WO2011078685A1

WO2011078685A1 - Vessel and method for assembly and installation of a wind turbine at sea

Info

Publication number: WO2011078685A1
Application number: PCT/NO2010/000468
Authority: WO
Inventors: Endre Racin BØEN; Darren Andrews
Original assignee: Teekay Shipping Norway As
Priority date: 2009-12-22
Filing date: 2010-12-16
Publication date: 2011-06-30
Also published as: NO330427B1; NO20093574A1

Abstract

There is described a vessel (1) for assembly and installation of a wind turbine (2) at sea, as the vessel (1) is provided with a tower manipulator (15) arranged to be able to fixedly hold a tower (21) in a horizontal position alongside and outside a vessel side (111) and also to turn the tower (21) to an upright position with a lower tower end portion (211) projecting down into a mass of water (3) at the vessel (1). Also described is a method for assembling and installing a wind turbine (1) at sea.

Description

VESSEL AND METHOD FOR ASSEMBLY AND INSTALLATION OF A WIND TURBINE AT SEA

The invention relates to a vessel for assembly and installation of a wind turbine at sea, more particularly in that the vessel is provided with a tower manipulator arranged to be able to hold a tower in a horizontal position alongside and outside a side of a vessel and also to turn the tower into an upright position with a lower tower end portion projecting down into a mass of water at the vessel. The invention also relates to a method for assembly and installation of a wind turbine at sea by employing said vessel. The invention is particularly directed toward installation of a floating wind turbine .

In installing wind turbines at sea, both such resting on a foundation on the seabed and such that are floating, a very careful and controlled cooperation between many vessels are required for such as moving and lifting. For a floating wind turbine it is for example normally required that the tower is brought to the installation site on a vessel or floating in the water and towed by a tugboat . At least one vessel

equipped with one or more cranes are utilized for lifting of the machinery housing, i.e. the so-called nacelle, and installation of same on top of the tower subsequent to the tower being ballasted to an upright position in the water. Subsequently the rotor blades are lifted and connected to the rotor projecting from the machine housing, all being done as the tower and the vessels involved are held stationary relative to each other. Such operations must normally be carried out in sheltered waters during good weather conditions to avoid wave and sea current induced motions that may result in damage to equipment and personnel involved in the operation. In addition the need for the operation to be carried out in sheltered waters normally leads to the assembly being carried out far from the planned operational site, and the completely assembled, floating wind turbine must then be moved by means of at least one tug, often more. For fixedly mounted wind turbines most of the assembly operations must be carried out in the field where one is at the mercy of actual wind and current conditions.

The object of the invention is to remedy or reduce at least one of the disadvantages of the prior art, or at least to procure a useful alternative to the prior art.

The object is achieved by the features disclosed in the below description and in the subsequent claims.

There is provided a transport and installation vessel arranged to bring the necessary mounting modules for a wind turbine to an operation site, carry out the assembly of the mounting modules and to place the complete assembled wind turbine in a predetermined position on the operation site, as a fixedly mounted wind turbine is placed on a preinstalled foundation, and a floating wind turbine is brought to a floating condition and anchored. Thereafter the wind turbine is connected to an energy distribution grid, without the vessel needing assistance from auxiliary vessels for positioning or lifting. The vessel of the invention exhibits deck space for temporary- storage of at least one wind turbine tower. The vessel is provided with conveyors arranged for horizontal displacement of the wind turbine tower from a stored position to an assembly position, where a tower manipulator holds the wind turbine tower in a releasable grip as the tower extends along the side of the vessel. The tower manipulator is arranged to be able to turn the wind turbine tower to an upright position at the vessel side, where the tower, after being freed from the tower manipulator, floats freely in the water or by ballasting is lowered down onto the foundation.

