SYSTEM FOR GENERATING ELECTRICITY

Abstract

A system (100) for producing electricity from wind energy is provided. The system comprises a balloon (110) configured for inflation with a buoyant gas. The system further comprises at least one turbine-generator system (120) coupled to the balloon, comprising a turbine and generator. The turbine is configured to rotate when subjected to an external airflow. The generator is coupled to the turbine and is configured to convert rotation of the turbine into electricity. The system further comprises an electrical storage system (230) for storing the generated electricity.

Claims

1-32. (canceled)

33. A system for producing electricity from wind energy, comprising: a balloon configured for inflation with a buoyant gas; at least one turbine-generator system coupled to the balloon, comprising a turbine and generator, the turbine configured to rotate when subjected to an external airflow, the generator coupled to the turbine and configured to convert rotation of the turbine into electricity; and an electrical storage system for storing the generated electricity.

34. A system of claim 33, wherein the turbine is a vertical axis wind turbine comprising: a shaft aligned substantially perpendicular to a ground level; and a plurality of blades coupled to said shaft.

35. The system of claim 34, wherein the generator is mechanically coupled to the shaft of the turbine.

36. The system of claim 33, wherein the turbine is a horizontal axis wind turbine comprising: a shaft aligned substantially parallel to a ground level; and a plurality of blades coupled to said shaft.

37. The system of claim 36, wherein the generator is mechanically coupled to the shaft of the turbine.

38. The system of any claim 33, wherein: the storage system comprises a power cable coupled between the generator and the storage system; and, optionally or preferably, wherein the storage system is at a ground level.

39. The system of claim 33, further comprising: a load cable configured to anchor the turbine-generator system and balloon to the ground; and, optionally or preferably, a winch fixed at or near ground level, wherein the load cable is coupled to the winch, the winch is configured to wind in or wind out the load cable to adjust a vertical height of the balloon and turbine-generator system above the ground level.

40. The system of claim 37, further comprising: a load cable configured to anchor the turbine-generator system and balloon to the ground; and, optionally or preferably, a winch fixed at or near ground level, wherein the load cable is coupled to the winch, the winch is configured to wind in or wind out the load cable to adjust a vertical height of the balloon and turbine-generator system above the ground level; and wherein the power cable and the load cable are the same cable and/or wherein the power cable and load cable are arranged in the same cable housing.

41. The system of claim 36, further comprising: a vane coupled to at least one of: the turbine; the generator; and/or the power or load cable (where present).

42. The system of claim 37, further comprising a support frame coupled to the turbine-generator system, wherein: the support frame is coupled, preferably pivotably, to the power and/or load cable above and below the turbine-generator system, such that the turbine-generator system can rotate freely with respect to the cable(s).

43. The system of claim 42, wherein the support frame further comprises a tilt adjustment system configured to adjust the angle of the turbine relative to the vertical.

44. The system of claim 42, wherein the tilt adjustment system comprises a weighted member coupled to the support frame, wherein the weighted member is configured to bias the turbine-generator system such that the turbine faces substantially perpendicularly to the external airflow, and to balance forces acting on the turbine-generator system.

45. The system of claim 43, wherein the tilt adjustment system comprises first and second arms and wherein the support frame is coupled above and below the turbine-generator system by the first and second arms respectively, and where the first and second arms are adjustably coupled together to form an angle therebetween, and whereby adjustment of the coupling alters the length of the first arm and the angle of the turbine-generator with respect to the second arm to cause the turbine-generator to tilt with respect to the vertical.

46. The system of claim 33, further comprising: a conversion means to convert water to hydrogen and oxygen gas using any excess generated electricity, situated at or near ground level.

47. The system of claim 46, further comprising: a water storage tank for storing water for use with the conversion means; and/or one or more gas storage tanks for storing the hydrogen and oxygen produced by the conversion means, wherein in the case of one gas storage tank, the tank is partitioned to keep the two gases separate; and, optionally or preferably, a compressor for compressing the produced hydrogen and oxygen for more efficient storage.

