scholarly journals Operating Small Hydropower Plants in Greece under Intermittent Flow Uncertainty: The Case of Tsiknias River (Lesvos)

Challenges ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 17 ◽  
Author(s):  
Ourania Tzoraki

In arid and semi-arid parts of the world, river exploitation is intensive, involving water storage for irrigation or hydropower generation. In Greece, 100 small hydropower plants (SHPs) take advantage of less than 10% of the hydropower potential of low flow streams (<2 m3/s), a very small amount in relation to the 70% of the European Union. The energy policy of complete decarbonization of the country by 2023 on a national scale opens the road for new investments in SHP projects, especially in intermittent-flow streams of the Greek islands. Simulated flows by the Modello Idrologico SemiDistribuito in continuo (MISDc model) are used to construct the annual flow duration curve (FDC) to study and assess the hydropower potential of an intermittent stream (Tsiknias river, Lesvos, Greece). For Tsiknias River, but also for six other intermittent-flow rivers of Crete island, the capacity factor (CF), which represents the mean annual power of the hydropower plant, should remain >75% to exploit the river’s potential. The FDC and CF are essential in designing SHP projects in intermittent-flow streams with long no-flow periods. The development of public participatory approaches and a closer cooperation among policy makers and stakeholders should work to promote hydropower exploitation and accelerate licensing procedures.

2020 ◽  
Vol 15 (3) ◽  
pp. 267-276 ◽  
Author(s):  
Kyu Kyu Thin ◽  
Win Win Zin ◽  
Zin Mar Lar Tin San ◽  
Akiyuki Kawasaki ◽  
Abdul Moiz ◽  
...  

The need for electricity is rapidly increasing, especially in developing countries. There is vast hydropower potential existing globally that has not yet been explored. This could be the only solution to solve future global power shortage. Hydropower is a clean and renewable source of energy because it does not exploit the use of water. However, using the conventional approach to harness hydropower results in several challenges. It is difficult to identify suitable sites and assess site potential during the planning stage of hydropower projects. In this study, run-of-river hydropower potential for the Myitnge River Basin was estimated by intergrating a Geographic Information System (GIS) and Soil & Water Assessement Tool (SWAT) model. A GIS based tool was developed using Python to spot the potential locations of the hydropower plants. The hydrological model (SWAT) was designed in order to obtain the values of monthly discharge for all potential hydropwer sites. The flow duration curves at potential locations were developed and the design discharge for hydropower was identified. Forty-four run-of-river (ROR) type potential hydropower sites were identified by considering only the topographic factors. After simulation with SWAT model, twenty potential sites with a hydropower generation potential of 292 MW were identified. Currently, only one 790 MW Yeywa Hydropower Plant, which is the largest plant in Myanmar, exists in the Myitnge River Basin. The amount of estimated power generated from ROR may increase the existing power system of Myitnge Basin by 36%. This study will assist stakeholders in the energy sector to optimize the available resources to select appropiate sites for small hydropower plants with high power potential.


Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 266
Author(s):  
Md Rakibuzzaman ◽  
Sang-Ho Suh ◽  
Hyoung-Ho Kim ◽  
Youngtae Ryu ◽  
Kyung Yup Kim

Discharge water from fish farms is a clean, renewable, and abundant energy source that has been used to obtain renewable energy via small hydropower plants. Small hydropower plants may be installed at offshore fish farms where suitable water is obtained throughout the year. It is necessary to meet the challenges of developing small hydropower systems, including sustainability and turbine efficiency. The main objective of this study was to investigate the possibility of constructing a small hydropower plant and develop 100 kW class propeller-type turbines in a fish farm with a permanent magnet synchronous generator (PMSG). The turbine was optimized using a computer simulation, and an experiment was conducted to obtain performance data. Simulation results were then validated with experimental results. Results revealed that streamlining the designed shape of the guide vane reduced the flow separation and improved the efficiency of the turbine. Optimizing the shape of the runner vane decreased the flow rate, reducing the water power and increasing the efficiency by about 5.57%. Also, results revealed that tubular or cross-flow turbines could be suitable for use in fish farm power plants, and the generator used should be waterproofed to avoid exposure to seawater.


Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1041
Author(s):  
Francisco Javier Sanz-Ronda ◽  
Juan Francisco Fuentes-Pérez ◽  
Ana García-Vega ◽  
Francisco Javier Bravo-Córdoba

Fish need to move upstream and downstream through rivers to complete their life cycles. Despite the fact that fishways are the most commonly applied solution to recover longitudinal connectivity, they are not considered viable for downstream migration. Therefore, alternative facilities are recommended to facilitate downstream migration. However, a few recent studies have disagreed with this general assumption, showing the potential for bidirectional movements. This study advances our understanding of the potential of fishways for downstream migration by studying their efficiency in a run-of-the-river hydropower plant in the Duero River (Spain). To achieve this, downstream movements of the Iberian barbel (n = 299) were monitored in a stepped fishway for two years with passive integrated transponder (PIT)-tag technology, considering the effect of fish origin and release zone. The results showed that 24.9% of barbels descended through the fishway, with the origin and release zone affecting the fishway location. In addition, downstream movements were observed throughout the whole year, except in winter. The study concludes that, under specific scenarios, fishways could act as safe alternative routes for downstream migration.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Alberto Scotti ◽  
Roberta Bottarin

AbstractThe present dataset contains information about aquatic macroinvertebrates and environmental variables collected before and after the implementation of a small “run-of-river” hydropower plant on the Saldur stream, a glacier-fed stream located in the Italian Central-Eastern Alps. Between 2015 and 2019, with two sampling events per year, we collected and identified 34,836 organisms in 6 sampling sites located within a 6 km stretch of the stream. Given the current boom of the hydropower sector worldwide, and the growing contribution of small hydropower plants to energy production, data here included may represent an important – and long advocated – baseline to assess the effects that these kinds of powerplants have on the riverine ecosystem. Moreover, since the Saldur stream is part of the International Long Term Ecological Research network, this dataset also constitutes part of the data gathered within this research programme. All samples are preserved at Eurac Research facilities.


2021 ◽  
Vol 8 ◽  
Author(s):  
Claire Kathryn Aksamit ◽  
Mauro Carolli ◽  
Davide Vanzo ◽  
Christine Weber ◽  
Martin Schmid

As the demand for hydroelectricity progresses worldwide, small hydropower operators are increasingly examining the feasibility of using existing infrastructure (e.g., settling basins) in run-of-the-river schemes for intermittent power production. Such flexible production causes short-term discharge fluctuations (hydropeaking) in downstream reaches with potential adverse effects for the sensitive fauna and flora in alpine streams. In an experimental field study on a previously unregulated section of the upper Rhone River (Switzerland), we measured density and composition of macroinvertebrate drift in two habitats (riffle, pool) following a 15-minute hydropeaking wave. The experimental hydropeaking was replicated five times over 14 days with decreasing recovery times between peaks (8, 3, 2 days, and 24 h), and drift measurements were compared with kick samples for the benthic community. Results from the kick sampling showed that benthic macroinvertebrate abundance and composition did not significantly change between the experimental peaks. There were habitat specific reactions in macroinvertebrate drift to hydropeaking, with the pool experiencing more pronounced drift abundances than the riffle. Overall, drift abundance was not significantly correlated with recovery time, but results indicate taxa-specific differences. This research advocates for the importance of completing more in-situ field experiments in order to better understand the ecological impact of flexible power production in small hydropower plants.


Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2103 ◽  
Author(s):  
Martin Polák

Pumps as turbines (PAT) are used as an alternative to water turbines in small hydropower plants. The same devices can also be used for energy recovery in water distribution networks. They can replace pressure reduction valves that often lead to energy loss. However, PATs lack the parts that regulate flow so that when a hydropower potential change occurs, efficiency is reduced, as is economic gain. This article summarizes the influence of changing hydropower potential on PAT efficiency and presents comparisons of experimental results with the commonly used predictive model stemming from the theory of physical similarity, which presumes constant PAT efficiency. Our research indicates that the deviation between the model and the real power output calculation at varying potentials was minimal. Similarly, the affine parabola can be used to determine the relationship between total head and flow rate. Other relationships differ from reality the more the PAT efficiency changes. The flow rate and total head dependence on shaft speed are the main factors when setting the optimum operational parameters at varying hydropower potentials. Therefore, a change in efficiency must be included in predictive calculations to correctly optimize PAT operation. The problem is that a change in efficiency cannot be reliably predicted in advance, especially in the case of small-scale devices. For this reason, further research on the issue of changes in PAT efficiency is necessary.


