WO2009154475A2 - Wave power plant - Google Patents

Wave power plant Download PDF

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Publication number
WO2009154475A2
WO2009154475A2 PCT/NO2009/000229 NO2009000229W WO2009154475A2 WO 2009154475 A2 WO2009154475 A2 WO 2009154475A2 NO 2009000229 W NO2009000229 W NO 2009000229W WO 2009154475 A2 WO2009154475 A2 WO 2009154475A2
Authority
WO
WIPO (PCT)
Prior art keywords
power plant
wave power
propeller
plant according
turbine
Prior art date
Application number
PCT/NO2009/000229
Other languages
French (fr)
Other versions
WO2009154475A3 (en
Inventor
Julius Espedal
Original Assignee
Langlee Wave Power As
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Langlee Wave Power As filed Critical Langlee Wave Power As
Publication of WO2009154475A2 publication Critical patent/WO2009154475A2/en
Publication of WO2009154475A3 publication Critical patent/WO2009154475A3/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03B—MACHINES OR ENGINES FOR LIQUIDS
    • F03B17/00—Other machines or engines
    • F03B17/06—Other machines or engines using liquid flow with predominantly kinetic energy conversion, e.g. of swinging-flap type, "run-of-river", "ultra-low head"
    • F03B17/061—Other machines or engines using liquid flow with predominantly kinetic energy conversion, e.g. of swinging-flap type, "run-of-river", "ultra-low head" with rotation axis substantially in flow direction
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03B—MACHINES OR ENGINES FOR LIQUIDS
    • F03B13/00—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates
    • F03B13/12—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy
    • F03B13/14—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy
    • F03B13/22—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the flow of water resulting from wave movements to drive a motor or turbine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2240/00—Components
    • F05B2240/40—Use of a multiplicity of similar components
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/30—Energy from the sea, e.g. using wave energy or salinity gradient

