06-05-2013, 03:00 PM
Flying Windmills or Flying Electric Generator (FEG) technology
Flying Windmills.doc (Size: 1.56 MB / Downloads: 74)
ABSTRACT
High Altitude Wind Power uses flying electric generator (FEG) technology in the form of what have been more popularly called flying windmills, is a proposed renewable energy project over rural or low-populated areas, to produce around 12,000 MW of electricity with only 600 well clustered rotorcraft kites that use only simple autogyro physics to generate far more kinetic energy than a nuclear plant can.
According to Sky WindPower; the overuse of fossil fuels and the overabundance of radioactive waste from nuclear energy plants is taking our planet once again down a path of destruction, for something that is more expensive and far more dangerous in the long run. FEG technology is just cheaper, cleaner and can provide more energy than those environmentally unhealthy methods of the past, making it a desirable substitute/alternative.
The secret to functioning High Altitude Wind Power is efficient tether technology that reaches 15,000 feet in the air, far higher than birds will fly, but creating restricted airspace for pes and other aircraft.
The same materials used in the tethers that hold these balloons in place can also hold flying windmills in place; and with energy cable technology getting ever lighter and stronger .Flying windmills appear to be 90 percent more energy efficient in wind tunnel tests than their land-based counterparts
INTRODUCTION
Two major jet streams, the Sub-Tropical Jet and the Polar Front Jet exist in both Earth hemispheres. These enormous energy streams are formed by the combination of tropical region sunlight falling and Earth rotation. This wind resource is invariably available wherever the sun shines and the Earth rotates. These jet stream winds offer an energy benefit between one and two orders of magnitude greater than equalrotor-
area, ground mounted wind turbines operating in the lowest regions of the Earth’s boundary layer. In the USA,Caldeira and O’Doherty and Roberts have shown that average power densities of around 17 kW/m2 are available. In Australia, Atkinson et al show that 19 kW/m2 is achievable.These winds are available in northern India, China, Japan,Africa, the Mediterranean, and elsewhere.
Various systems have been examined to capture this energy, and these include tethered balloons, tethered fixed-winged craft, tether climbing and descending kites, and rotorcraft.
Our preferred option is a tethered rotorcraft, a variant of the gyroplane, where conventional rotors generate power and simultaneously produce sufficient lift to keep the system aloft. This arrangement, using a twin-rotor configuration, has been
described and flown at low altitude by Roberts and Blackler (Fig. 1). More recent developments have produced a quadruple rotor arrangement (Fig. 2).
THE BEST SPOTS TO PLACE FEGs
Based on the ERA-15 reanalysis of the European Centre for Medium-Range Weather Forecasts, we calculated the seasonal-mean, climate-zone wind power density from December 1978 to February 1994 .Computed power densities in high altitude winds exceed a 10 kW/m2 seasonal average at the jet stream’s typical latitudes and altitudes. This is the highest power density for a large renewable energy resource anywhere on Earth. It exceeds the power densities of sunlight, near surface winds, ocean currents, hydropower, tides, geothermal, and other large-scale renewable resources. For comparison, Earth surface solar energy is typically about 0.24 kW/m2 , and photovoltaic cell conversion of energy into electricity has an efficiency several times less than that of wind power.
High power densities would be uninteresting if only a small amount of total power were available. However, wind power is roughly 100 times the power used by all human civilization. Total power dissipated in winds is about 15 times 10 W. Total
Human thermal power consumption is about 13 times 10 W. Removing 1% of high altitude winds’ available energy is not expected to have adverse environmental consequences.
High altitude winds are a very attractive potential source of power, because this vast energy is high density and persistent. Furthermore, high altitude winds are typically just a few kilometres away from energy users. No other energy source combines potential resource size, density, and proximity so attractively.