Author(s):  
Sumer Chand Prasad

In this chapter the emerging control techniques for 25 MW small hydropower (SHP) plants which utilize fuzzy logic are compared with conventional PID control for the speed control of hydraulic turbine in terms of rise time, smoothness of response, settling time, and overshoot in wicket gate opening with the response to change in turbine speed. In the case of the PID controller, gain adjustment (tuning) is required. The fuzzy controller algorithm is based on intuition, experience, and it incorporates a simple, rule-based IF X AND Y THEN Z approach. These controllers obtained don't require gain adjustment. The work done is a small step towards the automation of the hydropower plants.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 826
Author(s):  
Geoffrey Gasore ◽  
Helene Ahlborg ◽  
Etienne Ntagwirumugara ◽  
Daniel Zimmerle

In Rwanda, most small-scale hydropower systems are connected to the national grid to supply additional generation capacity. The Rwandan rivers are characterized by low flow-rates and a majority of plants are below 5 MW generation capacity. The purpose of this study is to provide a scientific overview of positive and negative factors affecting the sustainability of small-scale hydropower plants in Rwanda. Based on interviews, field observation, and secondary data for 17 plants, we found that the factors contributing to small-scale hydropower plant sustainability are; favorable regulations and policies supporting sale of electricity to the national grid, sufficient annual rainfall, and suitable topography for run-of-river hydropower plants construction. However, a decrease in river discharge during the dry season affects electricity production while the rainy season is characterized by high levels of sediment and soil erosion. This shortens turbine lifetime, causes unplanned outages, and increases maintenance costs. Further, there is a need to increase local expertise to reduce maintenance cost. Our analysis identifies environmental factors related to the amount and quality of water as the main current problem and potential future threat to the sustainability of small-scale hydropower. The findings are relevant for energy developers, scholars, and policy-makers in Rwanda and East Africa.


Author(s):  
Burak Omer Saracoglu

<p>Turkey is a country that has had to deal with high electricity consumption due to its rapid growth and development. Attempts have been made to address this increase in demand by increasing the electricity supply by means such as boosting resources by privatization. The electricity generation sector has been privatized in Turkey; hence investors have been looking for the most appropriate electricity generation projects for a long while. Therefore, researchers and practitioners should focus on how the most suitable small hydropower plant project (SHPP) investments can be selected. In this study, the Analytic Hierarchy Process (AHP) was applied to make the most appropriate and satisfying decision according to the decision makers, experts or investors for a SHPP investment from amongst some alternative SHPP investments in Turkey. All of these SHPPs were assumed to be in the pre-development investment stage, which indicated that their pre-feasibility and feasibility studies had not been presented or taken into consideration until this study was performed. This main constraint forced the researchers to obtain the data and information from the information forms such as the application document to the General Directorate of State Hydraulic Works during the data and information gathering process. The AHP model of this study was structured in four levels with five main criteria, seventeen basic criteria and five alternatives on the Super Decisions Software. The results indicated that Alternative 1 and Alternative 5 should be primarily investigated in detail in subsequent SHPP investment investigation steps.</p>


Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2419
Author(s):  
Vidosava Vilotijević ◽  
Uroš Karadžić ◽  
Radoje Vujadinović ◽  
Vuko Kovijanić ◽  
Ivan Božić

Designing a small hydropower plant (SHPP) necessitates fulfillment of energy and ecological constraints, so a well-defined design flow is of the utmost significance. The main parameters of each SHPP are determined by appropriate techno-economic studies, whereas an improved approach to defining more precise SHPP installed parameter is presented in this paper. The SHPP installed parameter is the ratio of the design flow and averaged perennial flow obtained from the flow duration curve at the planned water intake location. Previous experiences in the design of SHPPs have shown that the SHPP installed parameter has a value in a wide range without the existence of an unambiguous equation for its determination. Therefore, with this aim, the thirty-eight (38) small watercources in the territory of Montenegro, denominated for the construction of SHPPs, have been investigated. SHPPs are divided into two groups depending on the installed capacity and the method of calculating the purchase price of electricity. For both groups, the range of SHPP installed parameter is determined according to the technical and economic criteria: the highest electricity production, the highest income, net present value (NPV), internal rate of return (IRR), and payback period (PB).


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