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EP-4405241-B1 - FLOATING PLATFORM FOR A WIND TURBINE

EP4405241B1EP 4405241 B1EP4405241 B1EP 4405241B1EP-4405241-B1

Inventors

  • VASSILOPOULOS, Anastasios

Dates

Publication Date
20260506
Application Date
20220916

Claims (19)

  1. A system (100) for generating electric power (26) and hydrogen (28) comprising: a floating platform (1) configured to float on a waterbody; a wind turbine (23) supported by said floating platform (1); a generator (25) coupled to the wind turbine configured for transforming the mechanical power output (24) of said turbine into electrical power (26); an electrolyzer (27) configured to produce hydrogen (28) from water (29) using electrical power (26) produced by said generator (25); at least one hydrogen storage chamber (30) configured for collecting said hydrogen (28) generated by the electrolyzer (27); wherein said floating platform (1) comprises: a vertically arranged support (10) of said wind turbine (23); characterized in that said floating platform further comprises: a toroidal body (11) arranged coaxially around said support (10), so that a vertical axis of the support (10) passes through the centre of the toroidal body (11); the support (10) having a connection seat (12) for a tower (3) of said wind turbine (23) and a lower portion (13) which extends below the toroidal body (11); the platform further comprising a plurality of connection arms (14, 15) which extends radially between the support (10) and the toroidal body (11) so that the support and the toroidal body are rigidly connected by said arms, wherein the toroidal body (11) and the connection arms (14, 15) are made of a composite material which is a reinforced polymer material, wherein the at least one hydrogen storage chamber (30) includes a chamber which is arranged within one of the connection arms (14, 15) of the platform and/or within the toroidal body (11).
  2. A system according to claim 1 wherein said connection arms include first connection arms (14) which extend horizontally between the support (10) and the toroidal body (11), and second connection arms (15) which extend diagonally between the support and the toroidal body, each of said second connection arms (15) being connected to the lower portion (13) of the support (10) at a connection point below the toroidal body (11).
  3. A system according to claim 2 wherein the number of the first connection arms (14) is equal to the number of the second connection arms (15).
  4. A system according to claim 3 wherein the number of the first connection arms (14) is three and the number of second connection arms (15) is three.
  5. A system according to any of the previous claims wherein at least one of the vertically arranged support (10), the toroidal body (11) and the connection arms (14, 15) has a hollow structure.
  6. A system according to any of the previous claims wherein at least one of the support (10), the toroidal body (11) and the connection arms (14, 15) is made of a composite material which is a natural fibre reinforced composite material.
  7. A system according to claim 6 wherein said composite material includes at least a natural fiber and a glass fiber.
  8. A system according to claim 7 wherein said composite material includes a sandwich structure including a layer of flax fibre pultruded elements with a protective coating layer of a glass fibre.
  9. A system according to any of the previous claims wherein the support (10), the toroidal body (11) and the connection arms (14, 15) are all made of one or more composite material(s).
  10. A system according to any of the previous claims wherein the vertically arranged support (10) is cylindrical or substantially cylindrical.
  11. A system according to any of the previous claims wherein the vertically arranged support (10) includes a lower end connection (114) for a ballast.
  12. A system according to any of the previous claims, wherein the buoyancy line of the platform in seawater intersects the toroidal body.
  13. A system according to any of the previous claims including at least one mooring line which includes a cable (21) and said cable forms a loop (22) around one arm (15) of the platform, said cable being preferably made of a composite material.
  14. A system according to any of the previous claims, including a turbine tower (3) connected to the central support of the platform, wherein the tower and the central support are made of composite materials, and the tower is received in the connection seat of the central support and operatively connected by at least one adhesive, to said connection seat with no metal connection parts between the tower and the support.
  15. System (100) according to any of claims 1 to 14, wherein hydrogen (28) is stored as gas at a storage pressure greater than the hydrogen production pressure, the system comprising a compressor to raise the pressure of hydrogen so said storage pressure.
  16. System (100) according to any of claims 1 to 15 further including a fuel cell (32) for conversion of stored hydrogen (31) into electrical power (33).
  17. System (100) according to any of claims 1 to 16, further including one or more batteries (35) for storing electric power (26) produced by said electrical generator (25).
  18. System (100) according to any of claims 1 to 17, wherein said generator (25) is connected to an electrical grid (34) and said system further includes a control system configured to regulate the amount of electrical power supplied to the electrolyzer (27) and to said electrical grid (34).
  19. Use of a system (100) according to any of claims 1 to 18 for the production of renewable energy on demand, by converting wind energy into electric energy and by transferring said electric energy to a grid and/or storing said energy by means of production of hydrogen via electrolysis and storage of said hydrogen.

