WO2022013145A1 - Système d'amarrage pour une pluralité d'unités flottantes - Google Patents

Système d'amarrage pour une pluralité d'unités flottantes Download PDF

Info

Publication number
WO2022013145A1
WO2022013145A1 PCT/EP2021/069316 EP2021069316W WO2022013145A1 WO 2022013145 A1 WO2022013145 A1 WO 2022013145A1 EP 2021069316 W EP2021069316 W EP 2021069316W WO 2022013145 A1 WO2022013145 A1 WO 2022013145A1
Authority
WO
WIPO (PCT)
Prior art keywords
buoy
buoys
mooring system
lines
mooring
Prior art date
Application number
PCT/EP2021/069316
Other languages
English (en)
Inventor
Niklas NORMAN
Original Assignee
Semar As
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 Semar As filed Critical Semar As
Publication of WO2022013145A1 publication Critical patent/WO2022013145A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
    • B63B21/50—Anchoring arrangements or methods for special vessels, e.g. for floating drilling platforms or dredgers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
    • B63B21/20—Adaptations of chains, ropes, hawsers, or the like, or of parts thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B22/00—Buoys
    • B63B22/02—Buoys specially adapted for mooring a vessel
    • B63B22/021—Buoys specially adapted for mooring a vessel and for transferring fluids, e.g. liquids
    • B63B22/025—Buoys specially adapted for mooring a vessel and for transferring fluids, e.g. liquids and comprising a restoring force in the mooring connection provided by means of weight, float or spring devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
    • B63B35/44—Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices
    • 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
    • F03D—WIND MOTORS
    • F03D13/00—Assembly, mounting or commissioning of wind motors; Arrangements specially adapted for transporting wind motor components
    • F03D13/20—Arrangements for mounting or supporting wind motors; Masts or towers for wind motors
    • F03D13/25—Arrangements for mounting or supporting wind motors; Masts or towers for wind motors specially adapted for offshore installation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
    • B63B35/44—Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices
    • B63B2035/4433—Floating structures carrying electric power plants
    • B63B2035/446—Floating structures carrying electric power plants for converting wind energy into electric energy
    • 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
    • F05B2240/93—Mounting on supporting structures or systems on a structure floating on a liquid surface
    • 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
    • F05B2250/13—Geometry two-dimensional trapezial
    • F05B2250/132—Geometry two-dimensional trapezial hexagonal
    • 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
    • Y02E10/70—Wind energy
    • Y02E10/72—Wind turbines with rotation axis in wind direction
    • 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
    • Y02E10/70—Wind energy
    • Y02E10/727—Offshore wind turbines

