WO2013154740A1 - Floating windturbine configuration - Google Patents

Description

FLOATING WIND TURBINE CONFIGURATION

RELATED APPLICATION

[0001] This invention claims the benefit of U.S. Provisional Patent Application No. 61/622088 filed on April 10, 2012, which is hereby incorporated by reference in its entirety .

TECHNICAL FIELD

[0002] This invention relates, for example, to floating wind turbines. In particular, certain embodiments of the present invention relate to, for example, reducing investment, installation and operating cost of such wind turbines.

BACKGROUND OF THE INVENTION

[0003] Emission of greenhouse gases and security of supply are areas of high and increasing concern in relation to energy supply. As a consequence, several technologies have been developed and put into use to produce electric power without the use of fossil and nonrenewable sources of energy.

[0004] Such energy resources include, for example, hydro power, bio mass, geothermal and solar. However, over the last decades, wind power has become an important source of renewable energy globally. This development has resulted in the availability of larger and more efficient wind turbines. Favorable support regimes, particularly in Europe, have led to the development and introduction of wind turbines with capacity in excess of 6MW per unit. Still, one of the disadvantages of wind power is the incontroUable supply of wind, which results in relatively low utilization factors and the need for building expensive backup systems to cover situations without sufficient wind. To mitigate this, the wind industry is gradually moving its operation to offshore locations. This way, both the generally higher wind intensities as well as more stable wind conditions may be utilized for more profitable power production. In addition, when locating wind mills offshore, any negative public sentiment toward such stations may be reduced as problems with the visual and noise impression is significantly reduced. Today, building traditional mono towers with top mounted wind turbines is a proven technology. Still, these offshore wind farms are more expensive to build and operate than traditional land based systems. The maximum depth at which such offshore wind turbines may be constructed is normally limited to approximately 30 meters. Going beyond 50 meters of water depth requires other solutions than traditional sea bed mounted mono-towers.

[0005] Hence, different concepts for floating wind turbines are needed to facilitate wind farms in locations where the water depth is too deep or to place the turbines even further from shore to lessen any perceived negative impressions or impact from these turbines. Floating wind turbines may be relevant in depths beyond 100 meters because substructures need to be allowed sufficient free space at low tide conditions. This leaves a gap between 50 and 100 meters of water depth for locating a facility. So far, floating designs have proven prohibitively expensive to install as well as challenging to service in situations of strong wind and high waves. The limited space available also puts severe limitations on the amount of equipment any service personnel can take on board when servicing any offshore wind turbine, leaving the whole offshore wind industry with several challenges still to overcome. Floating wind turbines today are not commercially viable and significant cost reduction needs to be accomplished if floating offshore wind solutions shall ever become commercially viable. The present application addresses all these traditional challenges and shortfalls associated with floating wind turbines and represents a solution which is believed to significantly to reduce investment, installation and operating cost of such wind turbines.

SUMMARY OF INVENTION

[0006] Certain exemplary embodiments of this invention may, for example, include a floating wind turbine, a hull, optional mooring points connected to said hull, an energy storage system connected to said floating wind turbine capable of storing power produced by said wind turbine, and a generator connected to said floating wind turbine, wherein said mooring points are capable of adjusting the position of said hull, and wherein said mooring points may be capable of being connected to a sea bed at any practical depth beyond approximately 10 meters at low tide.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The accompanying drawings, which are included to provide a further

understanding of embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of embodiments of the invention.

[0008] FIG. 1 is a perspective depiction of an exemplary hull that could be used with an embodiment of the invention.

[0009] FIG. 2 is a top down vie of an embodiment of the present invention depicting mooring points attached to a hull according to an embodiment of the invention.

[0010] FIG. 3 is a perspective view of an embodiment of mono towers and top mounted mills and horizontal turbines according to an embodiment of the invention.

[0011] FIG. 4 is a front view of a tower and mill according to an embodiment of the invention.

[0012] FIG. 5 is a front view of a tower and mill according to embodiments of the invention.

[0013] FIG. 6 is a front perspective view of vertical wind turbines according to embodiments of the invention.

[0014] FIG. 7 is a front view of vertical wind turbines on a hull according to an embodiment of the invention.

