Search Results (29)

This article devises the Artificial Intelligence (AI) methods of designing models of short-term forecasting (in 12 h and 24 h horizons) of electricity production in a selected Small Hydropower Plant (SHP). Renewable Energy Sources (RESs) are difficult to predict due to weather variability. Electricity production by a run-of-river SHP is marked by the variability related to the access to instantaneous flow in the river and weather conditions. In order to develop predictive models of an SHP facility (installed capacity 760 kW), which is located in Southern Poland on the Skawa River, hourly data from nearby meteorological stations and a water gauge station were collected as explanatory variables. Data on the water management of the retention reservoir above the SHP were also included. The variable to be explained was the hourly electricity production, which was obtained from the tested SHP over a period of 3 years and 10 months. Obtaining these data to build models required contact with state institutions and private entrepreneurs of the SHP. Four AI methods were chosen to create predictive models: two types of Artificial Neural Networks (ANNs), Multilayer Perceptron (MLP) and Radial Base Functions (RBFs), and two types of decision trees methods, Random Forest (RF) and Gradient-Boosted Decision Trees (GBDTs). Finally, after applying forecast quality measures of Mean Absolute Error (MAE), Mean Absolute Percentage Error (MAPE), and Coefficient of Determination (R²), the most effective model was indicated. The decision trees method proved to be more accurate than ANN models. The best GBDT models’ errors were MAPE 3.17% and MAE 9.97 kWh (for 12 h horizon), and MAPE 3.41% and MAE 10.96 kWh (for 24 h horizon). MLPs had worse results: MAPE from 5.41% to 5.55% and MAE from 18.02 kWh to 18.40 kWh (for 12 h horizon), and MAPE from 7.30% to 7.50% and MAE from 24.12 kWh to 24.83 kWh (for 24 h horizon). Forecasts using RBF were not made due to the very low quality of training and testing (the correlation coefficient was approximately 0.3). Full article

Small-scale hydropower plants (SHP) have been losing competitiveness compared to other renewable sources in the global electricity matrix due to technical, environmental, regulatory, and economic issues. In this context, and to contribute to the development and strengthening of SHP’s integration into the country’s electricity matrix, this study proposes the Balanced Scorecard (BSC) as a strategic evaluation tool for SHP projects from the prospecting phase to the pre-implementation phase, taking into account financial and non-financial performance indicators. This study aims to structure a strategic map of the SHP source composed of economic, socio-environmental, institutional, and technical perspectives, adapted to the four perspectives of the BSC, with the required performance indicators for the strategic evaluation of SHP. The development of a computer program allowed data visualization from eight case studies focusing on indicators or perspectives that jeopardize the project’s strategic viability. The results showed that (i) the adaptation of the BSC methodology for the strategic evaluation of SHP feasibility proved effective and (ii) the developed computer program demonstrated robustness and effectiveness in analyzing SHP, even in different stages of development and with different technical and environmental characteristics. Finally, the strategic evaluation of SHP feasibility is an effective tool in assisting decision makers, indicating the positive aspects and weaknesses of the project under evaluation and providing a better understanding of the asset and the areas of development that deserve greater attention to improve its performance. Full article

Water is the basis of life for living creatures and is used for various purposes, especially in agriculture, industry, municipal services, and energy production. Assessing water quality in terms of its various uses is not without significance. This study investigates the water quality within two small hydropower plants (SHPs) in central European urban areas from an environmental perspective. Wrocław I and Wrocław II SHPs on the Odra River in Poland were selected as case studies. This study presents the results of four-year observations (2017–2020) conducted in different locations located upstream and downstream of the barriers. The following aspects were assessed: physicochemical status, trophic status, assessment of fish living conditions, and water quality indices. The results show that SHPs improved the average physicochemical status of the five-day biochemical oxygen demand (i.e., BOD₅; by 6.19% comparing the results downstream and upstream of the SHPs), dissolved oxygen (3.85%), PO₄-P (3.31%), and electrical conductivity (0.52%); however, they worsened in the case of the pH (by 2.63%) and NO₃-N (by 1.83%). Water near the study cases is classified as mesotrophic or eutrophic. The conditions for salmonids and cyprinids were not met due to the increased concentrations of NO₂ and BOD₅ values; in the case of salmonids, also due to the temperature and dissolved oxygen concentration. The water quality indices differed and indicated the quality from poor to good, depending on the classification. This study provides important insights for policymakers regarding the awareness of the impacts of SHPs on water quality in urban areas and the immediate measure needed to be considered to improve aquatic habitat conditions. Full article