Definitions

  • the present invention is related to wave power plants in ocean areas, and in particular to a wave power plant that is partially submerged in the ocean and where back and forth motions of the wave power plant are captured by a propeller-like device secured to a shaft member which, at its other opposite end, has a drift surface that aligns the wave power plant with a wave direction in the ocean area in which the wave power plant is located, and where the distance between the drift surface and the propeller-like device is equal to or approximately equal to a half wavelength identified as a statically predominant wavelength in that ocean area.
  • Waves in the ocean are a source of energy which it has long been desirable to utilise for the production of power.
  • Different forms of wave power plants have been proposed, and some have also been installed.
  • the technical challenges associated with the construction of wave power plants are many as the offshore environment can be extremely inhospitable.
  • Corrosion owing to sea salt and the problems associated with a hundred-year wave are examples of challenges that can be solved, but which often have the consequence that the costs of the construction and maintenance of such plants in operation are extremely high. These costs must be balanced against the power price that can, for example, be obtained by selling power from such plants.
  • There is therefore a desire and a need for simple and low-cost offshore installations which are inexpensive to build and require a minimum of maintenance.
  • buoyancy bodies secured to the wave power plant that give an adjusted buoyancy which provides a desired partially submerged depth of the wave power plant in the ocean area, wherein at least one propeller or one turbine-like device in the wave power plant is rotated by the back and forth motions of the plant in response to waves in the ocean area in which the wave power plant is partially submerged, wherein this rotation is converted into energy in a connected, adapted device, wherein at least one drift surface is arranged to a shaft member such that one side of the drift surface faces into a wave direction in the ocean area in which the wave power plant is located, and wherein the at least one propeller or turbine-like device is arranged to the shaft, such that the distance between the at least one drift surface and the at least one propeller or turbine-like device is equal to or approximately equal to a half of an identified statistically predominant wavelength in the ocean area in which the wave power plant is located.
  • the shaft member may be a straight shaft member.
  • the shaft connecting the at least one drift surface and the at least one propeller or turbine-like device is telescopically arranged so as to be adjustable in extent to a particular half-wavelength.
  • the adjustment of the extent of the shaft member to a particular wavelength is provided by an actuator device in the wave power plant that receives a signal indicating a measured wavelength, and which adjusts the extent of the telescopically arranged shaft member according to the information content of this signal.
  • the device in the wave power plant is such that it collects measurements of wavelengths at a given measuring frequency, and at given predetermined times initiates an adjustment of the extent of the shaft member in accordance with the measurements that are collected.
  • a plurality of propellers or turbine-like devices are arranged on their respective side of the drift surface secured to shaft members which pass through the drift surface such that the extent between each one of the plurality of respective propellers or turbine-like devices on their respective sides of the drift surface is equal to or approximately equal to a half of a statistically identified predominant wavelength in the ocean area in which the wave power plant is located.
  • the adapted device that converts the rotation into energy comprises a hydraulic pump.
  • the hydraulic pump is in fluid communication with an accumulator.
  • the adapted device that converts the rotation into energy comprises an electric generator.
  • the adapted device that converts the rotation into energy comprises a seawater desalination device.
  • the adapted device that converts the rotation into energy is located in a housing located on top of a surface structure supported by supports secured to the buoyancy bodies.
  • the wave power plant is moored to the seabed by slack chains that allow motion of the wave power plant back and forth in response to wave motions in the water.
  • At least one rotating propulsion propeller is arranged on a part of the wave power plant that is submerged in water, and where a control unit turns the direction of the propulsion propeller so that the wave power plant can be moved to or held in a particular position.
