Pumped Storage Hydropower Plants Research Articles

Loss of load probability for power systems based on renewable sources

An increasing number of small and variable power sources, such as wind and solar power plants, are being integrated into power systems, potentially affecting their reliability. This study was aimed at developing a method for evaluating reliability in terms of the loss of load probability. To this end, an algorithm capable of assessing the expanded role of renewable sources in the power system was established, which could take into account the specific roles and features of wind, solar, and hydro power plants, including pumped storage hydro power plants. Various models were developed and tested to closely emulate real power system behavior. A regional power system was evaluated over multiple years. The results indicated that the reliability of power systems fluctuates with the available capacity of renewable resources. These findings provide a foundation for a more precise specification of power reserves in such systems to prevent excessive reduction in reliability.

Nuclear and Hydrotechnical Expertise Combined: Gidroproekt and the South Ukraine Energy Complex

This article investigates the juncture of hydropower and nuclear engineering traditions at the South Ukraine Energy Complex in the USSR from the late 1960s onwards. Engineers from the hydrotechnical design institute Gidroproekt played a key role in the envisioning, planning and realisation of this unique project. It combined a nuclear power plant and its cooling water reservoir with a pumped-storage hydropower plant and an accompanying run-of-river hydropower plant, allowing for potential synergies with irrigation and pisciculture. A mixture of hydraulic and nuclear technocratic traditions manifested itself in a large-scale attempt to change the natural environment as proof of Soviet technological superiority.

A Score-Based Evaluation Model for Rehabilitation of Existing Pumped Storage Hydropower Plant Construction

As the proportion of new and renewable energy increases, power control demands are becoming more frequent due to variability in power generation. As a complementary means against this, the pumped storage hydropower plants (PSHP) are attracting attention as energy storage systems (ESS), but it has high construction costs. Therefore, this study aims to improve the economic feasibility by developing the evaluation model of the existing infrastructure into an upper/lower dam suitable for PSHP. The concept of upper dam capacity is newly defined, and the evaluation index is constructed using normalization. A new evaluation system is presented for five factors: environment, stability, energy, capacity, and economy. Finally, it is tested in the pilot area in Korea. Several candidates, including the PSHP in operation, are found to have been distributed with higher scores. These results will help to satisfy the selection of candidates during the preliminary feasibility study phase, and programming them will enable more accurate and rapid assessment.

Minimize Total Cost and Maximize Total Profit for Power Systems with Pumped Storage Hydro and Renewable Power Plants Using Improved Self-Organizing Migration Algorithm

This study presents the application of an improved self-organizing migration algorithm (ISOMA) for minimizing the total electricity production expenditure (TEPE) and maximizing the total electricity sale profit (TPRF) for hydrothermal power systems (HTPS) without and with renewable energies. Two power system configurations were employed to test the real efficiency of ISOMA while dealing with two objective functions. In the first configuration, there was one thermal power plant and one hydropower plant, while in the second configuration, wind and solar energy were both connected to the first system. The results achieved in the first configuration with the first objective function indicated that ISOMA not only outperformed SOMA according to all comparison criteria but was also superior to other methods such as evolutionary programming (EP), acceleration factor-based particle swarm optimization (AFPSO), and accelerated particle swarm optimization (APSO). The evaluation of the results achieved by ISOMA in the second configuration with the objective function of maximizing the TPRF revealed that ISOMA could reach better profits than SOMA in terms of maximum, mean and minimum TPRF values over fifty trial runs. As a result, it was concluded that pumped storage hydropower plants are very useful in integrating with renewable power plants to cut total cost for thermal power plants and in reaching the highest profit for the whole system. Also, ISOMA is a suitable algorithm for the considered problem.

Stability analysis of pumped storage hydropower plant in abandoned open-pit mine affected by dynamic surface subsidence of combined mining.