48. The system of claim 46, wherein the conversion means is or comprises an electrolyser and/or a fuel cell.

49. The system of claim 33, further comprising a control system configured to adjust several characteristics of the system, including at least one of: length of uncoiled cable (i.e. height of balloon); volume of gas used to inflate the balloon; buoyancy of said gas; and charging profile for the electrical storage system.

50. The system of claim 47, further comprising a control system configured to adjust several characteristics of the system, including at least one of: length of uncoiled cable (i.e. height of balloon); volume of gas used to inflate the balloon; buoyancy of said gas; and charging profile for the electrical storage system; and wherein the control system is further configured to adjust at least one of: gas compression power; hydrogen production rate; water flow rate; and selection of battery storage/grid export/hydrogen production for the generated electricity.

51. The system of claim 49, further comprising at least one sensor in communication with the control system, configured to measure at least one of: wind speed; altitude; pressure of stored gas; and force acting on the balloon/load cable.

52. The system of claim 33, further comprising: a condenser configured to extract water from the surroundings; and a second conversion means in fluid communication with the condenser, configured to convert the extracted water to hydrogen; wherein the conversion means is in fluid communication with the balloon, such that the hydrogen produced inflates the balloon.

53. The system of claim 52, wherein the second conversion means is coupled to the mouth of the balloon.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0081] Embodiments will be described, by way of example only, with reference to the drawings, in which

[0082] FIG. 1 illustrates a schematic of an example embodiment of the system;

[0083] FIG. 2 illustrates a schematic of an alternative embodiment of the system;

[0084] FIG. 3 illustrates a schematic of a storage unit according to an example embodiment;

[0085] FIG. 4 illustrates a schematic of a coupling mechanism according to an example embodiment of the system;

[0086] FIG. 5 illustrates a schematic of a tilt adjustment mechanism according to an example embodiment of the system; and

[0087] FIG. 6 illustrates a schematic of an alternative system according to an example embodiment of the invention.

[0088] It should be noted that the Figures are diagrammatic and not drawn to scale. Relative dimensions and proportions of parts of these Figures have been shown exaggerated or reduced in size, for the sake of clarity and convenience in the drawings. The same reference signs are generally used to refer to corresponding or similar features in modified and different embodiments.

DETAILED DESCRIPTION OF EMBODIMENTS

[0089] FIG. 1 illustrates a schematic of an example embodiment of the system 100. The system 100 comprises a balloon 110 configured for inflation, surrounded by netting 140. In the illustrated example, the balloon 110 is approximately spherical, but any reasonable shape is envisaged. A turbine-generator system 120 is coupled to the netting 140 via a coupling means 150. In a case where netting 140 is not provided as part of the system 100, the coupling means 150 may attach directly to the balloon 110. The coupling means 150 may be or comprise a magnetic bearing, or a standard bearing. The turbine-generator system 120 comprises a vertical-axis turbine 130 with a shaft 135 and a generator (not shown) coupled to the shaft 135. The turbine 130 is configured to rotate when subjected to an external airflow, and the generator configured to convert said rotation into electricity. The turbine-generator system 120 may also comprise a braking system (not shown). This may be an integral part of the coupling means 150 (e.g. if a magnetic bearing is used), or a separate component. This generated electricity is stored in electrical storage system 230.

[0090] The generator is connected to the electrical storage system 230 via a power cable 160. The system may also include a load cable 170. The load cable 170 anchors the turbine-generator system 120 and balloon 110 to the ground. In the embodiment shown this is connected to a winch 180. The winch 180 is configured to wind in/out the load cable 170 (and power cable 160) to adjust the vertical height of the balloon 110 and turbine-generator system 120. The load cable 170 may be made of a higher strength and stiffness material than the power cable 160. The load cable 170 may be or comprise a metal such as steel, or other strong, lightweight material such as Kevlar rope. While the power cable 160 and the load cable 170 are separate cables in the illustrated example, however, a single cable could be used in order to, for example, save on material costs. In the illustrated example, a vane 175 is coupled to the load cable 170, but could conceivably couple to any of the turbine-generator system 120, the load cable 170 or the power cable 160.

