Method of building an offshore windmill

Patent metadata

Field	Value
Publication number	US-10550825-B2
Application number	US-201716328160-A
Country	US
Kind code	B2
Filing date	Aug 22, 2017
Priority date	Sep 2, 2016
Publication date	Feb 4, 2020
Grant date	Feb 4, 2020

Abstract

A method of building an offshore windmill includes, using a 3D-heave-compensated crane, placing on a windmill pedestal a lifting jack having a receiving region, and fixing the lifting jack to the windmill pedestal such that the lifting jack can be later removed, and such that a windmill column can be placed within the receiving region directly on the windmill pedestal. The windmill generator is installed using the 3D-heave-compensated crane. The windmill column is partially erected on the windmill pedestal using the 3D-heave-compensated crane and the lifting jack. Before the windmill is fully erected, windmill blades are placed on the windmill generator using the 3D-heave-compensated crane, and the erection of the windmill column on the windmill pedestal is completed using at least the lifting jack. Using the 3D-heave-compensated crane, the lifting jack is removed from the windmill pedestal.

First claim

The invention claimed is:

1. Method of building an offshore windmill on a windmill pedestal that is located offshore, comprising:
providing a floating vessel comprising a 3D-heave-compensated crane on a deck thereof;
providing at least one offshore windmill assembly and a lifting jack, wherein the offshore windmill assembly comprises a windmill generator, a plurality of windmill blades and at least two windmill column parts for forming a windmill column at a later stage, wherein the lifting jack is configured for receiving the windmill column in a receiving region thereof;
moving said floating vessel, the lifting jack and the at least one offshore windmill assembly in proximity of the windmill pedestal;
placing the lifting jack directly on the windmill pedestal using the 3D-heave-compensated crane and fixing the lifting jack to the windmill pedestal such that it can be later removed, and wherein the lifting jack is fixed to the windmill pedestal such that the windmill column can be placed within the receiving region directly on the windmill pedestal;
installing the windmill generator using the 3D-heave-compensated crane;
partially erecting the windmill column on the windmill pedestal using the 3D-heave-compensated crane and the lifting jack;
installing the windmill blades on the windmill generator using the 3D-heave-compensated crane at a stage where the windmill column has been partially erected;
fully erecting the windmill column on the windmill pedestal using at least the lifting jack;
removing the lifting jack from the windmill pedestal using the 3D-heave-compensated crane.

2. The method according to claim 1 , wherein the method further comprises, before placing the lifting jack, preparing the windmill pedestal for receiving the lifting jack.

3. The method according to claim 1 , wherein, in installing the windmill generator, the windmill generator is installed on the lifting jack.

4. The method according to claim 1 , wherein, in partially erecting the windmill column, at least a first one of the at least two windmill column parts is installed on the windmill pedestal, and wherein, in fully erecting the windmill column, the remaining ones of the windmill column parts are installed using the lifting jack for creating room between the windmill pedestal and the remaining part of the windmill column, as well as using the 3D-heave-compensated crane for moving the respective windmill column parts from the floating vessel to the pedestal.

5. The method according to claim 1 , wherein, in providing the floating vessel, the at least two windmill column parts that are provided on the floating vessel are in the form of a telescopic windmill column in its retracted state.

6. The method according to claim 5 , wherein, in partially erecting the windmill column, the telescopic windmill column is installed in its retracted state on the windmill pedestal, and wherein, in fully erecting the windmill column, the lifting jack is used to extend the telescopic windmill column.

7. The method according to claim 1 , wherein, in installing the windmill blades, the windmill blades are installed sequentially, wherein the windmill generator is used to manipulate a position of a windmill hub of the windmill generator such that the respective windmill blade can be mounted thereto.

8. The method according to claim 1 , wherein, in providing the floating vessel, the floating vessel is provided with an enhanced lifting jack that further comprises a cradle that is configured for i) receiving respective windmill parts, for ii) bringing said parts from a lower end of the lifting jack to an upper end of lifting jack for iii) manipulating, i.e. rotating, said parts to a vertical position, and for iv) bringing said parts to said receiving region.

9. Method of building an offshore windmill on a windmill pedestal that is located offshore, comprising:
placing a lifting jack having a receiving region on the windmill pedestal using a 3D-heave-compensated crane that is positioned on a floating vessel, and fixing the lifting jack to the windmill pedestal such that the lifting jack can be later removed, and such that a windmill column can be placed within the receiving region directly on the windmill pedestal;
installing a windmill generator using the 3D-heave-compensated crane;
partially erecting the windmill column on the windmill pedestal using the 3D-heave-compensated crane and the lifting jack;
installing a plurality of windmill blades on the windmill generator using the 3D-heave-compensated crane at a stage where the windmill column has been partially, but not fully, erected;
completing the erection of the windmill column on the windmill pedestal using at least the lifting jack;
removing the lifting jack from the windmill pedestal using the 3D-heave-compensated crane.

10. The method according to claim 9 , wherein the method further comprises, before placing the lifting jack, preparing the windmill pedestal for receiving the lifting jack.

11. The method according to claim 9 , wherein, installing the windmill generator comprises installing the windmill generator on the lifting jack.

12. The method according to claim 9 , wherein the windmill column comprises at least two windmill column parts, and wherein partially erecting the windmill column comprises installing at least a first one of the at least two windmill column parts on the windmill pedestal, and wherein completing the erection of the windmill column comprises installing the remaining ones of the windmill column parts using the jack for creating room between the windmill pedestal and the remaining part of the windmill column.

13. The method according to claim 9 , wherein the windmill column comprises at least two windmill column parts, and wherein the at least two windmill column parts are in the form of a telescopic windmill column in its retracted state.

14. The method according to claim 13 , wherein, in partially erecting the windmill column, the telescopic windmill column is installed in its retracted state on the windmill pedestal, and wherein, in completing the erection of the windmill column, the lifting jack is used to extend the telescopic windmill column.

15. The method according to claim 9 , wherein, in installing the windmill blades, the windmill blades are installed sequentially, wherein the windmill generator is used to manipulate a position of a windmill hub of the windmill generator such that the respective windmill blade can be mounted thereto.

16. The method according to claim 9 , wherein, the lifting jack comprises a cradle that is configured for i) receiving respective windmill parts, for ii) bringing said parts from a lower end of the lifting jack to an upper end of lifting jack, for iii) manipulating said windmill parts to a vertical position, and for iv) bringing said windmill parts to said receiving region.

Assignees

• Nat Oilwell Varco Norway As

Inventors

• Borøy Yngvar
• Strand Thor

Classifications

• E02B2017/0043

  Placing the offshore structure on a pre-installed foundation structure · CPC title

• E02B2017/0065

  Monopile structures · CPC title

• F05B2240/95

  offshore · CPC title

• E02B2017/0091

  Offshore structures for wind turbines · CPC title

• B63B2035/446

  for converting wind energy into electric energy · CPC title