Definitions

  • the present disclosure relates to a mooring system for an array of floating units, for example a farm of floating wind turbines.
  • a mooring system of a floating unit has a main purpose: station-keeping, i.e. make sure the offshore floating structure stays within the area required for intended operation.
  • the mooring-system needs three elements. a connection point to the seabed, also called an anchor, line elements, transferring the environmental forces applied on the floating unit to the anchor at the seabed.
  • Mooring lines need to transfer the average of the environmental dynamic forces acting on a floating offshore structure during the worst design storm down to the anchor, with as low dynamic force-amplification as possible
  • Catenary and taut mooring are the usual mooring concepts used for mooring of offshore structures.
  • Taut mooring consists of straight synthetic lines (most often polyester) or metal wires where the element providing flexibility to the mooring system is the elasticity of lines: the lines stretch when the environmental forces drive the floating unit away from the anchor point. When stretched, the elastic reaction forces participate to restore the floating unit to its initial position. Taut systems are normally used in deep water, where the length of the line enable extended stretching without overloading the lines.
  • Catenary systems consists of heavy steel-chains (possibly reinforced by clump-weights on chains or other type of lines) where the element providing flexibility to the mooring-system is based on the gravity-induced mostly vertical geometric adaptation of the chains and clump-weights.
  • Catenary lines are by far the most widely used of the two above described mooring concepts. Sometimes clump-weights are introduced for increased “catenary effect", and sometimes both synthetic taut-line-segments and catenary-line-segments, are combined in the same line. As synthetic lines are not allowed to get in contact with the seabed, small buoys may be attached to a line in order to lift the synthetic line enough for it not to touch the seabed.
  • the main challenges to be addressed designing a mooring system are the following. They are discussed in general for floating units, and in particular for floating wind turbines (FWT). Flexibility of the mooring system/mooring line tension vs floating unit offset: the mooring system of an array of floating units needs to be flexible even after the full static environmental loads are connected to the mooring system. This is challenging, in particular in shallow waters where the lines are shorter and less capable of absorb displacements and tensions, and in the case of wind farms because the environmental static wind-force is large for floating wind turbines (FWT) as they are designed to "catch" the wind. The rigidity of a mooring line under tension submitted to the additional environmental dynamic forced wave-motions increases rapidly, often exponentially.
  • Normally for gravity-based ( catenary) mooring systems, the way to achieve this is to add even more weight to the mooring line (here, a chain) by selecting thicker chain or heavier clump weight so that the mooring line keeps a marked curvature and is not submitted to excessive tension.
  • Traditional mooring-systems make anchor sharing challenging for most water depths as the general rule resulting from 1- required mooring flexibility and 2- required FWT spacing for hydrodynamic efficiency are generally not compatible.
  • Arbitrage results in excess mooring costs or reduced power production efficiency.
  • it has been common to design three anchor points per FWT.
  • Chain production costs and capacity catenary (chains) lines are the most commonly used today. Fleavy chains of high-grade steel are expensive and heavy. Production capacity of chains is limited, simply because the casting process for such heavy chains is slow.
  • Synthetic line stiffness-elongation challenges over time, in particular when submitting them to many stretching cycles, taut fibre or metal wires show elongation and stiffening, increasing risks of rupture.
  • Standardisation of components and scalability one-off mooring designs are expensive. Standardisation of mooring components is crucial for reducing capex and in less extent opex of floating windfarms. Components which production is scalable should be preferred. Production of heavy chains is little scalable.
  • Damage to the marine environment heavy mooring chains damage the seafloor when lifted up and down or sweeping the seafloor.
  • DNV GL Electrifying The Future
  • Hpvik 2014
  • DNV- GL represents in page 38 a concept to address some of the above listed challenges.
  • DNV-GL describes sharing anchor points at the seabed between six FWTs, thus reducing the ratio anchor per turbine. It also describes and illustrates in the above-mentioned Youtube video, a solution for deeper waters where the FWTs are connected to "buoyancy elements that are connected to the seabed".
  • the video illustrates well the concept by illustrating the migration towards deeper waters, and the substitution of the seabed anchor points with lifted anchor points.
