WO2007051034A2 - Static dynamic wind machine - Google Patents

Abstract

A tethered wind powered electricity generating hybrid aerostat (i.e., static- dynamic wind machine) is described utilizing a partially or fully lighter than aircraft additionally having a set of wings with lifting and stabilizing capacity.

Description

STATIC-DYNAMIC WIND MACHINE

RELATED APPLICATIONS

[0001] NOT APPLICABLE.

FIELD OF THE INVENTION

[0002] The present invention relates to generation of electricity using wind power, and in particular to devices for such electricity generation.

BACKGROUND OF THE INVENTION

[0003] The following discussion is provided solely to assist the understanding of the reader, and does not constitute an admission that any of the information discussed or references cited constitute prior art to the present invention.

[0004] A variety of rotor and generator designs have been proposed and utilized for generating electrical energy from wind.

[0005] For example, Winderl, U.S. Patent 4,039,848 describes a "wind generator employing counterrotating propellers." The propellers are "tied together on concentric shafts supported in a positive drive structure in which the shafts are tied together through gearing to insure positive starting and counter-rotation of the propellers in a positive equal drive system."

[0006] Most described wind generators are mounted on a solid structure, e.g., on a pylon. However, certain systems can be described as "windmill kites".

[0007] A design for a windmill kite is described in Roberts et al., U.S. Patent Appl. Publ. 2005/0067839, which states that "the invention consists in a windmill kite of the kind comprising a flying platform including a plurality of mill rotors, at least one tethering line ... , at least one dynamo on the platform drive-connected to said mill rotors, and conductor means." (See, paragraph 28.)

[0008] Another example is Kingsley, U.S. Patent Appl. Publ. 2005/0046197, which "relates to a kite designed to transmit mechanical energy to a ground mounted, stationary generator where it generates electricity or direct energy to mechanical equipment such as pumps." (See, paragraph 8.)

[0009] Mizzi, U.S. Patent 6,555,931 describes a renewable energy generating system utilizing one or two airfoils to drive a long-stroke open-channel reciprocating engine to drive a pump or an electrical generator.

[0010] In addition to strict aerostats, Peterson, U.S. Patent 5,1 15,997 describes a surveillance balloon that "includes an aerodynamic lifting device". The aerodynamic lifting device is indicated to "prevent excessive drifting and decreases in altitude in high wind conditions", such that the "lifting device acts to maintain the main inflatable body at the desired altitude even when the inflated main body is subjected to high wind conditions such as 50 mph winds."

SUMMARY OF THE INVENTION

[0011] Wind generators or wind turbines for producing electricity have been utilized for a substantial period of time. Most such generators are land mounted with the generators and rotors mounted at the tops of tall towers or pylons which elevate the rotors above the ground. Such designs suffer from the disadvantage that near ground wind speeds are typically much lower that at heights of a few hundred feet. Such low wind speeds effectively limit installation of wind generators to a few elevated locations where winds are usually strong near the ground and to certain marine locations at which strong winds are commonly present.

[0012] In contrast, the present invention concerns a system for positioning a generator at a higher elevation using a tethered aerostat, such as a tethered dirigible or blimp. In certain advantageous implementations the tethered aerostat is a hybrid aerostat.

[0013] As used herein, the term "aerostat" refers to an aircraft deriving its lift, at least in part, from the buoyancy resulting from displacement of the surrounding air by a body filled with a low density gas such as hydrogen or helium rather than from aerodynamic motion. Thus, a "tethered aerostat" is attached to a base platform, e.g., the ground, ship, or barge, using a tether, i.e., an attached cable or other such line.

[0014] As used herein, the term "hybrid aerostat" refers to an aerostat that also derives substantial lift from the movement of air over one or more aerodynamic surfaces, e.g. airfoils such as wings. Such a hybrid aerostat that includes a wind- powered generator is also referred to herein as a "static-dynamic wind machine".

[0015] Thus, in a first aspect, the invention provides a tethered aerostat that includes a wind powered generator, i.e., a wind powered generator aerostat. Typically, such aerostats are rigid or semi-rigid aerostats.

[0016] Typically such an aerostat includes a body that has at least one chamber containing a lighter than air gas or designed to contain such gas, a wind powered electrical generator located in the body; and at least one exposed rotor coupled with the generator. The generator generates electricity when tethered in a wind stream such that the rotor rotates.

[0017] In such aerostats, the generator can be an alternating current generator (i.e., an alternator); a direct current generator; the generator includes counter rotating magnet-containing current inducing portion and the winding-containing induced portion (e.g., stator and rotor portions in common generators).

[0018] The body of the aerostat can include a rigid shell or a flexible covering or combinations of rigid shell and flexible covering; the shell is a composite material; the shell include electrically conductive material (e.g., for lightning protection); the shell is metal-containing composite material, e.g., a fiber metal laminate, a metal laminate composite, or a metal matrix composite.

[0019] In advantageous embodiments, the aerostat is a static-dynamic wind machine (that is a wind generator hybrid aerostat) such that the body also includes aerodynamic surfaces providing lift in an airstream, such as at least a pair of airfoils projecting from opposite sides of the body, e.g., from opposite sides of a central fuselage. In certain embodiments, the body includes front airfoils projecting from opposite sides of the front half of the fuselage and rear airfoils projecting from opposite sides of the rear portion of the fuselage; the rear airfoils include elevators; the rear airfoils are stabilators; the front airfoils include ailerons; at least some of the airfoils include moveable control surfaces and the aerostat also includes a flight regulator controlling the moveable control surfaces, e.g., to control the flight attitude of the aerostat; the body also includes a vertical stabilizer; the vertical stabilizer includes a rudder; such flight regulator includes a microprocessor.

[0020] In certain embodiments, the rotor consists essentially of two counter-rotating sets of blades, which may be proximate or adjacent; the rotor includes at least one set of blades (e.g., 1 or 2 sets) where the pitch of the blades is adjustable, such adjustment may be automatically controllable or adjusted by remote signal (e.g., via wired or optical fiber connection or rf signal); such adjustment can be set to control the rate of rotation of the rotor. [0021] In certain embodiments, the aerostat is operationally placed at an elevation of at least 30, 40, 50, 75, 100, 150, 200, 300, 500, 1000, 2000, or 3000 meters above the surface to which the tether is attached; the aerostat is operationally placed at an altitude of 30-100, 100-200, 200-300, 300-500, 500-1000, 1000-2000, 2000-5000 meters; the aerostat operates at a location with a horizontal displacement no more than 100, 75, 50, 40, 30, 25, 20, or 15 percent of the vertical displacement from the ground attachment point for tether.

