Plant for storing mechanical energy and for generating power, and associated method

Abstract

The application relates to a plant (1) for storing mechanical energy and for generating power, comprising: at least one flywheel (10); at least one liquid column (20); a ballast / bag assembly (30) disposed in the liquid column (20); and at least one gas insufflation system (40) configured to insufflate gas into the gas bag (32) when the ballast / bag assembly (30) reaches a lower portion of the liquid column (20). The insufflation system (40) comprises a gas turbo (41) driven in rotation by the flywheel (10) and configured to provide a gas flow; a heating unit (42) configured to raise the temperature of the gas flow provided by the gas turbo (41) and at least one gas insufflation mechanism (43).

Description

MECHANICAL ENERGY STORAGE AND ELECTRICITY GENERATION FACILITY AND ASSOCIATED METHOD Technical field

[0001] The invention relates to the field of electricity production and in particular that of the production of renewable electricity.

[0002] The invention thus relates more particularly to a mechanical energy storage and electricity generation installation and a method for generating electricity on demand from at least one intermittent energy source by implementing such an installation. State of the prior art

[0003] Renewable energy production is generally linked to intermittent natural phenomena, such as sunlight, wind, or tides, and is therefore inherently intermittent. To overcome this intermittency, it is generally necessary to use chemical storage systems, such as batteries, which charge during energy production cycles and release the stored energy during non-production cycles.

[0004] However, such storage systems are not entirely suitable, as their capacity deteriorates over time and their manufacturing and recycling are particularly polluting. Therefore, there would be an interest in providing energy storage systems that are more environmentally friendly and sustainable. Statement of the invention

[0005] The invention aims to overcome the drawbacks mentioned above and thus aims to provide energy storage that is more environmentally friendly than the currently associated chemical batteries used to compensate for the intermittent energy supply linked to the production of renewable energy.

[0006] The invention relates to this purpose to a mechanical energy storage and electricity generation installation comprising: at least one flywheel capable of being rotated by an energy source external to the installation, at least one liquid column, at least one assembly comprising a ballast and a gas bag, hereinafter ballast / bag assembly, arranged in the liquid column and arranged in such a way that the fall of the ballast in the liquid column rotates the flywheel, the gas bag being configured to release a gas stored therein when the ballast / bag assembly reaches an upper portion of the liquid column, at least one gas blowing system at least partially arranged in the liquid column and which is configured to blow gas into the gas bag when the ballast / bag assembly reaches a lower portion of the liquid column,an electricity generator capable of being rotated by the flywheel to generate electricity, wherein the insufflation system comprises:, - a gas turbo driven in rotation by the flywheel and configured to provide a gas flow, - a heating unit configured to raise the temperature of the gas flow supplied by the gas turbo, - a gas blowing mechanism configured to blow the heated gas flow into the gas bag when the ballast / bag assembly reaches a lower portion of the liquid column.

[0007] Such an installation allows energy storage from the flywheel with at least partial self-maintenance by using the fall of the ballast / bag assembly. This self-maintenance is obtained with the energy input being that used to inflate the gas bag at the bottom of the liquid column and to obtain a rise of the ballast / bag assembly from the Archimedes thrust. This input is particularly optimized in the context of the invention since it is based on the use of a combination of gas turbo driven by the flywheel and a heating unit potentially provided by a system energy recovery. As a result, the installation according to the invention makes it possible to store in mechanical form (the rotation of the flywheel) the energy supplied by an intermittent energy source, preferably of the renewable type, to enable it to be supplied when it is required by the network. Due to the self-maintenance enabled by the ballast / bag assembly and the insufflation system, the mechanical storage is particularly optimized and sustainable and thus makes it possible to compensate for the intermittency of energy supply linked to renewable energy sources.

[0008] It should also be noted that since the installation is based on non-intermittent physical phenomena, namely the inertia of the flywheel, the potential energy of gravity and Archimedes' thrust, which are accessible throughout the world, it does not present any restrictions concerning the location to be equipped and its use, the electricity generated by the installation being able to be delivered on demand and not being subject to the intermittencies inherent in the renewable energy sources which are likely to power the installation. It should also be noted that the installation according to the invention can also be implemented in order to regulate peaks and troughs in electricity consumption in the case of constant energy production, as is the case for nuclear power plants.

[0009] A gas turbo generally comprises a centrifugal compressor which, in the context of the present invention, by the rotation transmitted by the flywheel, provides a gas flow intended to be blown into the gas bag.

