Pumped Storage Research Articles

Numerical Simulation of Fire Smoke Transport in Underground Spaces of a Pumped Storage Power Station

The present study employs numerical simulation to investigate the transportation of fire smoke within the underground powerhouse of a Pumped Storage Power Station. The obtained results reveal the spatial variation of fire smoke under the smoke exhaust effect inside the facility. For an 8 MW fire occurring on the generator, busbar, and turbine layer floors of the main powerhouse, recommended evacuation times are 86 seconds, 242 seconds, and 298 seconds respectively when utilizing a mechanical exhaust capacity of 85000 m3/h. In case three simultaneous fires occur at these three floor levels, the evacuation time is reduced to 45 seconds. Comparatively, when compared to situations without mechanical smoke exhaust systems, our simulations indicate that escape times for different fire scenarios were extended by only 6 seconds and 91 seconds respectively. These findings underscore the urgent need for optimizing the mechanical smoke exhaust system in order to provide valuable time for personnel evacuation during fire incidents.

Low‐head pumped hydro storage: An evaluation of energy balancing and frequency support

Low‐head pumped hydro storage: An evaluation of energy balancing and frequency support

Assessment of heat storage integration for water vapour compression heat pumps: thermodynamic and techno-economic perspectives

ABSTRACT The integrated system, consisting of a two-stage high-temperature heat pump (HTHP) and thermal energy storage (TES), has been proposed as an effective solution to reduce CO2 emissions in industrial processes effectively. The water vapour HTHP, which can supply heat at 200°C, demonstrated a coefficient of performance (COP) between 4.4 and 7.5. Two different TES systems were introduced: concrete sensible heat storage (SHS) and strontium bromide/water (SrBr2/H2O) thermochemical energy storage (TCES). While the concrete SHS is limited to temperature below 200°C, the SrBr2/H2O TCES can deliver heat between 196°C and 228°C with higher cycle efficiency. The integrated system of HTHP and SrBr2/H2O TCES achieved a net present value (NPV) of €464,559 and €182,374 over a 20-years lifespan, with internal rates of return (IRR) ranging from 15.8% to 23.6%. This HTHP and TCES system has sufficient potential to replace fossil-fuel industrial boilers, leading to significant reduction in CO2 emissions in industrial processes.

Hydraulic dissipation analysis in reversible pump with a novel double-bend impeller for small pumped hydro storage based on entropy generation theory

Hydraulic dissipation analysis in reversible pump with a novel double-bend impeller for small pumped hydro storage based on entropy generation theory

Thermodynamic performance of organic Rankine cycle based pumped thermal energy storage system with different working fluids

Thermodynamic performance of organic Rankine cycle based pumped thermal energy storage system with different working fluids

Critically analysis for fuel oil storage facilities using FMECA method

Abstract Fuel oil storage facilities, such as the PT.X Fuel Terminal, have an important role in maintaining a stable and safe energy supply for the community. Smooth operations and reliability of equipment in the storage facility are crucial factors in ensuring an adequate and safe fuel supply. In carrying out its operations, the landfill facility is faced with various challenges. One of the main challenges is maintaining complex and diverse equipment. Equipment such as storage tanks, connecting pipes, pumps and other equipment must be maintained regularly to prevent failures that could cause operational disruptions and potential safety risks. However, traditional maintenance approaches based on routine schedules are often inefficient and less responsive to the actual condition of the equipment. In this research, criticality analysis at the fuel oil terminal was carried out. This aims to carry out condition monitoring. By analyzing criticality, it will be easier to make decisions on the next steps. In this research, the FMECA method was used. This method is very good for finding criticality values in the system.