The vessel is further provided with a machinery housing manipulator suitable to be able to lift and move a machinery housing from a storage area on the vessel, for example in a hold in the vessel hull, to the upper end portion of the tower while the tower is still lying horizontally along the outside of the vessel side, where the machinery housing is connected to the tower with its rotor shaft pointing upwards in a vertical direction while the machinery housing and the tower are held in position by said manipulators. Thereafter the wind turbine blades are in turn moved in a horizontal position from a storage area on the vessel, such as a rack arranged on the vessel deck, to a position at the installed machinery housing where they in turn are connected to a rotor blade fitting on a rotor hub previously connected to the rotor shaft of the machinery housing. The turbine blades are moved and held in position by a rotor blade manipulator. After a rotor blade is connected to the rotor hub, this is turned one sector so that there is made room in the rotor blade manipulator movement area for the next rotor blade, as the next rotor blade is positioned relative to the movement path of the turbine blade manipulator. Thereafter the turbine blade manipulator is brought clear of the rotor. The same main unit may constitute the machinery housing manipulator and the turbine blade manipulator, possibly having changeable spreader bars adapted to different machinery hous ing and rotor blade types. The machinery housing and the tur bine blade manipulator may be a gantry crane able to be displaced in the vessel longitudinal direction, and provided with one or more cross arms extending out over the vessel side to be able to position a lifting device over the tower when this is located lying in the tower manipulator.

The tower manipulator is preferable arranged so that it is displaced away from the tower by the vessel moving in its longitudinal direction relative to the wind turbine after movable gripping devices are displaced away from the periphery of the tower.

When all the rotor blades are fitted and other possible prep aration work is done, the completely assembled wind turbine is turned to the vertical position by means of the tower manipulator, whereafter the tower is ballasted and positioned relative to a foundation projecting up from a seabed, or as floating wind turbine anchored to the sea bed in a per se known way. Thereafter the wind turbine is connected up to an energy distribution grid. During these operations the tower may be held in a loose stabilizing grip by the tower manipulator.

The vessel of the invention may possibly be used for maintenance of a wind turbine at sea, as the tower manipulator of the vessel may at least be used to hold the wind turbine steady relative to the vessel, whereafter personnel may have access to the wind turbine directly from the vessel.

Preferably the vessel is provided with a large deck area, as the vessel superstructure is located near the vessel stern o bow. The vessel is further preferably provided with means for dynamic positioning. For installation of ocean windmills having a total tower height of over 150 meters, a vessel having a size corresponding to a tanker of 100,000 tons dead weight is well suited. A useful property in tankers is that filling of the cargo tanks with water will typically increase the draught from 7-9 meters to about 13 meters, giving a considerable increase in vessel stability. A well-suited vessel may be procured by rebuilding of a so-called shuttle tanker well known from transport of oil from offshore petroleum fields.

In a first aspect the invention relates more particularly to a vessel for assembly and installation of wind turbines at sea, characterized in that the vessel is provided with a tower manipulator arranged to be able to hold fixedly a tower in a horizontal position alongside and outside a vessel side, and also to turn the tower to an upright position with a lower tower end portion projecting down into a mass of water near the vessel .

The tower manipulator may be provided with a tower support projecting outward from the vessel side and being rotatable in a vertical plane parallel to a vertical plane coincident with the vessel longitudinal axis.

The tower manipulator may be provided with one or more gripping devices arranged to hold the tower fixedly in a releas- able grip.

A machinery housing and rotor blade manipulator may be arranged to be able to be displaced over at least a portion of a storage area, and also to be able to displace a wind turbine module from the storage area to an upper tower end portion on the tower when it is arranged in its horizontal position alongside and outside the .vessel side. The machinery housing and rotor blade manipulator may be provided with a portal-shaped frame extending transversally over a substantial part of the vessel beam and being displaceable in the vessel longitudinal direction, and also a lifting device displaceable along an upper cross arm in the portal - shaped frame.

The gantry may extend out beyond the vessel side.

Manipulator rolling tracks extending in the vessel longitudinal direction outside the storage area may support the machinery housing and rotor blade manipulator.

The lifting device may be arranged for releasable interconnection with a spreader bar.

The machinery housing and rotor blade manipulator may comprise means arranged to be able to displace any manipulator element away from the tower motion path between horizontal and vertical positions.

The wind turbine may be arranged to be able to float in the mass of water.