[0010] The insufflation system may further comprise a reservoir for receiving the gas stream and storing it prior to being insufflated by the gas insufflation mechanism and wherein the heating unit is configured to raise the temperature of the gas stored in the reservoir which is formed by the gas stream.

[0011] Such a tank provides a reserve of pressurized gas to enable the gas bag to be inflated quickly and thus allow the ballast / bag assembly to move from the lower portion to the upper portion of the liquid column.

[0012] The heating unit may include a heat exchanger, such as a gas / liquid heat exchanger.

[0013] Such a heat exchanger makes it possible to efficiently transfer heat recovered from another heat source from a heat transfer liquid. Thus, in the case where the installation according to the invention is installed near an incineration plant or a factory generating a large quantity of heat, such as a foundry, it will be possible to transfer heat from this installation or factory to the gas in order to increase the pressure exerted by the gas flow.

[0014] The flywheel can be housed in a vacuum enclosure at least industrial, or even a primary vacuum.

[0015] With such a vacuum, losses due to friction and turbulence that can be generated by the movement of the flywheel are limited. This increases the durability of the mechanical energy storage enabled by the invention.

[0016] The liquid column may have a location with a reduced section, said location with a reduced section being arranged in the lower portion of the liquid column and being intended to receive the ballast / bag assembly at the end of its fall.

[0017] Such a reduced section location makes it possible to cushion the fall of the ballast / bag assembly at the end of its fall. This limits the risks of damage to the column and to elements of the installation such as the gas insufflation mechanism, which could result from the fall of the ballast / bag assembly if the latter entered the lower portion without cushioning.

[0018] The invention further relates to a method for generating electricity on demand from at least one energy source using a mechanical energy storage and electricity generation installation according to the invention, the method comprising the following steps: using the intermittent energy source as an external energy source to at least partly drive the flywheel in rotation, - generation of electricity from the electricity generator driven in rotation by the flywheel.

[0019] Such a method makes it possible to benefit from the energy storage permitted by the invention to obtain delivery of electricity on demand from energy sources which are intermittent and thus avoid the disadvantages associated with such energy sources.

[0020] The intermittent energy source may comprise a renewable energy source preferentially selected from the group comprising solar energy sources, wind energy sources, tidal energy sources and tidal energy sources. Brief description of the drawings

[0021] The present invention will be better understood upon reading the description of exemplary embodiments, given purely for informational purposes and in no way limiting, with reference to the appended drawings in which: Figure 1 schematically illustrates an installation for mechanical energy storage and electricity generation according to a first embodiment of the invention, Figure 2 schematically illustrates an example of a location with a reduced section capable of being used within the framework of an advantageous possibility of the invention, Figure 3 schematically illustrates a ballast / bag assembly capable of being implemented within the framework of the present invention,Figure 4 schematically illustrates a mechanical energy storage and electricity generation installation according to a second embodiment based on the use of two ballast / bag assemblies with antagonistic movement. Figure 5 schematically illustrates in close-up view a variant of the second embodiment in which the two ballast / bag assemblies are connected to the same cable in such a way that the cable is always driven by the descending ballast / bag assembly and therefore avoids the need for a rewinding system.

[0022] Identical, similar or equivalent parts of different figures bear the same numerical references so as to facilitate the transition from one figure to another.

[0023] The different parts represented in the figures are not necessarily on a uniform scale, to make the figures more readable.

[0024] The different possibilities (variants and embodiments) must be understood as not being mutually exclusive and can be combined with each other. Detailed description of specific embodiments

[0025] Figure 1 illustrates a mechanical energy storage and electricity generation installation 1 according to the invention adapted to store energy in mechanical form, this energy being able to come from an intermittent energy source, and to generate electricity on demand.

