Small-scale Hydropower Research Articles

Review of the sub-Saharan African small hydropower situation

The significance of renewable energy sources, such as generation of viable output from small hydropower (SHP), has been of great concern with several measures being taken to alleviate the serious shortfall of electricity supply in rural areas of sub-Saharan Africa. SHP can play very important roles in the electrification of rural areas. The potential for SHP is typically found away from the more populous areas and is a very suitable energy source for the purpose of rural electrification. It can be used either as standalone power source or as a hybrid system with other energy sources. Depletion of fossil fuels and inability to meet the rising demand for electricity are among the hindrances to the economic development of sub-Saharan Africa. This paper focuses on SHP situation in sub-Saharan Africa, especially off-the-grid areas where the central grid is inaccessible. There is a need to establish widespread SHP turbines to overcome this situation. This paper draws conclusions on the importance of designing and implementing SHP turbines for sub-Saharan Africa. It also highlights small-scale hydropower as one of the most cost-effective energy technologies to be considered for electrification, and proposes guidelines to help future implementation of this technology in a better way.

Internal flow and loss mechanisms of specific speed 160 m-kW shroudless hydro turbine

High efficiency and low-cost hydro turbines are becoming more popular for medium and small-scale hydropower generation in underdeveloped locations. Because of this, a shroudless hydro turbine of medium specific speed 160 [m-kW] was developed based on a low specific speed 80 [m-kW] design concept previously studied in the author’s laboratory. We are aiming to develop an optimal design method and further improve performances of the medium- specific speed 160 [m-kW] shroudless hydro turbine. The most important factors are the internal flow and the loss mechanism of each flow path component. In this study, the internal flow and loss mechanisms were investigated and clarified by experimental and computational approaches. The main loss mechanisms in the double circular cascade is the high swirling strength vortices extending from the guide vane inlet to the outlet near the end wall of guide vanes. Furthermore, it has been found that the interference of the secondary flow and leakage flow, and the tip leakage vortex are the predominant loss mechanisms of the shroudless runner.

The role of hydropower installations for sustainable energy development in Turkey and the world

Abstract Hydropower has the largest share among renewable energy sources in the world, supplying more than 16.6% of total global electricity to over 160 countries around the world. Global hydropower capacity increased to approximately 1096 GW with the addition of 25 GW of new hydropower capacity in 2016. With a 216 TWh per year generation capacity, Turkey’s hydropower potential is the largest in Europe. The increased rate of installed capacity in Turkey was ranked 7th in the world in 2016 with an annual installed hydroelectric capacity of 0.8 GW. The main objective of this paper is to review the developments of hydropower installations around the world and in Turkey with an emphasis on the potential of small scale hydropower systems such as waterwheels in utilizing low head water flow for household electricity usage. In the first part of this study, the growth of worldwide hydropower capacity is reviewed and the countries with the largest installed and new built hydropower capacities are reported. In the second part of this study, the current status of Turkey’s hydropower plants is discussed in detail with respect to annual regional rainfall, gross water mass flow and potential of Turkey’s major water basins to demonstrate the potential energy output that can be harnessed from small-scale systems implemented in low-head water sources. In addition, the most recent information on Turkey’s electricity generation and consumption rates are reported.

Development of weightage for criteria affecting in retrofitting of existing building in Higher Learning Institution with clean energy initiatives

Campus university building is the Higher Learning Institution (HLI) involves complex activities and operations, conserving the energy has become paramount important. There are several efforts taken by universities to improve its current energy use such as policy development, education, and adaption of energy conservation solution through retrofitting. This paper aims to highlight the importance of the criteria affecting in retrofitting of existing buildings with clean energy in order to achieve zero energy balance in buildings. The focus is given to the development of criteria for solar photovoltaic (solar PV), wind turbines and small-scale hydropower. A questionnaire survey was employed and distributed to the green building expert practitioner. Factor Analysis, Factor Score, and Weightage Factor were adapted as a method of analysis in order to produce the final result with weightage output for prioritization and ranking of the relevant criteria. The result performed assists to provide the stakeholders an overview of the important criteria that should be considered especially during the decision making to retrofit the existing buildings with clean energy resources. The criteria developed are also to establish a structured decision-making process and to ensure the selection of the decision or alternatives achieve the desired outcome.

