Hydroelectric System Research Articles

Twinned Renewable Energy Accumulation: Case of Wind and Hydro Energy

Abstract Renewable energy sources (RES) are the key element of sustainable energy systems. To accommodate the intermittency of wind (and solar) electricity generation, energy storage is critical. The aim of the study was to evaluate the potential of wind energy storage in the existing hydropower plant reservoirs in Latvia with the pumped hydroelectric energy storage (PHES) technology, considering the current and projected future wind energy capacities. An algorithm was developed and used for data aggregation and analysis, calculations, and forecasting. The three River Daugava hydroelectric power plants are the largest electricity producers in Latvia, and their generation capacity depends on seasonal variations. Currently, Latvia's electricity generation from RES is the highest during the spring season when maximum hydropower potential is utilized. However, wind energy has a potential to grow and could supplement hydropower throughout the year. Decreasing the existing administrative procedure heaviness to faster achieve the climate neutrality targets and energy autonomy by increasing RES development in Latvia is a way to create sustainable energy production. A rational future scenario in Latvia is to expand wind parks and integrate pumped hydroelectric energy storage systems in the existing cascade hydropower plants.

An Evaluation of Pumped Hydroelectric Storage Systems

In smart grids, storage systems are needed to increase the number of renewable energy sources connected to distribution systems and to ensure the continuity of energy. By supporting the system elements, energy storage can provide many services such as energy time shifting, interruption control, ensuring continuity in transmission and power quality improvements. In smart grid applications, difficulties are encountered in energy storage due to various problems such as charge/discharge, safety, size and cost. For this reason, energy storage systems should be developed for energy capacity, control and protection that can increase storage performance. Since there are interruptions and waves in renewable energy sources such as wind and solar, batteries are used for storage. In order to expand the use of clean energy and to ensure energy continuity, mechanical storage methods in large powerful systems have been emphasized. Storage studies have been carried out to increase efficiency, provide flexibility in electrical systems, reduce costs and improve storage time, and reduce power fluctuations. In this study, pumped hydroelectric storage plants, which is one of the storage methods, were examined. Advantages and disadvantages of pumped storage hydroelectric system are mentioned and hybrid pumped hydro storage is explained. Its economic contribution is also briefly mentioned. This storage method of PHES has also been found to be hybrid systems that can be connected to variable speed turbines, groundwater, seawater and renewable energies to increase efficiency, reduce costs and save space. Among these systems, it has been observed that the system in which solar and wind are used as a hybrid is also advantageous in providing high profitability in the energy market. Thanks to its integration with the sun and wind, carbon emissions are reduced.

Comparative Analysis of Energy Storage Methods for Energy Systems and Complexes

The daily non-uniform power demand is a serious problem in power industry. In addition, recent decades show a trend for the transition to renewable power sources, but their power output depends upon weather and daily conditions. These factors determine the urgency of energy accumulation technology research and development. The presence of a wide variety of energy storage mechanisms leads to the need for their classification and comparison as well as a consideration of possible options for their application in modern power units. This paper presents a comparative analysis of energy storage methods for energy systems and complexes. Recommendations are made on the choice of storage technologies for the modern energy industry. The change in the cost of supplied energy at power plants by integrating various energy storage systems is estimated and the technologies for their implementation are considered. It is revealed that in the large-scale power production industry, the most productive accumulation methods for energy systems and complexes are the following: pumped hydroelectric energy storage systems, thermal and thermochemical accumulations, and hydrogen systems. These methods have the best technical and economic characteristics. The resulting recommendations allow for the assessment of the economic and energy effect achieved by integration of storage systems at the stage of designing new power units.

