the topic carried out in Brazilian postgraduate programmes(2004-2018) (in Portuguese)

A conceptual approach to public participation in the environmental licensing of small hydroelectric plants: state of the art of research on the topic carried out in Brazilian postgraduate programmes(2004-2018) (in Portuguese)

Influence of Debris on Water Intake Gratings in Small Hydroelectric Plants: An Experimental Study on Hydraulic Parameters

Deposition of debris on the screens of hydroelectric power plants translates into measurable economic losses. Occurring plant debris, although it is an organic material, is characterised by different forms and structure. It is often leaves, branches, and grasses in lowland areas, while in mountainous regions, broken boughs and trees can be expected. On the trash racks of power plants, debris may be deposited in different forms, shapes, and places. This work aims to determine the impact of the degree of submergence of debris on the values of the force acting on the racks. This paper analyzes the influence of the rectangular shape of the debris deposited on the trash racks and its degree of submergence and weight on the obtained values of the force acting on the racks as a result of water pressure, which directly affects the hydraulic losses and productivity of hydroelectric power plants. Our research confirms the negative influence of the deposited plant debris on the value of forces recorded on the gratings. The increase in the recorded force, and thus the resistance on the grating, is obviously dependent on the degree of obstruction of the debris by the grating obtained by changing the degree of debris immersion and its weight. In the case of changing the degree of submergence, the increase in force recorded on the gratings varied during the experiment from about 25% recorded for the fully submerged debris compared to that of the partially submerged debris for the mass of 100 g; in comparison, an increase of about 31% was recorded for that of the mass of 200 g. However, comparing the values of the forces recorded on the obstructed grids to that of the forces recorded on the clean grids, the increase ranged from about 15–53%.

Remaining suitable areas for the critically endangered Brazilian Merganser (Mergus octosetaceus; Aves, Anseriformes) are threatened by hydroelectric power plants

The critically endangered Brazilian Merganser Mergus octosetaceus is one of the rarest waterfowls in the world. Only three isolated populations remain in the Brazilian Cerrado, totaling less than 250 individuals. We evaluated the potential influence of small hydroelectric plants (SHPs) and Protected Areas (PAs) on the species’ conservation. We identified suitable areas by using recent presence records and environmental predictors, and overlapped it with the species dispersion zone and the SHP impact zone. Suitable areas for the species are limited to 4% of the geographic space (142,899km2). Within the dispersion zone, we found 36 planned SHPs, which can impact 4.1% of the suitable area and 17.2% of the suitable area inside PAs. Our results expose the critical situation of the Brazilian Merganser, with few isolated suitable areas, high potential impacts for the three known populations, and a high proportion of suitable areas out of PAs. We highlight the need of considering SHPs impacts on the Brazilian Merganser in environmental impact assessment studies to reduce them. Furthermore, we appointed areas for search of new populations, and emphasize how urgent the implementation of effective conservation actions aiming to protect the remaining suitable habitats for the Brazilian Merganser is.

Evaluation of small hydropower plant at Ribb irrigation dam in Amhara regional state, Ethiopia

BackgroundEnergy is the main requirement for economic growth in any country and supports the modern economy. The energy sector is considered a vital element in developing countries because it meets energy needs. This article addresses the production of electricity using small hydroelectric power plants for rural applications. The main objective of this study was to assess the potential of the Ribb dam for small hydroelectric plants. The flow is very important for the production of hydroelectricity as the height of a proposed site is constant and the available flow is very variable.ResultThe flow duration curve is constant and it will vary from 20 to 50% from the nominal flow. Further, it will decrease when the percentage of the nominal flow increases. The best size of a small hydroelectric plant producing a maximum of electricity in the context of future projected flows in the study region. Further, the Ribb dam concluded that the average flow of 14.6331 m3/s, the smooth head of 70.37 m, and the average nominal power of 5.53 MW.ConclusionSmall hydro system (SHP) is a promising alternative for the production of cheap and renewable energy in rural or developing areas.