  • the DNV-GL concept presented for deep waters addresses a certain number of the above listed challenges, such as sharing of mooring components (lifted anchor points), good aerodynamical design (buoys allow keeping for deep waters the design of shallow waters), saving on chains (by artificially lifting the anchor points, length of chains is reduced), standardisation of components and scalability to some extent only (the length of catenary lines between the FWTs and the lifted anchor points may remain similar between shallow and deep waters), reduced damage to the marine environment (as the "lifted" catenary mooring lines do not contact the seabed), reduced installation and maintenance costs for less equipment in more shallow water , increased safety (shorter and probably lighter chains).
  • an object of the present invention is to provide a flexible and efficient mooring system for a plurality of offshore floating units which enables the use of lighter and cheaper material and components, reduces the footprint on seabed, and is safer and cheaper to install.
  • the present invention relates to a mooring system for an array of floating units, comprising a plurality of floating units, a plurality of buoys, a plurality of connection points to the seafloor such that for each buoy, there is at least a connection point to the seafloor, one or more tensioned lines linking each buoy to its one or several connection points,
  • a plurality of lines between the floating units and the buoys such that each floating unit is connected to several buoys and each buoy is connected to several floating units
  • the lines are slack lines made of fibre, metal wire or a fibre-metal composite, and the buoys account for the major part of the mooring system flexibility.
  • the buoy will be able to move like a pendulum around the connection point.
  • the buoy will be displaced in the same direction, thus moving deeper.
  • the buoyancy forces will increase, and so will participate to restoring forces on the floating unit.
  • the shared buoys of the system account for more than 50%, 75% or 85%, or even more than 90% or 95% of the incremental mooring system flexibility for any floating unit.
  • the system may be designed so that the buoys in direct contact with a floating unit provide nearly all the buoyancy flexibility, i.e. the influence of the buoys not in direct contact with the FWT account for a negligible effect.
  • the buoys in direct connection with the FWT account for more than 50%, 75% or 85%, or even more than 90% or 95% of the incremental mooring system flexibility for any floating unit.
  • the system of the invention is based on light lines, fibre lines, metal wires or composite fibre- metal lines. These are lighter, cheaper, easier to install and replace.
  • the buoy can be positioned at or close to the surface, between a position piercing the water surface and a position deep enough to provide safe vessel sailing.
  • the slack lines are close to the horizontal, and the restoring force from the system is close to the horizontal.
  • the horizontal component of the restoring force represents at least 50, 75 or 85%, or even at least 90 % or 95 % of the total restoring force.
  • the buoy is a spar buoy. This provides a more robust system, with improved restoration.
  • the mooring system of the invention may be well adapted to be stationed in a configuration based on the repetition of a pattern.
  • a buoy is connected to 2 to 6, preferably 3 to 6, even more preferably 3 floating units.
  • a floating unit is connected to 3 to 6 buoys, preferably 3 buoys.
  • the pattern is hexagonal, and the six angles of the hexagons are filled alternatively with a floating unit and a buoy.
  • the hexagonal grid may be formed by equiangular hexagons, like a honeycomb.
  • the array of floating units is a farm of floating wind turbines.
  • Fig.l a schematic representation of a prior art mooring system of a FWT by taut lines, a- under static forces with low wind, b- when submitted to environmental dynamic forces
  • Fig.2 a schematic representation of a prior art mooring system of a FWT by catenaries, a- under static forces with low wind, b- when submitted to environmental dynamic forces
  • Fig.3 a schematic representation of a prior art mooring system of a FWT by catenaries with lifted anchor points (DNV-GL reference), a- under static forces with low wind, b- when submitted to environmental dynamic forces
  • Fig.4 a schematic representation of an embodiment of the flexible mooring system of the invention, with two FWT sharing one anchor point a- under static forces with normal design wind, b- when submitted to environmental dynamic forces
  • Fig.5 a schematic representation of an embodiment of a FWT farm using the flexible mooring system of the invention in a honeycomb pattern
  • the invention will be described for the case where the floating units are floating wind turbines. However, the invention applies to all sorts of floating units and their arrays.
  • Fig.l illustrates how a taut lines mooring system for a FWT 25 of the prior art reacts to environmental dynamic forces such as in a storm, with wind W, rough waves F and currents C.