[0026] As shown in this figure, such a mechanical energy storage and electricity generation installation 1 comprises: at least one flywheel 10 capable of being rotated by an external energy source 2 to the installation, a liquid column 20, said liquid column 20 being, in the present embodiment, a water column, an assembly 30 comprising a ballast 31 and a gas bag 32, hereinafter ballast / bag assembly 30, arranged in the liquid column 20 and arranged in such a way that the fall of the ballast 31 in the liquid column rotates the flywheel 10, the gas bag 32 being configured to release a gas stored therein when the ballast / bag assembly 30 reaches an upper portion of the liquid column 20,at least one gas insufflation system 40 at least partially arranged in the liquid column 20 and which is configured to insufflate gas into the gas bag 32 when the ballast / bag assembly 30 reaches a lower portion of the liquid column 20, an electricity generator 50 capable of being rotated by the flywheel 10 to generate electricity. the insufflation system 40 comprises:, - a gas turbo 41 driven in rotation by the flywheel 10 and configured to provide a gas flow, - a reservoir 44 for receiving the air flow and storing it before being blown in by a gas blowing mechanism 43, - a heating unit 42 configured to raise the temperature of the gas stored in the tank 44, - a gas blowing mechanism 43 configured to blow the gas heated and stored in the reservoir 44, as a gas stream, into the gas bag 32 when the ballast / bag assembly 30 reaches a lower portion of the liquid column 20.

[0027] According to an advantageous characteristic of the invention, not shown, the flywheel 10 can be arranged under vacuum in order to limit the losses linked to friction and turbulence that can be generated by the movement of the flywheel 10. The flywheel 10 can thus be arranged under at least an industrial vacuum, that is to say between atmospheric pressure, that is to say approximately 100,000 Pa, and 100 Pa or, preferably, at least a primary vacuum, that is to say between 100 Pa and 0.1 Pa.

[0028] In order to enable it to be driven, the flywheel 10 may be driven, for example by means of a freewheel, by a motor 11 electrically powered by an external energy source 2. In accordance with the invention, this external energy source 2 is preferably a renewable energy source, which is essentially intermittent. This external energy source 2 may thus, for example, and in a non-limiting manner, be photovoltaic panels, wind turbines, hydro turbines or even tidal power installations. It will be noted that, according to one possibility of the invention illustrated in FIG. 1, in order to initialize the installation, that is to say to start setting the flywheel 10 in motion, or to enable storage of excess electricity from the network, the motor 11 may also be connected to an electricity distribution network 3.

[0029] The flywheel 10 is also driven in rotation by the fall of the ballast / bag assembly 30 along the liquid column 20. To do this, the flywheel 10 can be mechanically connected to a drive shaft 12 itself mechanically connected to a freewheel 37 and pulley 36 system around which a cable 35 connected to the ballast / bag assembly 30 is wound. The freewheel 37 is shaped in such a way that the drive shaft 12 is driven in rotation when the cable 35 unwinds under the effect of the fall of the ballast / bag assembly 30 and so that the pulley 36 is free to rotate relative to the drive shaft 12 when the cable is rewound around the pulley 36. In order to to allow an emergency stop of the installation, for example to allow a maintenance operation by a technician, the drive shaft, or another element integral in rotation with the flywheel, is preferably equipped with an emergency braking system 39, such as disc brakes.

[0030] The ballast / bag assembly 30 is arranged in the liquid column 20 by moving between the lower portion of the liquid column 20 in which the gas bag 32 is inflated by blowing gas supplied by the gas blowing system and the upper portion in which the gas bag 32 releases the gas it stores. The movement of the ballast / bag assembly 30 from the upper portion to the lower portion of the liquid column 20 is obtained by the force exerted by gravity on the ballast 31 this with a reduced drag because the gas bag 32 is deflated after having released the gas. This movement or fall of the ballast / bag assembly carries with it the cable 35 and sets the pulley, the drive shaft in rotation in order to transmit the energy released during the fall to the flywheel 10.

[0031] As regards the movement of the ballast / bag assembly 30 from the lower portion to the upper portion of the liquid column 20, this is obtained under the effect of the Archimedes thrust exerted on the gas bag once it is inflated via the inflation system 40. In order to accompany this rise of the ballast / bag assembly 30, the installation comprises a system for rewinding 38 the cable 35 onto the pulley 36 in order to rewind the cable 35 during the rise of the ballast / bag assembly 30. In the context of this first embodiment, the rewinding system 38 comprises both a spiral spring which, when tensioned during the fall of the ballast / bag assembly 30, allows a mechanism for driving the pulley by the flywheel which is engaged only during the rise of the ballast / bag assembly 30.Such a spiral spring forms an elastic return element arranged in such a way as to be biased during the fall of the ballast / bag assembly 30 from a depth in the predetermined liquid column 20. It will be noted that such an arrangement can be provided by a coupling system, not shown, capable of coupling the spiral spring with the pulley 36B with the spring when the ballast / bag assembly 30 reaches a given depth. To do this, the installation can, according to a possibility not illustrated, comprise a sensor capable of. detecting when the ballast / bag assembly 30 reaches a given depth in the liquid column and a control unit, connected to said sensor and which is configured to control the coupling system in order to couple the spiral spring with the pulley 36B.

