WO2009012575A1 - Système de stockage et d'extraction d'énergie immergé - Google Patents

Système de stockage et d'extraction d'énergie immergé Download PDF

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Publication number
WO2009012575A1
WO2009012575A1 PCT/CA2008/001337 CA2008001337W WO2009012575A1 WO 2009012575 A1 WO2009012575 A1 WO 2009012575A1 CA 2008001337 W CA2008001337 W CA 2008001337W WO 2009012575 A1 WO2009012575 A1 WO 2009012575A1
Authority
WO
WIPO (PCT)
Prior art keywords
energy
buoyant member
storage system
energy storage
buoyant
Prior art date
Application number
PCT/CA2008/001337
Other languages
English (en)
Inventor
Dan Wigglesworth
Original Assignee
Dan Wigglesworth
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dan Wigglesworth filed Critical Dan Wigglesworth
Publication of WO2009012575A1 publication Critical patent/WO2009012575A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03B—MACHINES OR ENGINES FOR LIQUIDS
    • F03B13/00—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates
    • F03B13/12—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy
    • F03B13/14—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy
    • F03B13/16—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem"
    • F03B13/20—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem" wherein both members, i.e. wom and rem are movable relative to the sea bed or shore
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03B—MACHINES OR ENGINES FOR LIQUIDS
    • F03B13/00—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates
    • F03B13/12—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy
    • F03B13/14—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy
    • F03B13/16—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem"
    • F03B13/18—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem" where the other member, i.e. rem is fixed, at least at one point, with respect to the sea bed or shore
    • F03B13/1805—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem" where the other member, i.e. rem is fixed, at least at one point, with respect to the sea bed or shore and the wom is hinged to the rem
    • F03B13/181—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem" where the other member, i.e. rem is fixed, at least at one point, with respect to the sea bed or shore and the wom is hinged to the rem for limited rotation
    • F03B13/1815—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem" where the other member, i.e. rem is fixed, at least at one point, with respect to the sea bed or shore and the wom is hinged to the rem for limited rotation with an up-and-down movement
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2240/00—Components
    • F05B2240/90—Mounting on supporting structures or systems
    • F05B2240/97—Mounting on supporting structures or systems on a submerged structure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2250/00—Geometry
    • F05B2250/10—Geometry two-dimensional
    • F05B2250/14—Geometry two-dimensional elliptical
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/30—Energy from the sea, e.g. using wave energy or salinity gradient

Definitions

  • This application relates to energy storage and extraction systems, and more particularly to systems for storing and extracting energy, for example electric energy, below a water surface using hydrostatic potential.
  • Electric energy, or electricity demand varies greatly during a typical day. For example, there are large spikes in demand for electric energy during the morning. This contrasts with significantly reduced demand for electric energy in the middle of the night. In order to meet peak demand, power generators must have adequate energy generation capacity. This can lead to an allocation problem, where there is a shortage of electric energy during peak times, and an overabundance of energy during non-peak times. In addition, the price of a unit of electric energy also varies greatly, with energy being relatively expensive during peak times, and relatively inexpensive during non-peak times.
  • Constructing energy generation capacity such as nuclear reactors, hydro dams, coal plants or wind turbines can be difficult.
  • constructing energy generation facilities can require significant and complex regulatory approvals, and can require significant investment.
  • a number of energy storage systems that store energy have been developed.
  • One example is a pumped water storage system, which is in use at many sites around the world.
  • inexpensive power is used during non-peak times to pump water from a lower elevation to a higher elevation.
  • the energy stored in the elevated water is harnessed during peak energy times by running the stored water through a hydroelectric turbine to produce electric energy.
  • Pumped water systems require a proper geographical setting, for example having proximate lower and higher elevation water reservoirs at sufficiently different elevations between which to pump and store very large amounts of water.
  • a suitable geographical setting requires significant modifications such as the installation of dams, penstocks, and the flooding of land used for other purposes. This can result in pumped water storage systems being feasible in only a limited number of locations and, due to their size, being expensive to implement.
  • the failure of a pumped water system for example a dam failure, can lead to severe problems such as sudden catastrophic flooding.
  • Flow batteries of sufficient capacity to be useful are very large, and can take up a significant amount of surface area to construct. Flow batteries typically also have limited life spans, require careful maintenance, and are therefore typically expensive to construct and maintain. In addition, the failure of a flow battery can result in the release of hazardous material.
  • an energy storage system comprises: a non-buoyant member submerged below a water surface; a link member coupled to an anchor; an energy conversion device coupled to the link member, and adapted to control the displacement of the non-buoyant member; and at least one tether coupling the non-buoyant member to the link member.
  • an energy storage system comprises: a buoyant member adapted to be submerged below a water surface; a link member coupled to the buoyant member, and submerged below the water surface; an energy conversion device coupled to the link member, and adapted to control the displacement of the buoyant member; and at least one tether coupling the buoyant member to an anchor.
  • an energy storage system comprises: a buoyant member adapted to be submerged below a water surface; a non-buoyant member submerged below the water surface; a link member coupled to an anchor, wherein the link member is submerged below a water surface; an energy conversion device coupled to the link member, wherein the energy conversion device is adapted to control the displacement of the non-buoyant member and the energy conversion device is adapted to control the displacement of the buoyant member; and a plurality of tethers wherein at least one tether couples the non-buoyant member to the link member, and at least one tether couples the buoyant member to the link member.
  • the link member can be adapted to displace the non-buoyant member.
  • the link member can be adapted to displace the buoyant member.
  • the link member can be adapted to displace the non-buoyant member and the link member is adapted to displace the buoyant member.
  • the energy conversion device can comprise an electric motor, and the electric motor can include an input terminal for inputting electric energy.
  • the energy conversion device can comprise an electric generator, - A -
  • the electric generator can include an output terminal for outputting electric energy.
  • the anchor can be a submerged ground surface.
  • the link member can be coupled to the anchor by at least one mooring line, and length of the mooring line can be adjustable thereby controlling the depth of the link member below the water surface.
  • the link member can be submerged below a water surface.
  • the non-buoyant member and the link member can be nestable.
  • the buoyant member and the link member can be nestable.
  • the buoyant member, the non-buoyant member and the link member can be nestable.
  • the buoyant member can comprise at least one ballast tank, and buoyancy of the buoyant member can be controlled by selectively filling and emptying the at least one ballast tank with water.
  • the energy conversion device can be adapted to couple to a power grid.
  • the energy conversion device can be portable and can be decoupled from the energy storage system.
  • the energy storage system and/or the energy conversion device can further comprise a wave harvester adapted to collect mechanical wave energy, the wave harvester can be coupled to the link member by a link tether, and the wave harvester can transmit energy to the energy conversion device.
  • the wave harvester can comprise a buoy.
  • the at least one tether can be detachable.
  • an energy storage system comprises: a non-buoyant member submerged below a water surface, the non-buoyant member comprising at least one hollow portion; and an energy conversion device adapted to control ingress and egress of water into and out of the at least one hollow portion.
  • the non-buoyant member can be coupled to an anchor.
  • the non-buoyant member can be coupled to a submerged ground surface.
  • the non-buoyant member can have sufficient mass to prevent the non-buoyant member from drifting.
  • the energy conversion device can comprise an electric motor and an input terminal for inputting electric energy.
  • the energy conversion device can further comprise a pump for pumping water out of the at least one hollow portion.
  • the energy conversion device can comprise an electric generator and an output terminal for outputting electric energy.
  • the energy conversion device can further comprise an energy extraction module for extracting energy from water as water fills the at least one hollow portion.
  • the energy extraction module can comprise a turbine.
  • an energy extraction system comprises: a fluid chamber having an inlet and an outlet; a buoyant member housed within the chamber; a link member coupled to the buoyant member; an energy conversion device coupled to the link member and adapted to control the displacement of the buoyant member; and at least one tether coupling the buoyant member to an anchor.
  • the energy extraction system can further comprise: a fluid source at a first hydrostatic potential in fluid communication with the inlet; and a fluid sink at a second hydrostatic potential in fluid communication with the outlet, the second hydrostatic potential being lower than the first hydrostatic potential.
  • the fluid source can be an upstream location along a river and the fluid sink can be a downstream location along the river.
  • At least two energy extraction systems can be arranged in combination, the at least two energy extraction systems arranged in an array and configured to maintain a substantially uniform flow rate of fluid into and out of the array.
  • an energy extraction system comprises: at least one buoyant member; at least one grappling member pivotally coupled to the at least one buoyant member; and an energy conversion device pivotally coupled to the at least one grappling member and adapted to control the displacement of the at least one buoyant member.
  • the at least one grappling member can be extendible and retractable.
  • Figure 1 is a schematic side elevation view of a first example energy storage system
  • Figure 2 is a schematic side elevation view of a second example energy storage system
  • Figure 3 is a schematic side elevation view of a third example energy storage system
  • Figure 4 is a schematic side elevation view of a fourth example energy storage system
  • Figure 5 is a schematic cross sectional view of a first example buoyant member
  • Figure 6 is a schematic cross sectional view of a first example non-buoyant member
  • Figure 7 is a schematic perspective view of a first example nestable energy storage system
  • Figure 8 is a further schematic perspective view of the nestable energy storage system of Figure 7;
  • Figure 9 is a schematic perspective view of a second example nestable energy storage system
  • Figure 10 is schematic perspective view of first example energy storage system coupled to a wave harvester
  • Figure 11 is a schematic side elevation view of a second example energy storage system coupled to a wave harvester
  • Figure 12 is a schematic side elevation of a fifth example energy storage system
  • Figure 13 is a schematic perspective view of a third example energy storage system couple to a wave harvester
  • Figure 14 is a schematic perspective view of a fourth example energy storage system coupled to a wave harvester
  • Figure 15 is a schematic perspective view of a fifth example energy storage system coupled to a wave harvester
  • Figure 16 is a schematic side elevation of a sixth example energy storage system
  • Figure 17 is a schematic side elevation of a seventh example energy storage system that can also be used as an energy extraction system
  • Figure 18 is a schematic side elevation of a eighth example energy storage system that can also be used as an energy extraction system.
  • FIG 19 is a schematic side elevation of a ninth example energy storage system that can also be used as an energy extraction system.
  • elements shown in the figures have not necessarily been drawn to scale. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.
  • FIG. 1 illustrates an energy storage system 100 made in accordance with a first example.
  • the energy storage system 100 comprises a non-buoyant member 102 submerged below a water surface 110, a link member 104, an energy conversion device 106 coupled to the link member 104, and a tether 108 coupling the non-buoyant member 102 to the link member 104.
  • the non-buoyant member 102 is submerged below a water surface 110.
  • the water surface 110 is typically the top surface of a body of water.
  • the body of water may be any body of water, for example an ocean, a lake, or a man made reservoir and the like.
  • the non-buoyant member 102 may be made of any material such that the non-buoyant member 102 has a density greater than water, such that the non-buoyant member 102 sinks when placed into a body of water.
  • the non-buoyant member 102 may be a solid block of concrete.
  • the non-buoyant member 102 may include outer walls 122, inner walls 124 and hollow portions 126.
