04-02-2017, 11:25 AM
Automatically controlled wing to harvest high-altitude wind energy
The high-altitude wind of the troposphere represents an untapped energy source that is larger than the world’s current energy needs. The concept of Kit energy is to use wings or power kites, linked to the ground by two ropes, to reach altitudes of about 800-1000 m above the ground. At such elevations, winds are stronger and more constant compared to the elevation where actual wind towers operate. The flight of the air foils is tracked using on-board wireless instrumentation and it is suitably driven by an automatic control unit, able to differential pull the ropes to influence the wing motion.
Electricity is generated at ground level by converting the traction forces acting on the wing ropes into electrical power, using suitable rotating mechanisms and electric generators placed on the ground. The system composed by the electric drives, the drums, the on-board sensors and all the hardware needed to control a single kite is denoted as Kite Steering Unit (KSU) and it is the core of the Kit energy technology.
Lightweight, dynamic and intelligent machines
The key idea of Kit energy is to harvest high altitude wind energy with minimal effort in terms of generator structure, cost and land occupation. In actual wind towers, the outermost 30% of the blade surface contributes to approximately 80% of the generated power. Therefore, the tower and the inside of the blades do not directly contribute to the generation of energy. However, the structure of a wind tower determines most of its cost and imposes a limit to the lift that can be reached.
To understand the concept of Kit energy, you can imagine that it will remove all the static and heavy structure of a wind tower and will keep the outside of the blades, which becomes a much lighter wing flying fast in conditions of crosswind , Connected to the ground only by the two strings. Thus, the rotor and tower of the current wind technology are replaced in the technology of Kit energy by the wing and its ropes, realising a wind generator that is largely lighter and cheaper. For example, in a wind turbine of 250 kW, the weight of the rotor and tower is typically about 50 t. A KITEnrg-yoyo generator of the same nominal power can be obtained using a wing of 250 m2 and strings of 1000 m long, with a total weight of only 10 t. Therefore, the construction costs of a KE-yoyo generator are expected to be lower than those of a wind tower of the same nominal power.
The power of high altitude wind
Kit energy generators will operate at heights significantly higher than the 150 m achieved by current wind tower technology, where stronger and more constant winds can be found practically everywhere. This basically translates into much higher amounts of energy generated annually. Due to wind intermittent, the average power produced by a wind generator during the year is only a fraction, indicated as Capacity Factor (CF), of the nominal power.
On good sites, the short-term goal of KITEnrg technology has a capacity factor approximately 35% higher than current wind power technology. Assuming a comparable total installation cost, economic performance with KITEnrg technology could improve significantly.
In addition, sub optimal sites for current wind power technology can still represent an economically convenient solution for KITEnrg technology.
Higher power density in wind farms
High-altitude wind has the highest energy per square meter (W / m2) compared to all renewable energy technologies. Wind power available at 800 m is approximately 4 times the power available for current wind turbines operating at about 80 m from the ground.
Kitenergy technology can achieve a higher energy density than the current wind turbines when considering a wind farm installation. Such exceptional figures can be achieved on the basis of greater flexibility in the optimisation of the distribution of wind farms, The possibility of flying the wings at different altitudes, thus avoiding aerodynamic interference.
A revolution in renewable energy generation
All aspects described so far have been considered to estimate the cost of high altitude wind power produced with Kit energy. In fact, the results indicate that this technology has the potential to generate renewable energy, available in large quantities almost everywhere, with production costs lower than those of fossil energy. The cost of energy produced with a 100 MW KITEnrg wind farm will be significantly lower than 50 € / MWh.
The high-altitude wind of the troposphere represents an untapped energy source that is larger than the world’s current energy needs. The concept of Kit energy is to use wings or power kites, linked to the ground by two ropes, to reach altitudes of about 800-1000 m above the ground. At such elevations, winds are stronger and more constant compared to the elevation where actual wind towers operate. The flight of the air foils is tracked using on-board wireless instrumentation and it is suitably driven by an automatic control unit, able to differential pull the ropes to influence the wing motion.
Electricity is generated at ground level by converting the traction forces acting on the wing ropes into electrical power, using suitable rotating mechanisms and electric generators placed on the ground. The system composed by the electric drives, the drums, the on-board sensors and all the hardware needed to control a single kite is denoted as Kite Steering Unit (KSU) and it is the core of the Kit energy technology.
Lightweight, dynamic and intelligent machines
The key idea of Kit energy is to harvest high altitude wind energy with minimal effort in terms of generator structure, cost and land occupation. In actual wind towers, the outermost 30% of the blade surface contributes to approximately 80% of the generated power. Therefore, the tower and the inside of the blades do not directly contribute to the generation of energy. However, the structure of a wind tower determines most of its cost and imposes a limit to the lift that can be reached.
To understand the concept of Kit energy, you can imagine that it will remove all the static and heavy structure of a wind tower and will keep the outside of the blades, which becomes a much lighter wing flying fast in conditions of crosswind , Connected to the ground only by the two strings. Thus, the rotor and tower of the current wind technology are replaced in the technology of Kit energy by the wing and its ropes, realising a wind generator that is largely lighter and cheaper. For example, in a wind turbine of 250 kW, the weight of the rotor and tower is typically about 50 t. A KITEnrg-yoyo generator of the same nominal power can be obtained using a wing of 250 m2 and strings of 1000 m long, with a total weight of only 10 t. Therefore, the construction costs of a KE-yoyo generator are expected to be lower than those of a wind tower of the same nominal power.
The power of high altitude wind
Kit energy generators will operate at heights significantly higher than the 150 m achieved by current wind tower technology, where stronger and more constant winds can be found practically everywhere. This basically translates into much higher amounts of energy generated annually. Due to wind intermittent, the average power produced by a wind generator during the year is only a fraction, indicated as Capacity Factor (CF), of the nominal power.
On good sites, the short-term goal of KITEnrg technology has a capacity factor approximately 35% higher than current wind power technology. Assuming a comparable total installation cost, economic performance with KITEnrg technology could improve significantly.
In addition, sub optimal sites for current wind power technology can still represent an economically convenient solution for KITEnrg technology.
Higher power density in wind farms
High-altitude wind has the highest energy per square meter (W / m2) compared to all renewable energy technologies. Wind power available at 800 m is approximately 4 times the power available for current wind turbines operating at about 80 m from the ground.
Kitenergy technology can achieve a higher energy density than the current wind turbines when considering a wind farm installation. Such exceptional figures can be achieved on the basis of greater flexibility in the optimisation of the distribution of wind farms, The possibility of flying the wings at different altitudes, thus avoiding aerodynamic interference.
A revolution in renewable energy generation
All aspects described so far have been considered to estimate the cost of high altitude wind power produced with Kit energy. In fact, the results indicate that this technology has the potential to generate renewable energy, available in large quantities almost everywhere, with production costs lower than those of fossil energy. The cost of energy produced with a 100 MW KITEnrg wind farm will be significantly lower than 50 € / MWh.