DESCRIPTION OF THE PREFERRED ENERGY CONVERSION
SYSTEM
The currently proposed new tethered craft consists of four identical rotors mounted in an airframe which flies in the powerful and persistent winds. The tether’s insulated aluminum conductors bring power to ground, and are wound with strong Kevlar-family cords. The conductor weight is a critical compromise between power loss and heat generation. We propose employing aluminum conductors with tether transmission voltages of 15 kV and higher, because they are light weight for the energy transmitted. To minimize total per kWh system cost and reduce tether costs, the design allows higher per meter losses and higher conductor heating than does
traditional utility power transmission. Depending on flight altitude, electrical losses between the tether and the converted power’s insertion into the commercial grid are expected to be as much as 20%, and are included in energy cost estimates
described in Section IX.
The flying electric generator units (FEGs) envisioned for commercial power production have a rated capacity in the 3 to 30 MW range. Generators arrays are contemplated for wind farms in airspace restricted from commercial and private
aircraft use. To supply all U.S. energy needs, airspace for power generation is calculated to restrict far less airspace than is already restricted from civil aviation for other purposes. While similar in concept to current wind farms, in most cases
flying generator arrays may be located much closer to demand load centers.
When operating as an electrical power source, four or more rotors are inclined at an adjustable, controllable angle to the on-coming wind. In general the rotors have their open faces at an angle of up to 50to this wind. This disk incidence is reduced in various wind conditions to hold the power output at the rated value without exceeding the design tether load.Rotorcraft can also function as an elementary powered
helicopter as described in section II.
Electrodynamic tether
Tether is the connecting media between the turbines up in the air to the grid on the surface. Electrodynamic tethers are long conducting wires, such as the one deployed from the tether satellite, which can operate on electromagnetic principles as generators, by converting their kinetic energy to electrical energy, or as motors, converting electrical energy to kinetic energy. Electric potential is generated across a conductive tether by its motion through the Earth's magnetic field. The choice of the metal conductor to be used in an electrodynamic tether is determined by a variety of factors. Primary factors usually include high electrical conductivity, and low density. Secondary factors, depending on the application, include cost, strength, and melting point.
An electrodynamic tether is attached to an object, the tether being oriented at an angle to the local vertical between the object and a planet with a magnetic field. When the tether cuts the planet's magnetic field, it generates a current, and thereby converts some of the orbiting body's kinetic energy to electrical energy. As a result of this process, an electrodynamic force acts on the tether and attached object, slowing their orbital motion. The tether's far end can be left bare, making electrical contact with the ionosphere via the phantom loop. Functionally, electrons flow from the space plasma into the conductive tether, are passed through a resistive load in a control unit and are emitted into the space plasma by an electron emitter as free electrons. In principle, compact high-current tether power generators are possible and, with basic hardware, 10 to 25 kilowatts appears to be attainable.
ELECTRICAL SYSTEM DETAILS
Flying electric generators need to ascend and remain aloft for short periods on grid-sourced energy. In low-wind conditions, only a small proportion of output rating as grid sourced energy is required to raise or maintain the craft aloft. Voltages at the terminals of both the generator/motor and at the grid interface need to be kept within designed tolerances and/or be adjusted by timely voltage regulation.
In a national regulated electricity market, such as that found in Europe and elsewhere, a System Impact Study (SIS) is required to connect a new generator to the grid if the generator’s capacity is above a minimum level, e.g. 5 MW. Even non-dispatchable “embedded generators“ require Grid System Impact Assessments. The generator proponent usually pays for the generator-to-grid network connection. Land and sea locations for generation from renewable energy sources, especially wind energy, are often remote from the existing grid, hence, connection costs are often 50% of the total investment for new generating capacity. Also where a renewable energy source generator is not n-1 reliable for availability, the Network Connection Contracts usually include the costs of back-up supply contingencies. These relate to
network charges when the renewable generator is not supplying.
Flying electric generators at altitude will have a relatively high availability, around 80%. Reliability and peak premium sales could be enhanced by a link to a pumped storage facility for off-peak filling/storage and peak-release energy sales and
delivery. Energy could be stored as hydrogen gas produced from electrolysis, or as water pumped-back and re-released for hydroelectric generation.