  • the mooring system comprises an anchor 21 at the seabed, a taut line line 26 mooring the floating unit 25 to the seabed.
  • these forces drive the FWT 25 away from its initial position with regard to the anchor 21 in a), the taut line 26 is stretched thus allowing displacement of the FWT 25.
  • the elastic reaction forces in the line 26 tend to restore the FWT 25 back to its position at a).
  • the restoring forces of taut lines have a dominant vertical component, and a limited horizontal one. Taut lines are repeatedly stretched by dynamic forces, which over time cause elongation and stiffer properties.
  • Fig.2 illustrates how a catenary mooring system for a FWT 35 of the prior art reacts to environmental dynamic forces such as in a storm, with wind W, rough waves F and currents C.
  • the mooring system comprises an anchor 31 at the seabed, a catenary line 36 mooring the floating unit 35 to the seabed.
  • environmental dynamic forces drive the FWT 35 away from its initial position with regard to the anchor 31 in a)
  • the catenary 36 is pulled thus allowing displacement of the FWT 35.
  • the weight of the catenary 36 - increased by the portion lifted from the seabed when straightened, tend to restore the FWT 35 back to its position at a).
  • Fig.3 illustrates how a catenary mooring system for a FWT 45 of the prior art, as described in the above referenced DNV-GL documents, reacts to environmental dynamic forces such as in a storm, with wind W, rough waves F and currents C .
  • the mooring system comprises an anchor 41 at the seabed, a buoy 43, an anchoring line 42, a catenary line 44 mooring the floating unit 45 to the buoy.
  • Fig.4 illustrates an embodiment of the invention.
  • the mooring system 10 comprises an anchor 1 at the seabed, a buoy 3, a tensioned line 2 mooring the buoy 3 to the anchor 1.
  • Flere, two floating units, the windmills 5, are moored to the buoy 3 by slack lines 4, of a non-catenary type such as a fibre line or a metal wire or other types, but not chains.
  • slack lines 4 of a non-catenary type such as a fibre line or a metal wire or other types, but not chains.
  • the horizontal component of the restoring force in the present invention is dominant, the vertical one is limited.
  • the horizontal component may thus represent at least 50, 75 or 85%, or even at least 90 % or 95 % of the total restoring force. That is, the present invention is very efficient in terms of geometrical horizontal restoring forces.
  • the means bringing restoration is shared between the floating units, it is common to them.
  • the flexibility and restoration capacity of mooring lies in the system design, more specifically at the level of the buoy. We have sharing of the buoy, and a very scalable system. Since elasticity requirements on the slack lines 4 are limited, cheaper lines can be used, and be standardized. With the present invention, one may imagine that from wind farm to wind farm, and for a given FWT type and meteorological/aerodynamical conditions, it is the buoy design which will vary most and accommodate the different variations.
  • system of the invention is well fitted for floating wind turbine (FWT), it may also apply to any floating structure which is part of an offshore array of units needing mooring, such as offshore oil and gas platforms or vessels, seabed mineral exploitation units, solar panel floating units etc...
  • connection point or anchor 1 needs to handle the constant uplift of buoy 3, and its design will also depend on seafloor soil-conditions. It can strictly be an anchoring means, or it can be any means for fastening or connecting to the seabed, for example a block of concrete etc...
  • Anchor 1 Compared to a catenary mooring design of the prior art for similar FWT and local environmental conditions, Anchor 1 will generally be designed for higher static forces and lower dynamic forces.
  • connection point may also be multiple smaller connections points, made solidary locally or at the level of the one or several lines to the buoy 3.
  • the buoy 3 is preferably positioned at the water surface, piercing it, or below but preferably close to the surface.
  • One reason is that the closer it is to the surface, the longest the tension line 2 to the anchor 1 will be, and the better system flexibility the buoy will provide.
  • the buoy 3 is connected to the anchor 1 by a tension line 2, also called vertical line in the description, even if it is not necessarily strictly vertical.
  • Line 2 will also be described as the anchoring line or anchor line.
  • the buoy 3 is designed with excess buoyancy, and line 2 shall have no slack.
  • Line 2 is preferably connected by "moment-free" connections, such as a hinge, to the anchor, and to the buoy preferably at a point below the buoy 3.
  • the anchor line 2 will preferably be non-catenary, made of one or several fibre lines or metal wires.
  • the anchor line could also be a chain, in which case the buoy 3 will need to be designed taking into account the extra chain weight.