The construction of a pumped storage hydropower plant (PSHP) in an abandoned open-pit mine is a potential alternative to green mining and energy storage, which can increase the utilization rate of renewable energy and develop residual resources of abandoned mines. Dynamic surface subsidence affected by combined underground and open-pit mining (CUOPM) seriously affects the construction and operation of the PSHP and is one of the critical scientific issues that needs to be solved immediately. The stability of the PSHP was analyzed and treatment scheme of the goafs was proposed based on on-site measurement, theoretical analysis, and numerical simulation. First, the distribution of goafs in the Haizhou open-pit mining area was investigated and surface subsidence value was obtained using InSAR technology and ground monitoring. Secondly, the surface subsidence mechanism affected by CUOPM is analyzed and indicates the subsidence maximum values and scope of influence are greater than those of single underground mining. A dynamic surface subsidence prediction model for combined mining is established based on the Knothe time function model. Thirdly, based on the CVISC model, the numerical calculation models were established by using FLAC3D, and the characteristics and laws of surface subsidence in different periods of CUOPM were studied. The comparative analysis of the observation results shows that the proposed model and numerical simulation calculation method have excellent applicability and accuracy. Finally, a stability evaluation method of PSHP was established, and the results of the evaluation show that the affected areas are the semi-ground powerhouse (SGPH) and the west side of the lower reservoir. The method of grouting filling was used to treat the goafs, and the results showed that it effectively alleviates the dynamic surface subsidence affected by CUOPM, and provides a safety guarantee for PSHP.

Open pit limit optimization considering the pumped storage benefit after mine closure: a case study

Repurposing a closed mine as lower reservoir is a cost-effective way for the construction of pumped storage hydropower (PSH) plant. This method can eliminate the expenses of mine reclamation, reservoir construction, and land acquisition, resulting in significant cost savings and benefits for the PSH project, known as the PSH benefit. The construction of PSH plants within a closed mine is divided into surface mode and semi-underground mode in this paper. Through a general comparison of two in-situ cases, the finding highlight that the surface mode can achieve a larger potential installed capacity and lower construction cost. Furthermore, the PSH benefit is quantified and internalized as an economic parameter in the ultimate pit limit (UPL) optimization by allocating it into unit ore. Taken an undisclosed open-pit iron mine as example, the UPL is optimized by considering the PSH benefit. The internalized PSH benefit is calculated to be 6.59 CN¥/t when the installed capacity is 2000 MW, and ore amount within the optimized UPL is increased by 1.4%. The results indicated that the PSH benefit does influence the shape and size of UPL, but not significantly. Besides, converting several bottoms in a single open-pit into lower and upper reservoirs presents more challenges for UPL optimization, which further explorations is needed.

Stochastic optimal scheduling of wind power and pumped-storage hydropower complementary systems with multiple uncertainties

The joint operation of wind farms (WFs) and pumped-storage hydropower plants (PSHPs) is an effective way to smooth out the random fluctuations of wind power and improve its consumption rate. In this paper, a novel method to describe the multiple uncertainties of wind power outputs is proposed. A WFs-PSHP joint optimal scheduling model based on chance-constrained programming is then developed. The optimization model aims to maximize the total generation profit of the WFs-PSHP complementary system, and comprehensively considers the hydraulic constraints, unit operation constraints and system power balance constraint of the PSHP. To improve the model solving efficiency, this study converts the previous model with high-dimensional, non-convex, nonlinear and stochastic characteristics to the deterministic mixed integer linear programming (MILP) one. The optimization results demonstrate that the PSHP not only compensates for the fluctuations in wind power output, but also increases the total generation profit of this complementary system to 966.48 × 104 CNY, which is 17.56 % higher than that of independent operation.

FED evaluation in a small double-suction reversible pump turbine considering sediment erosion

Double-suction pump-turbines are a special type of reversible pump-turbine which serves the pumped storage hydro power plant. Enhancing the energy conversion efficiency of the power station can be effectively achieved by reducing the internal Flow Energy Dissipation (FED) within the pump-turbine. The key to addressing this challenge lies in the identification of high FED regions and conducting visualized analyses. In this study, computational fluid dynamics (CFD), thermodynamic calculation methods and the Finnie erosion model are combined to perform two-phase flow numerical simulations of a specific double-suction pump-turbine model under both pump and turbine operating modes. We analyzed the FED in different regions off wall. The energy loss distribution is provided within these five regions for the volute casing, suction chamber, and impeller separately, and conducted an analysis of component wear. The research findings revealed that, in the pump mode, FED primarily concentrates within the volute casing, while in the turbine mode, it is concentrated within the suction chamber, with both regions accounting for over 70 % of the total energy dissipation. The proportion of internal FED in five regions at varying distances from the wall for each component showed significant disparities under different operating conditions, closely related to the internal flow characteristics of the components. In pump mode, wear primarily occurs in the volute casing, while the wear in the suction chamber and impeller can be considered negligible. In turbine mode, each component experiences some level of wear. This provides a foundation for reducing flow energy losses and preventing sediment erosion.