Entrainment effects of a small-scale diversion-type hydropower station on phytoplankton

Three diversion-type small-scale hydropower stations located in Jinggu County, Yunnan Province, China, were selected to study entrainment effects on phytoplankton. Samples were collected in May 2015 and November 2016, which were tested for the concentration of chlorophyll a, cell morphology structures, and the physiological and biochemical parameters of phytoplankton. Results showed that entrainment effects significantly resulted in approximately 20.63% decrease in phytoplankton biomass. Entrainment effects significantly increased the values of reactive oxygen species and fluorescein diacetate (p < 0.05), causing oxidative stress and activating the cell metabolism of the phytoplankton. Furthermore, the level of propidium iodide increased when algal individuals flowed through the hydropower station, indicating that the cell membrane integrity was damaged. Electron microscope observation results showed that parts of the algal cells were deformed through fractures and folding; some algae developed shrunken organelles, and cell walls and plasma membranes were fractured and broken. This research therefore demonstrates that small-scale hydropower stations can damage phytoplankton, but the negative impact of entrainment effects would recede if the stress diminished. However, a cumulative damage effect of the cascading diversion-type hydropower stations was not observed. This study provides a scientific proof for formulating ecological environment protection decisions when developing small-scale hydropower stations.

Powering institutions for development—Organizational strategies for decentralized electricity provision

The study addresses the question of how to achieve and sustain well-functioning local service delivery in institutionally difficult contexts, characterised by low levels of generalised trust, widespread corruption and poor institutions. We study a relatively successful case of decentralized electrification in Tanzania, and the process whereby an international NGO establishes a small-scale hydropower system with a local utility to own and operate it. Building on institutional theory, we investigate how to build trust in an organization, through a strategy of credible commitment; and how free-riding problems can be handled in a local development project. The qualitative study includes 119 semistructured interviews with project staff, villagers, and local and district government, observations and document analysis. The results indicate the importance of a positive ‘history of play’, sustained over time, and keeping distance from corrupt institutions, in order to build trust. Strict enforcement of rules was decisive for handling free riding behaviours, and impartiality in enforcement for perceptions of legitimacy and trustworthiness. Deviations undermined relations of trust. The results add nuance to more generic theoretical propositions and provide insights on un/intended consequences of institutional strategies. These are relevant for creating and sustaining local service organizations for electricity access and other public goods.

Development of a Model to Identify the Flow at any Location of an Ungauged Stream for Selection of Sites for Small Hydel in the Kalimpong Subdivision of West Bengal

ABSTRACT Before the implementation of any small scale hydropower scheme, it is essential to determine the availability of sufficient and reliable amount of water to make the scheme economically viable. The sites for small hydels are generally located in the inaccessible tracts of hilly regions. This hinders the proper evaluation of the site. The investments in the small hydels are also comparatively very low as compared to a big hydel power plant; as such not much of fund can be allocated to the initial site suitability decisions. Once a best site in a stream having suitable head has been identified then proper and detailed survey of the site could be undertaken for the construction of the plant. The streams on which small hydel plants are planned are mostly ungauged, which again poses a problem in identifying the amount of flow at certain location. In this work an attempt has been made to create a model for identification of flow at any location of a watershed. The two components of flow that is the base flow and runoff has been taken into consideration for calculating the flow. The base flow has been identified by direct measurement and run off has been delineated using the distributed curve number method. Finally a regression has been done to come to a generalized equation for determination of total flow at any point of a watershed in the Kalimpong subdivision.

Living in a bubble: potential gains from flexible water management policies

ABSTRACTWe study Swedish implementation of the European Union’s Water Framework Directive, and compare the current implementation strategy with more flexible ‘bubble’ schemes, where measures can be traded among various locations within the same river system to reach the overall environmental target. Two different Swedish river systems, the Mörrum system with small-scale hydropower plants, and the Ångerman system with larger plants, are studied. We find that the environmental benefits that current policies are likely to accomplish could be achieved at well under half the cost in the Mörrum system, and at less than a tenth of the cost in the Ångerman system.