[0015] Fig. 8 is a side view of a tower and vertical wind turbines mounted on a scaffold, on a hull, according to an embodiment of the invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0016] It is to be understood that the present invention is not limited to the particular methodology, compounds, materials, manufacturing techniques, uses, and applications described herein, as these may vary. It is also to be understood that the terminology used herein is used for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. It must be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include the plural reference unless the context clearly dictates otherwise. Thus, for example, a reference to "an element" is a reference to one or more elements, and includes equivalents thereof known to those skilled in the art. Similarly, for another example, a reference to "a step" or "a means" is a reference to one or more steps or means and may include sub-steps or subservient means. All conjunctions used are to be understood in the most inclusive sense possible. Thus, the word "or" should be understood as having the definition of a logical "or" rather than that of a logical "exclusive or" unless the context clearly necessitates otherwise. Structures described herein are to be understood also to refer to functional equivalents of such structures. Language that may be construed to express approximation should be so understood unless the context clearly dictates otherwise.

[0017] Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs. Preferred methods, techniques, devices and materials are described although any methods, techniques, devices, or materials similar or equivalent to those described may be used in the practice or testing of the present invention. Structures described herein are to be understood also to refer to functional equivalents of such structures.

[0018] All patents and other publications are incorporated herein by reference for the purpose of describing and disclosing, for example, the methodologies described in such publications that might be useful in connection with the present invention. These publications are provided solely for their disclosure prior to the filing date of the present application. Nothing in this regard should be construed as an admission that the inventors are not entitled to antedate such disclosure by virtue of prior invention or for any other reason.

1. The Platform

[0019] The wind power solution proposed herein includes, for example, a floating concept. A central characteristic of certain embodiments of this invention include the use of a dedicated floating structure, which may be in the form of a hull. The hull can either be purpose built or alternatively, an existing structure like the hull of an existing vessel.

[0020] New and more stringent environmental legislation and fierce competition forces many bulk or tanker vessels out of service as they are gradually being substituted by new, more safe and efficient ones. When taken out of service, these vessels are normally sent to scrapping and recycling of the steel. In this concept such a hull, possible cleared of the top structure normally used for living quarters and command bridges, any on deck equipment as well as the engine, may enter extended service as a basis for this wind mill concept.

[0021] On the deck of such new purpose built platform or former tank or bulk vessel, a series of wind mill installations could be mounted. Even if the vessel only has a single hull, when cleared of any on board remains from the cargo or bunker oil, the vessel as such may represent little or no pollution risk and should be possible to utilize for several years in passive service as a platform for wind mills before final scrapping.

[0022] Such vessels often had both helicopter platforms as well as living quarters during active service. When put to service as wind mill platforms, such landing pad as well as a number of housing quarters could be kept in order to accommodate easy access by helicopter as well as possible temporary living quarters for any maintenance crew servicing the wind mills. Hence, this solution is unique in that could accommodate the landing of a helicopter.

[0023] It would also be recommended, for certain embodiments, to keep or install a crane capable of lifting any service equipment or replacement parts deemed required for safe and efficient operations. Such equipment could then easily be lifted off any supply vessel. The crane could be placed on rails running the full length of the vessel. This way, the same crane may be used for servicing the wind turbines and blades.

[0024] In contrast to existing floating wind concepts requiring specialized vessels for deployment or deep water passage from assembly to production site, the present invention may, for example, need only sufficient draft for the vessel from a shipbuilding yard to the site of operation. No need for a specialized vessel is foreseen to be required in order to service certain of the embodiments of the off shore wind mills in this concept. The hull as such may, for example, use only conventional tug boats to be transported to the site of operation. Mooring points may also be included for use of conventional supply vessels and/or anchor handling vessels.

[0025] The spacious deck may additionally serve as, for example, a suitable "lay down" area for equipment during operation. In contrast to all other offshore wind mill concepts, this may offer a potential for significant operating cost reduction as the need for service vessels calling at the installations may be greatly reduced.

[0026] In a normal operating situation the cargo tanks may, for example, be empty. It is foreseen that one cargo department can be allocated for installing power conditioning equipment as well as the cable connection to other vessels or hulls forming collectively a wind mill farm and/or the transmission cable to shore. Hence, the cargo space may also accommodate exemplary substation equipment.

[0027] However, the hull may preferably have the capability of pumping ballast water in and out of some or all of the remaining former cargo compartments. The reason is that in high wind and wave conditions the cargo compartments may be filled with sea water to lower the hull in the water and thereby improve stability and reduce movements in the platform.