Economic Enhancement of Wind–Thermal–Hydro System Considering Imbalance Cost in Deregulated Power Market

Studying the property of the combination of renewable energy sources in the existing power systems is of great importance, and especially in the case of deregulated systems. The uncertainty of renewable sources is the largest barrier to integrating renewable-energy-producing units into the existing electrical infrastructure. Due to its uncertainty, integrating wind power into an existing power system requires extra consideration. In this work, the impacts of wind farm (WF) integration and a pumped hydroelectric storage system (PHES) on the electric losses, voltage profiles, generation costs, and system economy in a deregulated power market were studied. A comparative study was performed to determine the impact of wind farm integration on regulated and deregulated environments. Four locations in India were chosen at random for this work, and we used the real-time statistics for the actual wind speeds (AWSs) and forecasted wind speeds (FWSs) for each chosen location. To determine the system economy, surplus charge rates and deficit charge rates were developed to evaluate the imbalance cost resulting from the mismatch between the predicted and actual wind speeds. Considering the effect of the imbalance cost, the system profit/day varies by an average of 1.6% for the locations studied. Because of the reorganization of the power system, consumers constantly look for reliable and affordable power that is also efficient. As a result, the system security limit may be breached, or the system may run in a dangerous state. Lastly, in this paper, an economic risk analysis is presented with the help of heuristic algorithms (i.e., artificial bee colony algorithm (ABC) and moth–flame optimization algorithm (MFO)), along with sequential quadratic programming (SQP), and the way in which the PHES is used to compensate for the deviation in the WF integration in the real-time electricity market is also presented. The value at risk (VaR) and conditional value at risk (CVaR) were used as the economic risk analysis tools. According to the work, with the increase in the wind generation, the system risk improves. The results show that, as the wind generation increases by three times, there is an improvement in the risk coefficient values by 1%. A modified IEEE 14-bus test system was used for the validation of the entire work.

Nonlinear finite‐time control of hydroelectric systems via a novel sliding mode method

A nonlinear finite-time sliding mode control is proposed in this paper for the governing of complex hydroelectric systems with the finite/fixed setting time. The proposed control method is derived from the finite-time stability and sliding mode control theories. The finite settling time is calculated and bounded, not depending on the initial conditions of the system. The solution trajectory of the controlled hydroelectric system can reach the sliding manifold in a fixed settling time, regardless of initial values. Based on the Lyapunov theory, the controlled hydroelectric system also converges to a reference state within the fixed settling time. A simulation of a high-dimensional hydroelectric system verifies the feasibility of the proposed method. In addition, a comparison between the proposed method and the conventional PID method demonstrates the advantages of the proposed method in the shorter settling time and smaller overshoot. The proposed control method allows for the design of a flexible controller and provides an improvement in dynamic performance.

Energy and economic study of using Pumped Hydropower Storage with renewable resources to recover the Furnas reservoir

Hydroelectric power plants have been losing competitiveness to renewable resources in Brazil, specifically wind and solar power resources, given the current water crisis in the country, which has left main reservoirs in the Brazilian hydroelectric power system depleted. However, other renewable energy resources show disadvantages in terms of intermittence and energy storage. Pumped Hydropower Storage (PHS) can help mitigate this problem, supplying energy with fewer variations. This paper studied using PHS concepts together with solar and/or wind renewable resources to recover water levels at the Furnas reservoir in terms of energy and economic performance. The energy studies were developed by sizing the PHS and identifying solar and wind resource potential for supplying energy for pumps in the hydropower plant. The economic analyses considered three different scenarios (I; II and III), and used the NPV (Net Present Value), and LCOE (Levelized Cost of Electricity) methods for a period of 30 years. Energy calculations showed that 1692 MWh/day of energy could be generated using PHS. However, 2729 MWh/day of energy would be needed to store generated energy, and a 1037 MWh negative energy balance will be compensated for by using daily wind and/or solar photovoltaic power production. This would allow the Furnas reservoir to regain 0.45 m of its water level per year. The economic studies showed economic viability for PHS scenarios I and III, with estimated NPV at 151.5 million dollars, and 64.5 million dollars for the last year of the project, respectively. Scenario II was unviable, giving rise to several strong discussions on this application within Brazil.