[0032] Of course, the installation according to the invention can implement systems for rewinding 38 others, such as an electric motor, without departing from the scope of the invention.

[0033] In addition to the spiral spring of the rewinding system 38 and as shown in Figure 2, the installation according to the invention may comprise a device for braking the fall of the ballast / bag assembly 30 arranged in the lower portion of the liquid column. In the context of this first embodiment, the device for braking the fall of the ballast / bag assembly may comprise a location with a reduced section 22 arranged in the lower portion of the liquid column. This location with a reduced section 22 is shaped to receive the ballast / bag assembly 30 and has a section that gradually reduces in such a way that when the ballast / bag assembly 30 falls, the pressure exerted by the water under the thrust of the ballast / bag assembly 30 makes it possible to slow down the fall of the latter.To do this, in the example shown schematically in Figure 2, a set of three concentric containers 23 is provided, the section and height of which reduce from the outside to the inside. The most central container 23 has an opening slightly larger than the vertical projection of the ballast 31 so that when the ballast 31 arrives in said container 23, the liquid expelled by the fall of the ballast is a passage of reduced size left by the ballast 31 in order to offer maximum resistance to the fall of the ballast.

[0034] By opening slightly greater than the vertical projection of the ballast 31 it is understood above and in the rest of this document that during its passage, over the entire periphery of the ballast 31, the opening has a minimum distance of less than 20 cm, preferably 10 cm or even 5 cm.

[0035] Of course, if in the present embodiment, the variable section of the location 22 is provided by means of containers 23 with decreasing section, it is perfectly conceivable, as a variant and without departing from the scope of the invention, that it is the liquid column 20 itself which has a variable section.

[0036] Likewise, as a variant or in addition to such a location with variable section, the device for braking the fall of the ballast / bag assembly 30 arranged may comprise an element made of deformable material to absorb, by its deformation, at least part of the kinetic energy stored by the ballast / bag assembly 30 throughout its fall.

[0037] As specified above, the insufflation system 40 is adapted to allow the gas bag to be inflated by insufflating gas into it. The insufflation system 40 comprises the gas turbo 41 which is rotated by the flywheel in order to generate a gas flow, here an air flow. This air flow, as shown in Figure 1, makes it possible to supply the reservoir 44 with gas. The air flow thus stored in the reservoir 44 is then heated by means of the heating unit 42 in order to raise the pressure, in accordance with the ideal gas law (or its counterparts, the Gay Lussac, Boyle-Ma hotte and Charles laws). The air thus raised in temperature, and therefore in pressure, is delivered to an air blowing mechanism 43 as shown in FIG. 3. To allow such delivery of gas to the air blowing mechanism 43 without a significant drop in the air temperature, this delivery can be done by means of an insulated tube 45.This insulation is preferably obtained by a double-walled 45 tube with the space defined between the two walls which is preferably under an industrial, or even primary, vacuum.

[0038] To allow the blowing of air, the ballast 31 may for example have a through orifice opening into the gas bag 32 and provided with a valve 311 intended to cooperate with a complementary valve 431 of the blowing mechanism 43 in such a way that the valve 311 and the complementary valve 431 open to release the gas delivered from the reservoir 44 when they come into contact with each other after the fall of the ballast / bag assembly 30. Of course, as soon as a sufficient quantity of gas is introduced into the gas bag 32 so that the Archimedes thrust exerted on the gas bag compensates for the force of gravity exerted on the ballast 31 and the ballast / bag assembly 30 moves towards the upper portion of the liquid column 20, the valve 311 and the complementary valve 431 separate and close again.

[0039] The heating unit 42 may include a heat exchanger 42A, such as an air / liquid heat exchanger, to enable calories to be exchanged from a heat transfer liquid to the gas that is stored in the tank. The heat transfer liquid itself is heated from a 42B energy recovery system. This 42B energy recovery system can be associated with an industrial installation generating heat, such as a steel mill or a waste incinerator, thermal panels or even a geothermal installation.

