The Experts below are selected from a list of 4719 Experts worldwide ranked by ideXlab platform
Alain Dassargues - One of the best experts on this subject based on the ideXlab platform.
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The Impact of Hydrogeological Features on the Performance of Underground Pumped-Storage Hydropower (UPSH)
Applied Sciences, 2021Co-Authors: Estanislao Pujades, Philippe Orban, Angélique Poulain, Pascal Goderniaux, Alain DassarguesAbstract:Underground pumped Storage Hydropower (UPSH) is an attractive opportunity to manage the production of electricity from renewable energy sources in flat regions, which will contribute to the expansion of their use and, thus, to mitigating the emissions of greenhouse gasses (GHGs) in the atmosphere. A logical option to construct future UPSH plants consists of taking advantage of existing underground cavities excavated with mining purposes. However, mines are not waterproofed, and there will be an underground water exchange between the surrounding geological medium and the UPSH plants, which can impact their efficiency and the quality of nearby water bodies. Underground water exchanges depend on hydrogeological features, such as the hydrogeological properties and the groundwater characteristics and behavior. In this paper, we numerically investigated how the hydraulic conductivity (K) of the surrounding underground medium and the elevation of the piezometric head determined the underground water exchanges and their associated consequences. The results indicated that the efficiency and environmental impacts on surface water bodies became worse in transmissive geological media with a high elevation of the piezometric head. However, the expected environmental impacts on the underground medium increased as the piezometric head became deeper. This assessment complements previous ones developed in the same field and contributes to the definition of (1) screening strategies for selecting the best places to construct future UPSH plants and (2) design criteria to improve their efficiency and minimize their impacts.
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Underground Pumped-Storage Hydropower (UPSH) at the Martelange Mine (Belgium): Underground Reservoir Hydraulics
Energies, 2020Co-Authors: Vasileios Kitsikoudis, Estanislao Pujades, Philippe Orban, Alain Dassargues, Pierre Archambeau, Benjamin Dewals, Michel Pirotton, Sébastien ErpicumAbstract:The intermittent nature of most renewable energy sources requires their coupling with an energy Storage system, with pumped Storage Hydropower (PSH) being one popular option. However, PSH cannot always be constructed due to topographic, environmental, and societal constraints, among others. Underground pumped Storage Hydropower (UPSH) has recently gained popularity as a viable alternative and may utilize abandoned mines for the construction of the lower reservoir in the underground. Such underground mines may have complex geometries and the injection/pumping of large volumes of water with high discharge could lead to uneven water level distribution over the underground reservoir subparts. This can temporarily influence the head difference between the upper and lower reservoirs of the UPSH, thus affecting the efficiency of the plant or inducing structural stability problems. The present study considers an abandoned slate mine in Martelange in Southeast Belgium as the lower, underground, reservoir of an UPSH plant and analyzes its hydraulic behavior. The abandoned slate mine consists of nine large chambers with a total volume of about 550,000 m3, whereas the maximum pumping and turbining discharges are 22.2 m3/s. The chambers have different size and they are interconnected with small galleries with limited discharge capacity that may hinder the flow exchange between adjacent chambers. The objective of this study is to quantify the effect of the connecting galleries cross-section and the chambers adequate aeration on the water level variations in the underground reservoir, considering a possible operation scenario build upon current electricity prices and using an original hydraulic modelling approach. The results highlight the importance of adequate ventilation of the chambers in order to reach the same equilibrium water level across all communicating chambers. For fully aerated chambers, the connecting galleries should have a total cross-sectional area of at least 15 m2 to allow water flow through them without significant restrictions and maintain similar water level at all times. Partially aerated chambers do not attain the same water level because of the entrapped air; however, the maximum water level differences between adjacent chambers remain relatively invariant when the total cross-sectional area of the connecting galleries is greater than 8 m2. The variation of hydraulic roughness of the connecting galleries affects the water exchange through small connecting galleries but is not very influential on water moving through galleries with large cross-sections.