Multi objective short term hydro-thermal- CHP scheduling using social spider algorithm

Potential of cheap and emission free hydro electric generation and that of another non linear efficient distributed energy resource namely combined heat and power (CHP) are utilized in the present dissertation. Water discharge from cascaded multi-reservoir system, its net head and power generation from such a hydroelectric system bears a nonlinear relationship. Such a hydro system with water transport delay among reservoirs is considered here. Optimal utilization of these sources to serve demands over short term of 24 h of a day by scheduling their respective generations so as to achieve multi objectives of cost effective production, reduced emission and transmission loss have been studied using a bio-inspired social spider algorithm. Outcome of the first test system containing hydro-thermal units shows the efficacy of the utilized optimization method while compared to other existing optimization techniques. The second test system is designed for the first time to exhibit the usefulness of the used algorithm in hydro-chp scheduling concept. Provided Statistical analysis justifies the significance of the data of the test systems.

Short-range reservoir inflow forecasting using hydrological and large-scale atmospheric circulation information

Short and long range reservoir inflow forecast is essential for efficient real time operational planning, scheduling of hydroelectric power system and management of water resources. Large-scale climate phenomenon indices have a strong influence on hydrological processes under complex weather conditions, and it should be considered to forecast reservoir inflow for efficient dam operation strategies. This study aims to explore the relevance of large-scale climate phenomenon indices in improving the reservoir inflow prediction at short-term time scales. This paper presents a simple and effective framework to combine various data-driven machine learning (ML) algorithms for short-range reservoir inflow forecasting. Random Forest (RF), Gradient Boosting Regressor (GBR), K-Nearest Neighbors Regressor (KNN), and Long Short-Term Memory (LSTM) were employed for predicting daily reservoir inflows considering various climate phenomenon indices (e.g., Arctic Oscillation, North Atlantic Oscillation, and Southern Oscillation Index) and hydroclimatic variables (precipitation), accounting for time-lag effects. After training the individual ML algorithm, a framework was developed to create an ensemble model using a robust weighted voting ensemble method to quantify forecasting uncertainty and to improve the model performance by combining the inflow results of the single ML model and the highest vote is chosen based on the weights assigned to the single ML model. The developed framework was examined in two distinct reservoirs located in India and California, USA. The ensemble model consistently outperformed the standalone RF, GBR, KNN, and LSTM in predicting high (flood control and monsoon seasons) and low flows (runoff and non-monsoon seasons) of both study reservoirs. The demonstrated short-term reservoir forecasting model allows reservoir operators to adapt and add regional hydrological and large-scale climate indices in real-time decision-making. The presented framework can be applied for any reservoir inflow forecasting.

A hybrid robust-stochastic optimization approach for day-ahead scheduling of cascaded hydroelectric system in restructured electricity market

Uncertainties arising from complicated natural and market environments pose great challenges for the efficient operation of cascaded hydroelectric systems. To overcome these challenges, this paper studies the day-ahead scheduling of cascaded hydroelectric systems in a restructured electricity market with the presence of uncertainties in electricity price and natural water inflow. To properly model the uncertainty, we consider the unique characteristics of these two types of uncertainties and capture them via the uncertainty set and stochastic scenarios, respectively. A hybrid robust-stochastic optimization model is developed to simultaneously hedge against these two types of uncertainties, which is formulated as a large-scale non-convex optimization problem with mixed integer recourse. After introducing linearization of nonlinear terms, a tailored hybrid decomposition scheme combining Lagrangian relaxation and Dantzig-Wolfe decomposition is adopted to achieve efficient computation of the proposed model. Two real-world cases are conducted to demonstrate the capability and characteristics of the proposed model and algorithms.