  • control unit comprises a GPS receiver.
  • control unit receives control instructions from a user via a wireless connection.
  • the control unit comprises a measuring device that identifies a wave direction and a wavelength in the ocean area in which the wave power plant is located, and wherein the control unit uses this measurement data to control the propulsion propeller in order to turn the wave power plant into the wave direction whilst a given position of the wave power plant is maintained, and the extent of the shaft member is also adjusted in accordance with the measured wavelength.
  • the at least one drift surface is arranged at a first end (or near the first end) of the shaft member, and the at least one propeller or turbine-like device is arranged at a second end (or end portion) of the shaft member opposite the first end.
  • the at least one drift surface is configured as, or replaced by, a propeller or turbine-like device, wherein this propeller or turbine-like device also is rotated by the back and forth motions of the wave power plant in response to waves in the ocean area in which the wave power plant is partially submerged, and wherein this rotation is converted into energy in the connected adapted device. It is thus envisaged a wave power plant with two propellers arranged at a distance of Vz wavelength.
  • the wave power plant further comprises at least one additional propeller or turbine-like device secured to the shaft member between said drift surface and said propeller or turbine-like device.
  • at least one additional propeller or turbine-like device may be secured to the shaft member after said propeller or turbine-like device, namely further away from the drift surface.
  • the at least one additional propeller may beneficially be used when the present wavelength is less or longer than a half of a statistically identified predominant wavelength in the ocean area.
  • the at least one propeller or turbine-like device includes blades which are rotateable normal to the shaft member.
  • the propeller may always turn in the same direction regardless of the back and forth movement of the waves.
  • the blades may be turned when large waves are approaching or hitting the power plant to reduce the forces on the power plant.
  • the propeller may be a controllable pitch propeller, or a self-pitching propeller with free moving blades.
  • the rotational resistance or energy extraction of the at least one propeller or turbine-like device is adjustable.
  • the at least one propeller may be used for propulsion of the power plant through the ocean area, by increasing said resistance. With four propellers, the plant may be turned.
  • Fig. 1 illustrates an exemplary embodiment of the present invention.
  • Fig. 2 illustrates the wave effect that is utilised by the present invention.
  • Fig. 3 illustrates another exemplary embodiment of the present invention.
  • Fig. 4 illustrates yet another exemplary embodiment of the present invention.
  • Fig. 5 illustrates the mooring of a wave power plant according to the present invention.
  • Fig. 6 illustrates yet another exemplary embodiment of the present invention.
  • Fig. 1 is an exemplary embodiment of the present invention.
  • a vertical panel 1 forms a drift surface and shafts 3 connect the drift surface 1 to a propeller 2.
  • any device that converts waves into rotation can be used as a propeller in this connection.
  • Buoyancy bodies are arranged on the installation, for example, as a part or parts of tubular structures that form, for example, the shaft 3.
  • it is vertical tubes projecting up from the shaft 3 that form buoyancy bodies.
  • the buoyancy of these bodies is adapted to the weight of the wave power plant so that the plant is partially submerged, at least submerged so far that the propellers 3 are below the water surface.
  • the distance between a drift surface 1 and a propeller 2 is equal to or approximately equal to a 1 A wavelength of waves in the ocean area in which the wave power plant is located. This wavelength varies, but there is always a statistical wavelength that is a predominant wavelength in the area, as those of skill in the art will know. By identifying this statistically predominant wavelength, the length of the shaft 3 can be adapted thereto. This arrangement ensures that the wave power plant will move back and forth with the waves.
  • the drift surface 1 ensures that the wave power plant faces into the wave direction. In Figure 2 it is shown how these principles work.
  • Figure 2 shows how the drift surface 1 follows a wave 4 back and forth.
  • the wave turns after half a wave phase.
  • the drift surface 1 is moved back and forth by the wave and thus also the propellers 2 that are secured to the shafts 3.