  • the outer walls 122 and inner walls 124 may be comprised of any material such as, for example, steel, concrete, or carbon fiber reinforced composite materials.
  • the hollow portions 126 may be filled with sand, gravel, recycled crushed waste concrete, or any other fill.
  • the outer wall 122 of the non-buoyant member 102 is sufficiently strong to resist any water pressure forces that may be exerted on the non- buoyant member 102 at, for example, an increased depth of water to which the non-buoyant member 102 is to be lowered.
  • the outer walls 122 of the non-buoyant member 102 are not sealed to the surrounding water.
  • the non-sealed outer walls 122 permit the surrounding water to freely enter and exit any void spaces in the non-buoyant member 102, for example the hollow portions 126.
  • the presence of the water in the void spaces of the non-buoyant member can increase the density of the non-buoyant member 102, reducing the buoyancy of the non-buoyant member 102.
  • the non-buoyant member 102 may comprise sealable outer walls 122 that may be adapted to sealingly contain a liquid, for example water.
  • the non-buoyant member 102 may store the water in a hollow portion 126, or a plurality of hollow portions 126.
  • the water may help to increase the density of the non-buoyant member 102, thus reducing the buoyancy of the non-buoyant member 102, and also helping to ensure that the non-buoyant member 102 will not be crushed, or damaged by the water pressure forces exerted on the non-buoyant member 102 at an increased water depth.
  • the water may be introduced into the non-buoyant member 102 by a pump.
  • the hollow portions 126 may be selectively flooded or emptied with water from the body of water to increase or decrease the mass of the non-buoyant member 102.
  • Selectively increasing or decreasing the mass of the non-buoyant member 102 can aid in transporting the non-buoyant member 102. This may aid, for example, in transporting the non-buoyant member 102 from its location of construction (for example a shipyard) to its deployment location (for example adjacent a wind turbine farm, or a nuclear reactor).
  • a tugboat may more easily maneuver a non-buoyant member 102 with less mass.
  • a non-buoyant member 102 with increased mass can typically store more energy in the energy storage system 100 than a non-buoyant member 102 with less mass, therefore being able to alter the mass of the non-buoyant member can be helpful.
  • the non-buoyant member may have a mass from 10 tonnes to 10000 tonnes, with some embodiments having a mass of 3600 tonnes to 6000 tonnes.
  • the mass of the non-buoyant member 102 may depend on the materials available for construction of the non-buoyant member 102.
  • the mass of the non-buoyant member 102 may depend on the design and material used to construct the tether 108.
  • the mass of the non-buoyant member 102 may be limited by the strength capacity of the tether 108. For example, if the tether 108 is constructed of a relatively strong material, a greater mass may be used for the non-buoyant member 102. Whereas if the tether 108 is constructed of a weaker material the non-buoyant member 102 may have a reduced mass.
  • the self-weight of the tether 108 can reduce the permitted mass of the non- buoyant member 102.
  • the strength capacity of the tether 108 may be used to support the self-mass of the tether 108, reducing the mass of the non- buoyant member 102 that may be used.
  • the self-mass of the tether 108 may not be significant, and the mass of the non-buoyant member 102 may be increased.
  • the tether 108 By positioning the energy storage system 100 beneath the surface of the water allows the tether 108 to support a heavier non-buoyant member 102 than would be possible if the energy storage system 100 were not submerged.
  • the tether 108 displaces water merely by virtue of being submerged which causes a buoyant force to act on the tether, effectively reducing the weight of the tether 108 and allowing a greater proportion of the tether's strength to be used to support the weight of the non-buoyant member 102 rather than the weight of the tether itself 108.
  • the non-buoyant member 102 may have any shape.
  • the non-buoyant member 102 is a cube, or a sphere.
  • careful hydrodynamic designs may be undertaken to produce a non-buoyant member 102 with a low hydrodynamic drag.
  • the non-buoyant member 102 may have a shape similar to a submarine (for example an elliptical shape as seen in Figure 4), to permit the non-buoyant member 102 to be displaced through water with reduced water resistance.
  • fairings may be added to the non-buoyant member 102 to improve its hydrodynamic shape and reduce the water resistance acting against the non-buoyant member 102 as it displaces through water.
  • the non-buoyant member 1202 may be shaped such that the surface of the non-buoyant member 1202 has a curvature with two phases, each of which is, in one example, an exponentially decaying curve, one inverted from the other.
  • the second phase of the curvature of the non-buoyant member 1202, namely the portion of the non-buoyant member 1202 that faces towards the energy storage system 1200, is inwardly curved towards the longitudinal axis of the non-buoyant member 1202.
  • the multi-phase curvature of the non-buoyant member 1202 improves its hydrodynamic shape and reduces the water resistance acting against the non-buoyant member 1202 as it displaces through the water.
  • the reduced water resistance is generally useful in embodiments where the non-buoyant member 1202 has to rapidly move through the water in order to release the energy stored in the energy storage system 1200.
  • the link member 104 typically couples the non-buoyant member 102 to the energy conversion device 106. In one embodiment the link member 104 also couples the non- buoyant member 102 to the support structure 112.
  • the link member 104 may be located anywhere. In one embodiment, the link member 104 is stored in the support structure 112.
  • the support structure 112 may be any type of support, for example a boat, an ocean going platform, or a wind turbine pylon or the like. In other embodiments, the link member 104 may be an independent component (for example, not coupled to a support structure 112), and the link member 104 may be submerged below the water surface 110.
  • the link member 104 is typically coupled to an anchor 114. In some embodiments, the link member 104 is indirectly coupled to the anchor
  • the link member 104 may be coupled to a support structure 112, which is in turn coupled to a mooring line 116, where the mooring line 116 is in turn coupled to the anchor 114.
  • the anchor 114 is a submerged ground surface 118, for example the ocean floor, or a lakebed.
  • the anchor 114 may be non- submerged land, or any means of securing the mooring line 116, such as a pile driven into the submerged ground surface 118, a large block of concrete placed on a submerged ground surface 118 or on a non-submerged surface (not shown) and the like.
  • a standard mechanism such as a ships anchor, for example an aircraft carrier or an oceanic transport anchor, may be used to couple the mooring line 116 to the anchor 114.
  • a single mooring line 116 may be used.
  • a plurality of mooring lines 116 may be used to couple the support structure 112 to the anchor 114.
  • three mooring lines 116 may be used to ensure that the support structure 112 is secured in a triangular fashion to prevent the support structure 112 from moving.
  • the use of a plurality of mooring lines 116 may reduce the forces exerted on the mooring line 116, and in turn on the anchor 114. The reduced forces may result from the distribution of the forces over the plurality of mooring lines 116.
  • the reduced forces exerted on the mooring lines 116 may also reduce the requirements for the mechanism used to couple the mooring line 116 to the anchor 114. For example, a smaller ships anchor may be used. In addition, each individual anchor 114 may also be less robust. For example, if a concrete block is used as an anchor 114, it may be a smaller size.
  • the mooring line 116 may be a rope, cable, a chain or any other similar device.
  • the mooring lines 116 may be made of nylon, steel, aramid fibers or any other like material. In some embodiments, the mooring line 116 may be made of a high strength material, while in other embodiments it may be made of regular material. For example, as mentioned above, if a plurality of mooring lines 116 are used, the force exerted on the mooring line 116 may be reduced, thus reducing the required strength of each individual mooring line 116.
  • the link member 104 may be directly coupled to the anchor 114 by a mooring line 116, for example as seen Figure 4. Coupling the link member 104 to anchor 114 may help to maintain the energy storage system 100 in one location and prevent it from drifting away in the currents of the body of water. In addition, coupling the link member 104 to anchor 114 helps to ensure that the desired components of the energy storage system 100 remain submerged below the water surface 110, and do not float to the surface.
  • the length of the mooring line 116 can be adjusted to increase or decrease the submersion of the energy storage system 100, or components of the energy storage system 100 below the water surface 110.
  • the mooring line 116 may be coupled to a powered pulley system that can draw in or let out the mooring line 116, thus adjusting its effective length.
  • a system for weighing and retracting a standard ship anchor may be used to let out or draw in the mooring line 116.
  • the link member 104 may comprise a sealed shell (not shown) to prevent the inflow of water, to the components of the link member 104 that are contained in the sealed shell.
  • the link member 104 may comprise an outer shell that permits water to enter and interact with the components of the link member 104, for example to provide cooling and lubrication to the link member 104 components in use.
  • the link member 104 includes a means of drawing in or letting out the tether 108.
  • the link member 104 comprises a mechanical advantage (not shown) to aid in the drawing in or letting out of the tether 108.
  • the link member 104 may comprise a system of pulleys, for example a gypsy, to draw in or let out the tether 108.
  • a block and tackle or a gearbox may be used to aid the link member 104 to draw in or let out the tether 108.
  • the link member 104 may comprise a wildcat for drawing in and letting out the tether 108.
  • the design of the mechanical advantage may depend, for example, on the resistant force of the tether 108 (for example the weight of the non-buoyant mass coupled to the tether 108), and the acceleration applied to the tether 108 as it is drawn in or let out.
  • a shaft (not shown) controls the rotation of the system of pulleys in the link member 104, and therefore the drawing in or letting out of the tether 108 from the link member 104.
  • the shaft may be rotated in one direction, for example clockwise, to draw the tether 108 into the link member 104, and rotated in the opposite direction, for example counterclockwise, to let the tether 108 out of the link member 104.
  • the tether 108 is drawn in, the excess tether 108 that gathers in the link member
  • 104 can be, for example, gathered on a drum co-rotating with the system of pulleys.
  • the tether 108 can be detachable.
  • the non-buoyant member 102 When in the low energy state, that is when the non-buoyant member 102 and the support structure 112 are at their greatest separation, the non-buoyant member 102 can be detached from the tether 108 and stored on the submerged ground surface 118.
  • the non-buoyant member 102 When in the high energy state, that is when the non-buoyant member 102 and the support structure 112 are at their closest proximity, the non-buoyant member 102 can be coupled to the support structure 112, and the tether 108 can be detached so that the non-buoyant member 102 is stored proximate to the support structure 112 to maintain the high energy state.
  • the tether 108 can also be detached from the support structure 112 for use elsewhere. If detachable, the tether 108 can include a relatively small buoy (not shown) towards the surface 110 and optionally a ballast (not shown) towards the submerged ground surface 118, the buoy and ballast operating to keep the tether 108 generally vertically stabilized when it is not attached between the non-buoyant member 102 and the link member 104. In addition to maintaining the tether 108 in a generally vertical orientation, a buoy and a ballast can also render the tether 108 negatively, positively or neutrally buoyant, depending on the adjustable ballast. Given a plurality of systems 100, the detachable tether 108 can be maneuvered from between the non-buoyant member 102 and the link member 104 of system 100 to another adjacent system 100 and successively attached.
  • a plurality of tethers 108 may be used to couple the non-buoyant member 102 to the link member 104. Multiple tethers 108 may be used when the weight of the non-buoyant member 102 is too large for a single tether 108. In some embodiments, multiple pulley systems may be deployed in the link member 104 to draw in or let out the plurality of tethers 108. In other embodiments, where a plurality of tethers 108 are used a single pulley system may be used to draw in or let out the plurality of tethers 108.