[0040] Figure 3 also shows the opening 321 provided at the upper part of the gas bag 32 so that the gas / air stored in the gas bag 32 is released when the gas bag 32 reaches the upper portion of the liquid column 20, this upper portion preferably being a portion in which the opening 321 of the bag is emerged so as to prevent any liquid from entering the gas bag. In order to allow such an opening, the upper portion of the liquid column 20 is preferably provided with a member, not shown, intended to cooperate with the opening 321 in order to allow an opening of the gas bag 32. This member is also adapted to allow a closing of said opening 321 when the gas bag 32 has released the gas stored therein.

[0041] It will be noted that to allow inspection and / or maintenance of the insufflation mechanism, the installation 1 may comprise a platform 21 on which the insufflation mechanism 43 is arranged, and possibly the containers 23. The installation 1 further comprises lifting cables 211 to allow the platform and the insufflation mechanism 43 that it supports to be raised.

[0042] In order to enable recovery of the kinetic energy stored in the flywheel 10, the installation 1 comprises an electricity generator 50 capable of being driven in rotation by the flywheel 10. The installation 1 may thus comprise a system for coupling / uncoupling a rotor of the generator with the flywheel 10 so as to enable generation of electricity on demand. The electricity generator 50 comprises an output in order to deliver the electricity to the electricity distribution network.

[0043] Such a mechanical energy storage and electricity generation installation 1 is adapted to enable the implementation of a method for generating electricity on demand from at least one intermittent energy source, the method comprising the following steps: use of the intermittent energy source 2 as an external energy source to at least partially drive the flywheel 10 in rotation, - generation of electricity from the electricity generator 50 driven in rotation by the flywheel 10.

[0044] The electricity generated in such a process can be fed into an electricity distribution network, such as a general electricity distribution network or that of an isolated village, a factory or even a public facility such as a hospital.

[0045] Of course, within the framework of such a method, an initialization step can be provided using electricity taken from the electricity distribution network.

[0046] Figure 4 illustrates a mechanical energy storage and electricity generation installation 1 according to a second embodiment in which the installation comprises two ballast / bag assemblies 30A, 30B arranged to have opposing movements.

[0047] In such a configuration, the installation preferably includes: - a second column of liquid 20B, - a second assembly 30B comprising a second ballast 31B and a second gas bag 32B, hereinafter second ballast / bag assembly 30B, arranged in the second liquid column 20B and arranged in such a way that the fall of the second ballast 31B into the second liquid column 20B drives the flywheel 10 into rotation, the second gas bag 32B being configured to release a gas stored therein when the second ballast / bag assembly 30B reaches an upper portion of the second liquid column 20B.

[0048] In order to enable a gas supply to the second gas bag 32B, the insufflation system 40 further comprising a second gas insufflation mechanism 43B configured to insufflate the heated gas flow into the second gas bag 32B when the second ballast / bag assembly 30B reaches a lower portion of the second liquid column 20B.

[0049] In order to enable the flywheel 10 to be driven by the fall of the second ballast / bag assembly 30B, the installation comprises a second cable 35B, a second pulley 36B, a second freewheel 37B and a second rewinding system. equipping the second column 20B according to a configuration similar to those equipping the liquid column 20A. It will be noted in particular that the second pulley and the second freewheel 37B are arranged to drive the drive shaft 12 in rotation during the fall of the second ballast / bag assembly 30B along the second column 20B.

[0050] As indicated above, the bag / ballast assembly 30A and the second bag / ballast assembly 30b are arranged to have opposing movements, that is to say that the first ballast / bag assembly 30A reaches the lower portion of the at least one liquid column 20A when the second ballast / bag assembly 30B reaches the upper portion of the second liquid column 20B. Of course, if such an arrangement is to be preferred, it is also conceivable that the bag / ballast assembly 30A and the second bag / ballast assembly 30B have parallel movements between them or even according to any offset.

[0051] Likewise, in the present embodiment, the ballast / bag assembly 30A and the second ballast / bag assembly 30B are arranged respectively in the liquid column 20A and the second liquid column 20B, it is also conceivable without departing from the scope of the invention that the ballast / bag assembly 30A and the second ballast / bag assembly 30B are arranged in the same liquid column.

[0052] Figure 5 illustrates a variant of the second embodiment in which the mechanical energy storage and electricity generation installation 1 comprises a single cable 35 connecting the first and second ballast / bag assemblies 30A, 30B and driving both the pulley 36A and the second pulley 36B in rotation. An installation according to this variant differs from an installation according to the second embodiment in that only a single cable 35 is provided driving both the pulley 36A and the second pulley 36B and in that a transmission system is provided adapted so that the drive shaft 12 is driven in rotation when the pulley 36A rotates in one direction and when the second pulley 36B rotates in another direction.