[0022] In certain embodiments, the aerostat includes a body that has a generally cylindrical central portion, a rounded front portion, and a tapered rear portion or a flattened projecting portion, wherein the front or central portion includes two wings projecting from opposite sides of the that portion, and at least two wings projecting from opposite sides of the rear portion.

[0023] In particular embodiments, the aerostat includes a warning beacon (e.g., one or a plurality of red lights which may be flashing); the tether includes warning lights.

[0024] A related aspect concerns an electrical power generating and storage system that includes a wind powered generator aerostat as described herein electrically connected with an energy storage subsystem.

[0025] In particular embodiments, the energy storage sub-system includes an electrical energy storage sub-system, such as battery sub-system; the energy storage sub-system includes a kinetic energy storage sub-system; the energy storage sub-system includes a chemical energy storage sub-system, for example a hydrogen storage sub-system, which may include an electrolytic hydrogen generator and storage sub-system.

[0026] Another related aspect concerns an electricity generating array that includes an energetically linked plurality of wind powered electrical generators that includes at least one wind powered generator aerostat as described herein in physical proximity and operated under common control. The additional wind powered generators may be additional aerostats as described herein and/or may be other types of generators, e.g., pylon-mounted wind generators. In many cases, the array will include at least 2, 3, 4, 5, 8, 10, 15, or 20 of the present aerostats. [0027] In particular embodiments, the energetic linkage involves electrical linkage in which the aerostats direct generated electricity into a common distribution system, or into a common energy storage system, or both.

[0028] Also in particular embodiments, the array is located in a marine location; the array is located in a land location; the array is located in an arctic location.

[0029] A further related aspect concerns a method for generating electrical power by deploying at least one tethered wind powered generator aerostat, or an array of such aerostats, as described herein.

[0030] In particular embodiments, the electricity produced by the aerostat(s) is fed to a regional electricity net; the electricity is utilized locally; the electricity is utilized on a ship.

[0031] Yet another related aspect concerns a method for locating a tethered wind powered generator aerostat by selecting a location at which winds at at least one elevation that the aerostat can attain averages at least 4 meters per second (m/s) and deploying an aerostat as described herein at such elevation.

[0032] In certain embodiments, the elevation is at least 10, 20, 30, 50, 100, 200, 300, 500, 1000 meters; the wind in the selected location averages at least 6, 8, 10, 12, 15, 20, 25, or 30 m/s; the deploying involves releasing a fully lighter than air aerostat and allowing the tether to extent until the aerostat is at the desired altitude; the deploying involves towing an aerostat (e.g., an aerostat that requires dynamic lift for flight) to a deployment location (e.g., towing using a winch and/or a moving vehicle); the deploying involves extending an aerostat up from a cradle or mooring position such that stronger wind is encountered such that increased dynamic lift is obtained (e.g., such that an aerostat requiring such dynamic lift for flight will fly); the selected elevation is in a range of 30-500 meters, 500-1000 meters, 1000-2000 meters, 2000- 5000 meters; the selected elevation is in a range as described in the first aspect above.

[0033] For specification of wind speeds, the an average wind speed at a particular location is taken as the average wind speed over a period of at least one hour, and preferably an average over longer periods, e.g., 1 day, 1 week, 1 month, 1 year, or during daylight hours over such periods.

[0034] As used herein, the term "wind powered generator aerostat" means a tethered aerostat that includes a wind powered electrical generator.

[0035] As used herein, the terms "wind powered generator" and "wind generator" refer to an electrical generator configured such that it converts wind energy to electrical energy, which can be provided in the form of either alternating current (AC) or direct current (DC).

[0036] As used herein, the term "airfoil" refers to a surface designed to produce lift from the movement of air over it. Ideally, it should present the greatest amount of lift with the least amount of drag. The front of the airfoil is the leading edge and is usually a rounded section. The back of the airfoil is the trailing edge and usually tapers to nearly a point. The distance between the two is the wing chord. The top surface of the airfoil is usually curved to allow smooth airflow and produce lift. While wind powered generator rotor blades, e.g., propeller blades, are generally airfoils, as used herein the term "airfoil" does not include such rotor blades unless expressly modified to indicate the relationship. Examples of such modified terms include "rotor airfoil", "blade airfoil", "propeller airfoil" and the like.

[0037] In reference to the present aerostats, the term "body" refers to the structure of the aerostat, e.g., including a fuselage or central shape, and also includes any directly attached airfoils (excluding rotors) that are part of the aerostat. The "body" includes the outer shape-defining envelope or shell as well as any internal frame or other support structure.

[0038] In the context of gas confinement as used herein, the term "chamber" refers to a closed, essentially gas-tight space.

[0039] As used herein the unmodified term "rotor" refers to a wind driven rotor, e.g., that drives a generator. It is recognized that generators can also include rotors; such rotors are referred to herein as generator rotors or rotor portions or otherwise clearly indicated to be part of the electrical generator. [0040] As used herein in relation to rotors for driving wind powered generators, the terms "blade" and "propeller" refer to generally elongated rotator surfaces designed to be wind-driven. Such blade will often be shaped similarly to a conventional propeller with an airfoil shape.

[0041] In the context of placement of rotors in the present aerostats, the term "adjacent" means that the rotors are located next to each other but not touching with, no intervening components except that there may be components for preventing adjacent rotors from contacting each other during rotation, e.g., a fuselage spacer creating separation between the adjacent rotors.

[0042] As used herein unless expressly modified the term "generator" includes both direct current generators and alternating current generators (commonly referred to as alternators).

[0043] In the context of the present generators, the term "current inducing portion" or "inducing portion" refers to the magnet-containing portion of the generator that induces current in an induced portion passed through the magnetic field from the magnets.

[0044] Also in the context of the present generators, the term "induced portion" refers to the winding-containing portion of the generator in which current is induced by passing through the magnetic field from the magnets in the current inducing portion.

[0045] In reference to a pair of wind driven rotors, the term "counter-rotating" indicates that the two rotors rotate in opposite directions about the same rotational axis, e.g., about the longitudinal axis of the aerostat.

[0046] In the context of the present aerostats, the term "tether" refers to a line connecting an aerostat with an anchor point, and can include both a restraint and an electrical conductor which can be the same or different.