  • tether 108 is drawn into the link member 104, an equal portion of tether 108 that has already been drawn into, and passed through the link member 104, is simultaneously let out of the link member 104.
  • the remainder of the tether 108 not in the link member 104 is at one end being used to couple the link member 104 to the non-buoyant member 102, and at the other end is extending from the link member 104 and is not coupled to anything.
  • the energy conversion device 106 is typically coupled to the link member 104. In some embodiments, the energy conversion device 106 is coupled to the shaft that controls the rotation of the system of pulleys in the link member 104, thus controlling the drawing in and letting out of the tether
  • the energy conversion device 106 is an electric motor adapted to convert electric energy into mechanical energy.
  • the electric motor includes an input terminal for receiving and inputting electric energy.
  • the energy conversion device 106 may receive input electric energy at its input terminal, the electric motor then converts that input electric energy into mechanical energy, for example by rotating a shaft which in turn rotates the system of pulleys in the link member 104.
  • the energy conversion device 106 is an electric generator adapted to convert mechanical energy into electric energy.
  • the electric generator may include an output terminal for delivering and outputting electric energy.
  • the energy conversion device 106 may have mechanical energy input to the electric generator, for example by the rotation of a shaft coupled to the system of pulleys in the link member 104, the electric generator then converts the input mechanical energy into electric energy to be output by the output terminal.
  • the energy conversion device 106 may comprise both an electric motor and an electric generator.
  • the electric motor and the electric generator may be the same device. For example, when electric energy is input to the energy conversion device 106, the device acts as an electric motor, whereas when mechanical energy is input to the energy conversion device 106, the energy conversion device 106 acts as a generator, outputting electric energy.
  • the energy conversion device 106 may also be capable of converting mechanical energy to mechanical energy.
  • a wind turbine (not shown) may be coupled to the energy conversion device 106 such that mechanical energy (for example a spinning shaft, or a cable being displaced) generated by the wind turbine is input to the energy conversion device 106.
  • the energy conversion device 106 then converts the input mechanical energy into other mechanical energy, for example to a spinning shaft coupled to a system of pulleys in the link member 104, thus converting the input mechanical energy from the wind turbine into other mechanical energy capable of being used and stored by the energy storage system 100.
  • the conversion of mechanical energy to other mechanical energy may comprise altering the type of input mechanical energy, for example from a displacing cable to a shaft, or it may comprise a type of transmission to change the gearing or speed of the input mechanical energy into mechanical energy useful to the energy storage system 100.
  • the energy conversion device 106 may be an integral part of the link member 104.
  • the energy conversion device 106 and the link member 104 may be the same device.
  • the energy conversion device 106 may be contained in the same shell as the link member 104, and may be coupled to the means of drawing in or letting out the tether 108 contained in the link member 104.
  • the energy conversion device 106 may be integrally coupled to the shaft in the link member 106 that drives the system of pulleys.
  • the energy conversion device 106 is portable, and can be decoupled from the link member 104, and therefore from the energy storage system 100.
  • the energy conversion device 106 can be decoupled from an energy storage system 100 in one location, and coupled to an energy storage system 100 in another location. This can permit, for example, maintenance to be performed on an energy conversion device 106, without stopping the energy storage system 100 from operating.
  • the energy conversion device 106 can be operably linked to an energy generator or to a power grid.
  • Some example energy generators include a wind turbine or a plurality of wind turbines, a nuclear reactor, a coal plant, a natural gas generator, or a hydro dam.
  • the power grid may be any power grid of any size or configuration, for example the power grid may comprise an oil extraction platform, or a deep-sea wind turbine farm, or the power grid may be the North American power grid or the like.
  • the power grid may, for example, typically provide power for residential requirements, or the power grid may provide for specific industrial requirements for example an oil extraction platform or a steel smelter.
  • the power grid may supply standard alternating current (AC), or it may supply direct current (DC) or other specialized power types to the power conversion device 106.
  • AC alternating current
  • DC direct current
  • the power conversion device 106 may be modified to output any type of power including AC or DC.
  • the energy conversion device 106 may be located remotely from the link member 104. See for example, the description of the energy storage system 600 found below. As described above, a remotely located energy conversion device 106 may aid in making the energy conversion device portable and where the energy conversion device can be de-coupled from the energy storage system 100.
  • the remote energy conversion device 106 may be floating on a support structure 112, while remaining remotely coupled to the link member 104, which is submerged below the water surface
  • a belt and pulley system (not shown), or cable and pulley system, similar to the system disclosed for the link member 104, may be used to remotely couple the link member 104 to the energy conversion device 106.
  • a belt, or a plurality of belts may couple at a first end to a pulley or a plurality of pulleys in the energy conversion device 106, and couple at a second end to a pulley or a plurality of pulleys in the link member 104.
  • the belt and pulleys therefore couple the link member 104 and the energy conversion device 106 together, and also permit the transmission of energy, typically mechanical energy, between the link member 104 and the energy conversion device 106.
  • the energy conversion device 106 is located remotely on a support structure 112
  • special care may be taken to ensure that when mechanical energy is being transferred between the energy conversion device 106 and the link member 104, the support structure 112 remains floating.
  • the support structure 112 may be larger than the pulley on the energy conversion device 106. The smaller pulley on the energy conversion device 106 may therefore spin faster and more responsively and result in less downward force being exerted on the energy conversion device 106 and in turn the support structure 112.
  • the electric energy input to the energy conversion device 106 may, in some embodiments, be conditioned to be electric energy that can be used by the energy conversion device 106.
  • the electricity may be conditioned from direct current (DC) to alternating current (AC), or vice versa.
  • the electric energy may be conditioned to a certain level of voltage or current, to be useful for the energy conversion device 106.
  • the same principle applies to the electric energy output by the energy conversion device 106, which may be conditioned for the intended purpose, for example to be output to a power grid.
  • the ability of the energy conversion device 106 to interface with a power grid or energy generator can permit electric energy to be transferred from a power grid, or an energy generator and stored in the energy storage system 100. Conversely, electric energy can be output by the energy storage system 100 through the energy conversion device 106 and transferred back to the power grid.
  • electric energy may be supplied to the energy storage system 100 at non-peak times.
  • the electric energy may then, in turn be output from the energy storage system 100 at peak times. This can reduce the overall generation capacity required by an electric system to meet peak electric energy demands. In addition, this may permit the purchase and storage of inexpensive electric energy at non-peak times, and the sale of that stored electric energy at peak times at a more expensive rate.
  • the tether 108 may be any means of coupling the non-buoyant member 102 to the link member 104.
  • the tether 108 has sufficient material and structural strength to support the weight of the non-buoyant member 102, together with the self weight of the tether 108, together with any acceleration forces exerted on the tether 108 when the non-buoyant member 102 coupled to the tether 108 is displaced.
  • the tether 308 typically has sufficient strength to resist the forces associated with restraining a buoyant member 320 together with any acceleration forces exerted on the tether 308 when the buoyant member 320 coupled to the tether 308 is being displaced.
  • the tether 108 may be a rope or a cable, made from any type of material for example steel, aramid fibers (for example Kevlar®), a carbon reinforced fiber, or any other type of high strength material.
  • the tether 108 may be comprised of interconnected links, such as a chain, for example an anchor chain.
  • the chain may be made of any material such as steel, or a carbon fiber reinforced composite material.
  • the tether 108 has a length of 10 meters to 7000 meters; in other embodiments the tether 108 has a length of 50 meters to 5000 meters. For example a common ocean depth is 5000 - 6000 meters. When the energy storage system 100 is deployed in the ocean, the tether 108 may have a length of 6000 meters. In other examples, such as deployment of an energy storage system such as energy storage system 100 in a lake having a depth of 100 meters, the tether 108 may have a maximum length of 100 meters.
  • the tether 108 couples the link member 104 to the non-buoyant member 102.
  • a single tether 108 is used to couple the link member 104 to the non-buoyant member 102.
  • a plurality of tethers 108 can be used to couple the link 104 to the non-buoyant member 102.
  • the tethers 108 may be substantially parallel to each other between the link member 104 and non-buoyant member 102.
  • a plurality of tethers 308 can be used to couple the buoyant member 320 to the anchor 314.
  • the tether 108 may be fitted with a sleeve (not shown), for example a polypropylene sleeve.
  • the sleeve which may be used with a tether 108 using interconnected links, is less dense than water, such that when the sleeve is placed independently in a body of water the sleeve will float.
  • the sleeve When the sleeve is affixed to the tether 108, the sleeve typically reduces the force exerted on the tether 108 by the tether's 108 own mass.
  • the reduction in force exerted on the tether 108 can permit the use of a non-buoyant member 102 with a greater mass.
  • the reduced force on the tether 108 can permit the use of a longer length for the tether 108 between the link member 104 and the non-buoyant member 102, for example a longer deployed length of tether 108. As is discussed in more depth below, this can permit the storage of greater amounts of energy in the energy storage system 100.
  • the length of the tether 108 at which the use of sleeves becomes relevant varies depending on the type of tether 108 used.
  • the use of sleeves may be useful for a number of reasons.
  • use of the sleeves may permit the tether 108 to be deployed to a greater length, or it may also increase the mass of the non-buoyant member 102 that can be coupled to the tether 108.
  • an anchor chain tether 108 can support its own weight up to a length of approximately 1200 meters, it may be advisable to use sleeves if that anchor chain tether 108 is to be used at lengths of greater than 500 meters.
  • the sleeve may be removed automatically from the tether 108 as the tether 108 enters the link member
  • the sleeve may also be replaced automatically on the tether 108 as the tether 108 exits the link member 104. This may help to maintain a proper frictional mechanical interaction between the tether 108 and the link member 104.
  • the automatic removal and replacement of the sleeve on the tether 108 may also reduce the required dimensions of the link member 104, and preserve the sleeve in serviceable condition, without exposing the sleeve to damage in the link member 104 when the link member 104 is drawing in or letting out the tether 108.
  • the tether 108 is coupled to the link member 104 in such a fashion as to permit the tether 108 to be drawn in (i.e. reducing the length of the tether 108 between the link member 104 and the non-buoyant member 102) or to be let out (i.e. increasing the length of the tether 108 between the link member 104 and the non-buoyant member 102). Because the tether 108 connects the link member 104 to the non-buoyant member 102, as the tether 108 is drawn in or let out by the link member 104, the non-buoyant member 102 is displaced.
  • the non-buoyant member 102 is typically displaced in one of two general directions by the tether 108: either towards the water surface 110, or towards the submerged ground surface 118. In addition, the non-buoyant member 102 may be held in a stationary position.
  • the energy conversion device 106 controls the drawing in or letting out of the tether 108 from the link member 104. In turn, therefore, the energy conversion device 106 also controls the displacement of the non-buoyant member 104. Displacement of the non- buoyant member 102 is typically used by the energy storage system 100 to store energy. Typically, the energy storage system 100 has three states: a storage state, a discharge state, and a stasis state. In the storage state, electric energy is typically input to the input terminal of the energy conversion device 106. The energy conversion device 106 converts the electric energy into mechanical energy that is used to displace (for example raise) the non-buoyant member 102 towards the water surface 110.