[0053] Thus, as shown in Figure 5, when the ballast / bag assembly 30A and the second ballast / bag assembly 30B (not shown) are both connected to the single cable 35 in such a way that when the ballast / bag assembly 30A passes from the lower portion to the upper portion of the liquid column, the second ballast / bag assembly passes from the upper portion to the lower portion of the second liquid column. The pulley and the second pulley 36A, 36B are thus both driven during the movements of the ballast / bag assembly 30A and the second ballast / bag assembly 30B. In order to allow recovery of the energy released during the fall (i.e. passage from the upper portion to the lower portion) of each of the ballast / bag assembly 30A and the second ballast / bag assembly 30B, the pulley 36A and the second pulley 36B are each arranged on a respective axis by means of a respective free wheel 37A, 37B, the second pulley 36B being arranged in engagement with the drive axis and the pulley 36A being arranged in engagement with a secondary axis 12A. The drive shaft 12 and the secondary shaft 12A are connected to each other with a rotation direction reversal transmission system, such that when the drive shaft rotates clockwise, the secondary shaft rotates counterclockwise.

[0054] As shown in Figure 5, such a rotation direction reversal transmission system may for example be provided by a first and a second gear 13A, 13B arranged to mesh with each other, the first gear 13A being integral in rotation with the secondary shaft 12A and the second gear 13B being integral in rotation with the drive shaft 12. Of course, according to this variant, each of the pulley and the second pulley is equipped with a respective freewheel 37A, 37B.

[0055] Such a variant of the second embodiment, implementing only a single cable 35 driven by each of the ballast / bag assembly 30A and the second ballast / bag assembly 30B, makes it unnecessary to equip the installation 1 with cable rewinding systems 38A, 38B.

[0056] It will also be noted that if in the present embodiments, each of the columns is physically delimited by a container, it is also possible, in a non-preferred manner, for such a column of liquid not to be physically delimited by walls, the installation being arranged in a larger liquid reservoir, whether natural or artificial.

[0057] It will be noted that if, in the context of the present embodiments, the liquid in the liquid column 20 and the gas supplied by the insufflation system are respectively water and air, it is of course possible, without departing from the scope of the invention, for one or the other to be of another type. Thus, for example, in the context of an arrangement of such an installation in an external environment subjected to temperatures below 0°C, it is perfectly conceivable that the liquid includes an additive, such as glycol. Similarly, the installation according to the invention can use gases other than air, such as for example combustion gases from a waste incinerator. Nomenclature of drawings 1 mechanical energy storage and electricity generation installation; 2 external energy source; 3 electricity distribution network; 10 flywheel; 11 engine; 12 drive axle; 12A secondary drive shaft; 13A first gear; 13B second gear; 20, 20A liquid column; 20B second column of liquid; 21, 21A platform; 21B second platform; 211, 211A lifting cables; 211B second lifting cables; 22 reduced section location; 23 containers; 30, 30A ballast / bag set; 30B second ballast / bag set; 31, 31A ballast; 31B second ballast; 311 valve; 32, 32A gas bag; 32B second gas bag; 321 opening; 35, 35A cable 35B second cable; 36, 36A pulley; 36B second pulley; 37, 37A freewheel; 37B second freewheel; 38, 38A system for rewinding; 38B second system for rewinding; 39 emergency braking system; 40 gas insufflation system; 41 gas turbo; 42 heating unit; 42A heat exchanger; 42B energy recovery system; 43, 43A gas insufflation mechanism; 43B second gas insufflation mechanism; 431 additional valve; 44 tank; 45 tube; 50 electricity generator.