Discussion on the Strength Calculation Method for Connecting Bolts between Head Cover and Stay Ring of Pumped Storage Power Station in Unit Runaway

Abstract The units of pumped storage power plants are frequently started and operate under complex modes. There have been many fracture accidents of connecting bolts between head cover and stay ring in China and abroad, resulting in flooding of the plants, affecting the safety of personnel and property. The unit runaway mode is one of the controlling modes in the calculation of head cover bolts. Due to the unstable flow in this mode, it is difficult to accurately obtain the head cover load, which affects the accuracy of bolt strength calculation. This article explores the relevant calculation methods through an example of the strength review calculation of the head cover and stay ring connecting bolts of a pumped storage power station. A method was proposed to perform CFD steady state calculations on several characteristic points of the runaway mode using one-dimensional transient calculation dates as boundary conditions, and then correct the result of head cover load calculation. The method in this article takes into account both the calculation time and accuracy, and has certain engineering practicality, which can be used as a reference for the industry.

Hydropneumatic Storage Methodology Towards a New Era of Hybrid Energy System's Efficiency and Flexibility

This research explores the link between hydropneumatic energy storage capacity and the efficiency and flexibility of hybrid energy systems in water-energy solutions. A new methodology is introduced, featuring mathematical models, experimental data collection, and hydraulic simulations using 1D and 2D CFD models for hydropneumatics modeling. A promised energy storage efficiency of around 30-50% was obtained on a small lab scale. The optimization of hybrid systems through Solver and Python algorithms with various objective functions enables optimal design choices tailored to specific needs such as drinking water supply, irrigation, or industrial processes. Hydropneumatic vessels emerge as an effective storage solution, combining pumped storage and hydropower in one circuit. When integrated with renewable sources, such as solar (PV) and wind energy, they offer a flexible, long-lasting energy management system, applicable across different water-energy sectors to support Sustainable Development Goals. A case study with 4.8 Mm³/year water allocation, producing 1000 MWh of hydropower and 13500 MWh of solar energy, achieved 100% water reliability and a 25-year cash flow of 2.5 million euros.

Power control of an autonomous wind energy conversion system based on a permanent magnet synchronous generator with integrated pumping storage

Wind energy plays a crucial role as a renewable source for electricity generation, especially in remote or isolated regions without access to the main power grid. The intermittent characteristics of wind energy make it essential to incorporate energy storage solutions to guarantee a consistent power supply. This study introduces the design, modeling, and control mechanisms of a self-sufficient wind energy conversion system (WECS) that utilizes a Permanent magnet synchronous generator (PMSG) in conjunction with a Water pumping storage station (WPS). The system employs Optimal torque control (OTC) to maximize power extraction from the wind turbine, achieving a peak power coefficient (Cp) of 0.43. A vector control strategy is applied to the PMSG, maintaining the DC bus voltage at a regulated 465 V for stable system operation. The integrated WPS operates in both motor and generator modes, depending on the excess or shortfall of generated wind energy relative to load demand. In generator mode, the WPS supplements power when wind speeds are insufficient, while in motor mode, it stores excess energy by pumping water to an upper reservoir. Simulation results, conducted in MATLAB/Simulink, show that the system efficiently tracks maximum power points and regulates key parameters. For instance, the PMSG successfully maintains the reference quadrature current, achieving optimal torque and power output. The system’s response under varying wind speeds, with an average wind speed of 8 m/s, demonstrates that the generator speed closely follows turbine speed without a gearbox, leading to efficient power conversion. The results confirm the flexibility and robustness of the control strategies, ensuring continuous power delivery to the load. This makes the system a feasible solution for isolated, off-grid applications, contributing to advancements in renewable energy technologies and autonomous power generation systems.