[0028] It is also forseen that the former cargo compartments may, for example, be used for other purposes as the hull in general may be used as a platform for wind mills as described herein. One such alternative use for certain compartments could be as breeding space for smolt or even fish farming. Growing algae suitable for environmental remediation, food and/or bio fuel production may also be accommodated, preferably using, for example, breeds which may thrive without light or using artificial lighting inside the cargo compartment(s).

[0029] As wind power by nature is less predictable than many other forms of power generation, power may be produced at times when it's not needed or when the market prices are low. To mitigate this, exemplary embodiments may combine wind power production with electricity storage systems. These could be large scale batteries or electrolyser units installed on the hull making hydrogen from fresh water which is stored in one cargo compartment and then store that hydrogen produced in a pressure tank in another compartment. When needed, the hydrogen could be routed back using a fuel cell to produce additional power.

[0030] Other system embodiments could, for example, use pressurized air utilizing excess power to store high pressure air inside cargo hulls. When the pressure is let down through a turbine, additional electric power could be produced. This way, the large hull is capable of serving multiple purposes beyond being just a basis for wind power units.

2. Mooring

[0031] As a base case, the passive vessel hull 10 may, for example, be kept in place by, for example, four mooring points 20, 30, 40, 50 as indicated in Figure 2.

[0032] The system could, for example, be constructed with four or more fixed mooring points on the sea bed capable of withstanding the forces of the vessel. However, the present invention may be accomplished using less than four mooring points, for example using zero, one, two or three mooring points. The vessel and the mooring points may be connected by, for example, cables 200, 300, 400, 500 such as steel cables or cables made of other synthetic materials with certain tension capacity and flexibility in order to accommodate the heaving and possible rolling of the hull. Such flexibility may be accommodated, for example, by spring systems, hydraulic suspension on the deck or vertical weights or buoyancy units placed on the cables between the hull and the mooring point.

[0033] The exemplary embodiment may, for example, benefit from the vessel being positioned with its side towards the prevailing wind direction. As the wind direction may change, the vessel position may be altered by, for example, adjusting, tightening or loosening the cables to facilitate the wind that may hit the vessel from various positions or directions, including along its side.

[0034] By placing the mooring points in sufficient angle to the vessel in certain embodiments, will allow, for example, almost 360 degrees catch of the wind, as it thereby may be irrelevant whether the wind comes from any particular direction.

[0035] On board the platform, the cables may, for example, be connected to a spool that can rotate and be powered by, for example, an electric engine. By rotating the four ( 4) spools the tension cables can be either wound or un-wound depending on the desired adjustment of the vessel position in relation to the wind direction at any given time. By having such an exemplary system, the risk of having wind turbines on a direct line without sufficient spacing and as a result having loss of efficiency is thereby reduced.

[0036] In the event of high wind speeds or waves beyond a recommended level coming directly on the vessel side, the system may, for example, offer in principle the following three exemplary countermeasures: a: pitching of the wind turbine blades to reduce the strain on the wind mill and on the forces acting on the vessel; b: filling the vessel with ballast water to lower its position in the water and thereby may provide more stability; and/or c: use of a mooring system to adjust the vessel position and secure an angle more into the wind.

[0037] In an embodiment employing, for example, a new purpose built platform instead of using an existing tanker or bulk carrier hull taken out of service, the hull may, for example, be deployed without fixed mooring. Instead, dynamic positioning may be included to provide more efficiency as it may secure optimal positioning of the hull in relation to any wind direction.

[0038] Additionally, a zero mooring point option is contemplated that, for example, could include the integration of global positioning technology and mechanisms such as bow and stem thrusters capable of positioning the ship with or without mooring points. 3. Mono Tower Wind Turbines

[0039] The most efficient wind turbine configuration may, for example, include the use of mono towers 600 with top mounted mills 700 and horizontal turbines 800 as depicted, for example, in Figure 3.

[0040] However, in order to be efficient, these towers may, for example, be placed with a minimum distance of, for example, from 3 to 5 times the wing span diameter in order to maximize efficiency per mill. This separation may accommodate turbulence created behind a wind mill which again reduces efficiency and increases stress on the downstream turbines. Even if such mono tower mounted wind mills are, for example, placed with certain spacing, the need for spacing may be significantly reduced in certain embodiments of the invention as the wind turbines may be able to face the wind standing on a parallel line. By adjusting the steel tension mooring cables, the hull position may be adjustable to allow the system to constantly face the wind with the long side of the "vessel" / platform. Even if the practical number of mono towers mounted on the platform deck may be limited, the number of such conventional wind mills may be optimized to maximize the installed Mega Watt capacity and efficiency of each installation. The towers 600 and mills 700 may, for example, be secured to the deck 900 of the platform or alternatively mounted in the bottom 910 of cargo compartments and stabilized when going up through the deck of the hull as indicated in Figures 4 and 5.