  • the buoy 3 will be able to move as a pendulum around the connection point. Its position will be comprised in the virtual sphere centered on the anchor point 1 and with a radius corresponding to the length of the tension line 2.
  • the buoy is linked to two floating units. It may in other embodiments be connected to multiple floating units, typically 3 to 6. Or it may be connected in some cases to only one.
  • the buoy 3 is preferably partly submerged piercing the water surface, but it may also be submerged. Partly submerged buoys will reduce the level of constant uplift force at the anchor in gentle weather and allow for shallower windfarms. FWT farms extend over huge surfaces, and having the slack lines under sailing depth of sailing vessels may be required, in particular for operation and maintenance vessels. Thus, placing the buoy 3 at 20, 30, 40 or 50 meters depth may provide a safe sailing environment.
  • the buoy 3 should always generate sufficiently high buoyancy force to avoid any slack in the anchor line 2, which elongation shall be monitored over time.
  • the buoy 3 is of a SPAR type. It is designed to minimize wave forces and added mass forces acting on it. When piercing the water surface, the SPAR buoy design will help adjust buoyancy restoration by adding the extra buoyancy of the statically emerged part of the buoy which goes submerged under strong dynamic forces.
  • the buoy is designed to rotate (pitching) at small angles to minimize fatigue challenges. It is also designed to provide optimal line-stiffness-properties to the FWTs to be moored without the need for additional gravity- elements such as clump-weights, chain or any special requirement on the elasticity properties of the slack lines 4.
  • the buoy 3 is designed so that the inside air pressure is higher or equal to the outer water-pressure. Internal over-pressure together with the moment-free coupling below the buoy allow this structure to be light and low cost.
  • the buoy is a steel structure.
  • the mooring system 10 of the invention could work with a buoy 3 of the same shape but another material such as an elastomer, or with a buoy with a different shape.
  • the dimensions of the buoy will depend on turbine size and other parameters like water depth and meteorological/ocean conditions. For turbine sizes known or planned today, in the range of 15 MW, and for SPAR type buoys, the diameter would typically be in the range of 3 and 8 meters and the height in the range of 20 to 60 meters.
  • the buoy 3 connects to one or several FWTs via lines 4. These are also called horizontal lines, even though they may not be strictly horizontal, or slack lines. They connect the FWTs 5 to the buoys 3, at or close to surface.
  • the lines are preferably light, made of fibre lines, metal wire, or a composite of fibre and metal.
  • the slack lines 4 may need to be kept at a certain depth of for example 20, 30, 40 or 50 m, in order to keep the area safe for sailing.
  • the slack lines 4 connecting FWTs 5 to the buoy 3 are not necessarily strictly horizontal.
  • the lines since the lines are flexible, they may sometimes be meandering in the water.
  • the system may easily accept an angle b with the horizontal of for example less than 35 or 25 degrees (angle defined by a segment joining attachment of line to FWT and to buoy), or less than 20, 15, or preferably less than 10 or 5 degrees.
  • the system is designed for the anchor line 2 and the FWT slack line 4 to keep an angle a far from 180 % (in line).
  • the buoy should be designed not to allow an angle a superior to 145 or 135. even preferably 125 or 115 or even more preferably 105 degrees.
  • the mooring system of the invention would very function with rigid lines between the FWTs and the buoys.
  • slack lines 4 will show some elasticity.
  • the buoys 3 can be designed to take over more than 50%, 75% or 85%, or even 90% or 95% of the mooring system flexibility. Even though quantifying flexibility and its share between the slack line and the buoy is not easy to measure on site, it is possible to have a reasonably good estimate by calculations and modelling.
  • One alternative is to model the incremental displacement of the FWT at the extreme design case, i.e. the worst storm the mooring system is designed for, also called Ultimate Limit State, where the offset of the FWT is at its maximum. It can be estimated which % of the incremental displacement is accounted for by the buoy system, and which % is accounted for by the stretched slack line.
  • the lines should preferably not be buoyant to ease submersion and provide sailing depth for passing ships.
  • Horizontal line-pre-tension can be adjusted, if required, to increase FWT yaw stiffness or other properties, preferably by adding weight to the horizontal line segments 4.
  • all line pre-tensioning adds on to the horizontal pre-tension, as opposed to concepts with steep gravity mooring lines (for example catenaries) with only a small component of line tension being horizontal and thus contributing to yaw-stiffness.