  • the non-buoyant member 102 resists being displaced toward the water surface 110 because of the gravitational force acting on the non- buoyant member 102, as well as the frictional and drag resistance associated with moving the non-buoyant member 102 through a fluid.
  • Displacing the non-buoyant member 102 against the gravitational force (for example elevating the mass against the gravitational force), stores energy in the system as potential energy.
  • Potential energy in a gravitational field can be expressed as mass multiplied by height multiplied by gravity. Since gravity is an approximately constant value, the amount of energy stored in a gravitational field is directly proportional to the mass, and the height of that mass in the gravitational field.
  • electric energy is typically output from the output terminal of the energy conversion device 106.
  • the energy conversion device 106 generates the electric energy output by allowing the non-buoyant member 102 to displace towards the submerged ground surface 118 (for example being lowered), which in turn creates mechanical energy (for example causing rotation of a shaft) that the energy conversion device 106 converts into electric energy.
  • the non-buoyant member 102 displaces towards the submerged surface 118 because of the gravitational force acting on the non-buoyant member 102.
  • the displacement of the non-buoyant member 102 is also resisted by frictional and drag resistance forces associated with moving the non-buoyant member 102 through a fluid.
  • the non-buoyant member 102 displaces towards the submerged ground surface 118 on its own as a result of gravitational force, the non- buoyant member's 102 stored potential energy is redeemed as mechanical energy, which the energy conversion device 106 in turn converts into electric energy which the energy conversion device 106 outputs through its output terminal.
  • the mass of the non-buoyant member 102 is relatively large, the velocity at which the non-buoyant member 102 is displaced through the water is relatively low. This may help minimize the frictional and drag forces acting on the non-buoyant member 102 as it displaces through the water.
  • the energy conversion device 106 is not displacing the non-buoyant member 102. Typically this means no energy is being input or output by the energy storage system 100.
  • the energy storage system 100 stores electric energy as described above, a significant part of the operation of the energy storage system 100 takes place below the water surface 110, and is therefore not typically visible above the water surface 110.
  • FIG 2 illustrates a second embodiment energy storage system 200.
  • the energy storage system 200 is substantially similar to the energy storage system 100, except that support structure 212 is submerged. Like parts are identified by like reference numbers and will not be further described except where material.
  • the support structure 212 can be maintained in a submerged position by the mooring line 216 having a length appropriate to restrain the support structure 212 below the water surface 210.
  • the length of the mooring line 216 may be adjustable to selectively submerge and to selectively float the support structure 212 below or above the water surface 210, as desired. Having the length of the mooring line 216 be adjustable also permits the depth of the link member 204 below the water surface 210 to be controlled.
  • the support structure 212 may comprise ballast tanks (not shown) that can be selectively filled or emptied. Filling or emptying the ballast tanks can control the level of submersion of the support structure 212 below the water surface 210, or allow the support structure 212 to float. Permitting the support structure 212 to float can aid in transporting the energy storage system 200. For example, when the energy storage system 200 is being transported to a shipyard for maintenance, or when the energy storage system 200 is being transported to the area where the energy storage system 200 is to be deployed, the support structure can be floated on the water surface 210.
  • a floating support structure 212 can be transported using a tugboat.
  • the support structure 112 as seen in Figure 1 , can be transported using a tugboat.
  • the non-buoyant member 102 may be drawn in (retracted) to be adjacent to the support structure 112, to reduce the risk of the non-buoyant member 102 striking a submerged hazard.
  • the selective submerging of the support structure 212 can permit the support structure 212 to be substantially invisible above the water surface 210. This may permit the energy storage system 200 to preserve valuable vistas even when fully deployed. In some embodiments, the energy storage system 200 can be submerged to a sufficient level to permit boats, including for example pleasure boats or commercial boats, to pass over the deployed energy storage system 200.
  • FIG. 3 illustrates an energy storage system 300.
  • Energy storage system 300 is similar to energy storage systems 100 and 200, except no support structure 112 is used, and a buoyant member 320 is used instead of a non-buoyant member 102. Like parts are identified by like reference numbers and will not be further described except where material.
  • the energy storage system 300 comprises a buoyant member
  • the link member 304 is coupled to the anchor 314, and typically the energy conversion device 306 is adapted to control the displacement of the buoyant member 320.
  • the link member 304 and the energy conversion device 306 can be located adjacent to, or as a part of the buoyant member 320.
  • the link member 304 may be coupled directly to the buoyant member 320.
  • the link member 304 and the energy conversion device 306 can be located adjacent to an anchor 314. If, for example, the link member 304 is coupled the anchor 314, the link member 304 may then be coupled to the buoyant member 304 via the tether 308.
  • the link member 304 is typically located below a water surface 310. As discussed above with regards to energy storage systems 100 and 200, the energy conversion device 306 is coupled to the link member 304. In some embodiments, the energy conversion device 306 may be coupled directly to the link member 304, while in other embodiments the energy conversion device 306 may be remotely coupled to the link member 304.
  • the tether 308 couples the buoyant member 320 to an anchor
  • the tether 308 can be drawn in or let out as in the energy storage system embodiments 100 and 200. Drawing in or letting out the tether 308 displaces the buoyant member 320 towards the submerged surface 318 or towards the water surface 310 respectively. As previously discussed, the energy conversion device 306 controls the drawing in or letting out of the tether 308 through the link member 304, thereby controlling the displacement of the non-buoyant member 320.
  • the tether 308 may be the same member as a mooring line 316.
  • the mooring line 316 may be a separate member from the tether 308.
  • the mooring line 316 may be a separate member from the tether 308 where the tether 308 couples the anchor 314 to the buoyant member 320 during operation of the energy storage system 300, however a mooring line (not shown) may provide an alternative redundant coupling between anchor 314 and the buoyant member 320.
  • the redundant coupling from the mooring line to the buoyant member 320 may provide a backup restraint on the buoyant member 320 from floating to the water surface 310 should a component of the energy storage system 300 fail.
  • the tether 308 can be detachable.
  • the buoyant member 320 When in the low energy state, that is when the buoyant member 320 is at the water surface 310, the buoyant member 320 can be detached from the tether 308 and stored at the water surface 310. The buoyant member 320 can be moored in position at the water surface 320 to prevent drifting away.
  • the buoyant member 320 When in the high energy state, that is when the buoyant member 320 is submerged and in closest proximity to anchor 314, the buoyant member 320 can be coupled to the anchor 314, and the tether 308 can be detached so that the buoyant member 320 is stored proximate to the anchor 314 to maintain the high energy state.
  • the tether 308 can remain attached to the anchor 314, and reattached to the buoyant member 320 when desired.
  • the tether 308 can also be detached from the anchor 314 and shifted to another anchor 314, or to an additional mooring device (not shown).
  • the tether 308 can be operated as described herein to store energy.
  • the tether 308 may include a buoy and/or ballast (not shown) to maintain the tether 308 in a generally vertically orientation.
  • the buoyant member 320 is adapted to be submerged below a water surface 310.
  • the buoyant member 320 may be any member that has a density less than the fluid (for example water) in which the buoyant member 320 is situated.
  • the buoyant member 320 may be designed for use in salt or fresh water, or any type of fluid.
  • the required density of the buoyant member 320 to remain buoyant may vary depending on the density of the salt water or fresh water in which the buoyant member 320 is placed.
  • the buoyant member 320 may be made of any suitable material, such as concrete, wood, vinyl, plastic any metal such as steel and the like.
  • the buoyant member 320 comprises an outer shell 328, and a hollow portion 330.
  • the outer shell 328 may be made of concrete.
  • the hollow portion 330 contains air, and is sealed from allowing water in.
  • the outer shell 328 is of sufficient strength to resist any water pressure forces that are exerted on the buoyant member 320 at an increased depth of water to which the buoyant member 320 may be lowered.
  • the buoyant member 320 may have compressed gas or fluid, for example air, pumped into the buoyant member 320, for example in the hollow portion 330.
  • the compressed gas or fluid may help ensure that the buoyant member 320 will not be crushed, or damaged by the water pressure forces exerted on the buoyant member 320 at increased depth.
  • compressed gas may be introduced to the buoyant member 320 by a pump.
  • the buoyant member 320 may also comprise a ballast tank 332.
  • the buoyant member 320 may comprise a plurality of ballast tanks 332. The ballast tanks 332 are selectively filled and emptied with water, such as the water of the surrounding body of water.
  • ballast tanks 332 When the ballast tanks 332 are emptied of water they typically comprise air. Selectively emptying and filling the ballast tanks 332 can therefore control the buoyancy of the buoyant member 320. For example, filling the ballast tanks 332 may reduce the buoyancy of the buoyant member 320. Reduced buoyancy can decrease the force exerted on the tether 308 by the buoyant member 320, or reduced buoyancy can increase the submersion of the buoyant member 320 below a water surface 310.
  • emptying the ballast tanks 332 increases the buoyancy of the buoyant member 320 and can increase the force exerted by the buoyant member 320 on the tether 308, or the mooring line 316.
  • the increased buoyancy of the buoyant member 320 can permit the buoyant member 320 to float on the water surface 310. This may permit easier transportation of the buoyant member 320, for example by a tugboat.
  • the buoyancy of the buoyant member 320 when the ballast tanks 332 are empty may be sufficient to float the whole of or components of the other energy storage system 300.
  • Increasing the buoyancy of the buoyant member 320 increases the mechanical energy required to increase the level of submersion of (for example to lower) the buoyant member 320 below the water surface 310. Therefore, increasing the buoyancy of the buoyant member 320 typically increases the amount of mechanical energy that can be stored in the energy storage system 300. Similar to what was discussed for the energy storage system
  • the energy conversion device 306 can convert the stored mechanical energy into electric energy by displacing the buoyant member 320 as desired.
  • the energy storage system 300 operates similarly to the energy storage system 100, except instead of displacing a non-buoyant member 102 to store and discharge energy, a buoyant member 320 is displaced to store and discharge energy.
  • FIG. 4 illustrates another embodiment of an energy storage system 400.
  • Energy storage system 400 is similar to energy storage systems 100, 200, and 300 except energy storage system 400 includes both a buoyant member 420 and a non-buoyant member 402, but does not include a support structure.
  • Like parts are identified by like reference numbers and will not be further described except where material.
  • Energy storage system 400 comprises a buoyant member 420 adapted to be submerged below a water surface 410, a link member 404 where the link member 404 is typically submerged below the water surface 410, an energy conversion device 406 coupled to the link member 404, a plurality of tethers 408, at least one tether 408 coupling the link member 404 to the buoyant member 420, and at least one tether 408 coupling the link member 404 to the non-buoyant member 402.
  • the link member 404 is coupled to an anchor 414, and typically the energy conversion device 406 is adapted to control the displacement of the buoyant member 420 and the non-buoyant member 402.