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Underground Pumped-Storage Hydropower (UPSH) at the Martelange Mine (Belgium): Interactions with Groundwater Flow
Energies, 2020Co-Authors: Estanislao Pujades, Philippe Orban, Vasileios Kitsikoudis, Pierre Archambeau, Sébastien Erpicum, Alain DassarguesAbstract:Underground pumped-Storage Hydropower (UPSH) is a promising technology to manage the electricity production in flat regions. UPSH plants consist of an underground and surface reservoirs. The energy is stored by pumping water from the underground to the surface reservoir and is produced by discharging water from the surface to the underground reservoir. The underground reservoir can be drilled, but a more efficient alternative, considered here, consists in using an abandoned mine. Given that mines are rarely waterproofed, there are concerns about the consequences (on the efficiency and the environment) of water exchanges between the underground reservoir and the surrounding medium. This work investigates numerically such water exchanges and their consequences. Numerical models are based on a real abandoned mine located in Belgium (Martelange slate mine) that is considered as a potential site to construct an UPSH plant. The model integrates the geometrical complexity of the mine, adopts an operation scenario based on actual electricity prices, simulates the behavior of the system during one year and considers two realistic scenarios of initial conditions with the underground reservoir being either completely full or totally drained. The results show that (1) water exchanges may have important consequences in terms of efficiency and environmental impacts, (2) the influence of the initial conditions is only relevant during early times, and (3), an important factor controlling the water exchanges and their consequences may be the relative location of the natural piezometric head with respect the underground reservoir.
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Numerical study of the Martelange mine to be used as underground reservoir for constructing an Underground Pumped Storage Hydropower plant
Advances in Geosciences, 2018Co-Authors: Estanislao Pujades, Philippe Orban, Pierre Archambeau, Sébastien Erpicum, Alain DassarguesAbstract:Abstract. Underground Pumped Storage Hydropower (UPSH) using abandoned mines has been considered as a potential high capacity Energy Storage Systems. In UPSH plants, the excess of electricity is stored in the form of potential energy by pumping water from an underground reservoir (abandoned mine in this paper) to a surface reservoir, while electricity is produced (when the demand increases) discharging water from the surface into the underground reservoir. The main concerns may arise from the water exchanges occurring between the underground reservoir and the surrounding medium, which are relevant in terms of environmental impact and UPSH efficiency. Although the role of the water exchanges has been previously addressed, most studies are based on synthetic models. This work focuses on a real abandoned slate mine located in Martelange (Belgium). The effects of different rehabilitation works to prepare the mine as an underground reservoir are assessed in terms of groundwater exchanges and their associated consequences.
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Hydrochemical changes induced by underground pumped Storage Hydropower: influence of aquifer parameters in coal mine environments
Advances in Geosciences, 2018Co-Authors: Estanislao Pujades, Philippe Orban, Anna Jurado, Alain DassarguesAbstract:Abstract. Underground pumped Storage Hydropower (UPSH) induces hydrochemical changes when water evolves to reach equilibrium with the atmosphere (in the surface reservoir) and with the surrounding medium (in the underground reservoir). These hydrochemical changes may impact the environment and the efficiency of the system (i.e., the UPSH plant), especially in coal mine environments where the presence of sulphide minerals is common. For this reason, it is needed to assess the variables that control the behavior of the system in order to establish criteria for the selection of abandoned mines to be used as underground reservoirs in future UPSH plants. Coupled hydro-chemical numerical models are used for investigating the influence of hydraulic parameters on the hydrochemical changes when pyrite is present in the surrounding medium. Results show the role of the hydraulic conductivity and the porosity on the system behavior, which is helpful for selecting those abandoned mines where the hydrochemical changes and their associated consequences will be less.
Estanislao Pujades - One of the best experts on this subject based on the ideXlab platform.