  • One aspect of the invention is that a minimum of materials is used in the structure, partly to make it as inexpensive as possible, but also so as not to increase the inertia of the system.
  • a light structure will be moved much more easily by the waves.
  • the typical predominant wavelengths in an ocean area are between 40 and 60 metres.
  • the distance or the half wavelength used in the structure is thus set at 25 metres.
  • a wave power plant is equipped with four respective buoyancy points, for example, one in each corner of the installation, or buoyancy bodies.
  • Figure 3 shows an example of a vertical tube 6 projecting vertically from the shaft 3 which forms such a buoyancy point.
  • turbines etc. are arranged symmetrically around the drift surface 1. It is also advantageous to allow two propellers arranged side by side to rotate in their respective directions.
  • the drawings only show propellers with blades in the same direction, but it should be understood that any configuration of propeller blades is within the scope of the present invention.
  • the propeller(s) is/are connected to, for example, a rotating pump or electric generator 7, as shown in Figure 3.
  • Hydraulic hoses or cables 8 can transfer power (current) to a collecting point for distribution of power to shore.
  • Hydraulic solutions can feed hydraulically transferred power to a common motor that drives an electric generator, for example.
  • One advantage of using hydraulic solutions is that there is little hysteresis in the system when a wave changes direction (by half a wavelength), which means that a motor is in operation when the wave changes direction. Jolting and jerking in the system is therefore strongly reduced.
  • FIG 4 shows an example of an arrangement of a housing 11 on the top of the wave power plant according to the present invention.
  • a common generator and/or hydraulic installation 9, 10 can be installed in this housing 11, which is located high above the water surface.
  • the housing may contain a desalination plant as will be known to those of skill in the art. That means to say that the energy generated is used to desalinate seawater.
  • Figure 5 shows an example of the mooring of a wave power plant according to the present invention.
  • Slack chains hold the plant in position whilst the slack in the chains allows back and forth motion of the plant.
  • one of the chains may be or have within it a power transfer cable that transfers power from the plant to a cable on the seabed (not shown) which, for example, can be run to a collection point for a number of separate plants.
  • Figure 6 illustrates another exemplary embodiment of the present invention.
  • a propulsion propeller is arranged on, for example, the drift surface 1 as illustrated in Figure 6. It is within the scope of present invention to be able to arrange propulsion means of any type at any position on the installation.
  • These propellers can be remote- controlled by an operator as will be known to those of skill in the art. With such a solution, an operator in an attendant boat may steer the plant to a desired position for mooring.
  • the propulsion propellers are also used to hold the plant in place in a particular position. Deviation or drifting of the plant away from an initial position can be detected. Such measurements can be used to provide correction signals to the propulsion propellers.
  • the propulsion propellers may, for example, be turned in different directions which allow the steering of the plant in different directions.
  • a GPS receiver for example, can be used, and the deviations and steering of the direction and rotation of the propulsion propellers make it possible to correct any deviation in position such that the plant remains almost stationary at the same location.
  • wave direction and wavelength can also be measured. The measurement of the wave direction can be used to hold the plant into the wave direction at all times whilst the measurement of the wavelength can be used to adjust the distance between propeller 2 and drift surface 1.
  • the shaft 3 is telescopically arranged, and one or more actuators can this adjust the length of the shaft 3, for example, corresponding to a measured wavelength.
  • the at least one drift surface may be configured as, or replaced by, a propeller (not shown).
  • the wave power plant may further comprise at least one additional propeller (not shown) arranged on the shaft member between said drift surface and said propeller or turbine-like device and/or after said propeller or turbine-like device.
  • the at least one propeller or turbine-like device may include blades which are rotateable normal to the shaft member.
  • the rotational resistance or energy extraction of the at least one propeller or turbine-like device may be adjustable.

