High altitude platform

Abstract

An apparatus for generating electrical energy at altitude, comprising a tether connecting a substantially ground level location, part to a platform at an elevated location, the tether comprising a conduit coupled to an electrical generator at the platform, the conduit arranged to allow the flow of a fuel fluid from the substantially ground level location to the elevated location, and the electrical generator being operable to convert energy in the fuel fluid to electrical energy at the elevated location.

1 . An apparatus for providing high altitude services, the apparatus comprising:
 a platform at an elevated location; and   a tether connecting a substantially ground level location to the platform, wherein the tether is coated with a hydrophobic material.   
     
     
         2 . The apparatus of  claim 1 , wherein the apparatus is for generating electrical energy at altitude, the apparatus further comprising:
 an electrical generator at the platform;   wherein the tether comprises a conduit coupled to the electrical generator at the platform, the conduit arranged to allow the flow of a fuel fluid from the substantially ground level location to the elevated location; and   wherein the electrical generator is operable to convert energy in the fuel fluid to electrical energy at the elevated location.   
     
     
         3 . The apparatus of  claim 2 , wherein the conduit is a pipe with an internal circular or near-circular cross-section, through which the fuel fluid flows. 
     
     
         4 . The apparatus of  claim 3 , wherein the inside diameter, through which the fuel fluid flows, is from 1.5 to 30 mm. 
     
     
         5 . The apparatus of  claim 2 , wherein the conduit contains fuel fluid at a flow rate of from 0.00002 to 1.0 kg/s. 
     
     
         6 . The apparatus of  claim 2 , wherein the fuel fluid comprises hydrogen or a hydrocarbon fluid. 
     
     
         7 . The apparatus of  claim 6 , wherein the fuel fluid is a hydrocarbon fluid having an average molecular weight of less than 200. 
     
     
         8 . The apparatus of  claim 2 , further comprising:
 a fuel fluid pressurisation means, operable to raise the pressure of the fuel fluid at the substantially ground level location in excess of 100 MPa.   
     
     
         9 . The apparatus of  claim 2 , wherein the fuel fluid comprises hydrogen, the apparatus further comprising:
 a fuel fluid pressurisation means, operable to raise the pressure of the fuel fluid at the substantially ground level location to a pressure of 0.2 to 100 MPa.   
     
     
         10 . The apparatus of  claim 2 , wherein the electrical generator comprises a combustion engine, generating electricity by combustion of the fuel fluid. 
     
     
         11 . The apparatus of  claim 2 , wherein the electrical generator comprises a fuel cell. 
     
     
         12 . The apparatus of  claim 2 , wherein the electrical generator can produce from 0.5 to 20,000 kW of electrical power. 
     
     
         13 . The apparatus of  claim 2 , wherein the tether comprises one or more reinforcing cables which travel along the outside of the conduit to provide strength. 
     
     
         14 . The apparatus of  claim 2 , wherein the conduit is non-electrically conductive. 
     
     
         15 . The apparatus of  claim 1 , wherein the platform comprises an information services apparatus. 
     
     
         16 . The apparatus of  claim 1 , wherein the tether comprises one or more optical fibres from the substantially ground level location to the elevated location. 
     
     
         17 . The apparatus of  claim 1 , wherein the elevated location is at an altitude of from 300 m to 25,000 m. 
     
     
         18 . The apparatus of  claim 1 , further comprising:
 one or more balloons or dirigibles at the elevated location.   
     
     
         19 . The apparatus of  claim 18 , wherein the one or more balloons or dirigibles is capable of providing a lifting force of from 0.05 to less than 5.0 metric tonnes or at least 5.0 metric tonnes. 
     
     
         20 . The apparatus of  claim 1 , wherein the tether has a circular or non-circular cross-section and comprises a series of vanes or aerofoils at intervals along its length to provide lift to the tether from horizontal winds. 
     
     
         21 . The apparatus of  claim 20 , wherein the tether has a cross-section with an aspect ratio of from 1.5 to 20.0. 
     
     
         22 . The apparatus of  claim 20 , which, when air flows past the tether from a leading edge to a trailing edge, the tether has a cross-section with its centre of mass nearer to the leading edge than is the centre of aerodynamic pressure. 
     
     
         23 . The apparatus of  claim 20 , which, when air flows past the tether from a leading edge to a trailing edge, the tether has a cross-section with its centre of mass less than 25% of the chord length from the leading edge. 
     
     
         24 . The apparatus of  claim 20 , which, when air flows past the tether from a leading edge to a trailing edge, the tether has a cross-section with its centre of tension nearer to the leading edge than is the centre of aerodynamic pressure. 
     
     
         25 . The apparatus of  claim 20 , which, when air flows past the tether from a leading edge to a trailing edge, the tether has a cross-section with its centre of tension less than 25% of the chord length from the leading edge. 
     
     
         26 . The apparatus of  claim 20 , which, when air flows past the tether from a leading edge to a trailing edge, has a cross-section with its centre of shear nearer to the leading edge than is the centre of aerodynamic pressure. 
     
     
         27 . The apparatus of  claim 20 , which, when air flows past the tether from a leading edge to a trailing edge, the tether has a cross-section with its centre of shear less than 25% of the chord length from the leading edge. 
     
     
         28 . The apparatus of  claim 20 , which, when air flows past the tether from a leading edge to a trailing edge, the tether has a cross-section with its centre of mass, its centre of tension, and its centre of shear within a region of less than 10% of the chord length from the leading edge. 
     
     
         29 . The apparatus of  claim 20 , wherein the tether comprises fins which are powered to provide active control. 
     
     
         30 . The apparatus of  claim 29 , wherein the fins are ailerons forming part of the aerofoils. 
     
     
         31 . The apparatus of  claim 30 , wherein the ailerons and aerofoils are provided by gliders attached to the tether. 
     
     
         32 . The apparatus of  claim 29 , wherein the fins are powered by respective local wind energy turbines. 
     
     
         33 . The apparatus of  claim 1 , wherein the platform comprises a gyroscopic and/or a gravitational stabilisation means. 
     
     
         34 . The apparatus of  claim 1 , further comprising:
 a base station in the vicinity of the substantially ground level location;   wherein the platform comprises an information services apparatus at the elevated location;   wherein the tether comprises one or more optical fibres connecting the information services apparatus to the base station; and   wherein the base station comprises a means for modulating light by an electrical signal, the information services apparatus comprising an optical-to-electrical conversion means and at least one antenna, the arrangement being operable to transmit modulated light along the optical fibres to the information services apparatus where the signal is converted to electronic form and transmitted by the antenna.   
     
     
         35 . The apparatus of  claim 1 ,
 wherein the platform comprises an information services apparatus at the elevated location; and   wherein the platform is contained within a shroud to which it is not rigidly connected.   
     
     
         36 . The apparatus of  claim 35 , wherein the shroud is a balloon, a streamlined shape or aerostat, and the platform is suspended by the tether but is free to rotate with respect to the tether. 
     
     
         37 . The apparatus of  claim 1 , wherein the tether comprises a lightning strike conductor providing an electrical connection between the substantially ground level location and an elevated location on the tether. 
     
     
         38 . The apparatus of  claim 1 ,
 wherein the platform comprises an information services apparatus at the elevated location; and   wherein the tether comprises at least two electrical power cables operable to transport electrical power from the substantially ground level location to the platform.