Macrophytes banks as potential fish nursery areas in small hydropower reservoirs

Abstract: Aim This study verified if the macrophyte banks found in two reservoirs of small hydroelectric plants (SHPs) have a functional ecological role for the initial development of ichthyofauna. Additionally, we compared the differences in the structure of the fish assemblages along each reservoir compartment and between reservoirs. Methods Sampling was performed in March 2018, in lotic, intermediate, and lentic compartments of Palmeiras and Retiro reservoirs, Sapucaí-Mirim River (SP). Three distinct macrophyte banks in each stretch (triplicates), considering the most representative in terms of composition (recurrency/dominance), were sampled, resulting in 18 samples (nine per reservoir). For fish collection we used a sieve of 1 m2 of area, mesh size of 1 mm, which was manually hauled, from the boat, in the marginal aquatic vegetation (three hauls per sample). Simultaneously, we measured basic limnological parameters with a Horiba U-52 water probe, adjacent to the banks. Results The presence of juveniles of all fish orders found in the river, Characiformes, Siluriformes, Synbranchiformes, Gymnotiformes and Cichliformes, demonstrates that, at least in certain moment of their development cycle, the macrophyte banks are used by species with different ecological requirements. It was observed significant statistical differences in the structure of the ichthyofauna along the longitudinal axes of the reservoirs, but not between reservoirs. The same was seen for the limnological data (PCA). Conclusions The macrophyte banks found in the SHPs reservoirs have a potential role as nurseries for the local ichthyofauna, mainly, but not exclusively, for sedentary species and with parental care. This association is ecologically relevant, given the absence of typical lateral habitats for the initial development of the fish fauna. Additionally, despite the reservoirs small size, spatial organization was also important for the assemblage’s structure, with differences in terms of composition, size and development stages along the distinct sampling stretches.

The Positive Impacts of Sustainability in the Community

The Brazilian electric power matrix has always been profoundly dependent on hydroelectric power plants. According to the 2019 decennial plan by the Energy Research Company (EPE, in Portuguese), 60% of the instal led power from Brazil's electrical system is in large hydroelectric plants, and 4% is in small hydroelectric plants. Recently, however, between 2014 and 2016, the most representative Brazilian federative unit, in terms of gross domestic product, suffered a severe hydroelectric crisis, which highlighted discussions about the future of power generation.

Performance assessment of an Indalma hydro-turbine

Hydro-turbines for small heads have recently attained considerable attention as they show the possibility of achieving a good power performance. In Brazil, electricity is highly dependent on the hydroelectric generation due to high water availability and low long-term cost. For generation at smaller scales, conventional turbines such as Kaplan, Pelton and Francis generally do not present satisfactory efficiency and they typically have a high installation cost. In this way, there are some alternatives for small hydropower plants; one of them is the Indalma turbine, which was invented and built in the eastern Amazon region. The differential of this turbine is the shape of the blades and the shape of the spiral casing, having its efficiency experimentally verified by the National Reference Center in Small Hydroelectric Plants (CERPCH/UNIFEI-MG—Brazil). Since the design of this turbine was performed almost empirically, there is a need for an in-depth study of the pressure and velocity fields, as well as other phenomena that commonly occur in hydraulic turbines. Thus, this work presents a performance assessment of an Indalma pico-turbine through computational fluid dynamics, using a Reynolds-averaged Navier–Stokes formulation. As a result, the Indalma turbine has a good performance among conventional turbines at the nominal operating point. The highest turbine efficiency of \(80.8\%\) is found at a flow rate of 0.012 \(\hbox {m}^3/\hbox {s}\) and a rotational speed of 1460 rpm. Additionally, the results yield good agreement with experimental and theoretical data available in the literature, demonstrating that Indalma turbine is a good alternative for small hydropower plants.

Extended Isolation Forests for Fault Detection in Small Hydroelectric Plants

Maintenance in small hydroelectric plants is fundamental for guaranteeing the expansion of clean energy sources and supplying the energy estimated to be necessary for the coming years. Most fault diagnosis models for hydroelectric generating units, proposed so far, are based on the distance between the normal operating profile and newly observed values. The extended isolation forest model is a model, based on binary trees, that has been gaining prominence in anomaly detection applications. However, no study so far has reported the application of the algorithm in the context of hydroelectric power generation. We compared this model with the PCA and KICA-PCA models, using one-year operating data in a small hydroelectric plant with time-series anomaly detection metrics. The algorithm showed satisfactory results with less variance than the others; therefore, it is a suitable candidate for online fault detection applications in the sector.