Abstract

The present invention utilises the effect of the swaying back and forth of a partially submerged object in response to wave motions in an ocean area. A drift surface at one end of a shaft aligns a partially submerged wave power plant with a wave direction whilst a propeller-like device at the other end of the shaft converts the motions into rotation of the propeller which in turn is converted into energy, for example, electrical energy. The distance between the drift surface and the propeller-like device is equal to or approximately equal to a half wavelength identified as a statically predominant wavelength in the ocean area in which the wave power plant is located.

Description

Wave power plant
The present invention is related to wave power plants in ocean areas, and in particular to a wave power plant that is partially submerged in the ocean and where back and forth motions of the wave power plant are captured by a propeller-like device secured to a shaft member which, at its other opposite end, has a drift surface that aligns the wave power plant with a wave direction in the ocean area in which the wave power plant is located, and where the distance between the drift surface and the propeller-like device is equal to or approximately equal to a half wavelength identified as a statically predominant wavelength in that ocean area.
Waves in the ocean are a source of energy which it has long been desirable to utilise for the production of power. Different forms of wave power plants have been proposed, and some have also been installed. The technical challenges associated with the construction of wave power plants are many as the offshore environment can be extremely inhospitable. Corrosion owing to sea salt and the problems associated with a hundred-year wave are examples of challenges that can be solved, but which often have the consequence that the costs of the construction and maintenance of such plants in operation are extremely high. These costs must be balanced against the power price that can, for example, be obtained by selling power from such plants. There is therefore a desire and a need for simple and low-cost offshore installations which are inexpensive to build and require a minimum of maintenance.
Another phenomenon of wave power plants is that they should also be optimised as regards efficient extraction of the available energy that is in the waves. Efficiency is usually optimal only under some given specific conditions that are not always present in ocean environments. Thus, the output from the wave power plant might vary - which is unfortunate seen from a supply point of view. Consumers or buyers of the power want predictability for their supply of power.
These and similar matters are dealt with by the principles of a wave power plant according to the present invention as claimed in attached independent claim 1 and the advantageous embodiments according to dependent claims 2 to 20.
According to one exemplary embodiment of a wave power plant according to the present invention for location in an ocean area, there are buoyancy bodies secured to the wave power plant that give an adjusted buoyancy which provides a desired partially submerged depth of the wave power plant in the ocean area, wherein at least one propeller or one turbine-like device in the wave power plant is rotated by the back and forth motions of the plant in response to waves in the ocean area in which the wave power plant is partially submerged, wherein this rotation is converted into energy in a connected, adapted device, wherein at least one drift surface is arranged to a shaft member such that one side of the drift surface faces into a wave direction in the ocean area in which the wave power plant is located, and wherein the at least one propeller or turbine-like device is arranged to the shaft, such that the distance between the at least one drift surface and the at least one propeller or turbine-like device is equal to or approximately equal to a half of an identified statistically predominant wavelength in the ocean area in which the wave power plant is located. The shaft member may be a straight shaft member.
According to another exemplary embodiment, the shaft connecting the at least one drift surface and the at least one propeller or turbine-like device is telescopically arranged so as to be adjustable in extent to a particular half-wavelength.
According to another exemplary embodiment, the adjustment of the extent of the shaft member to a particular wavelength is provided by an actuator device in the wave power plant that receives a signal indicating a measured wavelength, and which adjusts the extent of the telescopically arranged shaft member according to the information content of this signal.
According to another exemplary embodiment, the device in the wave power plant is such that it collects measurements of wavelengths at a given measuring frequency, and at given predetermined times initiates an adjustment of the extent of the shaft member in accordance with the measurements that are collected.
According to another exemplary embodiment, a plurality of propellers or turbine-like devices are arranged on their respective side of the drift surface secured to shaft members which pass through the drift surface such that the extent between each one of the plurality of respective propellers or turbine-like devices on their respective sides of the drift surface is equal to or approximately equal to a half of a statistically identified predominant wavelength in the ocean area in which the wave power plant is located.
According to another exemplary embodiment, the adapted device that converts the rotation into energy comprises a hydraulic pump. According to another exemplary embodiment, the hydraulic pump is in fluid communication with an accumulator.