4. Vertical Wind Turbines

[0041] As the mono towers may be placed with a certain spacing in between to accommodate for turbulence and the free movement of the wing span, there may be a significant deck space remaining un-utilized. The advantage of using a platform as described herein in comparison to conventional systems is the ability to more efficiently utilize the "dead space" in between such mono towers.

[0042] Such free or "dead" space could, for example, be utilized by installing what could be described as a scaffold of vertical wind turbines 610 and small scale horizontal wind turbines. One embodiment could be to stack vertical turbines 610 of Helix design as shown in Figure 6. The turbine design allows multiple units to be installed adjacent to each other and as they will operate irrespective of wind direction, represent a preferred solution for certain embodiments as described herein. Each vertical turbine can, for example, be fitted with an individual generator 620 placed in the bottom of the wind turbine as indicated in Figure 6. Multiple vertical turbines could then be placed along the deck of the hull and in between the conventional mono tower wind turbines. The turbines could be supported on the top by a beam which could be built as part of a simple scaffolding structure.

[0043] Certain embodiments offer the added ability, for example, of stacking additional vertical turbines on top of each other on the deck of the hull. In this example, more Mega Watts can be furnished to the same base supporting structure whereas most wind turbines today only support one single wind mill.

[0044] The scaffolding structure for certain such embodiments may, for example, be arranged as indicated in Figure 7 (front / rear view) and Figure 8 (side view)

[0045] The wind mill of the mono tower 600 may be allowed to turn 360 degrees to catch the wind most efficiently. This may limit how close the scaffold 650 of vertical turbines 610 may be built to the mono tower 600.

[0046] To further utilize available space on top of the scaffold, certain embodiments may include smaller free standing horizontal turbines 640 may be mounted. The turbines may be able turn individually towards the wind such as proposed in the "Wind Tamer" concept developed by the Arista Power Company.

[0047] As the turbines may, for example, be mounted on a structure such as a large hull of a former oil tanker or bulk carrier, the solution offers certain improved possibilities for efficient service and maintenance than any other off shore wind mill solution. Service crew may spend several days working on the turbines and there are no practical limitations as to how much equipment they can bring onto the structure. Access for service personnel may either be through the use of helicopters or by using a conventional boat capable of pulling alongside the hull to, for example, allow the service crews to enter the platform using a conventional ladder. In certain embodiments, the whole structure may be freed of its mooring by disconnecting, for example, one or more steel cable tension connections and towed ashore for maintenance and/or for upgrades to the wind turbines as better wind capture technologies become available. As the hull may, for example, not be subject to any wear and tear beyond the normal effect of waves and the weather, it is expected that such off shore floating solutions may be operational for several decades even if the hull may have already been used for many years as, for example, a cargo ship.

5. Combining Wind and Liquid Fuel Powered Turbine

[0048] Traditionally, one of the main disadvantages of wind power is the unpredictable production of electricity due to the constantly changing wind speeds and directions. Consequently, if wind power is to cover a certain power demand, overcapacity may most preferably be installed or storage solutions as described above built in order to accommodate security and storage of the power supply. Contrary to conventional floating wind turbine concepts that are not easily accommodating a combination of wind power and turbines powered by a liquid fuel, the alternative in certain embodiments of the present invention to having a large vessel hull available, offers a unique possibility for combining both the power produced from the wind mills and also to optionally install additional turbine capacity be it of traditional axial or radial type and powered by, for example, liquid fuel or, for example, CNG or LNG.

[0049] The hulls in certain embodiments that may previously have been designed or used to store crude oil, oil products or bulk cargoes could be cleaned and converted to store, for example, the liquid fuel. The fuel could either be stored directly in the former cargo hulls or, for example, in container tanks brought on board. The storages could be refilled by undertaking a conventional board/board transfer operation from a supply ship coming regularly to call at the installation. From the storage, the fuel can be pumped to a turbine placed conveniently somewhere on the deck or in a compartment in the hull.