The Application of Piezoelectric Sensor as Energy Harvester from Small-scale Hydropower

Renewable energy technology nowadays is advancing in research and application as an alternative for non-renewable energy sources including fossil fuels and coals since it is considerably less hazardous for the environment. In recent years, many studies to harvest energy from water energy including ocean waves and hydropower has been conducted. The inherent characteristic of the piezoelectric sensor which can convert mechanical energy to electrical energy has created an alternative to generate energy from renewable sources. The main aim of this research is to harvest energy from water movements which include self-generated water waves, automated water waves, flowing water and falling water. The piezoelectric sensor used in this research is a pressure-based piezoelectric sensor which means when there is a pressure exerted on the surface, it will generate electricity. A prototype was designed and simulated by Proteus software and the prototype was fabricated for energy harvesting from water movements. In this study, four methods had been used to harvest energy from small scale hydropower where two methods are from water waves generated from a hairdryer and ultrasonic cleaner and another two methods from falling water and flowing water. The results obtained shows that harvested energy from falling water gives the best results in which it has accumulated up to 13V in the same amount of time as compared to water waves and water flow.

Computational Fluid Dynamic Predictions on Effects of Screw Number on Performance of Single Blade Archimedes Screw Turbine

One of the alternative solutions to reduce the impact of electricity crisis in Aceh and other isolated areas in Indonesia is by the construction of small-scale hydro power plants that can work efficiently on the heads lower than 10 meters. One suitable type of turbine applied to the head below 10 meters is the Archimedes screw turbine. Due to the lack of information about the application of low head power plants, resulting in applications of this type of turbine is still less in Indonesia. This paper examined the appropriate turbine model. Before experimental turbine testing, turbines were designed theoretically first and then analyzed numerically. The flow velocity and pressure patterns within the turbine were analyzed using ANSYS CFD (Computational Fluid Dynamic) software under design conditions for 7, 9 and 11 screw numbers for single blade turbine. Based on the results of pressure analysis, speed and turbulent kinetic energy, it found that turbine performance using 11 blades is better among the three turbines. However, the highest average speed was obtained on the turbine using 7 screws, which maximum pressure obtained on a turbine 7 screws of 1406 Pa, on 9 screws on plane 1301 Pa and at 11 screws of 1175 Pa. Based on the results of the analysis, it showed that the smaller the distance between the channel and turbine blades, the results were more efficient due to the absence of wasted streams. Therefore, the flow pressure in the inlet position all directly leaded to the tip off the blade to produce a momentum.

Trends of Small Scale Hydropower Generation Using Irrigation Water in Japan

Trends of Small Scale Hydropower Generation Using Irrigation Water in Japan

Upstream passage of adult sea trout (Salmo trutta) at a low-head weir with an Archimedean screw hydropower turbine and co-located fish pass

The exploitation of riverine systems for renewable energy has resulted in large numbers of small-scale hydropower schemes on low-head weirs. Although considered a clean and ‘green’ energy source in terms of emissions, hydropower can affect upstream migrating species by diverting flow away from viable routes over the impoundment and attract fish towards the turbine outfall. In an attempt to reduce this negative effect, hydropower outfalls with co-located fish-passage entrances are recommended, utilising turbine flows to attract fish towards the fish pass. The present study used acoustic telemetry to understand the performance of a co-located Larinier fish pass at a low-head hydropower scheme at a weir on the tidal Yorkshire Esk, England. The majority of the sea trout (anadromous Salmo trutta L.) individuals that approached the impediment were attracted to the hydropower and the co-located fish pass. Fish ascended through the pass under a wide range of river flows, tide heights, downstream river levels and hydropower flows, and there was no evidence that the hydropower operation affected fish-pass ascent. The information presented is urgently required to inform management decisions on the operation of hydropower schemes during the migratory period of salmonid fish, and help determine best-practice designs and operation at these facilities.

Evaluation of small-scale hydropower potential in watersheds using a rainfall-runoff model