There is currently a growing trend towards renewable energy sources, which are characterised by a guaranteed power supply and low failure rate. Hydropower plants (small or large) are an example of such a source. They supply a total of 16% of the world’s electricity. The advantages of a small hydropower plant include the relatively simple construction process and the lack of need for upstream water storage. SHPs are one of the most cost-effective and environmentally friendly energy technologies, which is why they are steadily increasing in popularity. One of the important components of SHPs are the trash racks in the inlet channels. Their main purpose is to catch debris and other elements carried downstream and to prevent these pollutants from reaching the turbine units. They can also protect migrating ichthyofauna such as larger fish. If trash racks are installed in the inlet channel, hydraulic losses are to be expected due to the reduction in the flow cross-section through the racks (bars) themselves and through the accumulation of debris and various types of trash on these racks. Energy losses on the trash racks affect the financial aspect of SHP investments. This paper presents the results of laboratory tests on trash racks for SHPs by taking into account the different shapes of the bars used, their number and spacing, and the angles of the trash racks to estimate the hydraulic losses on the trash racks. The measured values of hydraulic losses Δh on the trash racks varied according to the type of trash racks, the density of the bars in the cross-section, and the angle of the trash racks from the horizontal, reaching the highest values on the trash racks with angle bars (AB). They were almost eight times greater than those recorded on cylindrical-bar (CB) trash racks, although they involved different angles. It was shown that the discrepancy in the magnitude of losses on trash racks can be large, even for the same type of trash racks. It depends significantly on the design (shape and bar spacing) of the trash racks and the way the trash racks are installed. Depending on the inclination angle, the increase in energy losses reached 70% for angle bars, 60% for flat-bar trash racks, and almost 40% for cylindrical bars. The values of energy loss as well as the loss coefficient β varied non-linearly for the different bar types depending on the angle of inclination of the gratings, and the degree of this non-linearity depended on the type of bars and the blockage ratio of the section. The presented research results can be useful both during the design and the operation of an SHP. Full article

Before selecting a proper hydraulic turbine for power generation, conflicting factors frequently emerge from the wide range of available technology alternatives. The preliminary selection of hydraulic turbines (PSHT) has been usually carried out by overlooking and/or overshadowing downstream and upstream processes. The development of a new conceptual framework that allows for including more parameters into the decision-making process at company levels is still required to avoid the danger of engaging in a one-dimensional approach, which would not only result in a reduced and simplistic vision of the choice but would also overlook the trade-offs between individual aspects and the possible unintended side-effects. This paper aims to provide empirical evidence for the PSHT by proposing a well-thought-out framework based on a mixed methodology approach (analytical hierarchy process (AHP) and fuzzy-VIKOR multi-criteria methods) and focused on small hydropower projects. A total of 16 criteria are proposed and divided into 4 main categories—(i) turbine performance, (ii) turbine and generator costs, (iii) other equipment costs, and (iv) civil costs. Findings reported here reveal a specific alignment between investors’ preferences and experts’ judgments with real market practices. The 16 proposed criteria can be further considered to support the decision-making process for PSHT in different head and flow conditions. Full article

Obtaining energy from renewable resources is a worldwide trend in the age of increasing energy demand. Hydropower has some potential in this field, especially for low-power locations. However, construction of such facilities requires high expenses, which is why some attempts at lowering the costs have been made, i.e., by proposing alternative solutions to the classic ones. This paper proposes a selection of options for small hydropower plants (SHP) that lower the investment costs while keeping up profitable operations. The proposed solutions concern simplifying the turbine’s and generator’s integration by installing them in dedicated prefabricated concrete modules. A rare but simple and cheap semi-Kaplan type of turbine with a non-classical spiral inflow is proposed. The turbine operates a permanent magnet (PM)-excited generator, converting the energy at a variable rotational speed. Thanks to this approach, it is possible to simplify the regulation system and eliminate expensive mechanical transmission. However, on the power grid side, a power electronic converter (PEC) must be coupled with the generator. The advantage of this solution compared to the classical ones is that the reliability of power electronics is much higher than that of mechanical systems. This paper presents modeling research on semi-Kaplan turbines’ series development, and a dedicated PM generator is presented as an example of a complete hydro unit with 50 kW power. Full article