  • the horizontal lines 4 must be long enough to ensure that all environmental forces from any FWT is transferred to the closest one or two anchored buoys. This way, accumulating forces throughout the horizontal grid are avoided. Furthermore, any interaction grid-dynamical effects are avoided or minimized.
  • the mooring line system of the invention can be applied for water depth from around 40 m to about 2000 m, more often 80 to 1000 meters. Flexibility with regard to water depth distinguishes the invented mooring concept from other mooring systems of the prior art. In shallow waters, the mooring system of the invention allows greater flexibility compared to traditional mooring systems that tend to get too stiff when rough weather hits. It must be however assured that the vertical lines do not elongate throughout the lifetime to an extent where the vertical line can get slack.
  • the mooring system of the invention has no limitations in terms of horizontal line-lengths in order to function well. Their lengths can be decided according to the ideal aerodynamic FWT- spacing. Typical lengths of horizontal line segment can be in the range from 400 to 2000 meters.
  • One or several FWTs can be connected to a buoy, for example between 1 and 6, preferably between 2 and 5.
  • 3 FWTs connect to a shared buoy. This preferred configuration optimizes horizontal force distribution on the anchor, and limits possible resonance between oscillations of the connected FWTs when too many FWTs are connected to a buoy. Sharing anchor has also a clear economical advantage.
  • a given FWT connects to several buoys, preferably between 3 and 6.
  • a FWT connects to three anchors 1.
  • the mooring system find its best use for an array of floating units, such as a farm of FWTs.
  • the array of floating units for example the wind farm, can be optimized for aerodynamics, capturing as much wind energy as feasible, whatever the depth.
  • the flexibility means are shared, that they allow the generalized use of slack lines, thus making wind farms less expensive.
  • the mooring system of the invention would very function with rigid lines between the FWTs and the buoys.
  • slack lines 4 will show some elasticity.
  • the buoys 3 can be designed to take over more than 50%, 75% or 85%, or even 90% or 95% of the mooring system flexibility.
  • quantifying flexibility and its share between the slack line and the buoy is not easy to measure on site, it is possible to have a reasonably good estimate by calculations and modelling.
  • One alternative is to model the incremental displacement of the FWT at the extreme design case, i.e.
  • the worst storm the mooring system is designed for also called Ultimate Limit State, where the offset of the FWT is at its maximum. It can be estimated which % of the incremental displacement is accounted for by the buoy system, and which % is accounted for by the stretched slack line.
  • % flexibility can be expressed for the whole system, i.e. the buoys in the system account for the the given % flexibility for any FWT.
  • the mooring system is designed such that flexibility for a given FWT is accounted for essentially (say more than 75, 85 or 90 %) by the buoys in direct connection with the FWT. In other words, the buoys further away, which are not in direct contact with the FWT play a negligeable (less than 25, 15 or 10 %) role in the flexibility for the given FWT.
  • the array of FWTs and buoys are stationed according to a configuration with a repeated pattern.
  • they may represent the angles of a grid of polygons. If the slack lines are visible from above, they will then materialize the edges of the polygons.
  • a hexagonal pattern is such an embodiment, as it has generally an optimal aerodynamic capture configuration. It may be equiangular such as the honeycomb, but does not need to be. It may also be isogonal, thus allowing the hexagon to be flattened and reduce its number of symmetries.
  • Fig.6 shows such a honeycomb configuration, where the horizontal lines segments represent the edges, and the FWTs or the buoys, alternating, represent the angles.
  • a unit hexagon - as marked by the slack lines - has 3 angles with a FWT in alternance with 3 angles with a buoy.
  • One turbine is connected to three buoys, and one buoy is connected to three turbines.
  • This regular equiangular honeycomb pattern with 50/50 buoys and FWTs, where the horizontal lines have similar lengths also give favorable accidental load cases properties compared to other patterns:
  • this ratio may cover a wide range of values, for example less than 1/3, 1/4, 1/5 or less than 1/6 for shallow water, or more than 1/3, 1 ⁇ 2 or more than 1 for deeper water.
  • the flexible mooring system of the invention uses lighter lines, less mileage of lines thanks to anchor and buoy sharing, and scaled up components. This system is easier, cheaper and safer to install than prior art concepts. The vessels used are lighter, installation is faster.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Architecture (AREA)
  • Structural Engineering (AREA)
  • Civil Engineering (AREA)
  • Other Liquid Machine Or Engine Such As Wave Power Use (AREA)
  • Bridges Or Land Bridges (AREA)
  • Wind Motors (AREA)
  • Laying Of Electric Cables Or Lines Outside (AREA)