[0047] In connection with tethering of the present aerostats, the term "anchor point" refers to the base attachment point for a tether connected with an aerostat, and not to the attachment point of the tether to the aerostat. Such anchor point may be to any of a variety of structures, e.g., ground-based structures such as a mobile aerostat transporter, a fixed ground anchor structure, a building, a train, or to a water-based structure such as a ship- or barge-mounted anchor structure.

[0048] The term "rigid shell" is used to refer to an outer body portion that is generally rigid, i.e., resistant to bending. Thus, a rigid shell (or the portions thereof for a multi- piece shell) is sufficiently stiff and strong to hold its shape without added support in a static situation. It should be understood that such a shell will often be attached to internal support structures when installed in a present aerostat, but also may provide all or a substantial amount of the strength of the overall structure.

[0049] The term "elevator" is used in its conventional aeronautic sense to refer to a moveable control surface in an aircraft that controls the aircraft about the pitch axis (lateral axis) of the aircraft, e.g., an aerostat.

[0050] The term "aileron" is used in its conventional aeronautic sense to refer to a moveable control surface in an aircraft that controls the aircraft about its roll axis (longitudinal axis).

[0051] The term "rudder" is used in its conventional aeronautic sense to refer to a moveable control surface in an aircraft that controls the aircraft about its yaw axis (vertical axis), e.g., to control the horizontal direction of the aircraft.

[0052] The terms "moveable control surface", "control surface", and "flight control surface" refer to moveable portions of wings and other lift generating and stabilization

[0053] As used herein the term "flight regulator" means a system for controlling moveable control surfaces of a hybrid aerostat, e.g., to achieve or maintain an approximately level orientation and/or to position the aerostat relative to the anchor point, and/or to control the positioning of the aerostat during towing operations. Such flight controls can include remote controls (e.g., radio frequency (rf) controls) as well as automatic controls.

[0054] In reference to the flight positioning of an aerostat, the term "attitude" refers to the directional positioning, e.g., e.g., about the pitch, roll ;and/or yaw axes. [0055] In connection with the present systems, the term "energy storage sub-system" refers to a portion of an electricity and energy storage system such that the subsystem accepts generated electricity and converts it into an energy form that can be stored for a period of time. Thus, an "electrical energy storage sub-system" converts and stores energy in a form such that it is directly recoverable as electricity (e.g., batteries). A "kinetic energy storage sub-system" is one in which the generated electrical energy is converted to kinetic energy, e.g., high speed rotation of a flywheel. Such rotation can subsequently be used to drive a generator to regenerate electricity or can drive a mechanical load. A "chemical energy storage subsystem" is a non-battery sub-system that used the generated electricity to produce a chemical entity or entities (i.e., chemical compounds) that can release energy in a subsequent process, e.g., heat energy in a combustion reaction, or generation of electricity in a fuel cell.

[0056] In particular embodiments, hydrogen is stored in metal hydride tanks; in compressed hydrogen tanks; as liquid hydrogen; as chemically stored hydrogen; in carbon nanotubes; in glass microspheres; in liquid carrier storage; in a porous material.

[0057] The term "electrolytic hydrogen generator" refers to an apparatus (e.g., as part of a chemical energy storage sub-system) that produces hydrogen from water using electricity.

[0058] As used herein in connection with deployment of a plurality of aerostats, the term "array" refers to a plurality of such aerostats deployed in a local area under common control. It does not imply any particular geometric distribution of the aerostats.

[0059] In the context of electricity generated by the present generator aerostats, "energetically linked" means that the energetically linked aerostats are directly or indirectly connected to receive and/or provide electrical energy or a derivative energy form to or from the same source, storage system, or distribution channel. [0060] In reference to the deployment locations of multiple aerostats, the term "physical proximity" means that the units are sufficiently close to be operationally linked, e.g., with adjacent units being within 2 kilometers, 1 kilometer, 0.5 kilometer.

[0061] The phrase "operated under common control" is used to mean that same entity controls the operation of the referenced multiple aerostats or at least controls the electrical output from such multiple aerostats.

[0062] In reference to placement of the present aerostats, the term "deploying" refers to the process of placing the unit on-site and in operation. Thus, the process includes placing the aerostat in flight, at the desired location, and operationally connected with a tether to the anchor point and associated base station facilities.

[0063] In connection with distribution and utilization of electricity, the term "regional electricity network" (as like terms) refers to a wide area electricity distribution system providing electricity to large numbers of separate users. Different regional electricity networks may be connected to form larger regional electricity networks, e.g., national and/or transnational networks.

[0064] In reference to electrical energy generated by the present systems, the term "utilized locally" means the electrical energy or derivative energy form is utilized near the site of generation without being directed to a regional electricity net.

[0065] In reference to electrical energy generated by the present systems, the phrase "utilized on a ship" means that the electrical energy or a derivative energy form is utilized in operating a ship or equipment directly associated with such ship.

[0066] Additional embodiments will be apparent from the Detailed Description and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Fig. 1 shows a perspective view an exemplary static-dynamic wind machine, i.e., a wind powered generator aerostat.

[0068] Fig. 2 shows a cross-sectional diagrammatic view of the exemplary static- dynamic wind machine of Fig. 1.

[0069] Fig. 3 shows a perspective view of a second exemplary static-dynamic wind machine.

[0070] Fig. 4 shows a top view of the static-dynamic wind machine shown in Fig. 3.

[0071] Fig. 5 shows a front view of the static-dynamic wind machine shown in Fig. 3.

[0072] Fig. 6 shows a side view of the static-dynamic wind machine shown in Fig. 3.

[0073] Fig. 7 shows a rear view of the static-dynamic wind machine shown in Fig. 3.

[0074] Fig. 8 shows a bottom view of the static-dynamic wind machine shown in Fig. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0075] The present invention concerns tethered aerostats that include a wind powered generator, such that the aerostat can be deployed at an elevation above the ground or water surface. By deploying the aerostat in this manner, the wind generator will typically experience stronger winds than near the ground. Such stronger winds allow the aerostat to effectively generate electricity a much greater percentage of the time, and there is greater wind energy available for electricity generation.