Meza-Prieto. B., & Aparicio, J. (enero-febrero, 2018). Evaluacion del potencial hidroenergetico a pequena escala en cuencas hidrologicas con un modelo lluviaescurrimiento. Tecnologia y Ciencias del Agua , 9 (1), 69-87, DOI: 10.24850/j-tyca-2018-01-05. Una manera de impulsar proyectos con base en energias renovables, como los sistemas hidroelectricos a pequena escala, es determinando los lugares viables para el emplazamiento de dichos proyectos y la energia que podria explotarse. En este trabajo se expone un metodo de sencilla aplicacion para estimar el potencial hidroenergetico en cuencas hidrologicas. La bondad principal del metodo se debe al empleo de software libre para la modelacion hidrologica continua. Se utiliza el software ArcGis 10.1 para realizar la delimitacion y el procesamiento cartografico de las subcuencas hidrologicas y el trazo de perfiles longitudinales de cauces. Los criterios establecidos para la seleccion de sitios disponibles fueron los siguientes: pendiente del rio de al menos 3% y el desnivel topografico de tres metros o mas. Se elige un periodo comun de precipitacion y caudal medio diario para calibrar y validar el modelo hidrologico semidistribuido Soil Moisture Accounting ( SMA ). El metodo SMA es una herramienta adecuada para conocer el caudal medio en cuencas no aforadas. Se encontraron 578 sitios con un potencial hidroenergetico bruto de 49.2 MW. La metodologia empleada es practica, porque requiere conocimientos basicos de sistemas de informacion geografica y del manejo de HEC-HMS . La evaluacion economica muestra inversiones iniciales de $3,672,636.00 pesos mexicanos en promedio. Ante tales costos, puede ser factible invertir, si se considera una planeacion a largo plazo. El Q 90 es una buena alternativa para el diseno de pequenas centrales hidroelectricas al hilo de agua.

The challenge of sustainability in China's built environment: a comparison between urban and rural areas

The rapid economic growth in China is accompanied by an ever-increasing demand for energy in both urban and rural areas. Since 1978, China has experienced an annual growth rate of 4.98% in primary energy resources production. The primary energy consumption from 2000 to 2009 recorded an annual growth rate of 9.4%. Ostensibly, it is important to upgrade the power generation units and improve air quality. To enhance air quality, this article suggests the adoption of small-scale hydropower and biomass energy in rural areas and the construction of green and smart buildings in urban areas. Improvement in regulations and enforcement is also considered to be another useful means in enhancing urban sustainability. The adoption of big data and artificial intelligence in optimising the building and architecture design may be one of the major directions in moving toward sustainable built environment in urban areas.

A Case Study of Status and Potential of Small Hydro-Power Plants in Southern African Development Community

The Southern African development community is having a major challenge in connection with desires for energy in the region. There is the need to increase energy security and admittance to modern energy services immediately, particularly in the rural areas as well as addressing the challenges posed by the current energy systems on human health and the environmental. The rapid growth of renewable energy capacity in the region contains all the potentials that can answer to quite a lot of problems for instance: rapidly increasing electricity saturation, including remote areas detached from the grid infrastructure. Old resources need to be replaced as well as producing new once to adequately generate to meet the growing demand. Renewable energy and energy-efficient technologies in addition to services are an essential part of the new energy dynamic in the region. To meet these demands, the region needs to, rapidly develop and connect existing renewable energy resources and embrace energy efficiency, as a matter of priority. The existing potential sites in the region are mentioned and Small-scale hydropower is one of the most cost-effective energy technologies to be considered for electrification in the countries since it has low environmental impacts and can have a significant benefit if implemented in rural areas for electricity production. There is therefore the need for all development community, policy makers and regulators, local and global investors, developers and project promoters to support by providing funds, making good policies to protect the energy sector in other to solve the problem.

An Experimental Investigation of the Performance of Cross-flow Hydro Turbines

Renewable energy is the need of developing countries and cross-flow turbine is a promising means of small scale hydro-power production in locations where available head and discharge is comparatively low. The present work refers to experimental analysis of performance of cross-flow turbine for low head, low discharge sites. The work deals with the key parameters influencing the efficiency of the cross-flow hydraulic turbine which includes outer diameter of runner, breadth of the runner, angle of attack, thickness of water jet, spacing of blades in the runner, radius of blades curvature, number of blades, the blade exit angle for first stage and angle between relative velocity of entering water jet and turbine outer periphery. The variation of efficiency and runner speed with different angle of attack, nozzle tip elevation and nozzle tip distance from runner is analyzed in the present work. The runner consists of 12 blades symmetrically arranged between two circular end plates at the plate periphery. The setup is prepared for the sites where head available is relatively medium or low. The inlet angle β1 of blade is maintained at around 26º to 28º and outlet angle β2 as 90º i.e. outlet is radial. The key parameters such as nozzle inlet angle, nozzle tip elevation and its horizontal distance from center of the runner shaft are varied for different heads as per different site configurations.