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Underground pumped Storage Hydropower (UPSH) and its interaction with the saturated subsurface medium: effects of the water exchanges on the environment and the plant efficiency
2021Co-Authors: Estanislao PujadesAbstract:<p>Underground pumped Storage Hydropower (UPSH) is an alternative energy Storage system (ESS) for flat regions, where conventional pumped Storage Hydropower plants cannot be constructed due to topographical limitations. UPSH plants consist in two reservoirs, the upper one is located at the surface or possibly underground (but at shallow depth) while the lower one is underground. Although the underground reservoir can be drilled, the use of abandoned mines (deep or open pit mines) as underground reservoir is a more efficient alternative that is also beneficial for local communities after the cessation of mining activities. Given that mines are rarely waterproofed, water exchanges between UPSH plants and the underground medium are expected. Water exchanges may have negative consequences for the environment, but also for the feasibility of UPSH plants. The impacts on the environment and the plant efficiency may have hydraulic (changes of the natural piezometric head distribution, effects in the hydraulic head difference between the two reservoirs, etc.) or hydrochemical nature (dissolution and/or precipitation of minerals in the aquifer and in the reservoirs, corrosion of facilities, modification of pH, etc.). At this stage, it is required a sound understanding of all the impacts produced by the water exchanges and evaluate under which circumstances they are mitigated. This assessment will allow ascertaining criteria for the selection of the best places to construct future UPSH plants.</p>
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The Impact of Hydrogeological Features on the Performance of Underground Pumped-Storage Hydropower (UPSH)
Applied Sciences, 2021Co-Authors: Estanislao Pujades, Philippe Orban, Angélique Poulain, Pascal Goderniaux, Alain DassarguesAbstract:Underground pumped Storage Hydropower (UPSH) is an attractive opportunity to manage the production of electricity from renewable energy sources in flat regions, which will contribute to the expansion of their use and, thus, to mitigating the emissions of greenhouse gasses (GHGs) in the atmosphere. A logical option to construct future UPSH plants consists of taking advantage of existing underground cavities excavated with mining purposes. However, mines are not waterproofed, and there will be an underground water exchange between the surrounding geological medium and the UPSH plants, which can impact their efficiency and the quality of nearby water bodies. Underground water exchanges depend on hydrogeological features, such as the hydrogeological properties and the groundwater characteristics and behavior. In this paper, we numerically investigated how the hydraulic conductivity (K) of the surrounding underground medium and the elevation of the piezometric head determined the underground water exchanges and their associated consequences. The results indicated that the efficiency and environmental impacts on surface water bodies became worse in transmissive geological media with a high elevation of the piezometric head. However, the expected environmental impacts on the underground medium increased as the piezometric head became deeper. This assessment complements previous ones developed in the same field and contributes to the definition of (1) screening strategies for selecting the best places to construct future UPSH plants and (2) design criteria to improve their efficiency and minimize their impacts.
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Underground Pumped-Storage Hydropower (UPSH) at the Martelange Mine (Belgium): Underground Reservoir Hydraulics
Energies, 2020Co-Authors: Vasileios Kitsikoudis, Estanislao Pujades, Philippe Orban, Alain Dassargues, Pierre Archambeau, Benjamin Dewals, Michel Pirotton, Sébastien ErpicumAbstract:The intermittent nature of most renewable energy sources requires their coupling with an energy Storage system, with pumped Storage Hydropower (PSH) being one popular option. However, PSH cannot always be constructed due to topographic, environmental, and societal constraints, among others. Underground pumped Storage Hydropower (UPSH) has recently gained popularity as a viable alternative and may utilize abandoned mines for the construction of the lower reservoir in the underground. Such underground mines may have complex geometries and the injection/pumping of large volumes of water with high discharge could lead to uneven water level distribution over the underground reservoir subparts. This can temporarily influence the head difference between the upper and lower reservoirs of the UPSH, thus affecting the efficiency of the plant or inducing structural stability problems. The present study considers an abandoned slate mine in Martelange in Southeast Belgium as the lower, underground, reservoir of an UPSH plant and analyzes its hydraulic behavior. The abandoned slate mine consists of nine large chambers with a total volume of about 550,000 m3, whereas the maximum pumping and turbining discharges are 22.2 m3/s. The chambers have different size and they are interconnected with small galleries with limited discharge capacity that may hinder the flow exchange between adjacent chambers. The objective of this study is to quantify the effect of the connecting galleries cross-section and the chambers adequate aeration on the water level variations in the underground reservoir, considering a possible operation scenario build upon current electricity prices and using an original hydraulic modelling approach. The results highlight the importance of adequate ventilation of the chambers in order to reach the same equilibrium water level across all communicating chambers. For fully aerated chambers, the connecting galleries should have a total cross-sectional area of at least 15 m2 to allow water flow through them without significant restrictions and maintain similar water level at all times. Partially aerated chambers do not attain the same water level because of the entrapped air; however, the maximum water level differences between adjacent chambers remain relatively invariant when the total cross-sectional area of the connecting galleries is greater than 8 m2. The variation of hydraulic roughness of the connecting galleries affects the water exchange through small connecting galleries but is not very influential on water moving through galleries with large cross-sections.