[0076] In addition, by utilizing an aerostat, the generator can be operated even in relatively light winds, e.g., winds that would not be sufficient to keep a kite-type generating platform airborne. Further, by utilizing a static-dynamic wind machine (i.e., a wind powered generator hybrid aerostat) it is possible to obtain yet further advantages. The dynamic lift provided by the wings or other airfoils on the hybrid aerostat allows even small aerostats to provide substantial electricity generation because the additional lift allows a larger capacity generator to be installed (i.e., a generator of such size that the lift provided by the lighter than air gas in the aerostat would not be able to provide sufficient lift). Also, the lift provided by the airfoils allow the aerostat to be "flown" to a position more directly over the anchor point than if the airfoil lift were not available. Still further, the airfoils contribute to a more stable attitude for the airborne aerostat, and also allow active control of the aerostat position and attitude by the incorporation of a flight regulator (flight controls) and moveable control surfaces. As indicated above, such a hybrid aerostat that includes a wind-powered generator is also referred to herein as a static-dynamic wind machine.

Body Construction and Aerostat Configuration

[0077] The body for the present aerostats can be designed in many different ways and using different materials. In general, a sufficiently strong structure is desirable to support the generator with its associated rotor(s), and accept the drag of the tether, and to withstand strong winds. However, this can be accomplished with a variety of designs. [0078] For example, the aerostat design can be a semi-rigid aerostat, with a flexible envelope connected with a keel or other support structure. The envelope can itself form a bag for containing the gas, and/or can contain smaller gas bags within it, and can also include one or more ballonets. The keel or other support structure assists in maintaining the overall structure, can provide attachment support for the wings, and supports the generator with its associated rotor(s).

[0079] Alternatively, the aerostat can be a rigid design. A conventional approach for constructing a rigid aerostat is to use a rigid frame structure defining the outer contours of the aerostat, covered with a flexible skin, with gas bags inside the skin or with the skin defining a gas chamber. Generally the design will also include one or more ballonets (variable volume gas bags) for adjusting for changing lift gas volume.

[0080] Another approach is to use a rigid skin or shell, which can be constructed of various materials, e.g., a composite material. Especially for smaller aerostats, the shell can provide at least a substantial portion of the structural strength of the aerostat. For larger aerostats, usually there will also be a frame supporting the rigid skin. A rigid skin can be constructed of any of a variety of materials, e.g., materials that have been used for aircraft, including various composite materials. Such composite materials include those using both thermoset and thermoplastic matrix materials with various fibers, e.g., carbon, boron, and the like. An exemplary construction method is described in US Pat Publ 2004/00118977, entitled One-piece closed-shape structure and method of forming same, which is incorporated herein by reference in its entirety. Other fabrication methods are well-known to those in the field of aircraft production and in working with composite materials.

[0081] Usually an aerostat will include vertical and horizontal stabilizers or other such surfaces that wind can act on to cause the aerostat to align into the wind.

[0082] A large number of different composite materials have been described, some of which have been used in commercial and/or military aircraft. Such materials can be used for the present aerostats. In addition, exemplary materials are described, for example, in US Pat Publ 20030108763 describing metal fiber-reinforced composites and US Patent 5,118,558 describing a laminate material, and US Patent

4,082,864 all of which are incorporated herein by reference in their entireties. [0083] It is often desirable to provide lightning control for aircraft, such as the present aerostats. The techniques used can vary depending on the material of which the aerostat is constructed, and the design of the tether. In many cases, the lightning protection will include the provision of conductors in and/or on the aerostat skin to provide an exterior conduction path. Without being limited as to the actual mechanism, it is believed that such conductors protect the craft through a partial Faraday cage effect and/or through a "skin effect". Such protection is described, for example, in US Pat Publ 2005/0213278 entitled Lightning damage protection for composite aircraft, which is incorporated herein by reference in its entirety. Additional patents applicable to lightning protection include US Patent 5,370,921 entitled Lightning strike composite and process; US Patent 5,191 ,503 entitled Lightning surge protector; US Patent 5,126,507 entitled Arrangement for protection of electrical installation against electrical disturbance; US 5,043,527 entitled Dissipation array systems for lightning protection; US Patent 4,891,732 entitled Anti-lightning strike fasteners for composite material aircraft structures; and US Pat Publ 2004/0130842 entitled Lightning protection system for, e.g., wind turbine, wind turbine blade having a lightning protection system, method of creating a lightning protection system and use thereof, all of which are incorporated herein in their entireties.

[0084] The generator and tether (as well as flight controller if present) should also be protected. Typically such tether protection involves shielding and grounding of protective conductors in the tether. Exemplary tether protection is described, for example, in Beach et al., U.S. Patent 4,842,221 (incorporated herein in its entirety) which describes the use of a sacrificial, soft copper wrap attached to a grounding system.

[0085] For safety purposes, it is desirable for the aerostat to be marked with a warning beacon or beacons. Such beacon will typically include at least one light, which may be flashing, and will be a color accepted as a waning or danger light in the locality in which the aerostat is to be deployed. Examples include red and amber lights. The beacon light or lights should be visible from 360 degrees. An exemplary beacon light configuration utilizes an exposed beacon light on the top of the aerostat body and another exposed beacon light on the bottom of the body (e.g., on the top and bottom of a central fuselage). For cases in which the aerostat is to be deployed at higher elevations, it may also be desirable to provide a warning light or lights on the tether. Techniques for providing such tether lights have been described and can be utilized for the present devices.

[0086] As pointed out above, the present wind powered generator aerostats include rotors for driving the generators under wind power. In many cases, such rotors will include a plurality of blades that are oriented generally radially in a plane from the center of the rotor. Suitable rotor blades; can be designed in many different ways, so long as wind passing the blades will create a force causing rotation of the rotor. The blades can be shaped as airfoils but also can be flat blades or other cross- sectional shapes. The rotor blades should be distributed such that significant unbalanced forces are not created during rotor rotation, i.e., distributed in a balanced configuration. The number of blades in a rotor can also vary. However, usually the number of blades will be 2-4, and most commonly 3.

[0087] Rotor blades should be placed such that they do not interfere with the tether, e.g., do not strike the tether while the aerostat is changing position in shifting wind. Thus, the rotor blades are typically placed behind the front wings, but usually, but not necessarily, ahead of rear stabilizers. Typically, the rotors are multi-blade rotors, e.g., 3 equally spaced blades, that rotate in a plane perpendicular to the longitudinal axis of the aerostat. Advantageously, two blade sets (i.e., two rotors) can be incorporated, which can be counter-rotating blades. The blades are spaced sufficiently apart that they do not contact each other when stressed during operation. The rotors are coupled to the generator, driving rotation of the generator and generating electricity. In the case of counter-rotating rotors, one rotor can directly drive either the inducing or induced portion of the generator, with the other portion being stationary. The second rotor can then drive the same portion through an equal drive transmission. Alternatively, one rotor directly drives either the inducing portion or the induced portion, and the counter-rotating rotor directly drives the other of the inducing portion and the induced portion. In such embodiments, the effective rotation rate of the generator is doubled.

