When I feel low on energy, a cool breeze will help me gain it back. What if the intensity of the breeze is a little more? Yes, now it is called wind. If a breeze can help humans to pick up their lost energy, wind can be used to generate Energy. I am talking about wind power which can be converted into useful work by means of sophisticated technologies and appropriate methods.
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I firmly believe that renewable energy sources can satisfy all our energy needs. Sun, which is the ultimate source of energy, the driving force behind all other renewable energy sources except geothermal and tidal power. Wind energy is a completely cost-free, recurring, and everlasting form. But, the way we utilize it marks the difference in results.
When the earth is rich in these renewable sources of energy why should we suffocate with the use of fossil fuels which finally contaminates the earth? The fossil fuels are finite and its adverse effects are infinite. As long as the wind blows energy conversion is possible and that makes me smile!
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The most prevailing methods for wind energy conversions are on-shore and off-shore conversion. But here, we are more interested in another wind power conversion using high-altitude wind power (500 to2000m). You may be wondering about the need for a third mode while already two well-known systems exist.
On-shore wind energy uses that flow of wind from the sea towards the land while off-shore wind energy uses sea wind that moves from land to sea for the production of energy. But, we must focus on a fact that wind in its highest form is not present on the ground or in the sea.
Wind exists everywhere on earth and in certain places with high intensity especially in the high altitudes with greater density. Here, at this point, conversion using high altitude wind power becomes pertinent. Let us go through a brief discussion on on-shore and off-shore wind energy systems.
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On-Shore Wind Energy
This method is used for energy conversions for centuries. The 1800s saw the emergence of on-shore wind energy conversions techniques. In an on-shore system, the wind turbine is situated on the ground (land). It uses wind with high intensity, for trapping this wind the wind turbines are made taller to the highest extent. It requires a small amount of land and lower investment is needed when compared to offshore wind energy. So, it is more affordable. The time span to get results is also comparatively small. But, since the system is situated in the ground the height is limited and the intensity of wind is not at all predictable. We cannot use the wind potential to the maximum.
Off-Shore Wind Energy
Off-shore wind energy uses wind currents just above the sea. Since it has to be situated in the sea production cost of the entire system is large. In this case too one cannot predict the intensity of wind above the sea. The wind farms are built further from shore and in deeper waters. Off-shore wind turbines are typically similar to land-based turbines but with a greater rating and adapted to the marine environment. The operation and maintenance of wind farms are significantly more challenging in the case of off-shore than on-shore.
High Altitude Wind Energy
When we know the presence of high-density wind out there in the high altitudes, the whole world looks for a technology that possesses the ability to concentrate abundant wind power resources in high altitudes and make this resource available to human needs with low material investment. High altitude wind energy system does the exact function.
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On-shore and off-shore wind energy conversions have a lot of limitations due to lack of wind consistency there, it is not at all predictable. The exact positions of turbines really affect the results, even a change in 30m distance can double the results or sometimes adversely affects the results. In the conversion of high-altitude wind energy, we use airborne wind energy systems which are usually connected by a tether to the ground like tethered balloons or kites.
Sometimes these systems are allowed to fly freely in the high altitudes of the sky. But when the system is connected to the ground we can exploit relative velocity between air mass and the ground. However, to harvest wind power, they need to maintain a strong force against this relative motion. The Kite-like system is more sophisticated. These flying objects are even connected to another moving station like a sea-vehicle. Airborne wind turbine ascends to an altitude of 800 to 1950 feet in order to take advantage of winds in high altitudes.
Airborne wind energy systems need less investment than most other renewable energy sources. This makes high altitude wind energy conversion a more preferable option and is expected to be the future wind energy source.
The Limitations of On Land and off-shore wind turbines
As we discussed above, the wind turbines used in on-shore and off-shore are taller to an extent, why? The higher you go the higher the speed of the wind. To attain this massive wind, tons of material is required to make these turbines long and tall. In the case of high-altitude wind energy, it didn’t require giant steel and concrete towers, and no yaw mechanism, that keeps the traditional turbines facing into the wind as the direction of wind changes. The high altitude turbine produces very little noise and requires little maintenance when compared to other systems.
The development of high altitude wind energy is not complete yet. The world is working hard to get up to there within the next few years, with numerous designs and ideas aimed to utilize wind power in higher altitudes of the sky. The world cannot let go of a fuel that is eternal and carbon-free. So let us hope for the advancement of this technology which can perform better than the prevailing systems of onshore and offshore. If we were able to exploit its potential to the extreme, high altitude wind energy will be the future renewable wind energy source.
Credit: This article is written by Ashna George for New Physicist