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Underground Pumped-Storage Hydropower (UPSH) at the Martelange Mine (Belgium): Interactions with Groundwater Flow
Energies, 2020Co-Authors: Estanislao Pujades, Philippe Orban, Vasileios Kitsikoudis, Pierre Archambeau, Sébastien Erpicum, Alain DassarguesAbstract:Underground pumped-Storage Hydropower (UPSH) is a promising technology to manage the electricity production in flat regions. UPSH plants consist of an underground and surface reservoirs. The energy is stored by pumping water from the underground to the surface reservoir and is produced by discharging water from the surface to the underground reservoir. The underground reservoir can be drilled, but a more efficient alternative, considered here, consists in using an abandoned mine. Given that mines are rarely waterproofed, there are concerns about the consequences (on the efficiency and the environment) of water exchanges between the underground reservoir and the surrounding medium. This work investigates numerically such water exchanges and their consequences. Numerical models are based on a real abandoned mine located in Belgium (Martelange slate mine) that is considered as a potential site to construct an UPSH plant. The model integrates the geometrical complexity of the mine, adopts an operation scenario based on actual electricity prices, simulates the behavior of the system during one year and considers two realistic scenarios of initial conditions with the underground reservoir being either completely full or totally drained. The results show that (1) water exchanges may have important consequences in terms of efficiency and environmental impacts, (2) the influence of the initial conditions is only relevant during early times, and (3), an important factor controlling the water exchanges and their consequences may be the relative location of the natural piezometric head with respect the underground reservoir.
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An overview about the interaction between the underground pumped Storage Hydropower (UPSH) and the saturated subsurface medium: effects of the water exchanges on the environment and the plant efficiency
2020Co-Authors: Estanislao PujadesAbstract:<p>Underground pumped Storage Hydropower (UPSH) is an alternative energy Storage system (ESS) for flat regions, where conventional pumped Storage Hydropower plants cannot be constructed due to topographical limitations. UPSH plants consist in two reservoirs, the upper one is located at the surface or possibly underground (but at shallow depth) while the lower one is underground. Although the underground reservoir can be drilled, the use of abandoned mines (deep or open pit mines) as underground reservoir is a more efficient alternative that is also beneficial for local communities after the cessation of mining activities. Given that mines are rarely waterproofed, water exchanges between UPSH plants and the underground medium are expected. Water exchanges may have negative consequences for the environment, but also for the feasibility of UPSH plants. The impacts on the environment and the plant efficiency may have hydraulic (changes of the natural piezometric head distribution, effects in the hydraulic head difference between the two reservoirs, etc.) or hydrochemical nature (dissolution and/or precipitation of minerals in the aquifer and in the reservoirs, corrosion of facilities, modification of pH, etc.). At this stage, it is required a sound understanding of all the impacts produced by the water exchanges and evaluate under which circumstances they are mitigated. This assessment will allow ascertaining criteria for the selection of the best places to construct future UPSH plants.</p>
Philippe Orban - One of the best experts on this subject based on the ideXlab platform.
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The Impact of Hydrogeological Features on the Performance of Underground Pumped-Storage Hydropower (UPSH)
Applied Sciences, 2021Co-Authors: Estanislao Pujades, Philippe Orban, Angélique Poulain, Pascal Goderniaux, Alain DassarguesAbstract:Underground pumped Storage Hydropower (UPSH) is an attractive opportunity to manage the production of electricity from renewable energy sources in flat regions, which will contribute to the expansion of their use and, thus, to mitigating the emissions of greenhouse gasses (GHGs) in the atmosphere. A logical option to construct future UPSH plants consists of taking advantage of existing underground cavities excavated with mining purposes. However, mines are not waterproofed, and there will be an underground water exchange between the surrounding geological medium and the UPSH plants, which can impact their efficiency and the quality of nearby water bodies. Underground water exchanges depend on hydrogeological features, such as the hydrogeological properties and the groundwater characteristics and behavior. In this paper, we numerically investigated how the hydraulic conductivity (K) of the surrounding underground medium and the elevation of the piezometric head determined the underground water exchanges and their associated consequences. The results indicated that the efficiency and environmental impacts on surface water bodies became worse in transmissive geological media with a high elevation of the piezometric head. However, the expected environmental impacts on the underground medium increased as the piezometric head became deeper. This assessment complements previous ones developed in the same field and contributes to the definition of (1) screening strategies for selecting the best places to construct future UPSH plants and (2) design criteria to improve their efficiency and minimize their impacts.