The present paper indicates that hydropower, including small hydropower plants (SHPs), may play a very important role in Poland’s energy transformation in the near future. The development of SHPs may also increase water resources in the steppe Poland. Additionally, the aim of the present research is to conduct the PEST analysis of SHPs in Poland, taking into account the SHP potential. For the first time, maps showing the power and location of potential SHPs on the existing dams in Poland are presented. SHPs should be an important element of energy transition in Poland, especially on a local scale—it is stable energy production. Our analysis shows that there are 16,185 such dams in Poland, while the total capacity of potential hydropower plants in Poland would be 523.6 MW, and the total number of new jobs is estimated at 524. It was calculated that the annual avoided carbon dioxide emissions will amount to 4.4 million tons, which will reduce Poland’s emissions by 1.4%. The construction of SHPs can bring significant environmental and economic benefits. As far as the PEST analysis is concerned, the political environment of SHPs in Poland can be described as unfavorable (2.86 points). The economical nature of PEST analysis (3.86 points) should be considered as friendly for the development of SHPs. The social nature of PEST analysis can be considered as neutral (3.36 points). The technological nature of the PEST analysis can be considered as neutral (3.21 points). Full article

Hybrid hydro energy systems are usually analysed with pumped hydro storage systems, which can facilitate energy accumulation from other sources. Despite the lack of water storage, run-of-the-river hydropower plants are also attractive for hybrid systems owing to their low investment cost, short construction time, and small environmental impact. In this study, a hybrid system that contains run-of-the-river small hydro power plants (SHPs), PV systems, and batteries to serve local loads is examined. Low-power and low-head schemes that use variable-speed operation are considered. The novelty of this study is the proposal of a dedicated steady-state model of the run-of-the-river hydropower plant that is suitable for energy production analysis under different hydrological conditions. The presented calculations based on a real SHP of 150 kW capacity have shown that a simplified method can result in a 43% overestimation of the produced energy. Moreover, a one-year analysis of a hybrid system operation using real river flow data showed that the flow averaging period has a significant influence on the energy balance results. The system energy deficiency and surplus can be underestimated by approximately 25% by increasing the averaging time from day to month. Full article

Renewable energy sources (RES) play an important role in the European Union’s energy sector as a result of the energy policy framework adopted. Its share in the final energy consumption varies depending on the country and the adopted energy policy. The article presents the structure of electricity production from renewable energy sources in Poland in the years 2002–2019. It was found that the share of energy production from hydroelectric power plants in Poland in relation to the amount of energy produced from renewable energy sources in the analyzed years has strongly decreased. The reason for this state was an increase in the production of energy coming from wind and biomass energy combined with an increase in subsidies for these energy producers. Additionally, unstable hydrological conditions, mainly low river flows, may be the reason for the low share of energy produced in power plants. As a case study, data for five small hydropower plants (SHP) located on the Gwda river (north-western Poland) were analyzed. Electricity production volumes were analyzed depending on the size of the Gwda river flow. It was found that the lower amount of electricity produced at SHPs on the Gwda river is mainly due to lower flows in the river. In the future, unstable electricity production from renewable energy sources may have a significant impact on achieving Poland’s energy targets in 2030. Full article

