A flywheel assembly 10 comprising: at least one flywheel mass support 14, the or each said support having a shaft 19 that extends along a rotational axis 18 about which the support 14 can rotate in use, the or each said support 14 comprising a plurality of openings 24 that are each offset from said rotational axis 18, a flywheel mass 12 comprising a plurality of openings 16 that are each arranged to align with a corresponding opening in said support; and means 23 for coupling said flywheel mass 12 to the or each said support 14 so that the mass 12 can rotate with the or each support 14 in use, said coupling means 23 being configured to extend through the aligned openings in the or each support 14 and said flywheel mass 12; wherein said flywheel mass 12 comprises a plurality of generally planar flywheel mass elements sandwiched together to form a stack of elements, each said element including a plurality of openings 16 that align with the openings 24 in the or each said support 14 and with openings in neighbouring elements in said stack, said flywheel elements being coupled together and aligned with one another to form said flywheel mass solely by means of the coupling means 23 that extends through the aligned openings in said elements and the or each said support 14.

A flywheel energy storage system incorporates various embodiments in design and processing to achieve a very high ratio of energy stored per unit cost. The system uses a high-strength steel rotor rotating in a vacuum envelope. The rotor has a geometry that ensures high yield strength throughout its cross-section using various low-cost quenched and tempered alloy steels. Low-cost is also achieved by forging the rotor in a single piece with integral shafts. A high energy density is achieved with adequate safety margins through a pre-conditioning treatment. The bearing and suspension system utilizes an electromagnet that off-loads the rotor allowing for the use of low-cost, conventional rolling contact bearings over an operating lifetime of several years.

A flywheel assembly 10 comprising: at least one flywheel mass support 14, the or each said support having a shaft 19 that extends along a rotational axis 18 about which the support 14 can rotate in use, the or each said support 14 comprising a plurality of openings 24 that are each offset from said rotational axis 18, a flywheel mass 12 comprising a plurality of openings 16 that are each arranged to align with a corresponding opening in said support; and means 23 for coupling said flywheel mass 12 to the or each said support 14 so that the mass 12 can rotate with the or each support 14 in use, said coupling means 23 being configured to extend through the aligned openings in the or each support 14 and said flywheel mass 12; wherein said flywheel mass 12 comprises a plurality of generally planar flywheel mass elements sandwiched together to form a stack of elements, each said element including a plurality of openings 16 that align with the openings 24 in the or each said support 14 and with openings in neighbouring elements in said stack, said flywheel elements being coupled together and aligned with one another to form said flywheel mass solely by means of the coupling means 23 that extends through the aligned openings in said elements and the or each said support 14.

A flywheel assembly 10 comprises at least one flywheel mass support 14 that has a shaft 19 that extends along a rotational axis 18 about which the support 14 can rotate in use and a flywheel mass 12. The support 14 comprises a plurality of openings 24 that are each offset from the rotational axis 18. The flywheel mass 12 comprises a plurality of openings 16 that are each arranged to align with a corresponding opening in the support. The flywheel mass 12 is coupled to the support 14 so that the mass 12 can rotate with the support 14 in use. The flywheel mass 12 comprises a plurality of generally planar flywheel mass elements sandwiched together to form a stack of elements by fixing elements 23 that extend through the aligned openings in the mass elements and the support 14.

A flywheel energy storage system incorporates various embodiments in design and processing to achieve a very high ratio of energy stored per unit cost. The system uses a high-strength steel rotor rotating in a vacuum envelope. The rotor has a geometry that ensures high yield strength throughout its cross-section using various low-cost quenched and tempered alloy steels. Low-cost is also achieved by forging the rotor in a single piece with integral shafts. A high energy density is achieved with adequate safety margins through a pre-conditioning treatment. The bearing and suspension system utilizes an electromagnet that off-loads the rotor allowing for the use of low-cost, conventional rolling contact bearings over an operating lifetime of several years.

A flywheel assembly 10 comprising: at least one flywheel mass support 14, the or each said support having a shaft 19 that extends along a rotational axis 18 about which the support 14 can rotate in use, the or each said support 14 comprising a plurality of openings 24 that are each offset from said rotational axis 18, a flywheel mass 12 comprising a plurality of openings 16 that are each arranged to align with a corresponding opening in said support; and means 23 for coupling said flywheel mass 12 to the or each said support 14 so that the mass 12 can rotate with the or each support 14 in use, said coupling means 23 being configured to extend through the aligned openings in the or each support 14 and said flywheel mass 12; wherein said flywheel mass 12 comprises a plurality of generally planar flywheel mass elements sandwiched together to form a stack of elements, each said element including a plurality of openings 16 that align with the openings 24 in the or each said support 14 and with openings in neighbouring elements in said stack, said flywheel elements being coupled together and aligned with one another to form said flywheel mass solely by means of the coupling means 23 that extends through the aligned openings in said elements and the or each said support 14.

A flywheel energy storage system incorporates various embodiments in design and processing to achieve a very high ratio of energy stored per unit cost. The system uses a high-strength steel rotor rotating in a vacuum envelope. The rotor has a geometry that ensures high yield strength throughout its cross-section using various low-cost quenched and tempered alloy steels. Low-cost is also achieved by forging the rotor in a single piece with integral shafts. A high energy density is achieved with adequate safety margins through a pre-conditioning treatment. The bearing and suspension system utilizes an electromagnet that off-loads the rotor allowing for the use of low-cost, conventional rolling contact bearings over an operating lifetime of several years.

The present invention relates to a floating wind energy harvesting apparatus for offshore installation, the wind energy harvesting apparatus comprising: an elongated wind turbine body extending along a longitudinal wind turbine body axis, the wind turbine body comprising a lower body portion to be below a water surface when the wind energy harvesting apparatus is in operation and an upper body portion to be above the water surface when the wind energy harvesting apparatus is in operation; wind turbine blades attached to the upper body portion for converting wind energy to rotation of the wind turbine body around the longitudinal wind turbine body axis; an energy converter attached to the wind turbine body for converting the rotation of the wind turbine body in relation to a non-rotatable part to electrical energy; and anchorage means connecting the non-rotatable part to at least one anchor point via at least one float body.

A flywheel energy storage system incorporates various embodiments in design and processing to achieve a very high ratio of energy stored per unit cost. The system uses a high-strength steel rotor rotating in a vacuum envelope. The rotor has a geometry that ensures high yield strength throughout its cross-section using various low-cost quenched and tempered alloy steels. Low-cost is also achieved by forging the rotor in a single piece with integral shafts. A high energy density is achieved with adequate safety margins through a pre-conditioning treatment. The bearing and suspension system utilizes an electromagnet that off-loads the rotor allowing for the use of low-cost, conventional rolling contact bearings over an operating lifetime of several years.

There are provided a hub for a flywheel and an energy storage flywheel. The hub for a flywheel is provided between a rotor and a rotational shaft of a flywheel to allow the rotor to have the same rotation speed as that of the rotational shaft. The hub includes a hollow main dome in which a through hole into which the rotational shaft is inserted is formed in one end and an opening is formed in the other end in a longitudinal direction of the rotational shaft, and that is formed by winding a composite material therearound; and a sub dome that is bonded to the rotor and is formed by winding the composite material around an outer surface of the main dome. Any one of the main dome and the sub dome expands in a radial direction of the rotational shaft along with the rotation of the rotational shaft and the rotor to allow the sub dome and the rotor to be maintained at a bonded state therebetween.