  • the buoyant member 420, and non-buoyant member 402 are very similar to those described for the energy storage systems 100, 200 and 300.
  • the buoyant member 420 and non-buoyant member 402 have a optimized hydrodynamic shape.
  • the buoyant member 420 and non-buoyant member 402 have an elliptical shape similar to a ship or submarine nose, in order to reduce hydrodynamic losses that may occur when either the buoyant member 420 or non-buoyant member 402 are displaced through water. This can aid in reducing energy losses from the energy storage system 400 because of the displacement of the buoyant member 420 and non-buoyant member 402 through water.
  • These principles are applicable to any of the buoyant member or non-buoyant members described previously or below.
  • the mass of the non-buoyant member 402 may be designed to be sufficient to counter the buoyancy of the buoyant member 420.
  • the link member 404 may be coupled to two mooring lines 416 coupling the link member 404 to an anchor 414. In other embodiments, the link member 404 may be coupled to a single or more than two mooring lines 416, in order to couple the link member 404 to an anchor 414.
  • the mooring lines 416 can also be selectively drawn in or let out to increase or decrease the level of submersion of the energy storage system 400.
  • the link member 404 in the energy storage system 400 is adapted to be simultaneously coupled to both the buoyant member 420 and the non-buoyant member 402 via tethers 408.
  • the energy conversion device 406 is, as described before, coupled to the link member 404. Similar to the descriptions above, the energy conversion device 406 is adapted to control the displacement of the buoyant member 420 and the non-buoyant member 402 via the drawing in or letting out of the plurality of tethers 408 coupled to the link member 404.
  • coupling the link member 404 to both the buoyant member 420 and the non-buoyant member 402 may reduce the strength of the mooring line(s) 416 required, as well as reduce the force exerted on the anchor 414.
  • the buoyancy force of the buoyant member 420 may be approximately the same as the weight (force) of the non- buoyant member 402. This results in the link member 404 being subject to little net vertical force as a result of being linked to both the buoyant member 420 and the non-buoyant member 402.
  • the tether 408 can be detachable.
  • the buoyant member 420 and the non- buoyant member 402 can be detached from the tether 408 and stored.
  • the buoyant member 420 can be stored at the water surface 410
  • the non-buoyant member 402 can be stored at the submerged ground surface 418.
  • the buoyant member 420 and the non-buoyant member 402 When in the high energy state, that is when the buoyant member 420 and the non-buoyant member 402 are at their closest proximity, the buoyant member 420 and the non-buoyant member 402 can be coupled to one another, and/or each coupled to the link member 404, and the tether 408 can be detached so that the buoyant member 420 and the non-buoyant member 402 are stored proximate to the link member 404 to maintain the high energy state.
  • the tether 408 can also be detached from the link member 404 for use elsewhere.
  • the energy storage system 500 is similar to the energy storage system 400, except energy storage system 500 is nestable. Like parts are identified by like reference numbers and will not be further described except where material.
  • the energy storage system 500 has two states: a first nested state, and a second deployed state. For example in the first nested state, the buoyant member 520, the non-buoyant member 502, and the link member 504 nest together to form an energy storage system body 534. When nested together, the energy storage system body 534 typically has a reduced side profile than the deployed second state of the energy storage system 500.
  • the buoyant member 520 is shaped like a toroid so as to ring around the link member 504, where the link member 504 is in turn also a toroid that rings around the non-buoyant member 502.
  • the buoyant member 520, the non-buoyant member 502, and the link member 504 are adjacent to each other forming the energy storage system body 534.
  • the energy storage system 500 in a second deployed state, appears and functions similar to the energy storage system 400, described previously.
  • the buoyant member 520, link member 504, and the non-buoyant member 502 are located in approximately a single vertical column in a body of water, with the buoyant member 520 being adjacent to the water surface (not shown) the non-buoyant member 502 being adjacent to the submerged ground surface (not shown), and the link member 504 located in between the buoyant member 520 and the non-buoyant member 502.
  • the buoyant member 520 is coupled to the link member 504 via a plurality of tethers 508.
  • the non-buoyant member 502 is also coupled to the link member 506 via a plurality of tethers 508.
  • the first nested state of the energy storage system 500 is formed when the tethers 508 that couple the non-buoyant member 502 to the link member 504, and the tethers 508 that couple the buoyant member 520 to link member 504, are fully drawn in.
  • the second fully deployed state of the energy storage system 500 is formed when the tethers 508 that couple the non-buoyant member 502 to the link member 504, and the tethers 508 that couple the buoyant member 520 to link member 504, are fully let out.
  • the energy storage system 500 can also be in any state between the first nested state and the second deployed state, with varying levels of potential, and buoyant energy stored in the energy storage system 500.
  • the energy storage system 500 has an increased amount of energy stored when in a first nested state.
  • the energy storage system 500 typically has a decreased amount of energy stored in a second fully deployed state.
  • Figure 9 illustrates another embodiment of an energy storage system 600.
  • the energy storage system 600 is also nestable, similar to energy storage system 500.
  • the energy storage system 600 is similar to the energy storage systems 100, 400, and 500. Like parts are identified by like reference numbers and will not be further described except where material.
  • the energy storage system 600 when in a second deployed state similar to the energy storage system 500, forms an approximately vertical column with the buoyant member 620 being adjacent to the water surface, the non-buoyant member 602 being adjacent to the submerged ground surface 618, and the link member 604 located in between the buoyant member 620 and the non-buoyant member 602.
  • the non-buoyant member 620 and the buoyant member 602 are shaped approximately as cubes with a hollow vertical column section.
  • the link member 604 is dimensioned to nest into the hollow vertical column section of the non-buoyant member 602, and the non-buoyant member 602 is dimensioned to nest into the hollow vertical column section of the buoyant member 620.
  • the energy storage system 600 when the energy storage system 600 is in a first nested state (not shown) the plurality of tethers 608 connecting the buoyant member 620 to the link member 604, and the plurality of tethers 608 connecting the non-buoyant member 602 to the link member 604 are fully drawn in.
  • the first nested state of the energy storage system 600 permits the energy storage system 600 to be, for example, more easily transported because of the energy storage system's 600 reduced size below the water surface 610.
  • the reduced size of the energy storage system 600 below the water surface 610 may permit the energy storage system 600 to be transported in navigable waterways without colliding with the submerged ground surface 618, or any other underwater obstructions.
  • the energy storage system 600 is fully deployed when the tethers 608 connecting the buoyant member 620 to the link member 604, and the tethers 608 connecting the non-buoyant member 602 to the link member 604 are fully let out.
  • the energy storage system 600 may be in any state between a first fully nested state and second fully deployed state.
  • energy storage system 600 comprises an energy conversion device 606 that is remotely coupled to the link member
  • energy conversion device 606 is located in support structure 612, whereas the link member 604 is submerged below the water surface 610, and as described above, the link member 604 is located in vertical column between the buoyant member 620, and the non-buoyant member 602.
  • the link member 604 and the energy conversion device 606 are coupled together via link tether 636.
  • the link tether 636 translates mechanical energy between the energy conversion device 606 and the link member 604.
  • electric energy can be input or output from the energy conversion device 606.
  • the energy conversion device 606 converts the input electric energy into mechanical energy, for example by rotating a shaft that draws in the link tether 636.
  • the drawn in link tether 636 in turn provides mechanical energy to the link member 604, which in turn uses the provided mechanical energy to draw in the plurality of tethers 608.
  • the electric energy input to the energy conversion device 606 is stored as the displacement of the buoyant member 620 and the non-buoyant member 602, where the energy conversion device 606 controls the displacement of the buoyant member 620 and the non-buoyant member 602.
  • the energy conversion device 606 may output electric energy by converting the mechanical energy it receives via the link tether 636 into electric energy.
  • the link tether 636 may be drawn in by the link member 604, meaning the link tether 636 is let out by the energy conversion device 606, thus providing the energy conversion device 606 with the requisite input mechanical energy to be converted into the output electric energy.
  • the energy conversion device 606 may be located adjacent to link member 604.
  • the link tether 636 typically does not transfer mechanical energy between the energy conversion device 606 and the link member 636. Rather, the link tether 636 anchors the link member 604 to the support structure 612 and provides a conduit for transmitting electric energy between the support structure 612 and the energy conversion device 606.
  • FIG 10 illustrates another embodiment of an energy storage system 700.
  • the energy storage system 700 is similar to the energy storage system 600, except that it is linked to a wave harvester 738. Like parts are identified by like reference numbers and will not be further described except where material.
  • the wave harvester 738 is adapted to collect mechanical energy, and transmit the mechanical energy to the conversion device 706.
  • the wave harvester 738 is also typically coupled to the link member 704, and thus the energy storage system 700, by link tether 736.
  • the energy conversion device 706 may be separate from, but coupled to, the wave harvester.
  • the wave harvester 738 typically floats on the water surface 710. Because the wave harvester 738 floats on the water surface 710, the wave harvester 738 is adapted to rise and fall as the water surface 710 rises and falls. In some embodiments the wave harvester 738 may rise and fall periodically as a result of waves. In other embodiments, the wave harvester 738 may rise and fall as a result of tides. The wave harvester 738 is adapted to convert its rising and falling movements into mechanical energy. In some embodiments, the wave harvester 738 may have an outer form similar to a buoy flotation device. In other embodiments the wave harvester 738 may be a water going vessel, such as a small boat or barge. Any size of wave harvester 738 may be used.
  • the wave harvester 738 is typically sized to be large enough to allow it to rise with the level of the water surface 710 when a wave passes under the wave harvester 738. However, the wave harvester 738 should generally not be larger than the average spacing between the crests of the waves expected in the region where the wave harvester 738 is deployed.
  • the size of the wave harvester 738 will affect the size and strength of the link tether 736 used. For example, a larger wave harvester
  • the wave harvester 738 may require the use of a larger chain, or cable link tether 736 to link the wave harvester 738 to the link member 704.
  • the size of the wave harvester 738 will also affect the size and strength of the mooring lines 716 required to couple the energy storage system 700 to the anchor 714.
  • a larger wave harvester 738 may exert larger forces on the energy storage system 700 and require larger mooring lines 716 to hold the energy storage system 700 in place.
  • a single wave harvester 738 may be used, while in other embodiments a plurality of wave harvesters 738 may be used.
  • a plurality of wave harvesters 738 may be used in embodiments where using a single wave harvester 738 would result in the energy storage system 700 being dislodged from the mooring lines 716 when the single wave harvester 738 rises with the water surface 710.
  • a plurality of wave harvesters 738 may also be used in embodiments where using a single wave harvester 738 would result in significant stress being applied to the mooring lines 716 when the single wave harvester 738 rises with the water surface 710.
  • Using a plurality of smaller wave harvesters 738 instead of a single large wave harvester 738 reduces the risk of dislodging the energy storage system 700 while capturing a similar amount of mechanical energy since each of the plurality of wave harvesters 738 typically reaches their respective peak vertical positions at different times.
  • the plurality of wave harvesters 738 are spaced apart to minimize interference between the plurality of the wave harvesters 738 and components of the energy storage system 700.