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Underground Pumped-Storage Hydropower (UPSH) at the Martelange Mine (Belgium): Underground Reservoir Hydraulics
Energies, 2020Co-Authors: Vasileios Kitsikoudis, Estanislao Pujades, Philippe Orban, Alain Dassargues, Pierre Archambeau, Benjamin Dewals, Michel Pirotton, Sébastien ErpicumAbstract:The intermittent nature of most renewable energy sources requires their coupling with an energy Storage system, with pumped Storage Hydropower (PSH) being one popular option. However, PSH cannot always be constructed due to topographic, environmental, and societal constraints, among others. Underground pumped Storage Hydropower (UPSH) has recently gained popularity as a viable alternative and may utilize abandoned mines for the construction of the lower reservoir in the underground. Such underground mines may have complex geometries and the injection/pumping of large volumes of water with high discharge could lead to uneven water level distribution over the underground reservoir subparts. This can temporarily influence the head difference between the upper and lower reservoirs of the UPSH, thus affecting the efficiency of the plant or inducing structural stability problems. The present study considers an abandoned slate mine in Martelange in Southeast Belgium as the lower, underground, reservoir of an UPSH plant and analyzes its hydraulic behavior. The abandoned slate mine consists of nine large chambers with a total volume of about 550,000 m3, whereas the maximum pumping and turbining discharges are 22.2 m3/s. The chambers have different size and they are interconnected with small galleries with limited discharge capacity that may hinder the flow exchange between adjacent chambers. The objective of this study is to quantify the effect of the connecting galleries cross-section and the chambers adequate aeration on the water level variations in the underground reservoir, considering a possible operation scenario build upon current electricity prices and using an original hydraulic modelling approach. The results highlight the importance of adequate ventilation of the chambers in order to reach the same equilibrium water level across all communicating chambers. For fully aerated chambers, the connecting galleries should have a total cross-sectional area of at least 15 m2 to allow water flow through them without significant restrictions and maintain similar water level at all times. Partially aerated chambers do not attain the same water level because of the entrapped air; however, the maximum water level differences between adjacent chambers remain relatively invariant when the total cross-sectional area of the connecting galleries is greater than 8 m2. The variation of hydraulic roughness of the connecting galleries affects the water exchange through small connecting galleries but is not very influential on water moving through galleries with large cross-sections.
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Underground Pumped-Storage Hydropower (UPSH) at the Martelange Mine (Belgium): Interactions with Groundwater Flow
Energies, 2020Co-Authors: Estanislao Pujades, Philippe Orban, Vasileios Kitsikoudis, Pierre Archambeau, Sébastien Erpicum, Alain DassarguesAbstract:Underground pumped-Storage Hydropower (UPSH) is a promising technology to manage the electricity production in flat regions. UPSH plants consist of an underground and surface reservoirs. The energy is stored by pumping water from the underground to the surface reservoir and is produced by discharging water from the surface to the underground reservoir. The underground reservoir can be drilled, but a more efficient alternative, considered here, consists in using an abandoned mine. Given that mines are rarely waterproofed, there are concerns about the consequences (on the efficiency and the environment) of water exchanges between the underground reservoir and the surrounding medium. This work investigates numerically such water exchanges and their consequences. Numerical models are based on a real abandoned mine located in Belgium (Martelange slate mine) that is considered as a potential site to construct an UPSH plant. The model integrates the geometrical complexity of the mine, adopts an operation scenario based on actual electricity prices, simulates the behavior of the system during one year and considers two realistic scenarios of initial conditions with the underground reservoir being either completely full or totally drained. The results show that (1) water exchanges may have important consequences in terms of efficiency and environmental impacts, (2) the influence of the initial conditions is only relevant during early times, and (3), an important factor controlling the water exchanges and their consequences may be the relative location of the natural piezometric head with respect the underground reservoir.
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Numerical study of the Martelange mine to be used as underground reservoir for constructing an Underground Pumped Storage Hydropower plant
Advances in Geosciences, 2018Co-Authors: Estanislao Pujades, Philippe Orban, Pierre Archambeau, Sébastien Erpicum, Alain DassarguesAbstract:Abstract. Underground Pumped Storage Hydropower (UPSH) using abandoned mines has been considered as a potential high capacity Energy Storage Systems. In UPSH plants, the excess of electricity is stored in the form of potential energy by pumping water from an underground reservoir (abandoned mine in this paper) to a surface reservoir, while electricity is produced (when the demand increases) discharging water from the surface into the underground reservoir. The main concerns may arise from the water exchanges occurring between the underground reservoir and the surrounding medium, which are relevant in terms of environmental impact and UPSH efficiency. Although the role of the water exchanges has been previously addressed, most studies are based on synthetic models. This work focuses on a real abandoned slate mine located in Martelange (Belgium). The effects of different rehabilitation works to prepare the mine as an underground reservoir are assessed in terms of groundwater exchanges and their associated consequences.