According to another exemplary embodiment, the adapted device that converts the rotation into energy comprises an electric generator.
According to another exemplary embodiment, the adapted device that converts the rotation into energy comprises a seawater desalination device.
According to another exemplary embodiment, the adapted device that converts the rotation into energy is located in a housing located on top of a surface structure supported by supports secured to the buoyancy bodies.
According to another exemplary embodiment, the wave power plant is moored to the seabed by slack chains that allow motion of the wave power plant back and forth in response to wave motions in the water.
According to another exemplary embodiment, at least one rotating propulsion propeller is arranged on a part of the wave power plant that is submerged in water, and where a control unit turns the direction of the propulsion propeller so that the wave power plant can be moved to or held in a particular position.
According to another exemplary embodiment, the control unit comprises a GPS receiver.
According to another exemplary embodiment, the control unit receives control instructions from a user via a wireless connection.
According to another exemplary embodiment, the control unit comprises a measuring device that identifies a wave direction and a wavelength in the ocean area in which the wave power plant is located, and wherein the control unit uses this measurement data to control the propulsion propeller in order to turn the wave power plant into the wave direction whilst a given position of the wave power plant is maintained, and the extent of the shaft member is also adjusted in accordance with the measured wavelength. According to another exemplary embodiment, the at least one drift surface is arranged at a first end (or near the first end) of the shaft member, and the at least one propeller or turbine-like device is arranged at a second end (or end portion) of the shaft member opposite the first end.
According to another exemplary embodiment, the at least one drift surface is configured as, or replaced by, a propeller or turbine-like device, wherein this propeller or turbine- like device also is rotated by the back and forth motions of the wave power plant in response to waves in the ocean area in which the wave power plant is partially submerged, and wherein this rotation is converted into energy in the connected adapted device. It is thus envisaged a wave power plant with two propellers arranged at a distance of Vz wavelength.
According to another exemplary embodiment, the wave power plant further comprises at least one additional propeller or turbine-like device secured to the shaft member between said drift surface and said propeller or turbine-like device. Alternatively or complementary, at least one additional propeller or turbine-like device may be secured to the shaft member after said propeller or turbine-like device, namely further away from the drift surface. The at least one additional propeller may beneficially be used when the present wavelength is less or longer than a half of a statistically identified predominant wavelength in the ocean area.
According to another exemplary embodiment, the at least one propeller or turbine-like device includes blades which are rotateable normal to the shaft member. In this way, the propeller may always turn in the same direction regardless of the back and forth movement of the waves. Also, the blades may be turned when large waves are approaching or hitting the power plant to reduce the forces on the power plant. The propeller may be a controllable pitch propeller, or a self-pitching propeller with free moving blades.
According to another exemplary embodiment, the rotational resistance or energy extraction of the at least one propeller or turbine-like device is adjustable. In this way, the at least one propeller may be used for propulsion of the power plant through the ocean area, by increasing said resistance. With four propellers, the plant may be turned.
Fig. 1 illustrates an exemplary embodiment of the present invention. Fig. 2 illustrates the wave effect that is utilised by the present invention.
Fig. 3 illustrates another exemplary embodiment of the present invention.
Fig. 4 illustrates yet another exemplary embodiment of the present invention.
Fig. 5 illustrates the mooring of a wave power plant according to the present invention.
Fig. 6 illustrates yet another exemplary embodiment of the present invention.
Fig. 1 is an exemplary embodiment of the present invention. A vertical panel 1 forms a drift surface and shafts 3 connect the drift surface 1 to a propeller 2. According to another aspect of the present invention, any device that converts waves into rotation can be used as a propeller in this connection. Buoyancy bodies are arranged on the installation, for example, as a part or parts of tubular structures that form, for example, the shaft 3. In Figure 1 it is vertical tubes projecting up from the shaft 3 that form buoyancy bodies. The buoyancy of these bodies is adapted to the weight of the wave power plant so that the plant is partially submerged, at least submerged so far that the propellers 3 are below the water surface. One aspect of the present invention is that the distance between a drift surface 1 and a propeller 2 is equal to or approximately equal to a 1A wavelength of waves in the ocean area in which the wave power plant is located. This wavelength varies, but there is always a statistical wavelength that is a predominant wavelength in the area, as those of skill in the art will know. By identifying this statistically predominant wavelength, the length of the shaft 3 can be adapted thereto. This arrangement ensures that the wave power plant will move back and forth with the waves. The drift surface 1 ensures that the wave power plant faces into the wave direction. In Figure 2 it is shown how these principles work.