  • the spacing between the plurality of wave harvesters 738 can further be varied to increase each wave harvester's 738 exposure to mechanical energy imparted by the waves on the water surface 710.
  • wave harvesters 738 are separated from each other by approximately three to four wavelengths.
  • the plurality of wave harvesters 738 are arranged in a large circular configuration.
  • the wave harvester 738 has a tension relief mechanism (not shown) that reduces the tension exerted on the mooring lines
  • the link tether 736 is connected to the wave harvester 738 by a variable length linkage that extends the link tether 736 to reduce the tension exerted on the mooring line 716 by the wave harvester 738.
  • variable length linkage comprises a retractable rod that, under regular conditions, is retracted into the wave harvester 738.
  • the retractable rod extends from the base of the wave harvester 738, thereby extending the length of the link tether 736 and reducing the tension exerted on the mooring lines 716.
  • the variable length linkage comprises a reel around which a portion of the link tether 736 is wound. The reel further comprises a locking mechanism that, under regular conditions, prevents the reel from rotating thereby maintaining the length of link tether 736.
  • the locking mechanism unlocks to allow the reel to rotate and release portion of the link tether 736 wound around the reel, thereby extending the length of the link tether 736 and reducing the tension exerted on the mooring lines 716.
  • the wave harvester 738 further includes a vertical displacement detector that monitors the vertical displacement of the wave harvester 738. If the vertical displacement of the wave harvester 738 or the plurality of wave harvesters 738 exceeds a predetermined level, the variable length linkage is activated to extend the length of the link tether 736.
  • the vertical displacement detector comprises an accelerometer that detects the vertical distance traveled by the wave harvester 738, and activates the variable length linkage when the vertical distance traveled exceeds a predetermined range.
  • the vertical displacement detector comprises a plurality of accelerometers, one in each of the plurality of wave harvesters 738, adapted to wirelessly communicate with each other in order to determine the net vertical displacement of the plurality of wave harvesters 738.
  • the plurality of accelerometers are further adapted to determine which of the plurality of wave harvesters 738 should activate their respective variable length linkages in order to effectively reduce the tension on the mooring lines 716.
  • the wave harvester 738 transmits the mechanical energy that it collects to the link member 704 through link tether 736.
  • the wave harvester 738 comprises the energy conversion device 706.
  • the energy conversion device 736 converts the input mechanical energy into other mechanical energy adapted to draw in or let out the link tether 736, thus providing mechanical energy to the link member 704.
  • a mechanical advantage such as a block and tackle system, is used in the link member 704.
  • the mechanical advantage in the link member 704 permits even small displacements of the link tether 736 by the wave harvester 738 to be harnessed by the link member 704 to displace the buoyant member 720 and/or non-buoyant member 702, thus allowing the energy storage system 700 to store energy.
  • the mechanical advantage required in the link member 704 may be smaller or in some examples, non-existent.
  • the mechanical advantage may be coupled to the energy conversion device 706, while in other example the mechanical advantage may be coupled to the link member 704. In yet other embodiments the mechanical advantage may be coupled to both the energy conversion device 706 and the link member 704.
  • energy storage system 700 may comprise an additional second energy conversion device (not shown) adapted to convert mechanical energy into electric energy.
  • the second energy conversion device can convert the mechanical energy from the displacing link tether 708 into electric energy that may be output to a power grid.
  • the wave harvester 738 should generally be maintained in its properly functional position. Proper functional position is when the wave harvester 738 is located so as to be able to generated energy from the rising and falling level of the water surface 710. In some examples, the proper functional position for the wave harvester 738 is substantially adjacent to the buoyant member 720 on the water surface 710.
  • the link tether 736 is typically kept under tension to prevent the wave harvester 738 from drifting away from its proper functional position on the water surface 710.
  • the base of the wave harvester 738 has a sufficiently large surface area so as to counter downward forces that are exerted on the wave harvester 738 by the link tether 36 when the wave harvester 738 begins to drift.
  • the link tether 736 attempts to submerge the wave harvester 738 by exerting a downward force on the wave harvester 738 due to the tension in the link tether 736. Since the base of the wave harvester 738 is generally large, the wave harvester 738 counters this downward force, thereby maintaining the wave harvester 738 in its proper functional position.
  • the non-buoyant member may comprise a guide (not shown) to maintain the wave harvester 738 in proper functional position.
  • the guide may be, for example, a ring located in the hollow vertical shaft of the buoyant member 720.
  • the ring permits the link tether 736 to pass through intermediate the wave harvester 738 and the link member 704, but typically the hole is dimensioned to restrain the link tether 736 from displacing beyond a range where the wave harvester 738 would be no longer be in its proper functional position.
  • the wave tether 738 may have mooring lines (not shown) attached to couple the wave harvester 738 to an anchor 714, thus maintaining the wave harvester 738 in proper functional position.
  • FIG 11 illustrates another embodiment of an energy storage system 800.
  • the energy storage system 800 is similar to the energy storage systems 400 and 700, except that the wave harvester 838 is coupled to the link member 804 using a different guide 840.
  • Like parts are identified by like reference numbers and will not be further described except where material.
  • energy storage system 800 is very similar to energy storage system 700.
  • a plurality of wave harvesters 838 are coupled by link tethers 836 to link member 804.
  • the wave harvesters 838 are deployed on the water surface 810 substantially adjacent to the buoyant member 820.
  • the wave harvesters 838 may be deployed on the water surface 810 adjacent the outer perimeter of the buoyant member 820.
  • the link tethers 836 are coupled to the buoyant member 820 via guides 840.
  • the guides 840 may be rollers, permitting the link tether 838 to move smoothly with reduced friction relative to the buoyant member 820.
  • the guides 840 may be rings, or the like, which simultaneously permit the link tether 836 to move smoothly with reduced friction relative to the buoyant member 820, while also restraining the wave harvester(s) 838 in proper functional position.
  • a single wave harvester 838 may be used. In other embodiments a plurality of wave harvesters 838 may be used. In some embodiments, a single guide 840 may be used to couple a link tether 838 to the non-buoyant member 820, while in other embodiments a plurality of guides 840 may be used to couple a link tether 838 to the non-buoyant member 820.
  • the link tether 1336 is a cable having one end coupled to the wave harvester 1338 and the other end partially wound around and anchored to a rotateable link member pulley 1344.
  • the link tether 1338 may be a chain.
  • the link member pulley 1344 is coupled to link member 1304 by a shaft 1346.
  • link tether 1336 also rises and thereby rotates link member pulley 1344.
  • the rotating link member pulley 1344 then drives the link member 1304 via shaft 1346 in order to displace the non-buoyant member 1302 and buoyant member 1320.
  • Shaft 1346 typically includes a ratchet mechanism 1348 that allows shaft 1346 to drive the link member 1304 when it rotates in a direction that corresponds to the wave harvester 1338 rising with the level of the water surface 1310, but prevents shaft 1346 from driving the link member 1304 when it rotates in an opposite direction that corresponds to the wave harvester 1338 falling with the level of the water surface 1310.
  • the rotated link member 1304 subsequently draws in tethers 1308 to lower the buoyant member 1320 and to raise non-buoyant member 1302, thereby storing the mechanical energy harvested from the water surface 1310 in the energy storage system 1300.
  • Shaft 1346 further includes a return mechanism 1350, such as a spring, to rotate shaft 1346 and link member pulley 1344 in a direction corresponding to the wave harvester 1338 falling with the level of the water surface 1310 to maintain sufficient tension in the link tether 1336 as the wave harvester 1338 falls with a falling water surface 1310.
  • the link member pulley 1344 generally has a large diameter to ensure that there is a sufficient mechanical advantage in the system to harness the rising and falling motion of the wave harvester 1338 and store the converted energy in the energy storage system 1300.
  • the diameter of the link member pulley 1344 is such that the circumference of the link member pulley 1344 is generally much larger than the average amplitude of the waves that are typically found in the region where the wave harvester 1338 is deployed. As a result, the link member pulley 1344 typically does not need to rotate by more than a few degrees in either direction.
  • the link member pulley 1344 is generally circular in shape.
  • the link member pulley 1344 may be an elongate lever of sufficient length.
  • the link member pulley 1344 may be irregularly shaped so as to operate as a cam.
  • the distance from the axis of the link member pulley 1344 to the point on the perimeter of the link member pulley 1344 where the link tether 1336 first contacts the link member pulley 1344 varies as the link member pulley 1344 is rotated, thereby varying the resulting mechanical advantage deployed by the link member pulley 1344 and the link tether 1336 to harvest wave energy.
  • a larger diameter link member pulley 1344 is required when the wave harvester 1338 reaches the crest of the wave than is required when the wave harvester 1338 beings to rise from the trough of a wave.
  • the link tether 1436 is a belt 1452 with a lower end portion coupled to a link member pulley 1444, which is coupled to link member 1404 by a shaft 1446.
  • Belt 1452 has an upper end portion coupled to a guide pulley 1448 and a tensioning pulley 1450.
  • Belt 1452 is coupled to the pulleys such that belt 1452 travels around the three pulleys: link member pulley 1444, guide pulley 1448, and tensioning pulley 1450. Additional pulleys and belts may be used in some embodiments.
  • Guide pulley 1448 is rotatably coupled to wave harvester 1438.
  • Tensioning pulley 1450 is also rotatably coupled to wave harvester 1438 and is further adapted to travel towards and away from guide pulley 1448. Tensioning pulley 1450 travels away from guide pulley 1448 in a generally horizontal plane, but may travel in alternate planes in some embodiments. Tensioning pulley 1450 further includes a biasing member, such as a spring, that biases tensioning pulley 1450 away from guide pulley 1448.
  • the guide pulley 1448 and the tensioning pulley 1450 further include alternating locking mechanisms (not shown) that maintain one pulley in a locked configuration while the other pulley rotates to ensure that guide pulley 1448 and tensioning pulley 1450 do not rotate simultaneously.
  • the alternating locking mechanism may be controlled by an accelerometer coupled to the wave harvester 1438 or otherwise coupled to system 1400.
  • the accelerometer in the wave harvester may be configured to control the alternating locking mechanism by inverting the lock/unlocked of the two pulleys when the accelerometer registers "zero" (i.e. when the harvester reverses course at a crest or in a trough).
  • the alternate locking mechanism may be coupled by monitoring the relative position of the two pulleys. When the two pulleys move closer together, one pulley is locked while the other is unlocked. When the pulleys are not moving closer together, the first pulley is locked while the other is unlocked.
  • the alternating locking mechanism reverses such that the previously locked pulley becomes unlocked and the unlocked pulley becomes locked.
  • the tensioning pulley 1450 simultaneously begins to travel away from guide pulley 1448 to maintain tension in the belt 1452, and to rotate link member pulley 1444 in the opposite direction.
  • the rotating link member pulley 1444 drives the link member 1404 via shaft 1446.
  • Shaft 1446 typically includes a ratchet mechanism 1454 that allows shaft 1446 to drive the link member 1404 when it rotates in a direction that corresponds to the wave harvester 1438 rising with the level of the water surface 1410, but prevents shaft 1446 from driving the link member 1404 when it rotates in an opposite direction that corresponds to the wave harvester 1438 falling with the level of the water surface 1410.