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Hydrochemical changes induced by underground pumped Storage Hydropower: influence of aquifer parameters in coal mine environments
Advances in Geosciences, 2018Co-Authors: Estanislao Pujades, Philippe Orban, Anna Jurado, Alain DassarguesAbstract:Abstract. Underground pumped Storage Hydropower (UPSH) induces hydrochemical changes when water evolves to reach equilibrium with the atmosphere (in the surface reservoir) and with the surrounding medium (in the underground reservoir). These hydrochemical changes may impact the environment and the efficiency of the system (i.e., the UPSH plant), especially in coal mine environments where the presence of sulphide minerals is common. For this reason, it is needed to assess the variables that control the behavior of the system in order to establish criteria for the selection of abandoned mines to be used as underground reservoirs in future UPSH plants. Coupled hydro-chemical numerical models are used for investigating the influence of hydraulic parameters on the hydrochemical changes when pyrite is present in the surrounding medium. Results show the role of the hydraulic conductivity and the porosity on the system behavior, which is helpful for selecting those abandoned mines where the hydrochemical changes and their associated consequences will be less.
Jorge Loredo - One of the best experts on this subject based on the ideXlab platform.
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economic feasibility of underground pumped Storage Hydropower plants providing ancillary services
Applied Sciences, 2020Co-Authors: Javier Menendez, Jesus M Fernandezoro, Jorge LoredoAbstract:The electricity generated by some renewable energy sources (RESs) is difficult to forecast; therefore, large-scale energy Storage systems (ESSs) are required for balancing supply and demand. Unlike conventional pumped Storage Hydropower (PSH) systems, underground pumped Storage Hydropower (UPSH) plants are not limited by topography and produce low environmental impacts. In this paper, a deterministic model has been conducted for three UPSH plants in order to evaluate the economic feasibility when considering daily turbine cycle times at full load (DTCs) between 4 and 10 h. In the model, the day-ahead and the ancillary services markets have been compared to maximize the price spread between the electricity generated and consumed. Secondary regulation, deviation management and tertiary regulation services have been analyzed to maximize the income and minimize the cost for purchasing energy. The capital costs of an open-loop UPSH plant have been estimated for the case of using the existing infrastructure and for the case of excavating new tunnels as lower reservoirs. The net present value (NPV), internal rate of return (IRR) and payback period (PB) have been obtained in all scenarios. The results obtained show that the energy generation and the annual generation cycles decrease when the DTC increases from 4 to 10 h, while the NPV and the IRR increase due to investment costs. The investment cost of a 219 MW UPSH plant using the existing infrastructure reaches 366.96 M€, while the NPV, IRR and PB reached 185 M€, 7.10% and 15 years, respectively, participating in the ancillary services markets and considering a DTC of 8 h.
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Transient Simulation of Underground Pumped Storage Hydropower Plants Operating in Pumping Mode
Energies, 2020Co-Authors: Javier Menendez, Monica Galdo, Jesús M. Fernández-oro, Jorge LoredoAbstract:The increasing penetration of variable renewable energies (VRE) in the European electricity mix requires flexible energy Storage systems (ESS), such as pumped Storage Hydropower (PSH). Disused mining voids from deep closed mines may be used as subsurface reservoirs of underground pumped-Storage Hydropower (UPSH) plants. Unlike conventional PSH plants, the air pressure in UPSH plants is variable and it differs from the atmospheric conditions. In this paper, the hydraulic transient process of an UPSH plant operating in pumping mode was investigated and a preliminary thermodynamic analysis of the closed surge tank was carried out. Analytical and CFD three-dimensional numerical simulations based on the volume of fluid (VOF) model with two-phase flow have been performed for analyzing the transient process. In the transient simulation, air and water are considered as ideal gas and compressible liquid, respectively. Different guide vanes closing schemes have been simulated. The obtained results show that the dimensioning of underground reservoir, surge tank, and air ducts is essential for ensuring the hydraulic performance and optimizing the operation of UPSH plants. The static pressure in the air duct, surge tank and lower reservoir reaches −1.6, 112.8 and −4 kPa, respectively, while a heat flux of −80 W was obtained through the surge tank walls.