[0091] The power cable 160 passes from the winch 180 to the electrical storage system 230. The storage system may comprise a series of rechargeable batteries. In the illustrated example, electricity generated in excess of the storage capacity of the storage system is used to convert water to hydrogen and oxygen gas with conversion means 220. Conversion means 220 may be a fuel cell or electrolyser. The produced gas is piped to gas storage system 200 via piping 210. An example gas storage system 200 is described in more detail with reference to FIG. 3, but in brief may comprise a compressor 204 and one or more storage tanks 202, 203.

[0092] The system may further comprise a control system and at least one sensor (not pictured). The control system may be configured to adjust several characteristics of the system, such as the height of the balloon 110. This could be controlled directly, or indirectly by controlling the length of load cable which is uncoiled or the volume/buoyancy of gas used to inflate the balloon together or separately. The control system may also adjust the charging profile for the electrical storage system, gas compression power, hydrogen production rate, water flow rate, and may be configured to select the ‘destination’ of the generated electricity (e.g. selection of whether the generated electricity is stored/exported to the grid/used for hydrogen production). The sensor(s) may be configured to measure at least one of wind speed, altitude, pressure of stored gas, or the force acting on the balloon/load cable.

[0093] In the illustrated example, the winch 180, control system, electrical storage system 230, conversion means 220 and gas storage system 200 are separately fixed to the ground. In other examples, these components may be part of a fixed structure anchored to the ground, and individual components may be raised. As an example, the winch 180 and control system may be elevated with respect to the storage systems 200, 230 in order to make the overall system 100 more space efficient. This would be a particular consideration for a “balloon farm” (analogous to a wind farm), or where the system is used for a single household.

[0094] The system 100 may further comprise a secondary balloon system (not pictured) coupled to the turbine-generator system 120 as a safety measure. The secondary balloon system may comprise a high-pressure inflation mechanism (e.g. a hydrogen canister and pump) configured to inflate the secondary balloon on failure of or damage to the primary balloon 110. This failure may be detected by a rapid or not-instructed change of height of the turbine-generator system 120, or by a noticeable change in pressure in the primary balloon 110.

[0095] The system 100 may optionally further comprise a second conversion means 115 and condenser 116. Where implemented, the condenser 116 is configured to extract water from the surroundings of the system 100 (i.e. moisture from the air). The second conversion means 115 is in fluid communication with the condenser 116, and configured to convert the water to hydrogen. This hydrogen can be used to maintain buoyancy of the balloon 110—the second conversion means 115 is also in fluid communication with the balloon 110. A pump (not shown) may be utilised to inflate the balloon 110 with the generated hydrogen.

[0096] The second conversion means 115 and condenser 116 may be powered by the electricity generated by turbine-generator system 120. The second conversion means 115 (and condenser 116) may be in communication with the control system (not pictured), such that the second conversion means 115 is configured to convert the water to hydrogen on receipt of a signal generated by the control system, when, for example, either the balloon pressure or force acting on the load cable drop below a preset level. The second conversion means 115 and condenser 116 may be idle at other times, to reduce consumption of the generated electricity.

[0097] It is anticipated that the second conversion means 115 and condenser 116 are to a smaller scale than the ‘ground-level’ conversion means, such as 10% to 50%, and configured to only produce sufficient gas to maintain balloon buoyancy.