  • the energy conversion device 1406 may be located in the link member 1404. For example, as the wave harvester 1438 rises and falls, the mechanical energy generated is transmitted to the energy conversion device 1406 located in the link member 1404 via displacement of the link tether 1436. The energy conversion device 1406 then converts the input mechanical energy into other mechanical energy used by the link member 1404 to draw in or let out the tethers 1408 to raise and lower the non-buoyant member 1402 and buoyant member, respectively.
  • FIG. 15 illustrates another embodiment of an energy storage system 1500.
  • the 1500 is similar to energy storage systems 400, 700, and 800, except that the plurality of wave harvesters 1538 are coupled to the link member 1504 by a submerged wave harvester ring 1542 that extends around the energy storage system 1500.
  • the plurality of wave harvesters 1538 are coupled to the link member 1504 by a submerged wave harvester ring 1542 that extends around the energy storage system 1500.
  • Like parts are identified by like reference numbers and will not be further described except where material.
  • energy storage system 1500 is very similar to energy storage system 800.
  • the plurality of wave harvesters 1538 are coupled to the wave harvester ring 1542 in order to restrain the wave harvesters 1538 in proper functional position on the water surface 1510, and in order to reduce the likelihood of the wave harvesters
  • a plurality of guides 1540 on the wave harvester ring 1542 guide the link tether 1536 to the link member 1504.
  • the wave harvester ring 1542 is typically moored to the energy storage system 1500. In an alternate embodiment, the wave harvester ring 1542 is moored to the submerged ground surface 1518.
  • FIG 16 illustrates another embodiment of an energy storage system 1600.
  • the energy storage system 1600 is similar to energy storage systems 100 and 200 except that the non- buoyant member 1602 contains at least one sealed hollow portion 1626 and the energy conversion device 1606 and the anchor 1614 are located adjacent, and coupled directly to, the non-buoyant member 1602, obviating the need for the link member, tethers and mooring lines.
  • Like parts are identified by like reference numbers and will not be further described except where material.
  • the non-buoyant member 1602 is located adjacent the anchor 1614 and typically, the anchor 1614 is integrally coupled to the non-buoyant member 1602.
  • the mass of the non-buoyant member 1602 alone will prevent the non-buoyant member 1602 from drifting.
  • the hollow portion 1626 of the non- buoyant member 1602 may be partially filled with the surrounding fluid, for example water, in order to increase the mass of the non-buoyant member 1602 so as to prevent drifting.
  • the non-buoyant member 1602 contains multiple hollow portions any or all of which may be filled or partially filled with fluid.
  • the hollow portion 1626 may include ballast tanks that may be selectively filled or emptied. Filling or emptying the ballast tanks can control the mass of the non-buoyant member 1602. Emptying the ballast tanks may allow the non-buoyant member to float, for example to facilitate transport to the site where the energy storage system 1600 is to be deployed while filling the ballast tanks may increase the mass of the non-buoyant member 1602 to prevent drifting.
  • the energy conversion device 1606 is located adjacent the non-buoyant member 1602. Typically, the energy conversion device 1606 is coupled directly to the non-buoyant member 1602.
  • the energy conversion device 1606 is adapted to control the amount of fluid, for example water, contained in the at least one hollow portion 1626 of non-buoyant member 1602. Controlling the amount of fluid contained in the at least one hollow portion 1626 allows the storage and retrieval of energy.
  • the energy conversion module is adapted to use the difference in hydrostatic potential between outside the non-buoyant member 1602 and inside the at least one hollow portion 1626 of the non-buoyant member 1602 to store and retrieve energy. Since non-buoyant member 1602 is submerged, fluid will flow spontaneously from the high potential position outside the non- buoyant member 1602 to the low potential position inside the at least one hollow portion 1626 when the energy conversion device 1606 allows it to do so. When energy, for example electric energy, is supplied to the energy conversion device 1606, fluid may be pumped out of the at least one hollow portion 1626. When energy output from the energy conversion device 1606 is desired, the energy conversion device 1606 allows fluid to flow into the at least one hollow portion 1626 permitting recovery of energy first used to pump the fluid out.
  • energy for example electric energy
  • the energy conversion device 1606 may be adapted to convert hydrostatic potential energy into electric energy and electric energy into hydrostatic potential energy.
  • the energy conversion device 1606 comprises a pump for pumping fluid, for example water, out of the at least one hollow portion 1626.
  • the energy conversion device 1606 may be coupled to any combination of sources of input energy, as described above, for example a wind turbine or multiple wind turbines, a nuclear reactor, a coal fired power plant, a hydro dam or any other source of energy.
  • the energy conversion device 1606 comprises a turbine for extracting energy from the fluid as it flows into the at least one hollow portion.
  • the energy conversion device 1606 may be further coupled to a power grid or any size or configuration, as described above, for example, a ship or ocean going platform's power grid, any other local power grid or a continental power grid such as the North American power grid.
  • the total amount of energy that can be stored using energy storage system 1600 is dependent on the mass of fluid that the at least one hollow portion 1626 can contain and the depth below the fluid surface 1610 to which the non-buoyant member 1602 is submerged.
  • a larger mass of fluid stored and greater depth below the fluid surface 1610 allow for increased energy storage. It is therefore desirable that the energy storage system 1600 be deployed at as great a depth as possible in order to maximize the amount of energy that can be stored.
  • the energy storage system could be deployed at the bottom of an ocean with a depth of, for example, 5-6 km.
  • Energy storage system 1700 is similar to energy storage system 300 except that energy storage system 1700 is confined within a chamber 1760 having a bottom 1718, sidewalls 1762, an inlet 1764 and an outlet 1766. Like parts are identified by like reference numbers and will not be further described except where material.
  • the buoyant member 1720 is coupled to the link member 1704 that is coupled to an anchor 1714 via a mooring line 1716.
  • the anchor 1714 may be coupled to the bottom 1718 of the chamber 1760.
  • the chamber 1760 is generally cylindrical with any convenient cross section.
  • Buoyant member 1720 is sized so that the cross section of the buoyant member 1720 is smaller than the cross section of the chamber 1760, leaving a gap 1768 between the buoyant member 1720 and the sidewalls 1762 of the chamber 1760.
  • the buoyant member 1720 is sized to fit closely within the sidewalls 1762 such that the gap 1768 is small while still allowing the buoyant member 1720 to move vertically within the chamber 1760 while avoid frictional contact with the sidewalls 1762.
  • Buoyant member 1720 is adapted to be alternatively submerged or floating at or near the surface 1710 of the fluid in the chamber.
  • the fluid may be introduced into the chamber 1760 via an inlet 1764 and may be evacuated from the chamber via an outlet 1766.
  • the fluid may need to be evacuated from the chamber 1760, for example to perform maintenance on the energy storage system 1700. All the possible configurations discussed above for energy storage system 300 are possible for energy storage system 1700.
  • Energy storage system 1700 may be operated in the same manner as energy storage system 300 once sufficient fluid has entered the chamber 1760 and any possible variations of energy storage system 300 can also be applied to energy storage system 1700.
  • the mooring line 1706 is a tether 1708.
  • the mooring line may comprise a gear or array of gears mounted to the buoyant member that mesh with teeth mounted to one or more of the sidewalls 1762 to control the movement of the buoyant member within the chamber 1760.
  • the mooring line may be a gear mounted to the buoyant member 1720 that interacts with a chain mounted to the sidewalls 1762 or to the bottom 1718.
  • the buoyant member 1720 When fluid is introduced into the chamber 1760, the buoyant member 1720 may begin to rise with the surface of the fluid 1710. As the buoyant member 1720 rises it pulls on tether 1708. If the energy conversion device 1706 lets out the tether 1708 as the buoyant member 1720 rises with the fluid surface 1710, energy may be recovered and outputted by the energy conversion device 1706, for example as electric energy. Conversely, when fluid is evacuated from the chamber 1760 the buoyant member 1720 may begin to fall with the surface of the fluid 1710. As the buoyant member 1720 falls with the fluid surface 1710, slack appears in the tether 1708.
  • the energy storage system 1700 may be used as an energy extraction system to extract energy from an existing hydrostatic potential difference.
  • fluid for example water
  • the rising fluid surface 1710 causes the buoyant member 1720 to rise, converting the hydrostatic potential into mechanical energy.
  • the rising buoyant member 1720 pulls on the tether 1708 allowing the energy conversion device 1706 to convert the mechanical energy into output electric energy.
  • the inlet 1764 is closed, the outlet 1766 is opened and the fluid is allowed to leave the chamber 1760.
  • the fluid exits the chamber 1760 through the outlet 1766 to a second, lower, hydrostatic potential.
  • the tether 1708 is drawn in.
  • the inlet 1764 is opened and the process repeats. In this way it is possible to extract energy from an existing hydrostatic potential difference, for example the difference between an upstream and a downstream location along a river.
  • the energy extraction system 1700 does not require large differences in hydrostatic potential.
  • two or more energy extraction systems 1700 can be combined in an array to extract energy from an existing hydrostatic potential difference.
  • the two or more energy extraction systems 1700 in the array can alternately be filled and evacuated.
  • the filling and evacuating of the two or more energy extraction systems 1700 can be coordinated to achieve a substantially constant flow rate of fluid into and out of the array of energy extraction systems 1700. This enables energy to be extracted from a substantially constant supply of fluid.
  • At least a portion of a river's flow may be directed into an array of energy extraction systems 1700 at an upstream location with a first hydrostatic potential while the at least a portion of the river's flow may rejoin the river, after passing through the array of energy extraction systems 1700, at a downstream location with a second, lower, hydrostatic potential.
  • the energy extracted may be outputted in any manner discussed above, for example as electric energy.
  • System 1800 is similar to energy storage and extraction systems described above except that system 1800 is installed adjacent to a sidewall 1862 of a land portion that is adjacent to a body of water known to have a varying level of the surface 1810.
  • the body of water can be a body of water known to have substantial tides, or a canal lock.
  • Like parts are identified by like reference numbers and will not be further described except where material.
  • the buoyant member 1820 is coupled to a grappling member 1870.
  • the grappling member 1870 may take the form of a shaft, for example.
  • the buoyant member 1820 can be coupled to the grappling member by swivel joint 1872, allowing the grappling member
  • the grappling member 1870 to swivel relative to the buoyant member 1820.
  • the grappling member 1870 is further coupled to the sidewall 1862.
  • the grappling member 1870 can be coupled to the sidewall 1862 by swivel joint 1874, allowing the grappling member 1870 to swivel relative to the sidewall 1862.
  • the grappling member 1870 can be coupled to an upper surface 1876 of the land portion, instead of the sidewall 1862.
  • Buoyant member 1820 is adapted to be floating at or near the surface 1810 of the body of water. The buoyant member 1820 may rise or fall with the water surface 1810. As the buoyant member 1820 rises or falls it causes the grappling member 1870 to swivel relative to the sidewall 1862.