Effect of the Vortex on the Movement Law of Sand Particles in the Hump Region of Pump-Turbine

The pump turbine, as the core equipment of a pumped storage power plant, is most likely to operate in the hump zone between condition changes, which has a great impact on the stable operation of the power plant, and the high sedimentation of a natural river will lead to wear and tear in the overflow components of the equipment. Therefore, this paper is based on the Euler–Lagrange model, and seeks to investigate the distribution of vortices in the hump zone of the pump turbine and its effect on the movement of sand particles. The study shows that as the flow rate increases, the strip vortex in the straight cone section of the draft tube becomes elongated, and the cluster vortex in the elbow tube section gradually decreases. The strip vortex encourages the sand particles to move along its surface, while the cluster vortex hinders the movement of the sand particles. The accumulation areas of the sand particles in the straight cone section and the elbow tube section increase axially and laterally, respectively. The blade vortex in the runner gradually occupies the flow channel as the flow rate increases, and the blade vortex near the pressure surface encourages the sand particles to move towards the suction surface, resulting in the serious accumulation of sand particles on the suction surface. As the flow rate increases, the number of blades where sand particles accumulate increases and the accumulation area moves towards the cover plate and the outlet. The flow separation vortex in the double-row cascade decreases as the flow rate increases, which drives the sand movement in the middle and lower sections of the vanes. The area of sand accumulation in the stay vane decreases with increasing flow rate, but the area of sand accumulation between the guide vanes increases and then decreases. The vortex on the wall surface of the volute gradually decreases with the flow rate, and the vortex zone at the outlet first decreases, then disappears, and finally reappears. The vortex at the wall surface suppresses the sand movement, and its sand accumulation area changes from elongated to lumpy and finally to elongated due to the increase in flow. The results of the study provide an important theoretical reference for reducing the wear of pump turbine overflow components.

ADJUSTMENT OF THE ELEMENTS OF THE FLOW PART OF THE HIGH-EFFICIENCY OF PUMP- TURBINE

The problem of the development of pumped storage power plants in Ukraine is considered, especially in the conditions of military operations, which damaged the energy infrastructure and created capacity shortage. The pumped storage power plants will help stabilize the power system by storing energy during periods of low load and efficiently using it during peak needs or accidents. All this has a positive impact on the role of energy autonomy and the integration of renewable energy sources. Efficiency increase of the hydro-turbine equipment of the PSPP requires the improvement of the water passage of the reversible hydraulic machines. This work shows that the creation of high-efficiency reversible hydraulic equipment depends on the correct selection of the geometry of the pater passage elements of the reversible hydraulic machines, consequently ensure the necessary level of energy characteristics of the hydraulic equipment. The equation of the optimal mode was used for the calculated assessment of kinematic and energy characteristics, analysis of their formation and search for rational variants that provide the specified requirements for the runner energy characteristics of the reversible hydraulic machines. Calculations are carried out using dimensionless kinematic parameters, which simplifies the process and eliminates the need for complex calculations. The numerical analysis data on the influence of the hydrodynamic parameters of the water passage on the parameters of the optimal mode can be used both for profiling the blade system of the runner, with the aim of improving energy characteristics (increasing power, efficiency level, etc.), and for modifying the blade system. The numerical study method for finding optimal variants of the runner blade system is given. The proposed approach was used to estimate the kinematic and energy characteristics of water passages of Francis turbines, as well as high-head reversible hydraulic machines ОRО200 and ОRО500 (both for basic and modified variants of the water passage).

Fatigue fracture behaviors and damage evolution of coal samples treated with drying–wetting cycles investigated by acoustic emission and nuclear magnetic resonance

Constructing pumped-storage power stations using underground reservoirs in mines offers a promising method for large-scale energy storage. Watertight coal pillars have the potential to destabilize under the mine-shock cyclic dynamic loading and the drying–wetting cycles (DWCs). Understanding the fatigue damage mechanism and failure precursors in watertight coal pillars under cyclic dynamic loading disturbances in overburdened rock strata has become challenging. This study investigated the fatigue fracture behavior and precursor information of coal samples under acoustic emission (AE) monitoring over 1–7 DWC times. We analyzed the effects of DWC and fatigue cycles on the dynamic parameters and AE response, investigated crack spatial extension behaviors and the tensile-shear cracking evolution law, and analyzed the fatigue damage evolution law and failure precursor with energy and b-value. The results demonstrated that fatigue loading produced a strengthening effect on the DWC coal samples, and DWC promoted plastic softening damage to the specimens and increased the percentage of the elastic phase. The average dynamic fatigue strength and life of the specimens decreased exponentially under 7 DWC times. The average dynamic axial stiffness decreased by 15.67 %, the axial deformation increased by 6.1 × 10−4 in a single cycle, and the dynamic elasticity modulus of the fatigue damage instant decreased by 8.86 %. The greater the number of DWC, the smaller the b-value and the larger the fluctuation amplitude at fatigue failure of the specimen. A large short-term increase or decrease in the b-value can be regarded as a precursor to fatigue failure. This study provides a reference for the stability monitoring and forewarning of underground pumped-storage facilities.