[0088] In additional designs, a generator aerostat has a design that is not limited to a central fuselage carrying a generator. For example, a hybrid aerostat may include a pair of wings that are sufficiently long and of sufficient strength to carry a generator in each wing (instead of or in addition to a generator located in the fuselage). Similarly, a generator may be mounted in projections below and/or above and/or beside the fuselage (and may be combined with a fuselage generator and/or wing generators). In another example, a central body shape may be utilized for the lift gas-containing section that is itself an airfoil, either with or without wing structures. In such design, the generator placement is adapted to allow rotation of the rotors.

[0089] The gas chambers, bags, or ballonets can be constructed as conventional for aerostats, and can use materials as described for such applications, taking into consideration the particular application factors, e.g., the type of low density gas to be used, the wind conditions that will be experienced, the fill pressure, the desired useful life between filling, and the weight of the material and other components of the aerostat. Such gas chambers may be defined by the outer shell or covering or by gas bags or by other barriers. In addition to gas chambers or bags in the main portion of the body (e.g., the fuselage), in hybrid aerostats, the gas chamber(s) may also include the wing interiors.

[0090] The selected lift gas used to fill the gas chambers or bags (i.e., the low density gas used for providing buoyant lift) can be any of the gases described for such application. Hydrogen and helium are commonly used (though other gases have also been described). Hydrogen is preferred for the present application due to its greater lift capacity (i.e., lower density), but other low density gases can also be utilized.

[0091] A variety of different aerostat tethers have been described and can be used. For the present application, the tether should include at least one strength member, and sufficient electrical conductors to carry electricity generated by the aerostat generator. A tether may also include additional components such as signal conductors, optical fibers, lightning protection conductors, lighting conductors, and sealing, insulation, and/or protective layers.

[0092] The attachment of the tether to the aerostat should be constructed consistent with the particular aerostat construction characteristics. In cases in which rigid wings are incorporated, the tether can attach to solid portions of the structure, e.g., can connect using a harness attached at or near the bases of the wings, or if the wings are sufficiently strong, to the tips or intermediate points. Attachment may be to a single point,<or through multiple points, e.g., 2, 3, 4 different points. Where multiple attachment points are used, at least one of the attachment lines will carry the conductors. If attachment to flexible body components is desired, typically a multipoint attachment harness is used to spread the forces over larger areas.

Airfoils and Other Aerodynamic Surfaces

[0093] In advantageous embodiments, the present aerostats are static-dynamic wind machines (i.e., hybrid aerostats), and therefore, include aerodynamic lift surfaces, e.g., airfoils. As commonly recognized, airfoils can be designed in a variety of shapes. A simple design incorporates a pair of primary forward wings that project from opposite sides of the body in the front portion, and a pair of smaller rear wings. In this design, the forward wings provide the majority of lift and contribute to roll stability, and the rear wings contribute to stability (especially control of pitch) and attitude control. The lift contribution of the respective forward and rear wings can be designed variously, but should be balanced such that a generally horizontal attitude can be maintained. The lift of each wing can be designed based, for example, on length, width, cross-sectional shape, and angle of attack, and can be adapted or optimized for different wind speeds. In addition, moveable control surfaces can be incorporated allowing modification of the shape of the airfoil, thereby modifying the lift characteristics. In many designs, the forward wings provide the majority of the dynamic lift, while the rear wings are primarily used for stabilization and/or controlling the angle of attack. In the cases of both front and rear wings, more than one airfoil, e.g., two pair of forward and/or rear wings.

[0094] Advantageously, the forward wings are shaped as conventional wings, e.g., designed to provide effective lift with a wind speed of as little as 4 m/s over the wing, or by 6, 8, or 10 m/s. Preferably the wing will also provide effective lift at higher airspeeds, e.g., at 6-10, 10-20, 20-40, 40-60 m/s.

[0095] The rear wings can be fixed, fixed with moveable elevators, or fully moveable wings (i.e., stabilators). [0096] Typically the aerostat will also include a vertical stabilizer, with or without a rudder. Such vertical stabilizer may include an extension or projection from a central fuselage, or may be a flattened portion of the body essentially providing a fin area. During on-site operation, a vertical stabilizer assists in maintaining the heading of the tethered aerostat into the wind, and generally does not require rudder operation. During towing operations to place an aerostat, a rudder can be beneficial to control the positioning of the aerostat relative to the tow vehicle or aircraft. Typically, such rudder would then be fixed in a neutral position for operation on-site.

[0097] In aerostats having moveable control surfaces, automatic flight controls can be advantageously incorporated. Such flight controls will move the control surfaces in order to maintain the attitude of the aerostat, e.g., level flight, and/or the positioning of the aerostat relative to the anchor point despite changing wind conditions. Such controls can also be useful during deployment and/or retrieval and landing. Alternatively, remote control, for example through signal wires, optical fibers, or using radio control, can be used during such deployment and/or retrieval and landing operations, or even for adjustment or trimming during generating operation.

[0098] In addition, advantageously the aerostat includes control, (preferably automatic control) of rotor pitch, e.g., using electric servo motors or hydraulic cylinders to adjust the rotor blade angle. Such pitch control is useful to control rotor rotation speed over a very wide range of wind speeds.

Generators

[0099] Many different types of AC and DC generators have been described. Suitable generators for this application can be selected, adapted, or designed in view of the relevant considerations, e.g., lightweight and high output. The generator should be selected or designed to be adapted in weight and output to the size and lift of the aerostat.

[00100] The generator is coupled to the rotor(s), such that the generator induced portion and/or inducing portion are rotated to generate electricity. Energy Storage

[00101] In many installations, the electricity generated by the generator aerostat is fed directly to an electricity distribution network, or to a load site, e.g., a factory or a ship. However, in some cases, it is advantageous to store energy in a useable form. Such storage allows the energy to be used a later, e.g., during periods in which wind energy is unavailable or insufficient, and/or allows distribution of other energy form.

[00102] One such energy storage form is battery storage. Battery storage is well-known and a battery storage sub-system can be constructed using readily available systems and components, e.g., batteries and as needed, devices for altering to form of electricity, such as converting from AC to DC current and/or to change voltage (e.g., power inverters, transformers, and/or power converters). However, due to the size and cost of batteries, such storage is usually relatively small scale.