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Comparing Subsurface Energy Storage Systems: Underground Pumped Storage Hydropower, Compressed Air Energy Storage and Suspended Weight Gravity Energy Storage
E3S Web of Conferences, 2020Co-Authors: Javier Menendez, Falko Schmidt, Jorge LoredoAbstract:In the current energy context, intermittent and non-dispatchable renewable energy sources, such as wind and solar photovoltaic (generation does not necessarily correspond to demand), require flexible solutions to store energy. Energy Storage systems (ESS) are able to balance the intermittent and volatile generation outputs of variable renewable energies (VRE). ESS provide ancillary services such as: frequency, primary and voltage control to the power grid. In order to fulfil the power system control, ESS can switch within seconds for different operation modes. Many times, ESS imply environment impacts on landscape and society. To solve this problem, disused underground spaces, such as closed mines, can be used as underground reservoir for energy Storage plants. In this paper, a comparative analysis between underground pumped Storage Hydropower (UPSH), compressed air energy Storage (CAES) and suspended weight gravity energy Storage (SWGES) with suspended weights in abandoned mine shafts is carried out. Pumped Storage Hydropower (PSH) is the most mature concept and account for 99% of bulk Storage capacity worldwide. The results obtained show that in UPSH and CAES plants, the amount of stored energy depends mainly on the underground reservoir capacity, while in SWGES plants depends on the depth of the mine shafts and the mass. The energy stored in a SWGES plant (3.81 MWh cycle-1 with 600 m of usable depth assuming 3,000 tonne suspended weight) is much lower than UPSH and CAES plants.
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Numerical modelling of water subsurface reservoirs during the operation phase in underground pumped Storage Hydropower plants
E3S Web of Conferences, 2020Co-Authors: Javier Menendez, Jorge LoredoAbstract:Underground pumped Storage Hydropower (UPSH) plants may be an alternative to store subsurface energy with lower environmental impacts than conventional pumped Storage Hydropower (PSH) plants. Network of tunnels in closed mines (i.e. coal mines) could be used as water lower reservoir of UPSH plants. The amount of storable energy depends on the water mass and the net head between upper and lower reservoirs. Depending on the direction of the water flow rate, pumping or turbine modes may be used to produce or consume electrical energy. Filling and emptying processes during the operation stage in the underground reservoir are complicated due to the presence of two fluids (water and air) interacting inside the network of tunnels. This paper explores the underground reservoir during the operation stage considering a water flow rate of 55 m3 s-1 . Two-phase three dimensional CFD numerical models using Ansys Fluent have been developed in order to know the behaviour of the air flow on tunnels and ventilation shaft. Static pressure and air velocity have been analyzed in the simulations at the exit of the ventilation shaft as well as the junction zone between the ventilation shaft and the tunnels network. The results obtained show that a static pressure up to 8,600 Pa and air velocities up to 80 m s-1 could be reached in turbine mode considering a vent shaft with 1 m in diameter. The static pressure increases up to 258,000 Pa if a ventilation shaft of 0.5 m in diameter is considered.
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Efficiency analysis of underground pumped Storage Hydropower plants
Journal of Energy Storage, 2020Co-Authors: Javier Menendez, Monica Galdo, Jesús M. Fernández-oro, Jorge LoredoAbstract:Abstract Large-scale energy Storage systems, such as underground pumped-Storage Hydropower (UPSH) plants, are required in the current energy transition to variable renewable energies to balance supply and demand of electricity. In this paper, a novel method to determinate the round trip energy efficiency in pumped Storage Hydropower plants with underground lower reservoir is presented. Two Francis pump-turbines with a power output of 124.9 and 214.7 MW (turbine) and a power input of 114.8 and 199.7 MW (pump), respectively, have been selected to investigate the overall operation of UPSH plants. Analytical models and two-phase 3D CFD numerical simulations have been carried out to evaluate the energy generated and consumed, considering a typical water mass of 450,000 t and a maximum gross pressure of 4.41 MPa. The results obtained in both analytical and numerical models show that unlike conventional pumped-Storage Hydropower plants, the round trip energy efficiency depends on the pressure inside the underground reservoir. The round trip energy efficiency could be reduced from 77.3% to 73.8% when the reservoir pressure reaches -100 kPa. In terms of energy balance, the energy generation decreases down to 3,639 MWh −1 and the energy consumption increases up to 4,606 MWh year−1 compared to optimal conditions.
Sébastien Erpicum - One of the best experts on this subject based on the ideXlab platform.