[0098] FIG. 2 illustrates an alternative embodiment. In this illustrated example, the ground-level components (not pictured) are expected to be substantially the same as the embodiment shown in FIG. 1. In this example, the balloon 1000 surrounds the turbine-generator system 1020. The balloon 1000 comprises a conduit 1100 to direct external airflow 1300 to the turbine-generator system 1020. The conduit 1100 is configured to be funnelled towards the turbine-generator system 1020 (i.e. the conduit is thinner at the point where the turbine-generator system 1020 is attached than at the ends). The section 1200, which causes the funnel-like shape of the conduit may be inflated with gas, or may be a fixed structure. Section 1200 being an inflatable portion reduces weight, and increases ease of transporting the system when not in use, but a fixed structure improves stability and ease of coupling the turbine-generator system 1020 to the balloon 1000.

[0099] The turbine-generator system 1020 is substantially similar to turbine-generator system 120. However, the turbine 1030 may be to a smaller scale, or a horizontal-axis turbine. The funnelling effect of the section 1200 would cause an increased wind speed acting on the turbine, and so a smaller turbine (e.g. approximately 50% of the size of that of the earlier embodiment) could generate the same power output. This alternative embodiment at least partially addresses any issues of alignment associated with a horizontal-axis turbine, such that it may be preferred over a vertical-axis turbine.

[0100] The load cable 1070 may be coupled directly to the balloon, with the power cable 1060 coupled to the turbine-generator system 1020. Alternatively, they may both couple to the section 1200 in the case where section 1200 is a fixed structure. A further alternative is that both cables 1060, 1070 couple to the balloon 1000, and a further electrical wire is provided from the attachment point to the turbine-generator 1020, Otherwise, the cables 1060, 1070 are substantially the same as described in FIG. 1.

[0101] FIG. 3 illustrates an example gas storage system 200. The system 200 comprises two separate tanks 202 and 203 for storing hydrogen and oxygen respectively. In an alternative embodiment, a single tank with a non-permeable partition may be used. The tanks 202 and 203 are contained inside a housing 201. A compressor 204 for compressing the oxygen and hydrogen for storage is provided. In the illustrated example, a single compressor 204 and pipe 210 is used for both gases to optimise space usage, with gases being separated before entering the compressor 204 (via separate inlets). Alternatively, a separate compressor and pipe could be used for each gas, with separation being performed at the conversion stage.

[0102] FIG. 4 illustrates an example coupling mechanism 150 for coupling the turbine-generator system 120 to the balloon (not pictured) and the power cable 160 and/or load cable 170. The coupling mechanism 150 may comprise a support frame 151, which is configured to couple above and below the turbine-generator system 120, surrounding the system 120. The frame 151 may be configured to pivotably couple to the turbine-generator system 120. In the illustrated embodiment, the base 152 of the support frame 151 is provided in three rotatably coupled sections. The middle section of the base 152 is fixed to the turbine-generator system 120 via a stand 153 oriented perpendicular to the base 152 and configured to fixedly attach to the turbine generator system. In the illustrated embodiment, a weighted member 154 is fixedly coupled to the middle section of the base 152 and disposed opposite the stand 153. This weighted member 154 acts as a balance against the turbine-generator system 120, to ensure that the turbine 130 is oriented substantially perpendicular to the external airflow. This is designed to maximise the efficiency of the turbine-generator system 120 and may be particularly useful when the external airflow is travelling at high velocity.

[0103] The outer sections of the base 152 are coupled to the remainder of the frame which is in turn coupled to the power cable 160 and/or load cable 170 via additional cables 155 below the turbine-generator system 120, and coupled the balloon 110 via additional cables 155 above the turbine-generator system 120, The middle section of the base 152, and consequently the turbine-generator system 120 and weighted member 155, can therefore rotate freely with respect to said cables 155, 160, 170. These additional cables 155 may be electrically conductive, to conduct electricity generated by the turbine-generator system 120 to the electrical storage system 230 (FIG. 1) which is fixed at or near ground level. This arrangement also allows movement of the balloon 110 relative to the point at which the power and/or load cables 160, 170 are anchored at or near ground level, without the wind turbine being tilted relative to the ground,