[00103] Another such energy storage form is kinetic energy storage. Storage as kinetic energy typically uses one or more flywheels that are accelerated to high speed, e.g., using electrical motors. The kinetic energy can then be re-captured by using the spinning flywheels to drive one or more generators (or to directly drive a mechanical load), with the generated electricity being used in a conventional manner.

[00104] Yet another energy storage form is non-battery chemical energy storage. In this form, the initially generated electricity is used to directly or indirectly produce one or more chemical entities that can be used to release useable energy. Examples include combustible compounds and/or compounds that can be used in fuel cells. A particular example is hydrogen, which can be readily produced from water in an electrolytic hydrogen generator, and then can be stored, e.g., in tanks under high pressure or as a liquid. Hydrogen can be used as a combustion fuel, or in a fuel cell to perform mechanical work and/or to produce electricity. Other such chemical entities can similarly be produced and used. Thus, a chemical energy storage sub-system would include apparatus for producing the desired chemical entity, and components for storing such chemical entity, e.g., a tank or tanks, pipes, and if needed pumps, compressors, and/or cryogenic devices to convert the chemical into a desired storage form (e.g., converting from a gas to a liquid) and/or to transport the chemical into the tanks. The energy storage chemical can then be transported to other sites in conventional manner, and/or used on-site.

[00105] For example, hydrogen can be stored in a number of different ways. Hydrogen can be stored in metal hydride tanks where such metal hydrides are specific combinations of metallic alloys that act similar to a sponge soaking up water. Metal hydrides possess the ability to absorb hydrogen and release it later, either at room temperature or through heating of the tank. The total amount of hydrogen absorbed is generally 1 % - 7% of the total weight of the tank. Metal hydrides offer the advantages of safely delivering hydrogen at a constant pressure. The life of a metal hydride storage tank is directly related to the purity of the hydrogen it is storing. The alloys act as a sponge, which absorbs hydrogen, but it also absorbs any impurities introduced into the tank by the hydrogen. The result is the hydrogen released from the tank is extremely pure, but the tank's lifetime and ability to store hydrogen is reduced as the impurities are left behind and fill the spaces in the metal that the hydrogen once occupied.

[00106] Hydrogen can also be stored in compressed form in high-pressure tanks. This process requires energy to accomplish and the space that the compressed gas occupies is usually quite large resulting in a lower energy density when compared to a traditional liquid fuel tank. ,

[00107] Hydrogen can also be stored as a liquid. Liquid hydrogen typically has to be stored at 20° Kelvin or -253° C. The temperature requirements for liquid hydrogen storage necessitate expending energy to compress and chill the hydrogen into its liquid state. The cooling and compressing process requires energy, resulting in a net loss of about 30% of the energy that the liquid hydrogen is storing. The storage tanks are insulated, to preserve temperature, and reinforced to store the liquid hydrogen under pressure.

[00108] Hydrogen can also be stored a moieties of other chemicals. The hydrogen is combined in a chemical reaction that creates a stable compound containing the hydrogen. A second reaction occurs that releases the hydrogen, which is collected and utilized, e.g., by a fuel cell. The exact reaction employed varies from storage compound to storage compound. Some examples of various techniques include ammonia cracking, partial oxidation, methanol cracking, etc. These methods eliminate the need for a storage unit for the hydrogen produced, where the hydrogen is produced on demand.

[00109] Hydrogen can also be stored in certain type of structures, such as carbon nanotubes, which are microscopic tubes of carbon, about two nanometers (billionths of a meter) across, that store hydrogen in microscopic pores on the tubes and within the tube structures. Similar to metal hydrides in their mechanism for storing and releasing hydrogen, the advantage of carbon nanotubes is the amount of hydrogen they are able to store. Carbon nanotubes are capable of storing anywhere from 4.2% - to 65% of their own weight in hydrogen. Similarly, glass microspheres can be used for hydrogen storage. The glass spheres are warmed, increasing the permeability of their walls, and filled by being immersed in high-pressure hydrogen gas. The spheres are then cooled, locking the hydrogen inside of the glass balls. A subsequent increase in temperature will release the hydrogen trapped in the spheres.

[00110] Further, liquid carrier storage can be used, which refers to hydrogen being stored in the common fossil fuels. Whenever gasoline, natural gas methanol, etc. is utilized as the source for hydrogen, the fossil fuel requires reforming. The reforming process removes the hydrogen from the original fossil fuel. The reformed hydrogen is then cleaned of excess carbon monoxide, which can poison certain types of fuel cells, and utilized by the fuel cell.

Operation of Tethered Wind Powered Generator Aerostats

[00111] The present aerostats are applicable to a number of different types of uses, including both fixed and mobile installations.

[00112] In one type of installation, the aerostat is anchored to a fixed or mobile ground base. The base includes the anchor point for the tether, as well as connection of the electrical connectors in the tether to conductors to an electrical load, electricity distribution system, or an energy storage sub-system. Generally, the base connection includes a swivel or other component for maintaining the orientation of the tether anchor point with the wind.

[00113] When placed on-site, the dynamic lift provided by the airfoils (e.g., wings) in a hybrid aerostat (i.e., static-dynamic wind machine) assists in maintaining the aerostat in position over the anchor point, without excessive drift. Reducing downwind reduces the length, and thus the weight of tether, thereby minimizing electrical energy loss and maximizing the weight load capabilities.

[00114] Deployment of the aerostat is useful in many different situations. For example, such an aerostat can be used for electricity generation in remote areas where electricity is not available through normal distribution networks. In these types of applications, it can be useful to include an energy storage sub-system such that the aerostat system can also provide energy during periods of little or no wind. Included in such applications are ship-borne installations.

[00115] In some cases, however, the aerostat will be used as an additional electricity source, and will feed electricity into an existing distribution network, e.g., a regional electricity network.

[00116] The present units can be land-based or can be deployed off-shore. In some cases, offshore will be desirable in order to avoid potential visibility objections. Energy from offshore placements can be delivered to shore via submerged cables and/or using a derivative energy form, especially a chemical energy form, e.g., hydrogen.

[00117] The aerostats can be deployed in an array, such that there are multiple energetically linked aerostats in a local area, typically under common control. The aerostats need not be deployed in any particular pattern, but should be placed such that they will not interfere with neighboring units, e.g., during shifting or variable winds. Such an array can include at least 2, 3, 5, 10, 15, 20, or more such aerostats.