The Small-Scale Hydropower Plants in Sites of Environmental Value: An Italian Case Study

Since ancient times water has been accompanying technological change in the energy sector. Used as a source of hydraulic energy, it currently generates one-fifth of the global electricity production. However, according to collective imagination, hydroelectric plants are constructions of high environmental, acoustic, and visual impact, which may harm the preservation of the territory. This paper intends to address the topic of mini-hydropower that, in addition to providing the production of renewable energy, ensures a limited environmental impact even in delicate contexts with high landscape values, by elaborating a research methodology that makes these interventions compatible with them. The process of “global compatibility” checks developed to assess the feasibility of the intervention will be explained in the paper. We intend to describe here the research process undertaken to make the planning of this type of system sustainable, in contexts that need to be rehabilitated in relation both to the accessibility of citizens and to the environmental enhancement. The intervention planned will be characterized by the combined use of other renewable energy sources, in addition to water. The proposed methodology has been tested on a case study in the village of Roccacasale, in the province of L’Aquila.

Operation of Small-Scale Hydro Power Plants by Agricultural Cooperatives in the Chugoku Region and the Effects of the Feed-in Tariff on them

This study focused on the operation of small hydro power plants (generating 1,000 kW of power or less) owned by agricultural cooperatives in the Chugoku Region, and the effects of the Feed-in Tariff Scheme on their operation. The results reveal that the plants have provided employment opportunities in local communities, and suggest that the development of community power first requires financial support to revamp the plants and then further support to bring in a new generation of technicians to maintain them.

A new nozzle design methodology for high efficiency crossflow hydro turbines

Small-scale hydropower systems are mainly used in remote locations for generating electricity where reasonable hydropower resources are available. Many small-scale systems employ crossflow turbines due to their simplicity in design and manufacture, low cost, sturdy construction and longer life-span. However, compared to most advanced and efficient designs, such as Pelton and Francis turbines, they suffer from a lower maximum efficiency. In a crossflow turbine, the nozzle increases the velocity of the flow and directs it at a suitable angle to the runner whose axis is tangential to the flow. The runner extracts the angular momentum of the flow. Therefore, the runner entry flow is critical for the turbine efficiency. However, it is not yet known clearly how the entry flow affects the runner performance and how the best nozzle can be designed. This study presents a new nozzle design method so that high efficiency crossflow turbines can be designed. An analytical model is formulated to convert the head into kinetic energy at the entry and obtain a suitable flow angle. Three-dimensional Reynolds-Averaged Navier-Stokes simulations were conducted on a 7kW turbine with a measured maximum efficiency of 69% and a 0.53kW turbine with a maximum efficiency of 88%. The predictive capability of the computational model was assessed by comparing the computational and experimental results for the power over a range of operating conditions on both turbines. By redesigning only the nozzle of the 7kW turbine by the new method, the maximum efficiency increased from 69% to 87%. Thus the nozzle design has a significant influence on turbine performance, and we conclude that the conversion of head into kinetic energy and matching of the nozzle flow with the runner design are fundamental in turbine design.

The Role of Large and Small Scale Hydropower for Energy and Water Security in the Spanish Duero Basin

Hydropower has been increasingly seen as a two-fold solution to the provision of renewable energy and water storage. However, the massive deployment of both large and small scale hydropower projects has been reported to cause important environmental impacts at the basin scale. This study assesses the differential contributions to regional energy and water security of large (LHP) and small (SHP) scale hydropower deployment in the Spanish Duero basin, as well as associated cumulative environmental impacts. This is performed through a selection of indicators measured in absolute and relative terms. The results suggest that LHP deployment contributes more to energy and water security, performing better in 10 of the 12 indicators. It also shows higher absolute environmental impacts on flow regime and habitat loss. Meanwhile, when analyzed in relative terms, SHP shows greater impacts in all categories as a result of cumulative effects cascading along the rivers system. These findings suggest that optimizing the use of existing hydropower infrastructure would be beneficial for energy, water and environmental security. This could be implemented by substantially reducing the number of low capacity plants with almost no impact on final energy generation, while enhancing the pumping and storage potential of higher capacity plants.