Intelligent monitoring system for environmental protection during the construction period of pumped storage power station

Intelligent monitoring system for environmental protection during the construction period of pumped storage power station

Stability performance of pumped-storage units considering elastic water hammer effects in pressurized piping systems: Mechanism analysis and quantitative criterion

The flow characteristics of water columns in pressurized piping systems significantly influence the stability of pumped-storage power stations (PSPSs). However, the complex mathematical representation of the elastic water column often leads to its simplification to a rigid column in stability analyses. This study established elastic and rigid models of a PSPS system based on elastic and rigid water columns, respectively. The stability regions of the governor parameters for these two models were determined and compared. Results indicate that the stability region of the elastic model is smaller than that of the rigid model. Consequently, using a simplified rigid model to evaluate the stability of an actual elastic system would pose potential instability risks. Furthermore, the primary cause of the stability difference between the elastic and rigid models is identified as the water hammer wave velocity. As the wave velocity increases, the stability region of the elastic model expands, eventually approaching that of the rigid model. Lastly, the coupling mechanism between the pressurized pipe and the pumped-storage unit is clarified. The modulus of the water hammer reflection coefficient is proposed to quantify the stability performance of the pumped-storage unit. These findings provide crucial insights for ensuring the stable operation of PSPSs.

A Soft Start Method for Doubly Fed Induction Machines Based on Synchronization with the Power System at Standstill Conditions

Due to their exceptional operational versatility, doubly fed induction machines (DFIM) are widely employed in power systems comprising variable renewable energy-based electrical generation sources, such as wind farms and pumped-storage hydropower plants. However, their starting and grid synchronization methods require numerous maneuvers or additional components, making the process challenging. In this paper, a soft start method for DFIM, inspired by the traditional synchronization method of synchronous machines, is proposed. This method involves matching the frequencies, voltages, and phase angles on both sides of the main circuit breaker, by adjusting the excitation through the controlled power converter at standstill conditions. Once synchronization is achieved, the frequency is gradually reduced to the rated operational levels. This straightforward starting method effectively suppresses large inrush currents and voltage sags. The proposed method has been validated through computer simulations and experimental tests, yielding satisfactory results.

Strengthening of Reinforced Concrete Hydraulic Structures with External Reinforcement System Made of Carbon Fiber-Based Composite Materials with Development of Calculation Recommendations

During the long-term operation of hydraulic structures under the action of complex loads and impacts, non-design changes occur, which lead to a decrease in the bearing capacity and safety and, accordingly, to the need for structural reinforcements. Experiments were conducted to study the strengthening of reinforced concrete models of hydraulic structures with interblock construction joints (located in two directions) and with the low longitudinal reinforcement coefficients typical of hydraulic structures (μs = 0.0039 and μs = 0.0083), using the low concrete classes B15 and B25. These structures were strengthened using external reinforcement with carbon ribbons of the FibArm 530/300 type. The results revealed an increase in the bearing capacity (by 1.355- and 1.66-fold); accordingly, the high efficiency of this strengthening method for reinforced concrete hydraulic structures was proven. Using the results of these experiments, including the obtained special characteristic of the cracking of reinforced concrete structures and the results of studies by other authors, recommendations for calculations involving reinforced concrete hydraulic engineering structures strengthened with an external reinforcement system of carbon-fibre-based composite materials were developed and proposed. Carbon-fibre-based composite materials are used as elements of external reinforcement for building structures (unidirectional—tapes, bidirectional—meshes and fabrics). The calculation recommendations proposed by the authors can be taken into account for the creation of a regulatory framework for hydropower facilities, including hydroelectric power plants and pumped-storage power plants. They justify the use of an external reinforcement system made with carbon-fibre-based composite materials to strengthen hydraulic structures in operation and provide an increased level of safety for reinforced concrete structures and constructions.