[00118] In addition to the energy generating function, particularly for units deployed near cities and/or roadways, the aerostats can be used as communications billboards for notices and/or advertising, using pigmented or illuminated signs. [00119] In certain embodiments, the present aerostats can be used in a novel manner in ship anchored applications to generate electricity that is used directly or indirectly to power the ship. Such operation allows a ship to be wind powered, but to "sail" higher into the wind than would be possible for a sail driven ship, even to the extent of traveling directly into the wind. In effect, the aerostat will encounter an apparent wind that is the vector sum of the over-the-water wind velocity at the aerostat's altitude and the over-the-water velocity of the ship. In the case where the ship is traveling directly into the wind, the apparent wind speed would be the algebraic sum of the wind speed at aerostat altitude and the ship speed.

Exemplary Tethered Wind Powered Generator Aerostat

[00120] An exemplary design for a tethered wind powered generator aerostat is illustrated in the Drawings. Referring to Fig. 1, the aerostat 100 is shown in perspective view. The aerostat has a generally cylindrical central fuselage portion 110, with a rounded, roughly hemispherical front end portion 120, and a laterally tapering rear section 130, such that the rear of the fuselage acts as a vertical stabilizer. The aerostat body also includes forward wings 140, and rear wings 150. Although shown as fully fixed wings, the forward wings can include moveable control surfaces, e.g., ailerons and/or spoilers and the like. The rear wings as shown are moveable, allowing the attitude of the aerostat to be adjusted about the pitch axis. To drive the generator, the aerostat includes a first rotor 160 and a second rotor 170. The first and second rotors 160 and 170 include sets of blades 162 and 172 respectively, fixed to rotor rings 164 and 174 respectively. The aerostat is held on location with tether 180. In other embodiments the tether is connected centrally to the fuselage under the forward wings, or to a harness that connects to the underside at the base of each forward wing. The tether provides a restraint, as well as providing electrical connectivity for delivering generated electricity to a base station and associated facilities, and can also provide conductors for beacons and/or control and/or monitoring.

[00121] In Fig. 2, the aerostat of Fig. 1 is shown in schematic cross-section. As shown in Fig. 1, the aerostat 100 includes a generally cylindrical central fuselage portion 110, a generally hemispherical front portion 120, and a laterally flattened tail section 130. A forward wing 140 projects from the lateral midline near the front of the cylindrical central section, and a rear wing 150 connects to the upper part of the tail portion. Near the rear of the generally cylindrical fuselage portion are the first and second rotors 160 and 170 with respective blades 162 and 172, and rotor rings 164 and 174.

[00122] Figs. 3-8 illustrate an embodiment similar to that shown in Figs. 1 and

2, except that, as shown in Fig. 3, this embodiment includes a fuselage spacer 112 between rotors 160 and 170 to provide greater blade separation. Also, the design utilizes a three-point harness attachment with harness lines 182, 184, and 186 branching from tether 180. Such three-point harness provides additional stability as compared to the one point attachment illustrated in Fig. 1. This embodiment also includes upper and lower beacon lights 190 and 192 to provide safety warnings for aircraft operators. Figs. 4-8 show additional views of the same embodiment, with Fig. 4 being a top view, Fig. 5 a front view, Fig. 6 a side view, Fig. 7 a rear view, and Fig. 8 a bottom view. Components are the same as shown in Fig. 3.

[00123] All patents and other references cited in the specification are indicative of the level of skill of those skilled in the art to which the invention pertains, and are incorporated by reference in their entireties, including any tables and figures, to the same extent as if each reference had been incorporated by reference in its entirety individually.

[00124] One skilled in the art would readily appreciate that the present invention is well adapted to obtain the ends and advantages mentioned, as well as those inherent therein. The methods, variances, and compositions described herein as presently representative of preferred embodiments are exemplary and are not intended as limitations on the scope of the invention. Changes therein and other uses will occur to those skilled in the art, which are encompassed within the spirit of the invention, are defined by the scope of the claims.

[00125] It will be readily apparent to one skilled in the art that varying substitutions and modifications may be made to the invention disclosed herein without departing from the scope and spirit of the invention. For example, variations can be made to the shape and material used for the body. Thus, such additional embodiments are within the scope of the present invention and the following claims.

[00126] The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein. Thus, for example, in each instance herein any of the terms "comprising", "consisting essentially of and "consisting of may be replaced with either of the other two terms. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims.

[00127] In addition, where features or aspects of the invention are described in terms of Markush groups or other grouping of alternatives, those skilled in the art will recognize that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group or other group.

[00128] Also, unless indicated to the contrary, where various numerical values are provided for embodiments, additional embodiments are described by taking any 2 different values as the endpoints of a range. Such ranges are also within the scope of the described invention.

[00129] Thus, additional embodiments are within the scope of the invention and within the following claims.

Claims

WHAT IS CLAIMED IS:

1. A wind powered generator aerostat, comprising a body comprising at least one chamber containing a lighter than air gas; a wind powered electrical generator located in said body; and at least one exposed rotor coupled with said generator, wherein said generator generates electricity when tethered in a wind stream such that said rotor rotates.

2. The aerostat of claim 1 , wherein said generator is an alternating current generator.

3. The aerostat of claim 1 , wherein said generator is a direct current generator.

4. The aerostat of claim 1 , wherein said body includes a rigid shell.

5. The aerostat of claim 1 , wherein said body comprises a central fuselage and further comprises at least a pair of airfoils projecting from opposite sides of said fuselage providing lift in a wind stream.

6. The aerostat of claim 1 , wherein said body comprises a central fuselage and further comprises front airfoils projecting from opposite sides of the front half and rear airfoils projecting from opposite sides of the rear portion of said body.

7. The aerostat of claim 7, wherein said rear airfoils comprise elevators.

8. The aerostat of claim 7, wherein each said front airfoil further comprises an aileron.

9. The aerostat of claim 1 , wherein said body comprises a central fuselage and further comprises front airfoils projecting from opposite sides of the front half of said body and rear airfoils projecting from the rear half of said body, wherein at least some of said airfoils comprise moveable control surfaces; and wherein said aerostat further comprises a flight regulator controlling said moveable control surfaces to control the attitude of said aerostat.

10. The aerostat of claim 9, wherein said flight controller comprises a microprocessor.

11. The aerostat of claim 1 , wherein said generator comprises counter rotating inducing and induced portions.

12. The aerostat of claim 1 , wherein said rotor consists essentially of two counter-rotating sets of blades.

13. The aerostat of claim 12, wherein said two counter-rotating sets of blades are adjacent.

14. The aerostat of claim 1 , wherein said rotor comprises at least one set of blades, wherein the pitch of said blades is adjustable.