Abstract

La présente invention concerne un système d'amarrage pour un ensemble d'unités flottantes, comprenant - une pluralité d'unités flottantes, - une pluralité de bouées, - une pluralité de points de raccordement au fond marin de telle sorte que, pour chaque bouée, il y a au moins un point de raccordement au fond marin, - une ou plusieurs lignes tendues reliant chaque bouée à son ou ses points de raccordement, - une pluralité de lignes entre les unités flottantes et les bouées de telle sorte que chaque unité flottante est raccordée à plusieurs bouées et chaque bouée est raccordée à plusieurs unités flottantes. Selon la présente invention, - les lignes sont des lignes de mou constituées de fibre, de fil métallique ou d'un composite fibre-métal, et - la majeure partie de la flexibilité du système d'amarrage est due aux bouées.
PCT/EP2021/069316 2020-07-14 2021-07-12 Système d'amarrage pour une pluralité d'unités flottantes WO2022013145A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO20200826A NO347179B1 (en) 2020-07-14 2020-07-14 A mooring system for a plurality of floating units
NO20200826 2020-07-14

Publications (1)

Publication Number Publication Date
WO2022013145A1 true WO2022013145A1 (fr) 2022-01-20

Family

ID=73543288

Family Applications (3)

Application Number Title Priority Date Filing Date
PCT/EP2020/082934 WO2022012769A1 (fr) 2020-07-14 2020-11-20 Ensemble unitaire flottant
PCT/EP2021/069316 WO2022013145A1 (fr) 2020-07-14 2021-07-12 Système d'amarrage pour une pluralité d'unités flottantes
PCT/EP2021/082302 WO2022106619A1 (fr) 2020-07-14 2021-11-19 Ensemble unitaire flottant

Family Applications Before (1)

Application Number Title Priority Date Filing Date
PCT/EP2020/082934 WO2022012769A1 (fr) 2020-07-14 2020-11-20 Ensemble unitaire flottant

Family Applications After (1)

Application Number Title Priority Date Filing Date
PCT/EP2021/082302 WO2022106619A1 (fr) 2020-07-14 2021-11-19 Ensemble unitaire flottant

Country Status (4)

Country Link
EP (1) EP4247701A1 (fr)
KR (1) KR20230107268A (fr)
NO (2) NO347179B1 (fr)
WO (3) WO2022012769A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4201797A1 (fr) * 2021-12-23 2023-06-28 TotalEnergies OneTech Configuration sous-marine pour structures flottantes d'un parc éolien en mer

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114684324A (zh) * 2022-03-11 2022-07-01 中国华能集团清洁能源技术研究院有限公司 漂浮式风机组和漂浮式风机阵

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2859698A1 (fr) * 2003-09-15 2005-03-18 Thomas Huldt Systeme d'amarrage pour grands fonds
WO2007081221A1 (fr) * 2006-01-16 2007-07-19 Fobox As Systeme d'amarrage
EP2604501A1 (fr) * 2011-12-15 2013-06-19 Andreas Graf Système d'ancrage et d'amarrage de tours d'éolienne flottantes et procédés correspondants pour le remorquage et l'érection de celles-ci
CN110654510A (zh) * 2019-10-30 2020-01-07 惠生（南通）重工有限公司 一种共享系泊的海上风电平台群