Converting Second-Order Saddle Points to Transition States: New Principles for the Design of 4π Photoswitches.

Molecular photoswitches have demonstrated potential for storing solar energy at the molecular level, with power densities comparable to commercial batteries and hydroelectric energy storage. However, development of efficient photoswitches is hindered by limitations in cyclability and optical properties of existing materials. We here demonstrate that certain limitations in photoswitches based on electrocyclizations stem from the issue of controlling competition between Woodward-Hoffmann allowed and forbidden pathways. Our approach moves beyond the traditional view of activation barriers and reveals that second-order saddle points are crucial in dictating the competition between disrotatory and conrotatory pathways. These insights suggest new opportunities to manipulate the competition between these pathways through geometric constraints, fundamentally altering the connectivity of the potential energy surface. Our study also emphasizes the necessity of multi-reference methods and the need to conduct higher-dimensional explorations for competing pathways beyond photoswitch design.

Comparative optimization of the thermal performance for H2 – Metal hydride heat storage and heat pump systems

Metal hydride is very promising in hydrogen storage and simultaneously the thermal effect in the reversible hydrogenation process makes it possible in heat storage and heat pump area. The interaction of H2 – Metal – hydride pair and its further applications need comprehensive thermodynamic design and performance optimization. Therefore, this work makes thermodynamic comparative research of heat storage and heat pump systems by adopting H2 – Metal-hydride pair. According to the investigation, the thermodynamically optimal charging-discharging temperatures (Tm1,Tm2), the heat source temperature (Th1) and the ambient temperature (Tc1) meet the relationship of Tm1Tm2=Th1Tc1 for the heat storage system. Given the operating pressure (p), there exists a well-matched temperature (T) range to maximize the exergy performance of metal hydride heat storage system. Meanwhile, the running p-T is positively correlated, e.g., when the charging pressure is set at 0.2 MPa to 0.3 MPa, the well-matched T varies from 307 K to 317 K. When the discharging pressure is set at 0.4 MPa to 0.7 MPa, the well-matched T varies from 304 K to 320 K. For the metal hydride heat pump system, the optimal performance lies in maximizing the transported heat. Given the operating T, there exists a well-matched pressure range for the heat sink device, e.g., for the heat releasing process, when operating T is set at 353 K, 363 K, 373 K, 383 K and 393 K, the well-matched p are 2.3 MPa, 3.3 MPa, 3.8 MPa, 4.6 MPa and 6.1 MPa. Both the heat storage and heat pump performances are also affected by the operating pressure – temperature −transported heat, presenting improved region and degraded region. The optimal thermodynamic criterion and the matchability of the operating parameters provide a theoretical guidance for the MH-based thermodynamic system design and operation.

Optimising Malaysia’s power mix for a sustainable future: a multi-scenario modelling approach