Micro Grid of Hydroelectric Power Plant And Wind Power Plant

Electric energy, which is needed in all areas of life, plays an important role in raising the development level of the society. The demand for renewable energy sources has increased due to the continuous increase in energy need and the exhaustion of non-renewable energy sources. Micro-grids, which emerged as a solution to energy cuts and infrastructure problems in rural areas and areas far from the grid, are small energy grids that can operate independently or independently from the grid. In this study, micro-grids and the advantages of micro-grids, together with the energy production provided by micro-grids, are examined. Being a new energy source and being able to work independently from the grid is the most important feature of the micro grid. Therefore, the working principle of micro hydroelectric power generation systems and wind energy systems and the advantages of the micro grid are indicated by giving examples on their different aspects from other systems. In the MATLAB/SIMULINK program, a wind and micro hydro-electric hybrid power generation system model was designed and the simulation results were specified.

Techno economic viability of hydroelectric energy storage systems for high-rise buildings

Intermittent sustainable energy generation in the electrical grid from sources such as solar, hydro, and wind has increased significantly in recent years which for stability purposes has required the concurrent implementation of a wide array of large-scale energy storage solutions like chemical battery and pumped hydro plants. The current study assesses the potential techno-economic viability of two alternative hydroelectric energy storage systems - a building-based pumped hydro system, and a building-based gravity module system. The levelized electricity cost and variable storage cost are used as performance metrics in the study. A numerical model of the proposed systems is developed in Matlab® and analyzed over a number of scenarios in which system capacity and building height are varied. Further comparisons are made with the two following conventional rapidly deployable grid-scale energy generation and/or storage technologies - natural gas peaker plants, and lithium-ion battery plants. This research is unique as no such comparative study has been conducted to date. Results show that the building-based gravity module system is more financially viable and has a greater energy storage capacity than the building-based pumped hydro system in all scenarios considered. The building-based gravity module system can provide energy storage capacities as high as 1358 kWh in buildings that are 300 m tall. Moreover, this system has a lower levelized electricity cost than equivalent lithium-ion battery systems (≤$1.02/kWh) in all buildings that are taller than 156 m. The current study demonstrates that the levelized electricity cost is better suited than the variable storage cost as a metric for gauging the economic viability of grid energy storage systems since system lifetime costs and the time value of money are considered.

Load Frequency Control of Microgrid System by Battery and Pumped-Hydro Energy Storage

Energy security is one of the main factors in the development and diffusion of microgrid applications. In networks operating without storage, the operation of their systems is greatly affected by sudden load demand and intermittent generation fluctuations. The main purposes of using energy storage systems in microgrids are stabilizing the intermittent generation of renewable energy sources locally, to ensure that energy production matches energy demands, participating in the frequency regulation process, maintaining the energy balance between generation and demand in renewable energy microgrids, and increasing energy reliability. This study investigates the frequency and power balance of an isolated microgrid system, by including storage systems (battery and pump-hydro). Realistic data for wind and solar sources are used for the optimal tuning of the proportional-integral controller, using the integral of the absolute error criterion multiplied by time, with a Quasi-Newton method. Simulation studies have been carried out, to investigate the performance of the microgrid system, by including the hydroelectric power plant system with pump storage for 24 h, under various operating conditions. The results reveal that by including the storage units in the system, it exhibits a more consistent and smooth dynamic performance, using renewable energy efficiently.

DESIGN AND SIMULATION OF A PICO HYDROELECTRIC TURBINE SYSTEM

Hydroelectric power is both an efficient and reliable form of a clean source of renewable energy. It can be an excellent method of harnessing renewable energy from small rivers and streams. A Pico hydroelectric power system of a cross-flow turbine type is designed and simulated in this study. Model parameters such as runner diameter, runner length, blade spacing, radius of blade curvature, shaft diameter, water jet thickness, turbine speed, turbine power and the number of blades that play major role to achieve the turbine maximum efficiency were determined theoretically. The designed Hydro-electric power system’s maximum efficiency was estimated to be 87% with a head of 6390 mm at a flow rate of 0.089 . Numerically, analysis of the designed power generation system was carried out using (structural analysis and design) STAAD pro connect software and ANSYS tool. The performance evaluation results using the STAAD pro software for the system water reservoir sitting stanchion simulation indicated that the stanchion will not fail while carrying the load. Similarly, the numerical analysis of the designed cross-flow turbine type in this work using the ANSYS tool revealed that the shaft will be able to withstand deformation due to torsion when subjected to a maximum torque of 51.46 Nm. Hence the designed hydroelectric power system will be efficient to produce a 5kVA electrical power

