Offshore wind turbine assembly vessel

A vessel for assembling wind turbines and for installing the assembled wind turbine on a foundation, the vessel comprising:

• a floating hull;
• a wind turbine components storage deck, for storing components of a wind turbine;
• a wind turbine assembly station;
• and
• a wind turbine installation crane mounted on the floating hull,
• wherein the installation crane is configured to perform one or more wind turbine assembly steps,
• wherein the installation crane has an assembly side facing the wind turbine assembly station, and has an installation side,
• wherein the installation crane is provided with a wind turbine hoisting device having one or more wind turbine suspension elements, said wind turbine hoisting device being adapted to support and to raise and lower in a controllable manner an assembled wind turbine, the assembled wind turbine comprising a mast combined with the nacelle and the blades fitted,
• wherein the installation crane has a base section and a top section, wherein the top section is rotatable supported by a bearing, and wherein the top section can be rotated with the wind turbine hoisting device relative to the base section about a vertical axis, and wherein the hoisting device can thus transfer at least an upper mast part between the assembly stations and the installation side, and
• wherein the installation crane is configured for arranging the assembled wind turbine from the at least one wind turbine assembly station into a mounting position, above a wind turbine foundation adjacent the vessel, at the installation side of the installation crane, for supporting an assembled wind turbine at the installation side in a mounting position above a foundation and for lowering the wind turbine onto the foundation.

A method for assembling wind turbines on a wind turbine assembly vessel and for installing the assembled wind turbines on a foundation, using the wind turbine assembly and installation vessel,

• wherein the wind turbine assembly vessel comprises:
• a floating hull;
• a wind turbine components storage deck, for storing components of a wind turbine;
• at least one wind turbine assembly station;
• and
• an installation crane, mounted on the floating hull, wherein the installation crane has at least one assembly side facing the at least one wind turbine assembly station, and has an installation side,
• wherein the method comprises:
• moving one or more wind turbine components from the wind turbine components storage deck to the at least one wind turbine assembly station;
• and
• using the installation crane to:
• perform one or more assembly steps, by upending the wind turbine mast or by lifting the nacelle onto the top of the mast or the upper mast part;
• support the assembled wind turbine at the assembly side and arranging the assembled wind turbine from the assembly station into the mounting position, above a wind turbine foundation adjacent the vessel, at the installation side of the installation crane;
• and
• lower the assembled wind turbine onto the foundation.

A method for assembling wind turbines on a wind turbine assembly vessel, and for installing the assembled wind turbines using the wind turbine assembly vessel, Method The method wherein the wind turbine assembly vessel comprises:

• a floating hull;
• a wind turbine components storage deck, for storing components of a wind turbine, including a mast, a nacelle, and blades;
• a first assembly station, a second assembly station and a third assembly station;
• a handling crane and an installation crane, wherein the installation crane has an installation side, and is configured for supporting an assembled wind turbine at the installation side in a mounting position above a foundation and for lowering the wind turbine onto the foundation, and wherein the first assembly station is located on a first side of the installation crane, the second assembly station is located on a second side of the installation crane, the third assembly station is located on a third side of the installation crane, and the installation side is on a fourth side of the crane;
• and
• a blade handling apparatus, for transferring a blade between a horizontal supply position and a fastening position,
• wherein the method comprises:
• storing the wind turbine components on the wind turbine components storage deck;
• arranging the mast into the first assembly station using the wind turbine installation crane, and supporting the upper mast in an upright installation position;
• lifting the nacelle and hoisting the nacelle on the mast in the first assembly station, using the wind turbine installation crane, and mounting the nacelle on the mast;
• arranging the combined mast and nacelle from the first assembly station to the second assembly station, using the installation crane, lowering a bottom section of the mast into a deck recess and supporting the mast part in an upright installation position and with the nacelle in an installation position for mounting a blade to the nacelle;
• mounting the blades to the nacelle to provide an assembled wind turbine, the blades mounting process comprising;
• comprising:
• lifting a first blade into a fastening position adjacent the nacelle, mounting the first blade to the nacelle, and rotating the nacelle into a successive installation position, position;
• lifting a second blade into a fastening position adjacent the nacelle, mounting the second blade to the nacelle, and rotating the nacelle into a successive installation position;
• and
• lifting a third blade into a fastening position adjacent the nacelle, and mounting the third blade to the nacelle;
• arranging the assembled wind turbine from the second assembly station into the mounting position at the fourth side of the installation crane;
• and
• lowering the wind turbine onto a foundation, using the installation crane.