[0050] If needed, software may optionally be installed to monitor either constantly or periodically the power produced from the wind mills and adjust the output from the conventional turbine accordingly in order to accommodate a specific power demand. Alternatively, the full power of wind and the conventional turbine may at any time be allowed to be exported ashore.

[0051] What fuel to use can be a matter of evaluation and optimization. Typically diesel could be used to fuel such conventional turbines. Alternatively and if a clean fuel solution would be requested, several turbine manufacturers approve their turbines for use with methanol. Methanol is a clean burning fuel that also poses very low threat to the environment should there be spillage as it easily dilutes in the water and quickly bio degrades.

6. Power Conditioning and Cabling

[0052] As each turbine may be connected to its own generator, unsynchronized power can in certain embodiments be produced on board the hull. Cables can be brought to one of the former cargo hulls where "limit less" room may be available to set up the required power conditioning system. From there, a joint cable can be brought over the hull side and as in other off shore wind projects be brought ashore through a conventional AC or DC cable. Alternatively, as multiple hulls may be deployed in one location to form a larger wind park, one of the floating platforms may also serve as the joint power central unit bringing all the electricity produced to one unit for collection and onward transport through a single cable to shore. In traditional offshore wind farms such substations may require the construction of a separate structure to host the equipment required. The present invention may accommodate such substation equipment, for example, in one of the cargo hulls or on the deck.

[0053] Hence, various embodiments of the present invention do not require a separate structure to provide power conditioning and cable hook up. Significant cost savings may be possible when developing a wind farm using various embodiments of the present invention.

[0054] Certain embodiments of this offshore wind energy concept may include one or more of the following characteristics: a. Capability to deploy at any water depth from approximately 10 meters b. Capability to deploy at any distance from shore c. Capability to host any size of wind turbine available d. Capability to reduce the spacing between wind turbines e. Capability to significantly lower the capital cost per installed MW f. Capability to significantly lower the cost of and increase the accessibility for operation and maintenance g. Reduce or eliminate any need for specialized service vessels either for deployment or during operation h. Capability to and/or avoid the need for a separate installation to accommodate power conditioning and substation in a wind mill park i. Capability to offer a combination of wind and liquid fuel turbine power j. Capability to offer a combination of wind power with power storage, smolt, environmental remediation and/or algae production.

[0055] The embodiments and examples described above are exemplary only. One skilled in the art may recognize variations from the embodiments specifically described here, which are intended to be within the scope of this disclosure and invention. As such, the invention is limited only by the following claims. Thus, it is intended that the present invention cover the modifications of this invention provided that they come within the scope of the appended claims and their equivalents.

Claims

WHAT IS CLAIMED IS:

1. A floating wind turbine system, comprising:

a hull;

a wind turbine attached to said hull;

at least one mooring point connected to said hull by a connection mechanism;

an energy storage system connected to said wind turbine capable of storing power produced by said wind turbine; and

a generator connected to said wind turbine;

wherein said mooring point is capable of adjusting the position of said hull; and wherein said mooring point is capable of being connected to a sea bed at a depth of more than or equal to approximately 10 meters at low tide.

2. The system of claim 1 wherein said connection mechanism comprises a cable.

3. The system of claim 1 wherein said connection mechanism comprises a spring.

4. The system of claim 1 wherein said connection mechanism comprises a spool and electric engine.

5. The system of claim 1 further comprising substation equipment located in said hull.

6. The system of claim 1 further comprising a breeding compartment located in said hull.

7. The system of claim 1 further comprising a pressurized air storage compartment located in said hull and a power conversion system attached to said hull.

8. The system of claim 1 further comprising a scaffold attached to said hull and at least one vertical wind turbine attached to said scaffold.

9. A floating wind turbine system, comprising:

a hull;

a wind turbine attached to said hull;

at least one thruster connected to said hull; an energy storage system connected to said wind turbine capable of storing power produced by said wind turbine; and

a generator connected to said wind turbine;

wherein said thruster is adapted to receive control signals from an external positioning system and is capable of adjusting the position of said hull.

10. The system of claim 9 further comprising substation equipment located in said hull.

11. The system of claim 9 further comprising a breeding compartment located in said hull.

12. The system of claim 9 further comprising a pressurized air storage compartment located in said hull and a power conversion system attached to said hull.

13. The system of claim 9 further comprising a scaffold attached to said hull and at least one vertical wind turbine attached to said scaffold.

14. The system of claim 9 further comprising a global positioning satellite system configured to control said thruster.