Claims

Claims 1. Mechanical energy storage and electricity generation installation (1) comprising: - At least one flywheel (10) capable of being driven in rotation by an external energy source (2) to the installation, at least one liquid column (20, 20A, 20B), at least one assembly (30, 30A, 30B) comprising a ballast (31, 31A, 31B) and a gas bag (32, 32A, 32B), hereinafter ballast / bag assembly (30, 30A, 30B), arranged in the liquid column (20, 20A, 20B) and arranged in such a way that the fall of the ballast (31, 31A, 31B) in the liquid column drives the flywheel (10) in rotation, the gas bag (32) being configured to release a gas stored therein when the ballast / bag assembly (30, 30A, 30B) reaches an upper portion of the liquid column (20, 20A, 20B), at least one gas insufflation system (40) at least partially arranged in the liquid column (20, 20A, 20B) and which is configured to insufflate gas into the gas bag (32, 32A, 32B) when the ballast / bag assembly (30, 30A, 30B) reaches a lower portion of the liquid column (20,20A, 20B), an electricity generator (50) capable of being rotated by the flywheel (10) to generate electricity, wherein the insufflation system (40) comprises:, - a gas turbo (41) driven in rotation by the flywheel (10) and configured to provide a gas flow, - a heating unit (42) configured to raise the temperature of the gas flow supplied by the gas turbo (41), - at least one gas blowing mechanism (43, 43A, 43B) configured to blow the heated gas flow into the gas bag (32, 32A, 32B) when the ballast / bag assembly (30, 30A, 30B) reaches a lower portion of the liquid column (20, 20A, 20B).

2. Mechanical energy storage and electricity generation installation (1) according to claim 1, wherein the insufflation system (40) further comprises a reservoir (44) for receiving the gas flow and storing it before being insufflated by the gas insufflation mechanism (43; 43A, 43B) and wherein the heating unit (42) is configured to raise the temperature of the gas stored in the reservoir (44) which is formed by the gas flow.

3. Mechanical energy storage and electricity generation installation (1) according to claim 1 or 2, wherein the heating unit (42) comprises a heat exchanger (42A), such as a gas / liquid heat exchanger.

4. Mechanical energy storage and electricity generation installation (1) according to any one of claims 1 to 3, in which the flywheel (10) is housed in an enclosure under at least industrial vacuum, or even a primary vacuum.

5. Mechanical energy storage and electricity generation installation (1) according to any one of claims 1 to 4, in which the liquid column (20, 20A, 20B) has a location with a reduced section (22), said location with a reduced section (22) being arranged in the lower portion of the liquid column and being intended to receive the ballast / bag assembly (30, 30A, 30B) at the end of its fall.

6. Mechanical energy storage and electricity generation installation (1) according to any one of claims 1 to 5, wherein the ballast / bag assembly (30, 30A, 30B) is connected to the flywheel from a cable (35, 35A, 35B) and a freewheel (36, 36A, 36B) and in which an elastic return element is provided arranged in such a way as to be stressed during the fall of the ballast / bag assembly (30, 30A, 30B) from a predetermined depth in the liquid column (20, 20A, 20B), said elastic return element preferably being a spiral spring.

7. Mechanical energy storage and electricity generation installation (1) according to any one of claims 1 to 6 further comprising: at least one second assembly (30B) comprising a second ballast (31B) and a second gas bag (32B), hereinafter second ballast / bag assembly (30B), arranged in the at least one liquid column (20B) and arranged in such a way that the fall of the second ballast (31B) in the at least one liquid column (20B) drives the flywheel (10) into rotation, the second gas bag (32B) being configured to release a gas stored therein when the second ballast / bag assembly (30B) reaches an upper portion of the at least one liquid column (20B),the insufflation system (40) further comprising a second gas insufflation mechanism (43B) configured to insufflate the heated gas flow into the second gas bag (32B) when the second ballast / bag assembly (30B) reaches a lower portion of the at least one liquid column (20B), the installation preferably further comprising at least one second liquid column (20B), the ballast / bag assembly (30A) being housed in the liquid column (20A) and the second ballast / bag assembly (30B) being housed in the second liquid column (20B)., 8. Mechanical energy storage and electricity generation installation (1) according to claim 7, wherein the ballast / bag assembly (30A) and the second ballast / bag assembly (30B) are arranged in the at least one liquid column (20A, 20B) so that the first ballast / bag assembly (30A) reaches the lower portion of the at least one liquid column (20A) when the second ballast / bag assembly (30B) reaches the upper portion of the at least one liquid column (20B).

9. Method for generating electricity on demand from at least one intermittent energy source using a mechanical energy storage and electricity generation installation according to any one of claims 1 to 8, the method comprising the following steps: using the intermittent energy source (2) as an external energy source to at least partially drive the flywheel (10) in rotation, - generation of electricity from the electricity generator (50) driven in rotation by the flywheel (10).

10. A method of generating electricity on demand according to claim 9 wherein the intermittent energy source comprises a renewable energy source preferentially selected from the group comprising solar energy sources, wind energy sources, tidal energy sources and tidal energy sources.

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