PurposeThis study employs advanced modelling to assess the effectiveness of Malaysia’s current energy policies in achieving a low-carbon future. By optimising a 100% renewable energy mix, including energy storage, the research identifies pathways to decarbonise the power sector while minimising costs. These findings will inform the development of future policies.Design/methodology/approachThis study employs the Stockholm Environment Institute-developed Low Emissions Analysis Platform (LEAP) and Next Energy Modeling system for Optimization (NEMO) to construct and optimise a comprehensive Malaysian power sector model. The model encompasses both electricity supply, including diverse electricity generation sources and demand across key sectors. Three scenarios – existing policy, optimised existing policy and more ambitious policy (near-zero emissions) – are analysed.FindingsSolar photovoltaic (PV) is the dominant technology, but realising its full potential requires significant grid upgrades. While natural gas expansion underpins Malaysia’s decarbonisation strategy, solar and storage offer a cleaner and potentially cost-effective alternative. Rapid technological advancements in clean energy increase stranded asset risk for new gas power plants. Malaysia’s abundant bioenergy resources need more tapping. This can contribute to decarbonisation and rural development. Transitioning to a fully renewable grid necessitates substantial investments in energy storage and grid infrastructure. While falling battery costs and regional interconnection can mitigate costs, careful consideration of potential disruptions and cost fluctuations is essential for resilience.Research limitations/implicationsEnergy sector modelling results are inherently dependent on input assumptions, such as future technology costs, resource availability and fossil fuel prices. These factors can be highly uncertain. While this study did not conduct sensitivity analyses to explore how variations in these assumptions might affect the results (e.g. cost variations across scenarios, technology mix fluctuations), the core findings provide valuable insights into potential decarbonisation pathways for Malaysia’s power sector. Future studies could build upon this work by incorporating sensitivity analyses to provide a more comprehensive understanding of how key results might change under a wider range of future possibilities.Originality/valueThis study co-optimises a 100% renewable energy mix for Malaysia, incorporating a comprehensive range of renewable resources, battery and pumped hydro storage. The research also provides a unique perspective on the interplay of philosophical underpinnings, psychological maturity and energy policy.

Construction of pumped storage power stations among cascade reservoirs to support the high-quality power supply of the hydro-wind-photovoltaic power generation system

Multi-energy complementary technology has become one of the core elements to promote the structural transformation of global energy and cope with climate change. Faced with the rapid growth of wind power and photovoltaic, the uncertainty of its power generation will increase further, and it is urgent to explore more types of flexible regulation power sources to compensate for them. The construction of pumped storage power stations among cascade reservoirs is a feasible way to expand the flexible resources of the multi-energy complementary clean energy base. However, this way makes the hydraulic and electrical connections of the upper and lower reservoirs more complicated, which brings more uncertainty to the power generation. Hence, to support the high-quality power supply, this research explores the complementary characteristics of the clean energy base building different types of pumped storage power stations, and recognizes the efficient operation intervals of the giant cascade reservoir. First, a multi-dimensional uncertainty evaluation system is proposed to elaborate on the typical output scenarios of wind power and photovoltaic in more detail. Next, based on different utilization principles of wind power and photovoltaic, the multi-energy complementary operation models of the hydropower-wind-PV hybrid system, the hydropower-wind-PV hybrid system including pump stations, and the hydropower-wind-PV hybrid system including reversible hydro units are established. Further, a multi-dimensional scenarios random combination method is applied to investigate the response relationship between the operation parameters of the key reservoir and the operation indicators of the clean energy base. Finally, these above methods have been practiced in the clean energy base in the upper Yellow River basin. The main results of the research are as follows: (1) when the power output of wind-PV plants is high, the absorption rates of wind power and photovoltaic increase by 36% and 12% respectively, in hydropower-wind-PV hybrid systems with reversible hydro units and with pump stations, compared to the hydropower-wind-PV hybrid system; (2) when the power output of wind-PV plants is high, the load loss rates of the transmission channel decrease by 28.57% and 14.28% respectively, in hydropower-wind-PV hybrid systems with reversible hydro units and with pump stations, compared to the hydropower-wind-PV hybrid system; (3) for the hydropower-wind-PV hybrid system including reversible hydro units, the comprehensive utilization flow of the key reservoir respectively maintain 500-800 m3/s and 1000-1200 m3/s in the max scenario and min scenario of wind power and photovoltaic, which is beneficial to the efficient absorption of new energy and high-quality power transmission; (4) for the hydropower-wind-PV hybrid system including pump stations, the comprehensive utilization flow of the key reservoir should respectively keep 500-750 m3/s and 950-1100 m3/s in the max scenario and min scenario of wind power and photovoltaic.