Increasing Demand Covered by Renewable Energy in El Hierro Island

The power system of the El Hierro island comprises a wind farm, a pumped storage hydropower plant and a diesel power plant. Its operational history shows that the renewable energy participation in the energy mix is approximately 50%. In order to increase this participation, the installation of residential photovoltaic generation and battery storage has been considered. In this paper, the operation of the whole system is analyzed by simulation. Simulations consider historical data of electric supply and demand in addition to meteorological data to obtain the wind and solar power production. The simulation tool has been tuned to successfully reproduce past system performance. From the simulations, the effect of adding new renewable generation and storage has been assessed. Also, the effect of a different operation strategy has been analyzed. From the results of these simulations, adding batteries has a negligible effect in increasing renewable energy participation. By contrast, adding solar power provides an increase in renewable energy participation. However, eliminating the requirement of 50% of synchronous generation has the largest effect on increasing renewable energy participation in the energy mix.

Optimal scheduling of pumped storage hydropower plants with multi-type of units in day-ahead electricity market considering water head effects

Optimal scheduling of pumped storage hydropower plants with multi-type of units in day-ahead electricity market considering water head effects

Complementary scheduling rules for hybrid pumped storage hydropower-photovoltaic power system reconstructing from conventional cascade hydropower stations

The reconstruction of conventional cascade hydropower plants (CHP) into hybrid pumped storage hydropower plants (HPSH) by adding a pumping station has the potential to increase the hydropower's flexibility and promote the consumption of renewable energy into the power grid. However, the complex hydraulic and electric connections between cascade hydropower stations and multi-energy sources pose challenges to safe and economic operation. This study explores the complementary scheduling for hybrid pumped storage hydropower-photovoltaic (HPSH-PV) system and evaluates the operation benefit and risk. First, the complementary scheduling rules that consider the demand for long-distance and across-regions power transmission are proposed to guide the peak-shaving operation of the system. Then a case study is performed with a hydro-PV complementary project in China, and the benefit and risks are evaluated quantitatively while considering the uncertainty of PV power prediction. The results demonstrate that after a pumping station is added (1) the power generation profit can be increased, especially in the dry seasons and the upstream reservoir; (2) the regulation capacity and power-supply reliability of the upstream reservoir is increased, while that of the downstream reservoir is slightly reduced; (3) the reservoir water level fluctuation and operation risk increase, but it can be lowered as the inflow increases.

Challenges of Large Converter-Fed Synchronous Machines for Variable-Speed Pumped Hydro Storage

The green energy transition of electrical energy production is leading to an increasing share of total energy production for volatile renewable energy sources, mainly wind and solar power. To handle this volatile production, flexible and efficient energy storage is required. The development of high-power converters has enabled the generation of variable-speed pumped hydro storage power plants, combining the so-far-unequalled energy storage capacity of classical pumped-storage hydro power plants and the recently increased operation requirements. The introduction of large-scale converters has led to new challenges in the overall design of power plant systems. This paper intended to take a closer look at a large-scale converter-fed synchronous generator, especially the distribution of the current and voltage harmonics caused by the converter in the implemented generation system. Thereby, holistic design considerations for an ideal loss distribution as well as possible measures to limit the effects of harmonic coupling at the generator shaft and bearings are discussed. Furthermore, basic considerations of harmonic emission to the connected network are described. These topics are addressed by analyzing on-site measurements at an 85 MVA converter-fed synchronous generator with a voltage source inverter, underpinned with the theoretical background.

Valuing the social cost of carbon: Do economists really care about climate change?

The aim of the article is to analyse the scientific literature of the last decade on the social cost of carbon to identify and discuss the best values representing the external cost of CO2 emis-sions calculated with a damage valuation approach, to use in cost-benefit analysis and in other external costs applications, such as Life Cycle Assessment. The social cost of carbon repre-sents the present value of the global damages of climate change attributable to the emission of an additional ton of carbon dioxide into the atmosphere. The measurement of the social cost of carbon is fundamental in the transition to a net zero emissions economy because it allows bal-ancing the costs of investments needed for decarbonization with their benefits in terms of avoided climate damages. The paper develops and applies a method for identifying the best social cost of carbon estimates, that starts from study reviews conducted within institutional processes (IPCC, OECD, US Government bodies), to then analyse the study reviews made in academic or research contexts and only in the end it delves into selected academic studies that provide original estimates of the social cost of carbon. The method allowed to identify and dis-cuss a robust even if conservative estimate of the social cost of carbon for emissions in the period 2020-2080, recently elaborated by the US Environmental Protection Agency, that can be used worldwide, for example to update the reference external cost values for CO2 emis-sions recommended by the European Commission Handbook on external cost of transport.