Figure 2 shows how the drift surface 1 follows a wave 4 back and forth. As a person of skill in the art will know, the wave turns after half a wave phase. Thus, the drift surface 1 is moved back and forth by the wave and thus also the propellers 2 that are secured to the shafts 3.
One aspect of the invention is that a minimum of materials is used in the structure, partly to make it as inexpensive as possible, but also so as not to increase the inertia of the system. A light structure will be moved much more easily by the waves. In one exemplary embodiment, the typical predominant wavelengths in an ocean area are between 40 and 60 metres. The distance or the half wavelength used in the structure is thus set at 25 metres.
Another aspect of the wave power plant is to make the installation stable, that is to say that it is not desirable for the plant to be affected by a high or rough sea. hi one exemplary embodiment of the present invention, a wave power plant is equipped with four respective buoyancy points, for example, one in each corner of the installation, or buoyancy bodies. Figure 3 shows an example of a vertical tube 6 projecting vertically from the shaft 3 which forms such a buoyancy point. Furthermore, turbines etc. are arranged symmetrically around the drift surface 1. It is also advantageous to allow two propellers arranged side by side to rotate in their respective directions. The drawings only show propellers with blades in the same direction, but it should be understood that any configuration of propeller blades is within the scope of the present invention.
In one exemplary embodiment of the present invention, the propeller(s) is/are connected to, for example, a rotating pump or electric generator 7, as shown in Figure 3. Hydraulic hoses or cables 8 can transfer power (current) to a collecting point for distribution of power to shore. Hydraulic solutions can feed hydraulically transferred power to a common motor that drives an electric generator, for example. One advantage of using hydraulic solutions is that there is little hysteresis in the system when a wave changes direction (by half a wavelength), which means that a motor is in operation when the wave changes direction. Jolting and jerking in the system is therefore strongly reduced.
Figure 4 shows an example of an arrangement of a housing 11 on the top of the wave power plant according to the present invention. In this housing 11, which is located high above the water surface, a common generator and/or hydraulic installation 9, 10 can be installed. In another exemplary embodiment, the housing may contain a desalination plant as will be known to those of skill in the art. That means to say that the energy generated is used to desalinate seawater.
Figure 5 shows an example of the mooring of a wave power plant according to the present invention. Slack chains hold the plant in position whilst the slack in the chains allows back and forth motion of the plant. In one exemplary embodiment of the present invention, one of the chains may be or have within it a power transfer cable that transfers power from the plant to a cable on the seabed (not shown) which, for example, can be run to a collection point for a number of separate plants.
Figure 6 illustrates another exemplary embodiment of the present invention. A propulsion propeller is arranged on, for example, the drift surface 1 as illustrated in Figure 6. It is within the scope of present invention to be able to arrange propulsion means of any type at any position on the installation. These propellers can be remote- controlled by an operator as will be known to those of skill in the art. With such a solution, an operator in an attendant boat may steer the plant to a desired position for mooring. In another exemplary embodiment, the propulsion propellers are also used to hold the plant in place in a particular position. Deviation or drifting of the plant away from an initial position can be detected. Such measurements can be used to provide correction signals to the propulsion propellers. That means to say that the propulsion propellers may, for example, be turned in different directions which allow the steering of the plant in different directions. A GPS receiver, for example, can be used, and the deviations and steering of the direction and rotation of the propulsion propellers make it possible to correct any deviation in position such that the plant remains almost stationary at the same location. According to another aspect of this solution, wave direction and wavelength can also be measured. The measurement of the wave direction can be used to hold the plant into the wave direction at all times whilst the measurement of the wavelength can be used to adjust the distance between propeller 2 and drift surface 1. In one exemplary embodiment of the present invention, the shaft 3 is telescopically arranged, and one or more actuators can this adjust the length of the shaft 3, for example, corresponding to a measured wavelength.
The person skilled in the art realized that the present invention by no means is limited to the embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For instance, the at least one drift surface may be configured as, or replaced by, a propeller (not shown). Also, the wave power plant may further comprise at least one additional propeller (not shown) arranged on the shaft member between said drift surface and said propeller or turbine-like device and/or after said propeller or turbine-like device. Also, the at least one propeller or turbine-like device may include blades which are rotateable normal to the shaft member. Also, the rotational resistance or energy extraction of the at least one propeller or turbine-like device may be adjustable.