Optimization of On-Grid Hybrid Renewable Energy System: A Case Study on Azad Jammu and Kashmir

Expansion of modern power systems due to increasing energy demands face the challenges of grid reinforcement cost, size and complexity, transmission losses, and environmental factors. Placement of renewable energy sources (RES) based generation systems addresses these challenges. However, the size and placement location of RES-based system require optimization of installation and operational cost with better return on investment and reduction of greenhouse gas emissions. This paper presents an optimized solution for RES-based generation system to be installed with the existing power system of Azad Jammu and Kashmir (AJK) region that is facing power shortfall and load shedding. The weather and climate data from NASA and National Renewable Energy Laboratory (NREL) have been used and various models of on-grid hybrid renewable energy system (HRES) are compared to highlight their techno-economic benefits. An optimal hybrid photovoltaic, wind, and hydroelectric energy-based generation system is proposed with a significant reduction in cost of energy, net present cost, initial costs, and GHG emissions. Installation of the proposed hybrid RES-based generation system guarantees reduction in system power losses and line flows with an improved voltage profile of the system.

Feasibility of floating solar PV integrated pumped storage system for a grid-connected microgrid under static time of day tariff environment: A case study from India

This paper investigates the possibilities of a small-scale floating solar PV integrated Pumped Storage Hydroelectric (PSH) system in India, where a subsidized Time-of-Day tariff is employed. Finding and utilizing new reservoirs and water bodies in hilly areas for electrical energy storage and renewable energy integration is vital for more extensive renewable energy exploration. Prior studies in India have not explored the possibility of integrating floating solar PV systems with small-scale PSH systems. PSH systems and floating solar PV systems are modeled from fundamental relations. Objective function and constraints are formulated based on the operating conditions of the system and the grid energy tariff in India. The levelized cost of solar energy and the levelized cost of stored energy is estimated to analyze the economic aspects of the proposed system. For optimal scheduling, developed a linear programming solver-based optimization algorithm. In addition, this study utilized particle swarm optimization for optimal sizing of the system. The results of this study validate the feasibility of the proposed method. Economic savings of floating solar PV resulted in a levelized cost of 0.8518₹/kWh, and the availability of existing cascaded reservoirs brought on a levelized cost of 4.2713₹/kWh for stored energy. Compared to the grid-alone system, the proposed system reduced the daily operating cost and loss of load probability. The proposed system performs economically in a subsidized static tariff environment.

Performance evaluation of a residential building-based hydroelectric system driven by wastewater

• Building-based wastewater hydroelectric systems can offset pumping energy by 36%. • Electricity rate is the largest driver of economic value for these systems. • Annual energy generation and cost-effectiveness increase as building size increases. • These systems can act as a valuable city-scale distributed energy resource. Electricity is consumed in high-rise buildings for pumping domestic water from municipal supply lines to end users located several floors above ground level. Currently, the potential energy contained in this water is unutilized prior to being drained as wastewater to the sewer. This study assesses the potential techno-economic benefits of using a tank and turbine-generator system to recover energy from building wastewater systems. A numerical model is developed of the proposed system in the Matlab/Simscape™ environment, and simulations are conducted using measured water consumption data from a case study building located in Ottawa, Canada. An additional 2400 model scenarios are developed that correspond to buildings of varying size. Results show that the system can generate up to 1.3 megawatt hours of electricity annually; a quantity that is roughly equivalent to 36% of the building's annual domestic pumping electricity load. Additionally, the proposed system is found to be cost-effective when installed in buildings that have a minimum of 35 floors and at least 47 units per floor. However, this result is highly sensitive to the average rate of electricity charged in the building's jurisdiction. This study is novel as it is the first analysis of its kind to evaluate the techno-economic viability of building-based wastewater hydroelectric systems as a function of building size. Furthermore, the findings are important as they may be used as a tool for developers and/or policymakers for determining the viability of implementing a building-based wastewater hydroelectric system based on the building's height and unit distribution.