15. The aerostat of claim 14, wherein the pitch of said blades is set automatically to control the rate of rotation of the rotor.

16. The aerostat of claim 1 , wherein said aerostat is placed at an elevation of at least 50 meters above the surface to which said tether is attached.

17. The aerostat of claim 1 , wherein said aerostat is placed at an elevation of at least 100 meters above the surface to which said tether is attached.

18. The aerostat of claim 1 , wherein said aerostat is placed at an elevation of at least 200 meters above the surface to which said tether is attached.

19. The aerostat of claim 1 , wherein said aerostat is placed at an elevation of at least 300 meters above the surface to which said tether is attached.

20. The aerostat of claim 1 , wherein said aerostat operates at a location with a horizontal displacement no more than 100 percent of the vertical displacement from the ground attachment point for said tether.

21. The aerostat of claim 1 , wherein said aerostat operates at a location witn a horizontal displacement no more than 50 percent of the vertical displacement from the ground attachment point for said tether.

22. The aerostat of claim 1 , wherein said aerostat operates at a location with a horizontal displacement no more than 25 percent of the vertical displacement from the ground attachment point for said tether.

23. The aerostat of claim 1 , wherein said aerostat operates at a location with a horizontal displacement no more than 15 percent of the vertical displacement from the ground attachment point for said tether.

24. The aerostat of claim 1 , wherein said body comprises a generally cylindrical central portion, a rounded front portion, and a tapered rear portion, wherein said central portion comprises two wings projecting from opposite sides of said central portion, and at least two wings projecting from opposite sides of said rear portion.

25. The aerostat of claim 1 , further comprising a warning beacon.

26. An electrical power generating and storage system, comprising a wind powered generator aerostat electrically connected with an energy storage sub-system, wherein said wind powered generator aerostat comprises a body comprising at least one chamber containing a lighter than air gas; a wind powered electrical generator located in said body; and at least one exposed rotor coupled with said generator, wherein said generator generates electricity when tethered in a wind stream such that said rotor rotates.

27. The system of claim 26, wherein said energy storage sub-system comprises an electrical energy storage sub-system.

28. The system of claim 26, wherein said energy storage sub-system comprises a kinetic energy storage sub-system.

29. The system of claim 26, wherein said energy storage sub-system comprises a chemical energy storage sub-system.

30. The system of claim 29, wherein said chemical energy storage sub-system comprises an electrolytic hydrogen generator and storage sub-system.

31. The system of claim 26, wherein said generator is an alternating current generator.

32. The system of claim 26, wherein said generator is a direct current generator.

33. The system of claim 26, wherein said body includes a rigid shell.

34. The system of claim 26, wherein said body comprises a central fuselage and further comprises at least a pair of airfoils projecting from opposite sides of said fuselage providing lift in a wind stream.

35. The system of claim 26, wherein said body comprises a central fuselage and further comprises front airfoils projecting from opposite sides of the front half and rear airfoils projecting from opposite sides of the rear portion of said fuselage.

36. The system of claim 35, wherein said rear airfoils comprise elevators.

37. The system of claim 35, wherein each said front airfoil further comprises an aileron.

38. The system of claim 26, wherein said body further comprises front airfoils projecting from opposite sides of the front half of said body and rear airfoils projecting from the rear half of said body, wherein at least some of said airfoils comprise moveable control surfaces; and wherein said aerostat further comprises a flight regulator controlling said moveable control surfaces to control the attitude of said aerostat.

39. The system of claim 38, wherein said flight controller comprises a microprocessor.

40. The system of claim 26, wherein said generator comprises counter rotating induced and inducing portions.

41. The system of claim 26, wherein said rotor consists essentially of two counter-rotating sets of blades.

42. The system of claim 41, wherein said two counter-rotating sets of blades are adjacent.

43. The system of claim 26, wherein said rotor comprises at least one set of blades, wherein the pitch of said blades is adjustable.

44. The system of claim 43, wherein the pitch of said blades is set automatically to control the rate of rotation of the rotor.

45. The system of claim 26, wherein said aerostat is placed at an elevation of at least 50 meters above the surface to which said tether is attached.

46. The system of claim 26, wherein said aerostat is placed at an elevation of at least 100 meters above the surface to which said tether is attached.

47. The system of claim 26, wherein said aerostat is placed at an elevation of at least 200 meters above the surface to which said tether is attached.

48. The system of claim 26, wherein said aerostat is placed at an elevation of at least 300 meters above the surface to which said tether is attached.

49. The system of claim 26, wherein said aerostat operates at a location with a horizontal displacement no more than 100 percent of the vertical displacement from the ground attachment point for said tether.

50. The system of claim 26, wherein said aerostat operates at a location with a horizontal displacement no more than 50 percent of the vertical displacement from the ground attachment point for said tether.

51.The system of claim 26, wherein said aerostat operates at a location with a horizontal displacement no more than 25 percent of the vertical displacement from the ground attachment point for said tether.

52. The system of claim 26, wherein said aerostat operates at a location with a horizontal displacement no more than 15 percent of the vertical displacement from the ground attachment point for said tether.

53. The system of claim 26, wherein said body comprises a generally cylindrical central portion, a rounded front portion, and a tapered rear portion, wherein said central portion comprises two wings projecting from opposite sides of said central portion, and at least two wings projecting from opposite sides of said rear portion.

54. The system of claim 26, further comprising a warning beacon.

55. An electricity generating array, comprising an energetically linked plurality of wind powered generator aerostats of any of claims 1-25 in physical proximity and operated under common control.

56. The electricity generating array of claim 55, wherein said plurality comprises at least 10 aerostats.

57. A method for generating electrical power, comprising deploying at least one tethered wind powered generator aerostat of any of claims 1-25.

58. The method of claim 57, wherein electricity produced by said aerostat is fed to a regional electricity net.

59. The method of claim 57, wherein electricity produced by said aerostat is utilized locally.

60. The method of claim 57, wherein electricity produced by said aerostat is utilized on a ship.

61. A method for locating a tethered wind powered generator aerostat, comprising selecting a location at which average windspeed at at least one elevation above 30 meters is at least 20 kilometers per hour (kph); and deploying an aerostat of any of claims 1-25 at said elevation.

2. The method of claim 61 , wherein said elevation is at least 100 meters.