Flying Windmills.doc (Size: 1.56 MB / Downloads: 74)
ABSTRACT
High Altitude Wind Power uses flying electric generator (FEG) technology in the form of what have been more popularly called flying windmills, is a proposed renewable energy project over rural or low-populated areas, to produce around 12,000 MW of electricity with only 600 well clustered rotorcraft kites that use only simple autogyro physics to generate far more kinetic energy than a nuclear plant can.
According to Sky WindPower; the overuse of fossil fuels and the overabundance of radioactive waste from nuclear energy plants is taking our planet once again down a path of destruction, for something that is more expensive and far more dangerous in the long run. FEG technology is just cheaper, cleaner and can provide more energy than those environmentally unhealthy methods of the past, making it a desirable substitute/alternative.
The secret to functioning High Altitude Wind Power is efficient tether technology that reaches 15,000 feet in the air, far higher than birds will fly, but creating restricted airspace for pes and other aircraft.
The same materials used in the tethers that hold these balloons in place can also hold flying windmills in place; and with energy cable technology getting ever lighter and stronger .Flying windmills appear to be 90 percent more energy efficient in wind tunnel tests than their land-based counterparts
INTRODUCTION
Two major jet streams, the Sub-Tropical Jet and the Polar Front Jet exist in both Earth hemispheres. These enormous energy streams are formed by the combination of tropical region sunlight falling and Earth rotation. This wind resource is invariably available wherever the sun shines and the Earth rotates. These jet stream winds offer an energy benefit between one and two orders of magnitude greater than equalrotor-
area, ground mounted wind turbines operating in the lowest regions of the Earth’s boundary layer. In the USA,Caldeira and O’Doherty and Roberts have shown that average power densities of around 17 kW/m2 are available. In Australia, Atkinson et al show that 19 kW/m2 is achievable.These winds are available in northern India, China, Japan,Africa, the Mediterranean, and elsewhere.
Various systems have been examined to capture this energy, and these include tethered balloons, tethered fixed-winged craft, tether climbing and descending kites, and rotorcraft.
Our preferred option is a tethered rotorcraft, a variant of the gyroplane, where conventional rotors generate power and simultaneously produce sufficient lift to keep the system aloft. This arrangement, using a twin-rotor configuration, has been
described and flown at low altitude by Roberts and Blackler (Fig. 1). More recent developments have produced a quadruple rotor arrangement (Fig. 2).
THE BEST SPOTS TO PLACE FEGs
Based on the ERA-15 reanalysis of the European Centre for Medium-Range Weather Forecasts, we calculated the seasonal-mean, climate-zone wind power density from December 1978 to February 1994 .Computed power densities in high altitude winds exceed a 10 kW/m2 seasonal average at the jet stream’s typical latitudes and altitudes. This is the highest power density for a large renewable energy resource anywhere on Earth. It exceeds the power densities of sunlight, near surface winds, ocean currents, hydropower, tides, geothermal, and other large-scale renewable resources. For comparison, Earth surface solar energy is typically about 0.24 kW/m2 , and photovoltaic cell conversion of energy into electricity has an efficiency several times less than that of wind power.
High power densities would be uninteresting if only a small amount of total power were available. However, wind power is roughly 100 times the power used by all human civilization. Total power dissipated in winds is about 15 times 10 W. Total
Human thermal power consumption is about 13 times 10 W. Removing 1% of high altitude winds’ available energy is not expected to have adverse environmental consequences.
High altitude winds are a very attractive potential source of power, because this vast energy is high density and persistent. Furthermore, high altitude winds are typically just a few kilometres away from energy users. No other energy source combines potential resource size, density, and proximity so attractively.