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Underground Pumped-Storage Hydropower (UPSH) at the Martelange Mine (Belgium): Underground Reservoir Hydraulics
Energies, 2020Co-Authors: Vasileios Kitsikoudis, Estanislao Pujades, Philippe Orban, Alain Dassargues, Pierre Archambeau, Benjamin Dewals, Michel Pirotton, Sébastien ErpicumAbstract:The intermittent nature of most renewable energy sources requires their coupling with an energy Storage system, with pumped Storage Hydropower (PSH) being one popular option. However, PSH cannot always be constructed due to topographic, environmental, and societal constraints, among others. Underground pumped Storage Hydropower (UPSH) has recently gained popularity as a viable alternative and may utilize abandoned mines for the construction of the lower reservoir in the underground. Such underground mines may have complex geometries and the injection/pumping of large volumes of water with high discharge could lead to uneven water level distribution over the underground reservoir subparts. This can temporarily influence the head difference between the upper and lower reservoirs of the UPSH, thus affecting the efficiency of the plant or inducing structural stability problems. The present study considers an abandoned slate mine in Martelange in Southeast Belgium as the lower, underground, reservoir of an UPSH plant and analyzes its hydraulic behavior. The abandoned slate mine consists of nine large chambers with a total volume of about 550,000 m3, whereas the maximum pumping and turbining discharges are 22.2 m3/s. The chambers have different size and they are interconnected with small galleries with limited discharge capacity that may hinder the flow exchange between adjacent chambers. The objective of this study is to quantify the effect of the connecting galleries cross-section and the chambers adequate aeration on the water level variations in the underground reservoir, considering a possible operation scenario build upon current electricity prices and using an original hydraulic modelling approach. The results highlight the importance of adequate ventilation of the chambers in order to reach the same equilibrium water level across all communicating chambers. For fully aerated chambers, the connecting galleries should have a total cross-sectional area of at least 15 m2 to allow water flow through them without significant restrictions and maintain similar water level at all times. Partially aerated chambers do not attain the same water level because of the entrapped air; however, the maximum water level differences between adjacent chambers remain relatively invariant when the total cross-sectional area of the connecting galleries is greater than 8 m2. The variation of hydraulic roughness of the connecting galleries affects the water exchange through small connecting galleries but is not very influential on water moving through galleries with large cross-sections.
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Underground Pumped-Storage Hydropower (UPSH) at the Martelange Mine (Belgium): Interactions with Groundwater Flow
Energies, 2020Co-Authors: Estanislao Pujades, Philippe Orban, Vasileios Kitsikoudis, Pierre Archambeau, Sébastien Erpicum, Alain DassarguesAbstract:Underground pumped-Storage Hydropower (UPSH) is a promising technology to manage the electricity production in flat regions. UPSH plants consist of an underground and surface reservoirs. The energy is stored by pumping water from the underground to the surface reservoir and is produced by discharging water from the surface to the underground reservoir. The underground reservoir can be drilled, but a more efficient alternative, considered here, consists in using an abandoned mine. Given that mines are rarely waterproofed, there are concerns about the consequences (on the efficiency and the environment) of water exchanges between the underground reservoir and the surrounding medium. This work investigates numerically such water exchanges and their consequences. Numerical models are based on a real abandoned mine located in Belgium (Martelange slate mine) that is considered as a potential site to construct an UPSH plant. The model integrates the geometrical complexity of the mine, adopts an operation scenario based on actual electricity prices, simulates the behavior of the system during one year and considers two realistic scenarios of initial conditions with the underground reservoir being either completely full or totally drained. The results show that (1) water exchanges may have important consequences in terms of efficiency and environmental impacts, (2) the influence of the initial conditions is only relevant during early times, and (3), an important factor controlling the water exchanges and their consequences may be the relative location of the natural piezometric head with respect the underground reservoir.
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Numerical study of the Martelange mine to be used as underground reservoir for constructing an Underground Pumped Storage Hydropower plant
Advances in Geosciences, 2018Co-Authors: Estanislao Pujades, Philippe Orban, Pierre Archambeau, Sébastien Erpicum, Alain DassarguesAbstract:Abstract. Underground Pumped Storage Hydropower (UPSH) using abandoned mines has been considered as a potential high capacity Energy Storage Systems. In UPSH plants, the excess of electricity is stored in the form of potential energy by pumping water from an underground reservoir (abandoned mine in this paper) to a surface reservoir, while electricity is produced (when the demand increases) discharging water from the surface into the underground reservoir. The main concerns may arise from the water exchanges occurring between the underground reservoir and the surrounding medium, which are relevant in terms of environmental impact and UPSH efficiency. Although the role of the water exchanges has been previously addressed, most studies are based on synthetic models. This work focuses on a real abandoned slate mine located in Martelange (Belgium). The effects of different rehabilitation works to prepare the mine as an underground reservoir are assessed in terms of groundwater exchanges and their associated consequences.