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0407662B2 (fr) * 1989-07-14 1999-06-23 Single Buoy Moorings Inc. Dispositif pour positionner un corps de bouée
CN111071400B (zh) * 2019-12-23 2021-08-17 中国能源建设集团广东省电力设计研究院有限公司 漂浮式海上风电场及漂浮式海上风电场的系泊集成方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2859698A1 (fr) * 2003-09-15 2005-03-18 Thomas Huldt Systeme d'amarrage pour grands fonds
WO2007081221A1 (fr) * 2006-01-16 2007-07-19 Fobox As Systeme d'amarrage
EP2604501A1 (fr) * 2011-12-15 2013-06-19 Andreas Graf Système d'ancrage et d'amarrage de tours d'éolienne flottantes et procédés correspondants pour le remorquage et l'érection de celles-ci
CN110654510A (zh) * 2019-10-30 2020-01-07 惠生（南通）重工有限公司 一种共享系泊的海上风电平台群

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
HOVIK: "Floating Wind Turbine Technology - A Power Source For 2050", GLOBAL ELECTRIFICATION OUTLOOK 2050: DNV GL: ELECTRIFYING THE FUTURE, 2014

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4201797A1 (fr) * 2021-12-23 2023-06-28 TotalEnergies OneTech Configuration sous-marine pour structures flottantes d'un parc éolien en mer
WO2023117460A1 (fr) * 2021-12-23 2023-06-29 Totalenergies Onetech Configuration sous-marine pour structures flottantes d'un parc éolien en mer

Also Published As

Publication number Publication date
NO20200826A1 (en) 2022-01-17
KR20230107268A (ko) 2023-07-14
WO2022106619A1 (fr) 2022-05-27
NO20230565A1 (en) 2023-05-12
WO2022012769A1 (fr) 2022-01-20
NO347179B1 (en) 2023-06-19
EP4247701A1 (fr) 2023-09-27

Similar Documents

Publication Publication Date Title
JP5244822B2 (ja) 水流からエネルギを生成するためのフローティング装置
EP2382389B1 (fr) Eoliennes de haute mer amovibles dotées d'un système d'amarrage installé au préalable
Harris et al. Mooring systems for wave energy converters: A review of design issues and choices
AU2014233070B2 (en) Wave energy converter system
US8446026B2 (en) System for mooring a floating plant for the production of energy from currents in water
US10689071B2 (en) Stabilized floating platform structure
CN112523969B (zh) 一种桁架拉索型漂浮式海上风电机组结构
WO2014163501A1 (fr) Éolienne flottante
WO2022013145A1 (fr) Système d'amarrage pour une pluralité d'unités flottantes
CN109941397A (zh) 一种半潜式海上风力发电机平台及海上风力发电设备
EP4240644A1 (fr) Système d'amarrage comprenant des bouées et des ancres
KR20120038708A (ko) 부유식 해상 풍력발전설비
CN116812075A (zh) 一种漂浮单柱式风电平台系泊系统
CN214092145U (zh) 一种桁架拉索型漂浮式海上风电机组结构
CN212716998U (zh) 一种自动偏航的十字型基础漂浮式海上风力发电装置
KR101201476B1 (ko) 부유식 해상 풍력발전설비
CN221214504U (zh) 一种水上光伏组件的支撑台及水上光伏电站
Crowle et al. Challenges during installation of floating wind turbines
KR101201475B1 (ko) 부유식 해상 풍력발전설비
JP2023515869A (ja) タワーアレイ
KR20140058060A (ko) 해상 부유식 풍력발전장치

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21743461

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21743461

Country of ref document: EP

Kind code of ref document: A1