In a second aspect the invention relates more particularly to a method for assembly and installation of a wind turbine at sea, characterized in that the method comprises the following steps :

a) a vessel as described above transports wind turbine elements to an installation site;

b) a tower is displaced from a storage area to a tower manipulator, where the tower is positioned horizontally and parallel to and outside a vessel side, as the tower is strapped down to tower support;

c) a machinery housing is displaced with a machinery housing and rotor blade manipulator from a storage area to an up- per tower end portion, where the machinery housing is fastened to the tower with a rotor hub facing upward and a rotor axis arranged in an approximately vertical position;

d) one by one the rotor blades are displaced with the machinery housing and rotor blade manipulator from a storage area to an upper tower end portion, where the rotor blade is fastened to the rotor hub, whereafter the rotor is turned a sector corresponding to the angular spacing of the rotor blades on a completed rotor until the last rotor blade is fastened;

e) the assembled wind turbine is up-righted in an adjacent mass of water by turning the tower manipulator about a horizontal axis arranged transversally to the longitudinal direction of the vessel; and

f) the tower is freed from the tower support.

Before step e) above the elements of the machinery housing and rotor blade manipulator may be displaced from an estimated motion path for the tower between the horizontal and upright positions.

Step f) above comprises bringing the wind turbine to a floating position in the mass of water, or alternatively lowering the wind turbine to a supported position on a foundation in the mass of water.

In the following is described an example of a preferred embodiment as illustrated in the accompanying drawings, wherein :

Fig. 1 shows a vessel during loading of wind turbines at a jetty;

Fig. 2 shows a tower arranged on a tower manipulator

alongside a vessel side; Fig. 3 shows a portion of a storage area and also a machinery housing and rotor blade manipulator connected to a rotor blade;

Fig. 4 shows an upper tower end portion whereon a machinery housing is fitted and where a rotor is under assembly;

Fig. 5 shows an assembled wind turbine about to be turned to an upright position;

Fig. 6 shows the wind turbine freed from the vessel and displaced away from the tower manipulator (some elements being submerged in the mass of water are also shown for clarity) ; and

Fig. 7 shows a principle sketch of a vessel provided with means for dynamic positioning.

In the figures the reference numeral 1 indicates a transport and installation vessel comprising a hull 11 provided with a bow 112, a stern 113, vessel sides 111 and also a vessel superstructure 114 arranged here at the vessel stern 113. The vessel 1 is provided with a dynamic positioning system 13 of a per se known kind (see figure 7) , comprising a control unit 131 and positioning facilities 132 in the form of propellers and appurtenant drive motors (not shown) . Drift generating external forces acting on the vessel 1 are indicated with multiple arrows 133.

The vessel 1 is provided with a tower manipulator 15 comprising a tower support 151 projecting out over one side 111 of the vessel 1 and arranged parallel with this. The tower support 151 is rotatably supported about a rotation axis 152 arranged perpendicular to a vertical plane coinciding with a longitudinal axis through the vessel 1. The tower manipulator 15 is further provided with a turning actuator 154 (see figure 5) arranged to be able to turn the tower support 151 between a horizontal position parallel to the deck of the vessel 1 forming a tower storage area 121, and a vertical position at the vessel side 111. In a shown embodiment the turning actuator 154 is formed by a winch 154a provided with a wire 154c extending over a free end portion of an outrigger 154b projecting from the vessel 1 side 111 near the vessel 1 bow 112. The function is described more closely in the following.

The tower support 151 is further provided with multiple gripping devices 153 arranged to be able to releasably fixedly hold a wind turbine tower 21.

The tower manipulator 15 is arranged to be able to receive, carry, fixedly hold and turn a wind turbine 2 of the kind that may float upright in a mass of water 3. A releasable pawl 155 (see figure 2) arranged in the hull 11 is arranged to be able to engage a portion of the tower support 151.

The wind turbine 2 comprises a tower 21 having a lower tower end portion 211 arranged to be able to be submerged in the mass of water 3, and an upper tower end portion 212 arranged to be able to extend up over the mass of water 3 and carry a machine housing 22 provided with a rotor 23 formed by a rotor hub 231 and multiple rotor blades 232, as the rotor 23 is ro- tatable about a rotor axis 233.

The vessel 1 is provided with a storage area 12 arranged for receiving at least one tower 21 on a lengthy tower storage area 121 extending in a substantial part of the vessel's 1 longitudinal direction. Near the vessel's 1 superstructure 114 is arranged a machinery housing storage area 122 formed in the hold of the hull 11. Between the machinery housing storage area 122 and the superstructure 114 is formed a rotor blade storage area 123 where a series of rotor blades 232 may^¬ be stored having their longitudinal direction lateral to the vessel 1 longitudinal direction, and supported by remedies 124 suited for the purpose.