[0104] FIG. 5 illustrates a tilt-adjustment mechanism according to an example embodiment of the system. An arm 156 extends from the support frame 151 at an angle to the vertical, and is coupled to the turbine-generator system 120 with a joining member 157. Joining member 157 is fixedly attached to the turbine-generator system 120. Joining member 157 is coupled to the arm 156 with an adjustable coupling means 158 such that the length of the member 157 disposed between the arm 156 and the turbine-generator system 120 is adjustable. For example, the adjustable coupling means 158 may comprise a threaded male and female connection, such that rotation of either the male or female component changes the length of the male member that is disposed within or through the female component. Alternatively, the joining member 157 may be a cable and the adjustable coupling means 158 a winch or reel. Reducing the length of the joining member 157 tilts the turbine-generator system 120 towards the arm 156. Conversely, extending the length of the joining member 157 tilts the turbine-generator system 120 away from the arm 156. Rotation may be driven by a motor, in communication with an external control system. The arm 156 may be directly coupled to the balloon (not pictured).

[0105] FIG. 6 illustrates a schematic diagram of a high-altitude system 2000. It is anticipated that the balloons 2100, 2300 may be spaced up to 1000 m apart in altitude. The velocity of the external airflow 2500 is greater at higher altitudes, as indicated in the figure.

[0106] The turbine-generator system 2200 is suspended between the balloons 2100, 2300. The turbine-generator system is substantially similar to the embodiment described with relation to FIG. 1, and may comprise a support frame 150 as described in FIG. 4. The turbine-generator system 2200 may operate at a different scale to that of the embodiment described in FIG. 1. For example, because it is expected to operate at higher altitudes and as such be exposed to an external airflow with higher velocity, a greater amount of electricity may be generated. Additionally, a high-altitude system does not have similar concerns of noise pollution or of being an ‘eyesore’ as a lower-altitude system easily visible from ground level. Therefore, the turbine-generator system 2200 may operate on a larger scale to turbine-generator system 120. Alternatively, the higher altitude system may be associated with and provide power to a separate system, such as a telecommunications system, in an otherwise remote and/or difficult to access area. This lower energy requirement may result in a smaller, lighter turbine-generator system 2200 that imparts less stress on the balloons 2100, 2300 and so requires less maintenance. Reduced maintenance requirement is an important consideration for a system that not accessible regularly.

[0107] Each of balloons 2100, 2300 are coupled to and in fluid communication with a condenser/conversion means 2120, 2320. Each condenser/conversion means condenser/conversion means 2120, 2320 is configured to extract water from the surroundings (i.e. moisture from the air convert said water to hydrogen. This hydrogen can be used to maintain buoyancy of the balloons 2100, 2300. The condenser/conversion means 2120, 2320 may be powered by the electricity generated by the turbine-generator system 2200.

[0108] From reading the present disclosure, other variations and modifications will be apparent to the skilled person. Such variations and modifications may involve equivalent and other features which are already known in the art of renewable energy, and which may be used instead of, or in addition to, features already described herein.

[0109] Although the appended claims are directed to particular combinations of features, it should be understood that the scope of the disclosure of the present invention also includes any novel feature or any novel combination of features disclosed herein either explicitly or implicitly or any generalisation thereof, whether or not it relates to the same invention as presently claimed in any claim and whether or not it mitigates any or all of the same technical problems as does the present invention.

[0110] Features which are described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. The applicant hereby gives notice that new claims may be formulated to such features and/or combinations of such features during the prosecution of the present application or of any further application derived therefrom.

[0111] For the sake of completeness it is also stated that the term “comprising” does not exclude other elements or steps, the term “a” or “an” does not exclude a plurality, and reference signs in the claims shall not be construed as limiting the scope of the claims.