Energy is the prerequisite for social and economic development of a community and country. In Japan, national government is promoting small hydropower (SHP) through a renewable energy policy by providing a high FIT price of 34 yen (≒0.32 US$/kWh) on energy generated from an SHP of less than 200 kW. Until now, the energy generation was controlled by national government agencies, but now independent power generation businesses are growing at the local community level in rural Japan. For the future growth of SHP, it is necessary to make electricity generation at the local community level. Therefore, these local communities will install and manage their renewable electricity by themselves. It will help to make the community self-sustainable and independent from the national government, and at the same time, it will also lead them to achieve the Sustainable Developments Goals (SDGs) target from community-based action. This paper aimed to discuss an SHP development business model in which local community will become the business owner of the SHP. It means “of the community, by the community and for the community”. The community identifies their renewable energy potential and needs, they borrow money from the financial organization or banks, install the power plant and do necessary maintenance and management by themselves. The revenue earned by selling electricity is used to repay the loan, and the rest is used for community development directly (such as local roads construction, agriculture land improvements, community hall maintenance, waterways maintenance, welfare, etc.). This paper also discussed a community-based 50 kW SHP installed in Miyazaki prefecture of Japan as a case study. This SHP is one of the best examples of a community ownership model (Community-based business model). A detailed explanation from planning to investment has been discussed. The local community is getting approximately 112,000 USD per year by selling the electricity, and 162-ton CO₂ is estimated to decrease yearly, which will support the achievement of SDGs. Finally, installing this kind of SHP in remote areas will provide managerial skills to the local community directly, plant operation knowledge, and education to local students. Local communities learn the problem-solving skills, which lead them to solve the local problem on a community level by themselves. Full article

The interest in renewable energy to replace fossil fuel is increasing as the problem caused by climate change has become more severe. In this study, small hydropower (SHP) was evaluated as a resource with high development value because of its high energy density compared to other renewable energy sources. SHP may be an attractive and sustainable power generation environmental perspective because of its potential to be found in small rivers and streams. The power generation potential could be estimated based on the discharge in the river basin. Since the river discharge depends on the climate conditions, the hydropower generation potential changes sensitively according to climate variability. Therefore, it is necessary to analyze the SHP potential in consideration of future climate change. In this study, the future prospect of SHP potential is simulated for the period of 2021 to 2100 considering the climate change in three hydropower plants of Deoksong, Hanseok, and Socheon stations, Korea. The results show that SHP potential for the near future (2021 to 2040) shows a tendency to be increased, and the highest increase is 23.4% at the Deoksong SPH plant. Through the result of future prospect, we have shown that hydroelectric power generation capacity or SHP potential will be increased in the future. Therefore, we believe that it is necessary to revitalize the development of SHP to expand the use of renewable energy. In addition, a methodology presented in this study could be used for the future prospect of the SHP potential. Full article

Small hydropower (SHP) plants are advantageous as they have a short construction period and can be easily maintained. They also have a higher energy density than other alternative energy sources as environmentally-friendly energy sources. In general, hydropower potential is estimated based on the discharge in the river basin, and the discharge can be obtained from the stage station in the gaged basin. However, if there is no station (i.e., ungaged basin) or no sufficient discharge data, the discharge should be estimated based on rainfall data. The flow duration characteristic model is the most widely used method for the estimation of mean annual discharge because of its simplicity and it consists of rainfall, basin area, and runoff coefficient. Due to the characteristics of hydroelectric power depending on the discharge, there is a limit to guaranteeing the accuracy of estimating the generated power with only one method of the flow duration characteristic model. Therefore, this study assumes the gaged basins of the three hydropower plants of Deoksong, Hanseok, and Socheon in Korea exist as ungaged basins and the river discharges were simulated using the Kajiyama formula, modified-TPM(Two-Parameter Monthly) model, and Tank model for a comparison with the flow duration characteristics model. Furthermore, to minimize the uncertainty of the simulated discharge, four blending techniques of simple average method, MMSE(Multi-Model Super Ensemble), SMA(Simple Model Average), and MSE(Mean Square Error) were applied. As for the results, the obtained discharges from the four models were compared with the observed discharge and we noted that the discharges by the Kajiyama formula and modified-TPM model were better fitted with the observations than the discharge by the flow duration characteristics model. However, the result by the Tank model was not well fitted with the observation. Additionally, when we investigated the four blending techniques, we concluded that the MSE technique was the most appropriate for the discharge simulation of the ungaged basin. This study proposed a methodology to estimate power generation potential more accurately by applying discharge simulation models that have not been previously applied to the estimation of SHP potential and blending techniques were also used to minimize the uncertainty of the simulated discharge. The methodology proposed in this study is expected to be applicable for the estimation of SHP potential in ungaged basins. Full article