A machinery housing and rotor blade manipulator 16 is arranged to be able to extend over at least the machinery housing and rotor blade storage areas 122, 123, as two manipulator arms 161 projects from the hull's 11 sides 111. A gantry 163 extends between the upper portions of the frames 161 and projects out over the vessel sides 111 as it forms a guide track for several lifting devices 164, shown here schematically as winches. The machinery housing and rotor blade manipulator 16 is moreover arranged to be able to be displaced in the longitudinal direction of the vessel 1 on manipulator rolling tracks 115 suited for the purpose. Spreader bars 166 adapted to the units 22, 232 to be lifted may be releasably fastened to the lifting devices 164 (shown schematically in figures 3 and 4) .

Loading ramps 41 arranged on a quay structure 4 may be connected to the vessel 1 (see figure 1) . In supporting the tower 21 by multiple transport means (not shown) arranged to be able to be displaced along the loading ramps 41 and trans- versally to the longitudinal direction of the tower storage area 121, the tower 21 may be moved in its horizontal position from the quay structure 4 to the vessel 1.

Said transport means (not shown) are also used in moving the tower 21 from the tower storage area 121 to the tower support 151. There is expediently formed a tower rolling track 141 projecting out from the vessel side 111 between the tower manipulator 15 and the machinery housing storage areas 122. The tower support forms correspondingly two tower rolling tracks 141. A not shown fourth tower rolling track displaceable between a pulled- in position and a position projecting out from the vessel side 111 between the bow 112 and the tower manipulator 15 may be formed in the extension of the loading ramp 41 nearest the bow 112.

When the tower 21 is placed on the tower support 151, the gripping devices 153 are turned to abut against the tower 21.

The tower 21 is positioned such that a complete wind turbine 2 by means of gravity will be able to turn the tower manipulator 15 to an upright position with the lower tower end portion 211 submerged in the mass of water 3. Due to the engagement of the pawl 155 in the tower support 151, this cannot happen unintentionally. In addition the turning activator 154 is activated in that the lifting wire 154c extending from the winch 154a over the outrigger 154b, is made fast in the lower tower end portion 211 and tightened.

The machinery housing 22 is taken by means of the machinery housing and rotor blade manipulator 16 from its storage area 122 to the upper end portion 212 of the tower 21 where with the rotor hub 231 facing upwards it is fastened to the tower 21.

Thereafter one rotor blade 232 at a time is taken by means of the machinery housing and rotor blade manipulator 16 from their storage area 123 to the upper end portion 212 of the tower where they are fastened to the rotor hub 231. After one rotor blade 232 is fitted, the incomplete rotor 23 is turned one sector such that the next rotor blade 232 may be connected to the rotor hub 231.

The completely assembled wind turbine 2 is then brought to an upright position in the prescribed location, as the tower manipulator 15 pawl 155 is freed and the winch 154a in a con- trolled manner feeds out the lifting wire 154c. The position ing of the vessel 1 is carried out by means of the dynamic positioning system 13 of the vessel 1.

When a floating wind turbine 2 is brought into the upright position and sufficiently ballasted, it is freed from the gripper devices 153 and trimmed further, and by a relative movement between the vessel 1 and the wind turbine 2 in the longitudinal direction of the vessel, the wind turbine 2 is led clear of the tower manipulator 15.

If the wind turbine 2 is to be placed on a foundation (not shown) projecting up from the seabed, the wind turbine 2 is ballasted while it is still possibly held in a supporting grip by the tower manipulator 15, as the gripping devices 15 may be provided with means allowing the tower 21 to move sli dingly along the tower 21 side surface while the tower is gradually lowered down toward the foundation.

Claims

C l a i m s

1. A vessel (1) for assembly and installation of a wind turbine (2) at sea, c h a r a c t e r i z e d i n that the vessel (1) is provided with a tower manipulator (15) arranged to fixedly hold a tower (21) in a horizontal position alongside and outside a vessel side (111) and also to turn the tower (21) to an upright position with a lower tower end portion (211) projecting down into a mass of water (3) at the vessel (1) .