Power storage using sand and engineered materials as an alternative for existing energy storage technologies

The wider inclusion of solar and other intermittent renewables in the United States (US) energy mix has presented some unique management challenges and opportunities. Given the existing baseload production capacity, when renewable energy is available from solar power plants, and distributed rooftop solar there is an excess power that is hard to manage with just dispatchable generation. However, there are several environmental and ecological advantages to using these intermittent renewables that will incentivize their wider adoption. Large-scale energy storage offers an attractive additional tool to manage the grid system. In this discussion paper, we propose and theoretically discuss the efficacy of using manufactured sand or other engineered material (e.g., scrap metal) for developing such energy storage solutions. These proposed storage systems convert excess electricity into potential energy by lifting the bulk material and producing electricity similar to a hydropower power plant. These systems may be placed in existing natural or man-made depressions (e.g., old quarries). Compared to hydroelectric systems, these systems will have lower storage volume requirements and will be more environment-friendly by avoiding many of the problems associated with hydroelectric power generation, particularly those related to non-consumptive water loss. Manufactured sand and the engineered metal ball were studied in this discussion as an alternative for power generation. We estimate that such materials may produce 247 kW and 663 kW respectively, in 4 h of operation utilizing 5 h of electricity from solar excess. Based on theoretical calculations such systems were successful in recovering about 56% of the solar excess that may be utilized throughout the day to enhance the base capacity.

Efficient Physical and Multidisciplinary Approaches in Combinations of Nanoparticles towards Power Generations, Energies Production Methods and Photocatalysis Mechanism

To progress toward sustainable growth, future hydro-power development must pay a bit more attention towards how changing climate may impact hydropower output, as well as make massive action to limit the environmental costs borne by people who live near dams. Long term projections help in providing data for power network risk analysis as well as identifying wind power generation potential in particular places, delivering important data for electricity planners. Hydro-electric power system is an enhanced energy process because it effectively converts mechanical power into grid power, but both are high-energy methods. The utilization of wind turbines for renewable power source has turned out to be one of the greatest viable alternate wells-prings of electricity age because of the little recompense, for instance, being profitable and efficient and environment friendly. Many foundations, organizations, associations, and experts have demonstrated that wind turbines are presumed to comprehend the imperativeness order. In compared to conventional power plants, although wind-power plants have little impact on the environment, concern exists over the noise produced by the turbine blades and visual impacts to the landscape and turbine blade. While wind turbines are connected to the small scale or isolated network, the power product from another source should be varied in reply to these variant and change in sequence to retain system density and voltage with in pre-set limit.

Energy analysis and evaluation of an innovative hybrid compressed air and pumped hydroelectric energy storage system

Energy analysis and evaluation of an innovative hybrid compressed air and pumped hydroelectric energy storage system

The dependence of hydropower planning in relation to the influence of climate in Northeast Brazil

Water scarcity in Northeast Brazil has caused latent perturbations in hydropower generation, which is undesirable for Energy Planning. Thus, this study aims to identify the influence of climate on hydropower generation by Sobradinho Dam in Bahia by: (i) assessing the streamflow climatology (1964-2017) and rainfall (1964-2015) through time series analysis, hypothesis testing and cluster analysis; (ii) assessing hydropower generation (2000-2017) using climate and energy data, through principal component analysis and dynamic regression models. The results indicated reductions of up to 30% in the mean climatological streamflow patterns; and reductions in rainfall amounts of 22.9%, 13.3% and 12.4% at latitudes 9°, 12°and 13°South, respectively. Decreasing trends were found in simulations of hydropower generation under the influence of different climate variables. Thus, the hydroelectric system operates in contingency, due to the growing energy load demand resulting in more energy imports in Northeast Brazil.