Bidding strategy of storage hydropower plants in reserve markets

The increasing share of intermittent sources of energy will increase the need for frequency-control reserves. However, the supply from gas and coal-fired power plants might decrease in the following years. Being the procurement of reserves mostly market-based in Europe, the market design should send price signals to encourage participation in these markets. This pa-per analyses the incentives provided by the French market design for seasonal storage and pumped storage hydropower plants to participate in reserve markets. To that end, a determinis-tic mixed-integer linear optimization model is presented. The objective is to maximize profits in the energy and reserve markets according to 2019 market prices. By optimising the trade-offs between the day-ahead and the reserve markets, the storage hydropower plant increase its profits. The pumped storage hydropower plant sometimes chooses the Frequency Contain-ment Reserve market or the day-ahead market only. The apparition of some hours of FCR par-ticipation with the pumped storage plant is explained by its higher number of generating hours and by the higher volatility of reserve energy prices. These two factors also explain the greater response of the pumped storage plant to the incentive measures on the FCR market.

Wind-hydro pumped storage systems to meet lebanese electricity demand

Lebanon is facing currently anacute energy crisis, due tolack of domestic energy resources, reduced production capacities and a growing demand for energy. Relying on wind energy could reduce the impact of this crisis. However, continuous change in wind speed from calm to stormy introduces challenges. One possible solution to address these challenges is to introduce new storage facilities or to use storage capabilities already available in the power generation system. Existing hydro power plants with large reservoirs or pumped storage hydro power plants are suitable for this purpose. Furthermore, Lebanon has a fairly high wind energy potential and hydro power resources. This paper is an attempt to analyze the design of a pumping station and the performance of a hybrid wind-hydro power plant, in three hydraulic plants to produce electricity in Lebanon (Markabi, Awali and Joun), in order to choose the most suitable plant to store electrical power. An economic analysis and an evaluation of the amount of water that could be pumped in each of the hydraulic plants are carried out in this study, in order to select the most suitable hydraulic plant to store the electricity surplus. Moreover, this study presents an economic evaluation of the implementation of wind turbines in Lebanon. It is shown that Markabi is the most suitable plant to store electrical power.

Optimal price-based scheduling of a pumped-storage hydropower plant considering environmental constraints

Optimal price-based scheduling of a pumped-storage hydropower plant considering environmental constraints

World's First Fully Rated Direct ac/ac MMC for Variable-Speed Pumped-Storage Hydropower Plants

World's First Fully Rated Direct ac/ac MMC for Variable-Speed Pumped-Storage Hydropower Plants

Battery and Flywheel hybridization of a reversible Pumped-Storage Hydro Power Plant for wear and tear reduction

Energy security and environmental challenges are some of the drivers for increasing the electricity generation from non-programmable Renewable Energy Sources (RES), adding pressure to the grid, especially if located in weakly connected (or isolated) islands, like Sardinia. Variable-speed Pumped Storage Hydro Power (PSHP) can offer a high degree of flexibility in providing ancillary services (namely primary and secondary regulations), but due to the hydro-mechanical nature of the equipment, sudden variations in the power output cause wear and tear. Other energy storage devices cannot compete with PSHP in terms of energy and power availability. The aim of this research is to assess the benefits derived from the hybridization of a PSHP with Battery Energy Storage System (BESS) and Flywheel Energy Storage System (FESS), to be installed in the Sardinia island (Italy). A dynamic model of the hybrid plant was made in MATLAB–Simulink® environment. A detailed model of the variable-speed pump-turbine was obtained from experimental data, and a simplified model of a fixed-speed turbine was produced. A detailed FESS model was provided by CIEMAT (Madrid, Spain) and a simplified BESS model was included. A dedicated control strategy to manage the power flows and accounting for State Of Charge (SOC) control, was implemented. A total of 100 combinations of BESS and FESS powers were taken into account, and the control strategy was calibrated for each one of them. The plant was simulated open-loop over a 3600s time period, feeding historical frequency and Automatic Generation Control (AGC) data. The simulations covered three PSHP operation modes: variable/fixed-speed turbine and variable-speed pump, and with/without hybridization. The performances of the hybridization were evaluated with wear and tear indicators for the PSHP (distance travelled by and number of movements of the wicket gate for turbine, fluctuations of the shaft torque for the pump) and capacity loss (life consumption) for the BESS. The results show that all the combinations of BESS and FESS powers result in the reduction of both the travelled distance and number of movements of the guide vanes. The best hybrid combination for the PSHP does not affect the BESS life consumption, which still is always in an acceptable range. A comparison between the non-hybrid variable-speed turbine and the hybrid fixed-speed counterpart shows that the electric powers do not differ substantially, but the hybridization smooths the movement of the guide vanes. The pump torque fluctuations sharply decrease with the hybridization, but more research is needed to validate that the change in the fluctuation index corresponds to a physical phenomenon. Overall, the hybridization improves the plant performances in terms of wear and tear reduction, and the presence of an additional FESS benefits both the BESS and the PSHP. The results also highlight the necessity for more research in variable-speed pumps providing ancillary services, and their impact.