2. A vessel according to claim 1, c h a r a c t e r i z e d i n that the tower manipulator (15) is provided with a tower support (151) projecting outward from the vessel side (111) and is rotatable in a vertical plane parallel with a vertical plane coincident with the vessel (1) longitudinal axis.

3. A vessel according to claim 1, c h a r a c t e r i z e d i n that the tower manipulator (15) is provided with one or more gripping devices (153) arranged to fixedly hold the tower (21) in a releasable grip.

4. A vessel according to claim 1, c h a r a c t e r i z e d i n that a machinery housing and rotor blade manipulator (16) is arranged to be able to be displaced over at least a portion (122, 123) of a storage area (12) and also to be able to displace a wind turbine module (22, 231, 232) from the storage area (122, 123) to an upper tower end portion (212) on the tower (21) when this is arranged in its horizontal position alongside and outside the vessel side (111) .

5. A vessel according to claim 4, c h a r a c t e r i z e d i n that the machinery housing and rotor blade manipulator (16) is provided with a portal shaped frame (161) extending transversally over a sub stantial part of the vessel (1) beam and being dis- placeable in the vessel (1) longitudinal direction, and also a lifting device (164) displaceable along an upper gantry (163) in the portal shaped frame (161) .

6. A vessel according to claim 5, c h a r a c t e r i z e d i n that the gantry (163) projects outside the vessel side (111) .

7. A vessel according to claim 4, c h a r a c t e r i z e d i n that the machinery housing and rotor blade manipulator (16) is supported by manipulator rolling tracks (115) extending in the vessel's (1) longitudinal direction outside the storage area (12) .

8. A vessel according to claim 4, c h a r a c t e r i z e d i n that the lifting device (164) is arranged for releasable interconnection with a spreader bar (166) .

9. A vessel according to any of the claims 4-8, c h a r a c t e r i z e d i n that the machinery housing and rotor blade manipulator (16) comprises means (115 163, 164) arranged to be able to displace any manipulator element (161, 163, 164, 166) along from the tower (11) motion track between horizontal and vertical positions.

10. A vessel according to claim 1, c h a r a c t e r i z e d i n that the wind turbine (2) is arranged t( be able to float in the mass of water (3) .

11. A method in assembling and installing a wind turbine at sea, c h a r a c t e r i z e d i n that the me- thod comprises the following steps:

a) a vessel (1) according to any of the preceding claims transports wind turbine elements (21, 22, 231, 232) to an installation site;

b) a tower (21) is displaced from a storage area (121) to a tower manipulator (15), where the tower (21) is positioned horizontally and parallel with and outside a vessel side (111) , as the tower is strapped down on a tower support (151) ;

c) a machinery housing (22) is displaced by a machinery housing and rotor blade manipulator (16) from a storage area (122) to an upper tower end portion (212) , where the machinery housing (22) is fastened to the tower (21) with a rotor hub facing upwards and a rotor axis (233) arranged in an approximately vertical position;

d) rotor blades (232) one by one are displaced with the machinery housing and rotor blade manipulator (16) from a storage area (123) to an upper tower end portion (212), where the rotor blade (232) is fastened to the rotor hub (231) , whereafter the rotor (231) is turned one sector corresponding to the angular distance between the rotor blades (232) on a completed rotor (23) until the last rotor blade is fastened; e) the assembled wind turbine (2) is put in an upright position in an adjacent mass of water (3) by turning the tower manipulator (15) about a horizontal axis (152) arranged transversally to the vessel's (1) longitudinal direction; and

f) the tower is freed from the tower support (151) .

12. A method according to claim 11, c h a r a c t e r i z e d i n that before step e) the elements (161, 163, 164, 166) of the machinery housing and rotor blade manipulator (16) are displaced away from an estimated motion path for the tower (11) between the horizontal and vertical positions.

13. A method according to claim 11, c h a r a c t e r i z e d i n that step f) comprises bringing the wind turbine (2) to a floating condition in the mass of water (3) .

14. A method according to claim 11, c h a r a c t e r i z e d i n that step f) comprises lowering the wind turbine (2) to a supported position on a foundation in the mass of water (3) .