A submersible hydraulic assembly for an energy storage plant is provided that includes at least one hydraulic machine and at least one first buoyancy chamber filled with at least one first buoyancy element. The at least one first buoyancy chamber is generally configured in such a way that the hydraulic machine is substantially neutrally buoyant when submerged in an environmental liquid. An energy storage plant is also provided as well as a method for performing maintenance operations on an energy storage plant and a method for assembling/disassembling an energy storage plant.

A method for performing uptower maintenance of a wind turbine in order to replace the main bearing on the turbine shaft is disclosed. Embodiments of this method to perform maintenance may include installing a rotor lock to resist rotation of the main shaft during maintenance, providing a lifting device in order to elevate the main shaft, removing the main bearing from its main bearing housing, and installing a replacement split main bearing. A crane may also be installed uptower to assist in the maintenance.

A system for de-erection and re-erection of a blade of a wind turbine, the system comprising at least one first pulley, at least one second pulley, at least one third pulley, a receptacle disposed over a substantial length of the blade, a lifting line passing over the at least one first pulley, the at least one second pulley, the at least one third pulley and attached back to the at least one second pulley, at least one load bearing mechanism configured for pulling and releasing of the lifting line to enable vertical motion of the receptacle disposed over the blade, a load supporting mechanism connected to an operative bottom portion of the blade and configured to support the blade during de-erection and re-erection thereof and at least one holding mechanism attached to the at least one third pulley, the at least one holding mechanism adapted to hold the receptacle.

A method for mounting or dismounting a wind turbine component of an energy generating unit in a multirotor wind turbine is disclosed. The multirotor wind turbine comprises a tower configured to support one or more load carrying structures each arranged for supporting at least two energy generating units arranged at or near its ends and at opposite sides of the tower. The method comprises positioning or dispositioning a first wind turbine component at a first end of the load carrying structure, yawing the load carrying structure approximately 180 degrees, and positioning or dispositioning a second wind turbine component at the second end of the load carrying structure opposite the first end. The method may be used in erecting or servicing a multirotor wind turbine.

A method for connecting a blade to a hub of a wind turbine, the method including pulling the blade towards the hub using a rope guided through an interior of the hub is provided. Thus, movements between the hub and the blade, in particular due to oscillations or waves, are reduced during the connection process.

A nacelle-mountable lift system for mounting and dismounting a rotor blade of a wind turbine involves a jib crane, the jib crane having a base removably mountable on a nacelle of the wind turbine and a jib mounted on the base. The jib has a boom arm supported on the base by at least one support strut extending between the base and the boom arm. A winch is mounted on the boom arm. At least two sheaves are rotatably mounted on the boom arm. A holder is connectable to the blade. At least two lift cables pass over the at least two sheaves connecting the holder to the winch. The boom arm is positionable to position the holder beyond a rotor hub of the wind turbine when the crane is mounted on the nacelle.

In a first aspect, a method for removing an electromagnetic module from an electrical machine is provided. The electrical machine comprises a plurality of electromagnetic modules having an electromagnetic material. The electromagnetic modules comprise base and a support extending from the base and supporting the electromagnetic material. The base comprises a bottom surface and a first side surface. The first side surface comprises an axially extending groove defining a cooling channel with an axially extending groove of a first side surface of an adjacent electromagnetic module. The method comprises inserting a rod in a cooling channel formed by the groove of the electromagnetic module to be removed and a groove of an adjacent electromagnetic module; releasing the electromagnetic module to be removed from a structure of the electrical machine; and sliding the electromagnetic module to be removed along the rod.

A system for assembling/disassembling a windmill in a supporting tower, comprising a intermediate fixing structure with hydraulic supports for attachment, by pressure, to the tower; a main structure capable of being attached to the tower at various working positions by absorbing the diametral differences of the latter; two pivoting arms hinged to the main structure and capable of being positioned by hydraulic actuators; a secondary structure for hoisting tower segments, equipped with four cranes of a minor size for handling the main structure and the pivoting arms during hoisting/descent, and a counterbalancing group adjustable in height by means of capstans. The main structure and the intermediate structure include a detachable side for their withdrawal and separation from the tower during disassembly.

A method for performing uptower maintenance of a wind turbine in order to replace the main bearing on the turbine shaft is disclosed. Embodiments of this method to perform maintenance may include installing a rotor lock to resist rotation of the main shaft during maintenance, providing a lifting device in order to elevate the main shaft, removing the main bearing from its main bearing housing, and installing a replacement split main bearing. A crane may also be installed uptower to assist in the maintenance.

A method for assembling and disassembling a module of gas turbine engine is provided, along with a gas turbine engine configured for modular assembly/disassembly. The engine includes a first shaft and a second shaft. The first shaft connects a compressor section and a first turbine section. The second shaft is connected to the second turbine section. The first and second shafts are rotatable about the engine rotational axis. The second shaft and the second turbine section together form a module that can be assembled, or disassembled, or both from the engine.