In terms of fuel resource, hydropower possesses a prominent advantage over any other large power plants which burn fossil fuels to generate electricity. Moreover, due to the abundance in resource availability (as a domestic source in small streams and rivers), small hydropower (SHP) plants are showing prominence all over the world. SHP plants have led to improved access to electricity usage in under-developed and developing nations, thereby contributing to sustainable development goals and social empowerment. SHP, as a technology, is regarded as the largest density renewable resource with high adaptability, and low investment costs. The primary objective of the paper is to study and analyze recent developments in SHP technologies with reporting statistical figures in terms of installed capacity and MW potential in several parts of the world. Methodologies adopted by researchers to conduct techno-economic analysis of SHP projects are reviewed. Various costs involved in conducting pre-feasibility studies—such as constructing, maintaining, and sustainably operating SHP projects—are studied. The results of the study indicate cost and regulatory issues are the major factors affecting the growth of the small hydropower sector in many nations. Major impediments to construction, development and deployment of SHP projects, mutually existing among the nations worldwide, are also reported. Technical hindrances include non-availability of the grid and very limited accessibility to SHP sites, emissions due to storage of water, disruptive technologies with limited manpower and non-technical hindrances include discouragement from local bodies and groups, lack of suitable and precise pathways to accomplish SHP goals of a nation, lack of incentives for encouraging private players to invest in SHP projects, complex approval processes, and many more. Full article

Hydropower plants produce renewable and sustainable energy but affect the river’s physico-chemical characteristics and change the abundance and composition of the aquatic organisms. The impact of large HPPs on the ecological conditions of surface water bodies have been extensively studied, but less attention has been paid to environmental impact studies of small hydropower plants (SHPs). The impact of hydropeaking on both the river flow regime and ecosystems has been well-studied for peaking mode plants, mainly medium to large-sized ones. However, for small hydroelectric power plants, and especially for those in lowland rivers, the available information on water quality, benthic macroinvertebrates communities and fish abundance, and biomass is not sufficient. Ten small hydropower plants were selected, and the ecological status of water bodies was assessed in different parts of Lithuania. The studies were performed at the riverbed upstream from the SHPs, where the hydrological regime has not changed, and downstream from the SHPs. It was found that the small hydropower plants do not affect the physico-chemical values of the water quality indicators. This study demonstrated that the total number of benthic macroinvertebrates taxa (TS) is influenced by the concentration of nitrogen and suspended solids, the water flow, the river area, and the current speed; the number of EPT (Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies)) taxa is influenced by the concentration of nitrogen and suspended solids. The studied indicators do not have a significant impact on biomass. The SHPs affect the fish abundance and biomass. The Lithuanian fish index (LFI) is influenced by the average depth and area of the river. Some SHPs operating in lowland areas may yield somewhat significant hydrograph ramping but more detailed investigation is needed to support the significance of this impact on the biological indices. Full article

In recent times, much attention has been paid to small hydropower plants (SHPs) with variable speed operation and different control techniques. Control complexity in SHPs is mainly caused by specific steady-state features of the water turbine, the long time constants of the hydraulic system and significant seasonal and/or aging-related deterioration in the system performance. This paper presents the most important features of the turbine model from a control point of view. It classifies control techniques for SHPs with variable speed operation in terms of the turbine type and SHP function (run-of-the-river and reservoir). Furthermore, various control methods are analysed taking into account the complexity of the method, dynamics, adaptability and applicability. The novelty of this study is the proposal of a simple, universal analytical formula, which, based on the basic dimensions of the turbine, determines the optimal operating curve. The proposed formula is verified on a real SHP 150 kW by comparison with measurements in the form of operational characteristics. The analysis of the annual energy production confirms the effectiveness of the approximation precision, yielding only 1% production losses, and shows an advantage of variable speed over constant speed in annual energy production of 16%. Full article