Numerical Study of the Internal Fluid Dynamics of Draft Tube in Seawater Pumped Storage Hydropower Plant

Pumped storage hydropower plants are renewable energy systems that are effective in saving energy and solving electricity peak-on shortage. Seawater pumped storage hydropower plants are a novel type of pumped storage hydropower plant specifically supplying electric power for ocean islands with the support of solar energy and wind energy. Compared with traditional pumped storage hydropower plants that are constructed on the mainland, seawater pumped storage hydropower plants should take the influence of the complex marine environment, such as extreme waves and winds, into consideration. Taking the characteristics of waves near islands in the East China Sea as an example, we explored the transient hydraulic characteristics in the draft tube of a pump turbine under wave disturbance using a sliding grid interface and the detached eddy simulation (DES) turbulence model. By analyzing the characteristics of unsteady flow in the draft tube, the vortex characteristics under the Q criterion, the frequency characteristics of the pressure pulsation, the evolution law of the internal fluid, and the propagation law of the pressure pulsation were explored. For the situation without wave disturbance, an obvious eccentric vortex in the straight cone section of the draft tube was observed in the case where the opening of the guide vane was small. With the increase in the opening of the guide vane, the eccentric vortex gradually dissipated. For the situation with wave disturbance, the main frequency of the draft tube equaled the frequency of the wave disturbance, the maximum pressure pulsation at the selected monitoring points increased 5 to 15 times, and the superposition of the wave pressure pulsation signals and the draft tube pressure pulsation produced more low-frequency, high-amplitude pressure pulsation signals. Even though the pressure pulsation frequency spectrum varied a lot, the frequency domain of the pressure pulsation without wave disturbance still existed. In addition, the wave disturbance merely varied with the pressure of the draft tube. The influence of wave disturbance on the pressure distribution in the draft tube was relatively small. The results can provide a reference for the operation of seawater pumped storage hydropower plants.

Implementation and Evaluation of a Complex Pumped-Storage Hydropower Plant with Four Units, Common Penstock, and Surge Tank in a Real-Time Digital Simulator

The demand for energy storage systems is rising together with the proportion of renewable energy sources (RES) in power systems. The highest capacity among the various energy storage systems in power systems is provided by pumped-storage hydropower (PSH). In this paper, the ability of the real-time digital simulator (RTDS), e.g., dSpace–SCALEXIO, to emulate a complex pumped-storage hydropower plant with four units, two common penstocks, a surge tank, and a long headrace tunnel is investigated. The RTDS is the smart brain of an advanced lab setup called power hardware in the loop (PHIL), which is an extremely safe and useful lab system for electrical power system research and testing hardware and methods under various conditions. In this research, the capability of an RTDS to emulate the behavior of a pumped-storage hydropower plant including four Francis pump-turbines, four short penstocks, two common penstocks, a surge tank, and a long headrace tunnel is evaluated. Francis pump-turbines are modelled based on the hill chart-based interpolation and waterways including penstocks and headrace tunnel are modelled based on the polynomial approximation of a hyperbolic function. Finally, the results from the RTDS are presented and discussed. According to the results of the paper, we confirm that the RTDS can accurately emulate the hydraulic, mechanical, and electrical transients of a pumped-storage hydropower plant with a complex configuration.