  • the grappling member 1870 is coupled, directly or indirectly, to an energy conversion device 1806 adapted to extract energy from the swiveling action of the grappling member 1870, i.e. conversion of mechanical energy into output electric energy. In this way it is possible to extract energy from an existing hydrostatic potential difference, for example the varying water level present in an existing tidal water body or a canal lock.
  • the energy conversion device 1806 can be operably linked to an energy generator or to a power grid. In some embodiments, the energy conversion device 1806 may be located remotely from the grappling member 1870. In other embodiments, the energy conversion device 1806 can be integral to the buoyant member 1802, which can enhance the portability of system 1800.
  • the energy conversion device 1806 can comprise both an electric motor and an electric generator.
  • the energy conversion device 1806 can be used to power the grappling member 1870 to raise or lower the buoyant member 1820 relative to the water surface 1810 when desirable, e.g., to clear the system 1800 from a canal lock to allow a ship to pass.
  • a hydraulic cylinder and pump system can be implemented to capture the mechanical energy of the swiveling grappling member 1870. Motion of the grappling member 1870 can drive the hydraulic cylinder and pump, which in turn can drive the electrical generator.
  • the hydraulic cylinder and pump system can be used to convert electricity into the mechanical energy required to raise or lower the buoyant member 1820.
  • Other configurations linking the buoyant member 1820 and the energy conversion device 1806 are possible.
  • FIG 19 illustrates another embodiment of an energy extraction system 1900.
  • System 1900 is similar to system 1800 described above except that system 1900 is installed between opposing sidewalls 1962 of a land portion that enclose a body of water known to have a varying level of the surface 1910.
  • the body of water can be a canal lock.
  • Like parts are identified by like reference numbers and will not be further described except where material.
  • the buoyant member 1920 is coupled to a two or more grappling members 1970.
  • the grappling members 1970 each may take the form of a shaft, for example, and can be readily extendible and retractable.
  • the buoyant member 1920 can be coupled to the grappling members by swivel joints 1972, allowing the grappling members 1970 to swivel relative to the buoyant member 1920.
  • the grappling members 1970 are further coupled to the sidewalls 1962, or as illustrated to the upper surfaces 1976 of the land portion. Swivel joints 1974 can couple the grappling members 1970 to the surfaces 1976, allowing the grappling members 1970 to swivel relative to the surfaces 1976.
  • Buoyant member 1920 is adapted to be floating at or near the surface 1910 of the body of water. The buoyant member 1920 may vertically rise or fall with the water surface 1910. As the buoyant member 1920 rises or falls it causes the grappling members 1970 to swivel relative to the surfaces 1976. As the buoyant member 1920 rises or falls, the grappling members 1970 can respectively retract and extend such that the buoyant member 1920 maintains a generally vertical path of motion.
  • the grappling members 1970 are coupled, directly or indirectly, to energy conversion devices 1906 adapted to extract energy from the swiveling action of the grappling members 1970, i.e. conversion of mechanical energy into output electric energy.
  • energy conversion devices 1906 adapted to extract energy from an existing hydrostatic potential difference, for example the varying water level present in a canal lock.
  • system 1900 can be implemented in an existing canal lock without requiring substantial modifications to the lock.
  • the buoyant member 1902 can be sized so as to substantially fill the lock in both length and width in order to capture the full potential of the hydrostatic energy of the lock.
  • the size and positioning of the grappling members 1970 can be selected so as to maximize the mechanical advantage in the swiveling action caused by the rise and fall of the water level 1910.
  • the grappling members can be selected so as to maximize the mechanical advantage in the swiveling action caused by the rise and fall of the water level 1910.
  • the system 1900 can be used reversibly, in that the system 1900 can be used to transform electrical energy into mechanical energy by submerging the buoyant member 1920 to effectively raise the water level 1910.
  • causing the water level 1910 to rise can be desirable to reverse the usual direction of water flow.
  • Driving the grappling members 1970 downwardly can raise the water level 1910 inside the lock, such that the buoyant member 1920 is submerged below the water level 1910.
  • the buoyant member 1920 must be of a sufficient size such that it can effectively raise the water level 1910 within the lock.
  • the buoyant member 1920 need not be entirely submerged below the surface 1910, but submerged sufficiently to raise the water level 1910 within the lock.
  • Some modifications to an existing canal lock may be required for the reversible operation of system 1900 to be effective. For example, height of the lock sidewalls and gates may need to be increased to enable the reversal of flow through the lock, allowing the water level inside the lock to exceed the water level on the other side of the up-stream gate without spilling over the gate and the sidewalls of the lock.
  • the extent to which the water level inside the lock exceeds the water level on the other side of the gate to an adjacent lock determines the rate of flow through valves connecting the two adjacent locks, and so the height of the sidewalls and banks can be selected in part to maximize the rate of water transfer.
  • the buoyant member 1902 By sizing the buoyant member 1902 to substantially fill the lock in both length and width, the amount of water than can be transferred in the reverse direction in one cycle of the machine can be maximized.
  • the buoyant member 1902 need not necessarily approach the overall dimensions of the lock in order to be effective at reversing the flow of water.
  • the buoyant member 1920 can be constructed of concrete, for example, and can have an open top configuration to reduce overall weight.
  • a ballast can also be included internally within the buoyant member 1920 in order to assist in stabilizing the buoyant member 1920 during transport, and, although not required, may be helpful in stabilizing the buoyant member 1920, as it rises and falls.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Other Liquid Machine Or Engine Such As Wave Power Use (AREA)

Abstract

L'invention concerne des systèmes de stockage et d'extraction d'énergie pour stocker et extraire de l'énergie électrique par l'utilisation d'un potentiel hydrostatique. Les systèmes peuvent comprendre l'un ou l'autre, ou les deux, d'un élément non flottant et d'un élément non flottant. L'élément flottant et l'élément non-flottant peuvent être couplés à un élément de liaison, dans certains cas des attaches, et l'élément de liaison peut être couplé à une ancre. L'élément de liaison peut également être couplé à un dispositif de conversion d'énergie qui est capable de convertir de l'énergie électrique en énergie mécanique, ou de l'énergie mécanique en énergie électrique, ou les deux. Dans certains modes de réalisation, au moins un dispositif d'exploitation des vagues est utilisé pour extraire l'énergie. Dans d'autres modes de réalisation, un élément flottant peut être confiné à l'intérieur d'une chambre ayant une entrée et une sortie. Dans encore d'autres modes de réalisation, un élément flottant est utilisé pour extraire de l'énergie à partir d'une masse d'eau ayant un niveau de surface variable.
PCT/CA2008/001337 2007-07-20 2008-07-21 Système de stockage et d'extraction d'énergie immergé WO2009012575A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US95102207P 2007-07-20 2007-07-20
US60/951,022 2007-07-20
US98641307P 2007-11-08 2007-11-08
US60/986,413 2007-11-08

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WO2011116100A3 (fr) * 2010-03-18 2012-08-16 Resolute Marine Energy, Inc. Convertisseur d'énergie des vagues
FR2978993A1 (fr) * 2011-08-08 2013-02-15 Michel Edouard Raymond Bourriaud Dispositif permettant de convertir l'energie de la houle et des vagues sous forme d'energie mecanique, d'energie hydraulique et d'energie electrique
JP2014511974A (ja) * 2011-04-18 2014-05-19 マスクリック リミテッド 運動をエネルギーに変換する装置および方法
KR20140097325A (ko) * 2011-11-08 2014-08-06 마린 파워 시스템즈 리미티드 웨이브 동력 발전기
GB2529210A (en) * 2014-08-13 2016-02-17 Bruce Gregory Improved wave energy converter
WO2016165941A1 (fr) * 2015-04-14 2016-10-20 Stevens Louis Systeme de stockage et production d'energie electrique en milieu marin
EP2504568A4 (fr) * 2009-11-24 2017-10-18 Tov Westby Procédé de mise en oeuvre d'un corps flottant d'une centrale houlomotrice et centrale houlomotrice
FR3056648A1 (fr) * 2016-09-26 2018-03-30 Patrice Christian Philippe Charles Chevalier Repartiteur differentiel pour systeme de stockage et de generation d'energie par deplacement d'un corps immerge, et procedes associes
WO2021194366A1 (fr) * 2020-03-23 2021-09-30 Tudorache Pitt Codruț Système de capture et de conversion de l'énergie houlomotrice en électricité
WO2023183992A1 (fr) * 2022-04-01 2023-10-05 Ceto Ip Pty Ltd Actionneur flottant et système de conversion d'énergie houlomotrice incorporant un actionneur flottant

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Publication number Priority date Publication date Assignee Title
EP2504568A4 (fr) * 2009-11-24 2017-10-18 Tov Westby Procédé de mise en oeuvre d'un corps flottant d'une centrale houlomotrice et centrale houlomotrice
WO2011116100A3 (fr) * 2010-03-18 2012-08-16 Resolute Marine Energy, Inc. Convertisseur d'énergie des vagues
JP2014511974A (ja) * 2011-04-18 2014-05-19 マスクリック リミテッド 運動をエネルギーに変換する装置および方法
FR2978993A1 (fr) * 2011-08-08 2013-02-15 Michel Edouard Raymond Bourriaud Dispositif permettant de convertir l'energie de la houle et des vagues sous forme d'energie mecanique, d'energie hydraulique et d'energie electrique
JP2014532839A (ja) * 2011-11-08 2014-12-08 マリン パワー システムズ リミテッド 波力発電機
KR20140097325A (ko) * 2011-11-08 2014-08-06 마린 파워 시스템즈 리미티드 웨이브 동력 발전기
KR102015571B1 (ko) * 2011-11-08 2019-10-21 마린 파워 시스템즈 리미티드 웨이브 동력 발전기
GB2529210A (en) * 2014-08-13 2016-02-17 Bruce Gregory Improved wave energy converter
WO2016023874A1 (fr) * 2014-08-13 2016-02-18 Bruce Gregory Convertisseur d'énergie des vagues amélioré
GB2529210B (en) * 2014-08-13 2018-01-31 Gregory Bruce Improved wave energy converter
AU2015303238B2 (en) * 2014-08-13 2019-01-24 Bruce Gregory Improved wave energy converter
US10190568B2 (en) 2014-08-13 2019-01-29 Bruce Gregory Wave energy converter
WO2016165941A1 (fr) * 2015-04-14 2016-10-20 Stevens Louis Systeme de stockage et production d'energie electrique en milieu marin
US10259543B2 (en) 2015-04-14 2019-04-16 Louis Stevens System for storage and production of electrical energy in a marine environment
FR3056648A1 (fr) * 2016-09-26 2018-03-30 Patrice Christian Philippe Charles Chevalier Repartiteur differentiel pour systeme de stockage et de generation d'energie par deplacement d'un corps immerge, et procedes associes
WO2021194366A1 (fr) * 2020-03-23 2021-09-30 Tudorache Pitt Codruț Système de capture et de conversion de l'énergie houlomotrice en électricité
WO2023183992A1 (fr) * 2022-04-01 2023-10-05 Ceto Ip Pty Ltd Actionneur flottant et système de conversion d'énergie houlomotrice incorporant un actionneur flottant

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