DESCRIPTION OF THE PREFERRED ENERGY CONVERSION
SYSTEM
The currently proposed new tethered craft consists of four identical rotors mounted in an airframe which flies in the powerful and persistent winds. The tether’s insulated aluminum conductors bring power to ground, and are wound with strong Kevlar-family cords. The conductor weight is a critical compromise between power loss and heat generation. We propose employing aluminum conductors with tether transmission voltages of 15 kV and higher, because they are light weight for the energy transmitted. To minimize total per kWh system cost and reduce tether costs, the design allows higher per meter losses and higher conductor heating than does
traditional utility power transmission. Depending on flight altitude, electrical losses between the tether and the converted power’s insertion into the commercial grid are expected to be as much as 20%, and are included in energy cost estimates
described in Section IX.
The flying electric generator units (FEGs) envisioned for commercial power production have a rated capacity in the 3 to 30 MW range. Generators arrays are contemplated for wind farms in airspace restricted from commercial and private
aircraft use. To supply all U.S. energy needs, airspace for power generation is calculated to restrict far less airspace than is already restricted from civil aviation for other purposes. While similar in concept to current wind farms, in most cases
flying generator arrays may be located much closer to demand load centers.
When operating as an electrical power source, four or more rotors are inclined at an adjustable, controllable angle to the on-coming wind. In general the rotors have their open faces at an angle of up to 50to this wind. This disk incidence is reduced in various wind conditions to hold the power output at the rated value without exceeding the design tether load.Rotorcraft can also function as an elementary powered
helicopter as described in section II.
Electrodynamic tether
Tether is the connecting media between the turbines up in the air to the grid on the surface. Electrodynamic tethers are long conducting wires, such as the one deployed from the tether satellite, which can operate on electromagnetic principles as generators, by converting their kinetic energy to electrical energy, or as motors, converting electrical energy to kinetic energy. Electric potential is generated across a conductive tether by its motion through the Earth's magnetic field. The choice of the metal conductor to be used in an electrodynamic tether is determined by a variety of factors. Primary factors usually include high electrical conductivity, and low density. Secondary factors, depending on the application, include cost, strength, and melting point.
An electrodynamic tether is attached to an object, the tether being oriented at an angle to the local vertical between the object and a planet with a magnetic field. When the tether cuts the planet's magnetic field, it generates a current, and thereby converts some of the orbiting body's kinetic energy to electrical energy. As a result of this process, an electrodynamic force acts on the tether and attached object, slowing their orbital motion. The tether's far end can be left bare, making electrical contact with the ionosphere via the phantom loop. Functionally, electrons flow from the space plasma into the conductive tether, are passed through a resistive load in a control unit and are emitted into the space plasma by an electron emitter as free electrons. In principle, compact high-current tether power generators are possible and, with basic hardware, 10 to 25 kilowatts appears to be attainable.
ELECTRICAL SYSTEM DETAILS
Flying electric generators need to ascend and remain aloft for short periods on grid-sourced energy. In low-wind conditions, only a small proportion of output rating as grid sourced energy is required to raise or maintain the craft aloft. Voltages at the terminals of both the generator/motor and at the grid interface need to be kept within designed tolerances and/or be adjusted by timely voltage regulation.
In a national regulated electricity market, such as that found in Europe and elsewhere, a System Impact Study (SIS) is required to connect a new generator to the grid if the generator’s capacity is above a minimum level, e.g. 5 MW. Even non-dispatchable “embedded generators“ require Grid System Impact Assessments. The generator proponent usually pays for the generator-to-grid network connection. Land and sea locations for generation from renewable energy sources, especially wind energy, are often remote from the existing grid, hence, connection costs are often 50% of the total investment for new generating capacity. Also where a renewable energy source generator is not n-1 reliable for availability, the Network Connection Contracts usually include the costs of back-up supply contingencies. These relate to
network charges when the renewable generator is not supplying.
Flying electric generators at altitude will have a relatively high availability, around 80%. Reliability and peak premium sales could be enhanced by a link to a pumped storage facility for off-peak filling/storage and peak-release energy sales and
delivery. Energy could be stored as hydrogen gas produced from electrolysis, or as water pumped-back and re-released for hydroelectric generation.