Description

Field of application The present invention relates to the field of the offshore wind energy production; particularly the invention relates to a floating platform for a wind turbine. Prior art Offshore wind turbines can benefit from a more constant and undisturbed flow of air compared to on-land wind turbines. For this reason, the offshore market is experiencing a significant growth and is expected to move faster in the near future. However, the offshore installation requires a suitable platform and the current technique of platforms for wind turbines is not fully satisfactory. The conventional platforms for wind turbines are designed on the basis of the experience gained with platforms for the oil and gas industry. Nevertheless, the requirements of oil and gas industry are much different from those of the wind energy industry. The adaptation to wind energy application of a platform originally designed for oil/gas application results in a in massive and expensive structure increasing the capital cost and the operational cost of offshore wind farms. In most cases, the platform of wind turbines is made of concrete and/or steel. Both materials however have disadvantages. Concrete is heavy, which complicates the transportation and deployment of the platform or parts thereof. Steel may suffer from corrosion in seawater; special steels resistant to corrosion in seawater are available but are generally expensive. The turbine is typically mounted on a tower. The connection between the tower and the platform is another crucial feature; the prior art typically uses metal parts, such as metal flanges, with the problems outlined above of corrosion, unless very expensive materials are used. Furthermore, the conventional platforms are generally fixed platforms which are unable to rotate in order to point the turbine in the direction of the wind. This disadvantage can be obviated by installing a wind turbine with a rotating head, which however increases the cost and complication of the turbine. EP 2 668 090 describes a floating platform which may be used for a wind turbine. It has the drawback, however, of an asymmetric position of the wind turbine with respect to the structure. A floating platform for a wind turbine is also described in US 10,598,155. WO 2011/057940 discloses a floating off-shore wind turbine. EP 3 339 634 discloses a system for generating electric power and hydrogen including a floating platform, a wind turbine, a generator of electrical power, an electrolyzer for producing hydrogen and a hydrogen storage. Summary of the invention The purpose of the invention is to overcome the above disadvantages and limitations of the prior art. The invention addresses the production of electric power and hydrogen with off-shore wind turbines. Among others, the invention addresses the need to provide a floating platform for an off-shore wind turbine having a lighter structure than the current platforms, a seamless assembly, a competitive manufacturing cost, a low maintenance required. A further aim of the invention is a platform easily orientable so that the wind turbine can point to the direction of the wind to maximize the output. The above problem is solved with a system for generation of electric power and hydrogen according to the claims. The platform comprises a vertically arranged support and a toroidal body arranged horizontally and coaxially around said support, so that a vertical axis of the support passes through the centre of the toroidal body. The support has an upper portion with a connection seat for the tower of a wind turbine and a lower portion which extends below the toroidal body. The platform further comprises a plurality of connection arms which extends radially to connect the support to the toroidal body; at least one of the support, the toroidal body and the connection arms is made of a reinforced composite material. The invention has, among others, the following advantages: the use of composites provides a seamless assembly of the various subparts, increasing the aesthetic appeal of the structure and reducing weak points induced by a riveted or bolted assembly. Composite materials are much lighter than steel/concrete, offering comparative advantages for the dragging from the shore to the site of installation; furthermore the installation is possible with smaller lifting equipment. Composite materials have better environmental footprint compared to steel and concrete; particularly in maritime installation they do not corrode and do not release heavy metals and toxic chemicals to the sea. The composite structure needs much less maintenance compared to the steel/concrete counterparts. The use of a composite (light weight) wind turbine tower can affect positively the system dynamic behaviour since the entire structure will be more flexible that the stiff metallic structures. The axis-symmetric shape of the inventive platform with a central main cylinder surrounded by a toroidal body provides a stab