Claims

P a t e n t c l a i m s
1.
A wave power plant for location in an ocean area, wherein buoyancy bodies secured to the wave power plant have an adjusted buoyancy that provides a desired partially submerged depth of the wave power plant in the ocean area, wherein at least one propeller or one turbine-like device in the wave power plant is rotated by back and forth motions of the wave power plant in response to waves in the ocean area in which the wave power plant is partially submerged, wherein this rotation is converted into energy in a connected adapted device, wherein at least one drift surface is arranged to a shaft member such that one side of the drift surface faces towards a wave direction in the ocean area in which the wave power plant is located, and wherein the at least one propeller or turbine-like device is arranged to the shaft member such that the distance between the at least one drift surface and the at least one propeller or turbine-like device is equal to or approximately equal to a half of an identified statistically predominant wavelength in the ocean area in which the wave power plant is located.
,
2.
A wave power plant according to claim 1, wherein the shaft member connecting the at least one drift surface and the at least one propeller or one turbine-like device is telescopically arranged so as to be adjustable in extent to a specific half wavelength.
3.
A wave power plant according to claim 2, wherein the adjustment of the extent of the shaft member to a specific half wavelength is provided by an actuator device in the wave power plant which receives a signal indicating a measured wavelength, and which adjusts the extent of the telescopically arranged shaft member in accordance with the information content of this signal.
4.
A wave power plant according to claim 3, wherein the device in the wave power plant collects the measurements of wavelengths at a given measurement frequency, and at given predetermined times an adjustment of the length of the shaft member in relation to the measurements collected is initiated.
5.
A wave power plant according to claim 1, wherein a plurality of propellers or turbine- like devices are arranged on their respective side of the drift surface attached to shaft members that pass through the drift surface such that the extent between each one of the plurality of respective propellers or turbine-like devices on their respective sides of the drift surface is equal to or approximately equal to a half of a statistically identified predominant wavelength in the ocean area in which the wave power plant is located.
6. A wave power plant according to claim 1, wherein the adapted device which converts the rotation into energy comprises a hydraulic pump.
7.
A wave power plant according to claim 6, wherein the hydraulic pump is in fluid communication with an accumulator.
8.
A wave power plant according to claim 1, wherein the adapted device which converts the rotation into energy comprises an electric generator.
9.
A wave power plant according to claim 1, wherein the adapted device which converts the rotation into energy comprises a seawater desalination device.
10.
A wave power plant according to claim 1, wherein the adapted device which converts the rotation into energy is placed in a housing located on top of a surface structure supported by supports secured to the buoyancy bodies.
1 1.
A wave power plant according to claim 1, wherein the wave power plant is moored to the seabed with slack chains that allow movement of the wave power plant back and forth in response to wave motions in the water.
12.
A wave power plant according to claim 1, wherein at least one rotating propulsion propeller is arranged on a part of the wave power plant which is submerged in water, and wherein a control unit turns the direction of the propulsion propeller so that the wave power plant can be moved to or held in a specific position.
13.
A wave power plant according to claim 12, wherein the control unit comprises a GPS receiver.
14.
A wave power plant according to claim 12, wherein the control unit receives control instructions from a user via a wireless connection.
15.
A wave power plant according to claims 3 and 12, wherein the control unit comprises a measuring device that identifies a wave direction and a wavelength in the ocean area in which the wave power plant is located, and wherein the control unit uses this measurement data to control the propulsion propeller in order to turn the wave power plant into the wave direction whilst a given position of the wave power plant is maintained, and the extent of the shaft member is also adjusted in accordance with the measured wavelength.
16. A wave power plant according to any preceding claim, wherein the at least one drift surface is arranged at a first end or near the first end of the shaft member, and wherein the at least one propeller or turbine-like device is arranged at a second end or end portion of the shaft member opposite the first end.
17.
A wave power plant according to claim 1, wherein the at least one drift surface is configured as a propeller.
18.
A wave power plant according to claim 1, further comprising at least one additional propeller or turbine-like device secured to the shaft member between said drift surface and said propeller or turbine-like device and/or after said propeller or turbine-like device.
19.
A wave power plant according to claim 1, wherein the at least one propeller or turbine- like device includes blades which are rotateable normal to the shaft member.
20.
A wave power plant according to claim 1, wherein the rotational resistance or energy extraction of the at least one propeller or turbine-like device is adjustable.
PCT/NO2009/000229 2008-06-20 2009-06-18 Wave power plant WO2009154475A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO20082853 2008-06-20
NO20082853A NO328608B1 (en) 2008-06-20 2008-06-20 Tensile power plant adapted to half wavelengths

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WO2009154475A2 true WO2009154475A2 (en) 2009-12-23
WO2009154475A3 WO2009154475A3 (en) 2010-12-23

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WO (1) WO2009154475A2 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1467093A1 (en) * 2001-07-11 2004-10-13 Hydra Tidal Energy Technology AS Generator for water current turbine with counter-rotating rotors.
WO2004104411A1 (en) * 2003-05-21 2004-12-02 Hydra Tidal Energy Technology As Arrangement for anchoring a floating structure
EP1878914A2 (en) * 2006-07-10 2008-01-16 Siegel Aerodynamics, Inc. Cyclical Wave Energy Converter

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1467093A1 (en) * 2001-07-11 2004-10-13 Hydra Tidal Energy Technology AS Generator for water current turbine with counter-rotating rotors.
WO2004104411A1 (en) * 2003-05-21 2004-12-02 Hydra Tidal Energy Technology As Arrangement for anchoring a floating structure
EP1878914A2 (en) * 2006-07-10 2008-01-16 Siegel Aerodynamics, Inc. Cyclical Wave Energy Converter

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NO328608B1 (en) 2010-03-29
WO2009154475A3 (en) 2010-12-23
NO20082853L (en) 2009-12-21

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